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David Needham

David Needham

Professor Emeritus in the Thomas Lord Department of Mechanical Engineering and Materials Science
Thomas Lord Department of Mechanical Engineering and Materials Science
d.needham@duke.edu
3391 Fciemas Building, Box 90300, Durham, NC 27708-0300
3391 Fciemas Building, Box 90300, Durham, NC 27708

Selected Publications

Niclosamide: A career builder.

Journal Article Journal of controlled release : official journal of the Controlled Release Society · May 2024 My contribution to honoring Professor Kinam Park celebrates and resonates with his scholarly career in drug delivery, his commitment to encouraging the next generation(s), and his efforts to keep us focused on clinically effective formulations. To do this ... Full text Cite

LPS-aggregating proteins GBP1 and GBP2 are each sufficient to enhance caspase-4 activation both in cellulo and in vitro.

Journal Article Proc Natl Acad Sci U S A · April 11, 2023 The gamma-interferon (IFNγ)-inducible guanylate-binding proteins (GBPs) promote host defense against gram-negative cytosolic bacteria in part through the induction of an inflammatory cell death pathway called pyroptosis. To activate pyroptosis, GBPs facili ... Full text Link to item Cite

Data from Preclinical Testing of a Novel Niclosamide Stearate Prodrug Therapeutic (NSPT) Shows Efficacy Against Osteosarcoma

Other · April 3, 2023 <div>Abstract<p>Therapeutic advances for osteosarcoma have stagnated over the past several decades, leading to an unmet clinical need for patients. The purpose of this study was to develop a novel therapy for osteosarcoma by reformulati ... Full text Cite

Data from Preclinical Testing of a Novel Niclosamide Stearate Prodrug Therapeutic (NSPT) Shows Efficacy Against Osteosarcoma

Other · April 3, 2023 <div>Abstract<p>Therapeutic advances for osteosarcoma have stagnated over the past several decades, leading to an unmet clinical need for patients. The purpose of this study was to develop a novel therapy for osteosarcoma by reformulati ... Full text Cite

Low-Density Lipoprotein Pathway Is a Ubiquitous Metabolic Vulnerability in High Grade Glioma Amenable for Nanotherapeutic Delivery.

Journal Article Pharmaceutics · February 2023 Metabolic reprogramming, through increased uptake of cholesterol in the form of low-density lipoproteins (LDL), is one way by which cancer cells, including high grade gliomas (HGG), maintain their rapid growth. In this study, we determined LDL receptor (LD ... Full text Cite

Extraction of niclosamide from commercial approved tablets into aqueous buffered solution creates potentially approvable oral and nasal sprays against COVID-19 and other respiratory infections.

Journal Article AAPS open · January 2023 MotivationThe low solubility, weak acid drug, niclosamide is a host cell modulator with broad-spectrum anti-viral cell-activity against many viruses, including stopping the SARS-CoV-2 virus from infecting cells in cell culture. As a result, a simp ... Full text Cite

The pH Dependence of Niclosamide Solubility, Dissolution, and Morphology: Motivation for Potentially Universal Mucin-Penetrating Nasal and Throat Sprays for COVID19, its Variants and other Viral Infections.

Journal Article Pharmaceutical research · January 2022 MotivationWith the coronavirus pandemic still raging, prophylactic-nasal and early-treatment throat-sprays could help prevent infection and reduce viral load. Niclosamide has the potential to treat a broad-range of viral infections if local bioava ... Full text Open Access Cite

Inhibition of the futalosine pathway for menaquinone biosynthesis suppresses Chlamydia trachomatis infection.

Journal Article FEBS letters · December 2021 Chlamydia trachomatis, an obligate intracellular bacterium with limited metabolic capabilities, possesses the futalosine pathway for menaquinone biosynthesis. Futalosine pathway enzymes have promise as narrow-spectrum antibiotic targets, but the activity a ... Full text Open Access Cite

The pH Dependence of Niclosamide Solubility, Dissolution, and Morphology Motivates Potentially Universal Mucin-Penetrating Nasal and Throat Sprays for COVID19, its Contagious Variants, and Other Respiratory Viral Infections

Journal Article · August 17, 2021 AbstractMotivationWith the coronavirus pandemic still raging, prophylactic nasal and early treatment throat sprays could help prevent infection and reduce viral load. Niclosamide has the p ... Full text Open Access Cite

Designing topographically textured microparticles for induction and modulation of osteogenesis in mesenchymal stem cell engineering.

Journal Article Biomaterials · January 2021 Mesenchymal stem cells are the focus of intense research in bone development and regeneration. The potential of microparticles as modulating moieties of osteogenic response by utilizing their architectural features is demonstrated herein. Topographically t ... Full text Open Access Cite

Preclinical Testing of a Novel Niclosamide Stearate Prodrug Therapeutic (NSPT) Shows Efficacy Against Osteosarcoma.

Journal Article Mol Cancer Ther · July 2020 Therapeutic advances for osteosarcoma have stagnated over the past several decades, leading to an unmet clinical need for patients. The purpose of this study was to develop a novel therapy for osteosarcoma by reformulating and validating niclosamide, an es ... Full text Open Access Link to item Cite

Development of clinically effective formulations for anticancer applications: why it is so difficult?

Chapter · January 1, 2020 To try and help answer the question, why is the “development of clinically effective formulations is so difficult?” especially for anticancer applications, this chapter is divided into two main parts. Part A deals with a series of nonscientific factors inc ... Full text Cite

Polymer Microparticles with Defined Surface Chemistry and Topography Mediate the Formation of Stem Cell Aggregates and Cardiomyocyte Function.

Journal Article ACS applied materials & interfaces · September 2019 Surface-functionalized microparticles are relevant to fields spanning engineering and biomedicine, with uses ranging from cell culture to advanced cell delivery. Varying topographies of biomaterial surfaces are also being investigated as mediators of cell- ... Full text Cite

Oleogelating properties of ethylcellulose in oil-in-water emulsions: The impact of emulsification methods studied by 13C MAS NMR, surface tension and micropipette manipulation studies

Journal Article Food Hydrocolloids · April 1, 2019 This study addressed the oleogelating properties of EC when EC-oleogel microdroplets are dispersed in an aqueous medium. By measuring the interfacial tension between oil-water, EC was found to be interfacial active. Oleogel-in-water emulsions were prepared ... Full text Cite

Micro-Surface and -Interfacial Tensions Measured Using the Micropipette Technique: Applications in Ultrasound-Microbubbles, Oil-Recovery, Lung-Surfactants, Nanoprecipitation, and Microfluidics.

Journal Article Micromachines · February 2019 Featured Publication This review presents a series of measurements of the surface and interfacial tensions we have been able to make using the micropipette technique. These include: equilibrium tensions at the air-water surface and oil-water interface, as well as equilibrium a ... Full text Cite

Uptake of New Lipid-coated Nanoparticles Containing Falcarindiol by Human Mesenchymal Stem Cells.

Journal Article Journal of visualized experiments : JoVE · February 2019 Nanoparticles are the focus of an increased interest in drug delivery systems for cancer therapy. Lipid-coated nanoparticles are inspired in structure and size by low-density lipoproteins (LDLs) because cancer cells have an increased need for cholesterol t ... Full text Cite

Chelation, formulation, encapsulation, retention, and in vivo biodistribution of hydrophobic nanoparticles labelled with 57Co-porphyrin: Oleylamine ensures stable chelation of cobalt in nanoparticles that accumulate in tumors.

Journal Article Journal of controlled release : official journal of the Controlled Release Society · December 2018 Background and motivationWhile small molecules can be used in cancer diagnosis there is a need for imageable diagnostic NanoParticles (NPs) that act as surrogates for the therapeutic NPs. Many NPs are composed of hydrophobic materials so the chall ... Full text Cite

Manipulating Single Microdroplets of NaCl Solutions: Solvent Dissolution, Microcrystallization, and Crystal Morphology.

Journal Article Langmuir : the ACS journal of surfaces and colloids · March 2018 A new "three-micropipette manipulation technique" for forming, dehydrating, crystallizing, and resolvating nanograms of salt material has been developed to study supersaturated single microdroplets and microcrystals. This is the first report of studies tha ... Full text Cite

Adsorption of ionic surfactants at microscopic air-water interfaces using the micropipette interfacial area-expansion method: Measurement of the diffusion coefficient and renormalization of the mean ionic activity for SDS.

Journal Article Journal of colloid and interface science · October 2017 The dynamic adsorption of ionic surfactants at air-water interfaces have been less-well studied than that of the simpler non-ionics since experimental limitations on dynamic surface tension (DST) measurements create inconsistencies in their kinetic analysi ... Full text Cite

Real-Time Visualization of the Precipitation and Phase Behavior of Octaethylporphyrin in Lipid Microparticles.

Journal Article Journal of pharmaceutical sciences · April 2017 The material properties of micro- and nanoparticles are fundamental for their bulk properties in suspension, like their stability and encapsulation efficiency. A particularly interesting system with potential biomedical applications is the encapsulation of ... Full text Cite

New sensitive micro-measurements of dynamic surface tension and diffusion coefficients: Validated and tested for the adsorption of 1-Octanol at a microscopic air-water interface and its dissolution into water.

Journal Article Journal of colloid and interface science · February 2017 Currently available dynamic surface tension (DST) measurement methods, such as Wilhelmy plate, droplet- or bubble-based methods, still have various experimental limitations such as the large size of the interface, convection in the solution, or a certain " ... Full text Cite

Data for the size of cholesterol-fat micelles as a function of bile salt concentration and the physico-chemical properties of six liquid experimental pine-derived phytosterol formulations in a cholesterol-containing artificial intestine fluid.

Journal Article Data in brief · February 2017 The data in this paper are additional information to the research article entiltled "Inhibition of cholesterol transport in an intestine cell model by pine-derived phytosterols" (Yi et al.,2016) [1]. The data derived from the measurement on six liquid form ... Full text Cite

Preface

Chapter · January 1, 2017 Full text Cite

An Activity-Based Dissolution Model for Solute-Containing Microdroplets.

Journal Article Langmuir : the ACS journal of surfaces and colloids · December 2016 When a solute is present in an aqueous droplet, the water activity in the droplet and the rate of droplet dissolution are both decreased (as compared to a pure water droplet). One of the main parameters that controls this effect is the dynamically changing ... Full text Cite

From single microparticles to microfluidic emulsification: Fundamental properties (solubility, density, phase separation) from micropipette manipulation of solvent, drug and polymer microspheres

Journal Article Processes · December 1, 2016 The micropipette manipulation technique is capable of making fundamental single particle measurements and analyses. This information is critical for establishing processing parameters in systems such as microfluidics and homogenization. To demonstrate what ... Full text Cite

Bottom up design of nanoparticles for anti-cancer diapeutics: "put the drug in the cancer's food".

Journal Article Journal of drug targeting · November 2016 Featured Publication The story starts in Basel at CLINAM in 2013, when I asked Pieter about making nanoparticles and he advised me to "try this solvent-exchange method we have developed for making limit sized particles". We are particularly interested in what are "limit size m ... Full text Cite

Micropipette Technique Study of Natural and Synthetic Lung Surfactants at the Air-Water Interface: Presence of a SP-B Analog Peptide Promotes Membrane Aggregation, Formation of Tightly Stacked Lamellae, and Growth of Myelin Figures.

Journal Article Langmuir : the ACS journal of surfaces and colloids · October 2016 The present study is a microscopic interfacial characterization of a series of lung surfactant materials performed with the micropipette technique. The advantages of this technique include the measurement of equilibrium and dynamic surface tensions while a ... Full text Cite

Inhibition of cholesterol transport in an intestine cell model by pine-derived phytosterols.

Journal Article Chemistry and physics of lipids · October 2016 We have quantified the inhibition of intestinal cholesterol transport by pine-derived phytosterols using an HT29-MTX intestine cell model that forms a mucus layer similar to that in the intestine. An artificial intestinal fluid consisting of digested fat, ... Full text Cite

Encapsulation and retention of chelated-copper inside hydrophobic nanoparticles: Liquid cored nanoparticles show better retention than a solid core formulation.

Journal Article European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V · May 2016 MotivationIn the field of imaging, (18)F-fluorodeoxyglucose (FDG) PET imaging allows evaluation of glucose metabolism and is the most widely used imaging agent clinically for metastatic cancer. While it can certainly detect the metastatic disease, ... Full text Cite

Enzyme dehydration using Microglassification™ preserves the protein's structure and function.

Journal Article Journal of pharmaceutical sciences · February 2015 Controlled enzyme dehydration using a new processing technique of Microglassification™ has been investigated. Aqueous solution microdroplets of lysozyme, α-chymotrypsin, catalase, and horseradish peroxidase were dehydrated in n-pentanol, n-octanol, n-decan ... Full text Cite

Two phase I dose-escalation/pharmacokinetics studies of low temperature liposomal doxorubicin (LTLD) and mild local hyperthermia in heavily pretreated patients with local regionally recurrent breast cancer.

Journal Article Int J Hyperthermia · August 2014 PURPOSE: Unresectable chest wall recurrences of breast cancer (CWR) in heavily pretreated patients are especially difficult to treat. We hypothesised that thermally enhanced drug delivery using low temperature liposomal doxorubicin (LTLD), given with mild ... Full text Link to item Cite

Quantitative optical microscopy and micromanipulation studies on the lipid bilayer membranes of giant unilamellar vesicles.

Journal Article Chemistry and physics of lipids · July 2014 This manuscript discusses basic methodological aspects of optical microscopy and micromanipulation methods to study membranes and reviews methods to generate giant unilamellar vesicles (GUVs). In particular, we focus on the use of fluorescence microscopy a ... Full text Cite

Microglassification™: a novel technique for protein dehydration.

Journal Article Journal of pharmaceutical sciences · March 2014 The dehydration of biologics is commonly employed to achieve solid-dose formulation and enhanced stability during long-term preservation. We have developed a novel process, Microglassification™, which can rapidly and controllably dehydrate protein solution ... Full text Cite

Novel radioisotope-based nanomedical approaches

Journal Article European Journal of Nanomedicine · December 1, 2013 Radioisotope therapy of cancer is on the rise applying mainly β-emitting radionuclides. However, due to exposure of healthy tissues, the maximum achievable radiation dose with these is limited. Auger-electron emitters (AEs) represent a promising alternativ ... Full text Cite

Mass transfer in the dissolution of a multicomponent liquid droplet in an immiscible liquid environment.

Journal Article Langmuir : the ACS journal of surfaces and colloids · November 2013 The Epstein-Plesset equation has recently been shown to predict accurately the dissolution of a pure liquid microdroplet into a second immiscible solvent, such as oil into water. Here, we present a series of new experiments and a modification to this equat ... Full text Cite

A method to convert MRI images of temperature change into images of absolute temperature in solid tumours.

Journal Article Int J Hyperthermia · September 2013 PURPOSE: During hyperthermia (HT), the therapeutic response of tumours varies substantially within the target temperature range (39-43 °C). Current thermometry methods are either invasive or measure only temperature change, which limits the ability to stud ... Full text Link to item Cite

Reverse engineering of the low temperature-sensitive liposome (LTSL) for treating cancer

Chapter · January 1, 2013 This chapter is as much about the process of reverse engineering as it is about a particular drug delivery system. It presents the materials science and materials engineering concepts that went into the design and testing of the LTSL including: the roles o ... Full text Cite

Overcoming limitations in nanoparticle drug delivery: triggered, intravascular release to improve drug penetration into tumors.

Journal Article Cancer Res · November 1, 2012 Featured Publication Traditionally, the goal of nanoparticle-based chemotherapy has been to decrease normal tissue toxicity by improving drug specificity to tumors. The enhanced permeability and retention effect can permit passive accumulation into tumor interstitium. However, ... Full text Link to item Cite

Phase separation behavior of fusidic acid and rifampicin in PLGA microspheres.

Journal Article Molecular pharmaceutics · May 2012 The purpose of this study was to characterize the phase separation behavior of fusidic acid (FA) and rifampicin (RIF) in poly(d,l-lactic acid-co-glycolic acid) (PLGA) using a model microsphere formulation. To accomplish this, microspheres containing 20% FA ... Full text Cite

Lipid structures: a brief history of multisomes.

Journal Article Nature nanotechnology · December 2011 Full text Cite

Nanoscale Drug Delivery and Hyperthermia: The Materials Design and Preclinical and Clinical Testing of Low Temperature-Sensitive Liposomes Used in Combination with Mild Hyperthermia in the Treatment of Local Cancer.

Journal Article Open Nanomed J · January 1, 2011 The overall objective of liposomal drug delivery is to selectively target drug delivery to diseased tissue, while minimizing drug delivery to critical normal tissues. The purpose of this review is to provide an overview of temperature-sensitive liposomes i ... Full text Link to item Cite

Hydration potential of lysozyme: protein dehydration using a single microparticle technique.

Journal Article Biophysical journal · March 2010 For biological molecules in aqueous solution, the hydration pressure as a function of distance from the molecular surface represents a very short-range repulsive pressure that limits atom-atom contact, opposing the attractive van der Waals pressure. Wherea ... Full text Cite

Comparative effects of thermosensitive doxorubicin-containing liposomes and hyperthermia in human and murine tumours.

Journal Article Int J Hyperthermia · 2010 PURPOSE: In previous reports, laboratory-made lysolecithin-containing thermosensitive liposome encapsulating doxorubicin (LTSL-DOX) showed potent anticancer effects in FaDu human squamous cell carcinoma. To further study the spectrum of LTSL-DOX activity, ... Full text Link to item Cite

The effect of hydrogen bonding on the diffusion of water in n-alkanes and n-alcohols measured with a novel single microdroplet method.

Journal Article The Journal of chemical physics · January 2010 While the Stokes-Einstein (SE) equation predicts that the diffusion coefficient of a solute will be inversely proportional to the viscosity of the solvent, this relation is commonly known to fail for solutes, which are the same size or smaller than the sol ... Full text Open Access Cite

PLGA and PHBV Microsphere Formulations and Solid-State Characterization: Possible Implications for Local Delivery of Fusidic Acid for the Treatment and Prevention of Orthopaedic Infections

Journal Article Pharmaceutical Research · July 2009 To develop and characterize the solid-state properties of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) microspheres for the localized and controlled release of fusidic acid (FA). The effects of FA ... Cite

Tumor microvascular permeability is a key determinant for antivascular effects of doxorubicin encapsulated in a temperature sensitive liposome.

Journal Article Int J Hyperthermia · September 2008 Previous data have demonstrated that doxorubicin (DOX) released from a lysolecithin-containing thermosensitive liposome (LTSL) can shut down blood flow in a human tumor xenograft (FaDu) in mice when the treatment is combined with hyperthermia (HT), suggest ... Full text Link to item Cite

Rationale for and measurement of liposomal drug delivery with hyperthermia using non-invasive imaging techniques.

Journal Article Int J Hyperthermia · February 2008 The purpose of this review is to present an overview of the state-of-the-art imaging modalities used to track drug delivery from liposomal formulations into tumors during or after hyperthermia treatment. Liposomes are a drug delivery system comprised of a ... Full text Link to item Cite

Functional bionetworks from nanoliter water droplets.

Journal Article Journal of the American Chemical Society · July 2007 We form networks from aqueous droplets by submerging them in an oil/lipid mixture. When the droplets are joined together, the lipid monolayers surrounding them combine at the interface to form a robust lipid bilayer. Various protein channels and pores can ... Full text Cite

Dynamics of neutrophil membrane compliance and microstructure probed with a micropipet-based piconewton force transducer.

Journal Article Annals of biomedical engineering · April 2007 A novel biointerface probe was implemented to study the deformability of the neutrophil membrane and cortical cytoskeleton. Piconewton scale forces are applied to the cell using an ultrasensitive and tunable force transducer comprised of an avidin-coated m ... Full text Cite

Temperature-triggered nanotechnology for chemotherapy: Rapid release from lysolipid temperature-sensitive liposomes

Journal Article 2006 NSTI Nanotechnology Conference and Trade Show - NSTI Nanotech 2006 Technical Proceedings · December 8, 2006 Lysolipid temperature-sensitive liposomes (LTSLs) demonstrate enhanced release of encapsulated drug contents via grain boundary permeabilization when heated to their phase transition temperature, resulting in dramatic in vivo tumor toxicity. Dithionite ion ... Cite

New technology and clinical applications of nanomedicine: highlights of the second annual meeting of the American Academy of Nanomedicine (Part I).

Journal Article Nanomedicine : nanotechnology, biology, and medicine · December 2006 The Second Annual Meeting of the American Academy of Nanomedicine (AANM) was held at the National Academy of Science Building in Washington, DC, September 9-10, 2006. The program included two Nobel Prize Laureate Lectures, two Keynote Lectures, and 123 inv ... Full text Cite

Phase I trial of doxorubicin-containing low temperature sensitive liposomes in spontaneous canine tumors.

Journal Article Clin Cancer Res · July 1, 2006 PURPOSE: To determine the maximum tolerated dose, dose-limiting toxicities, and pharmacokinetic characteristics of doxorubicin encapsulated in a low temperature sensitive liposome (LTSL) when given concurrently with local hyperthermia to canine solid tumor ... Full text Link to item Cite

Hyperthermia mediated liposomal drug delivery.

Journal Article Int J Hyperthermia · May 2006 Drug delivery systems have been developed for cancer therapy in an attempt to increase the tumour drug concentration while limiting systemic exposure. Liposomes have achieved passive targeting of solid tumours through enhanced vascular permeability, which ... Full text Link to item Cite

Microdroplet dissolution into a second-phase solvent using a micropipet technique: test of the Epstein-Plesset model for an aniline-water system.

Journal Article Langmuir : the ACS journal of surfaces and colloids · April 2006 The Epstein-Plesset model was originally derived for the dissolution of a single gas bubble in an infinite aqueous solution (Epstein, P. S.; Plesset, M. S. J. Chem. Phys. 1950, 18, 1505-1509). The micropipet manipulation technique was previously shown to t ... Full text Cite

Targeted bioavailability of drugs by triggered release from liposomes

Journal Article Future Lipidology · February 1, 2006 Full text Cite

Oligo-α-hydroxy ester cross-linkers: Impact of cross-linker structure on biodegradable hydrogel networks

Journal Article Macromolecules · December 27, 2005 We describe the synthesis of a series of biodegradable oligo-α-hydroxy ester cross-linkers and evaluate their impact on the degradation kinetics and macromolecule diffusion from a hydrogel network. By changing the steric and electronic environment at the s ... Full text Cite

Lysolipid incorporation in dipalmitoylphosphatidylcholine bilayer membranes enhances the ion permeability and drug release rates at the membrane phase transition.

Journal Article Biochimica et biophysica acta · October 2005 The enhanced permeability of lipid bilayer membranes at their gel-to-liquid phase transition has been explained using a "bilayer lipid heterogeneity" model, postulating leaky interfacial regions between still solid and melting liquid phases. The addition o ... Full text Cite

Water micro-droplets in simple hydrocarbons: Dissolution, free energies of adhesion and bilayer permeability.

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 13, 2005 Link to item Cite

The effects of a complexation reaction on travelling wave-fronts in a quadratic autocatalytic system

Journal Article Q. J. Mech. Appl. Math. (UK) · 2005 A model which describes the effect that a complexation reaction can have on the propagation of reaction fronts in a quadratic autocatalytic system is considered. An initial-value problem is set up, which involves the (dimensionless) parameters K, the equil ... Full text Link to item Cite

A mathematical model for the spread of morphogens with density dependent chemosensitivity

Journal Article Nonlinearity (UK) · 2005 A system of reaction-diffusion equations with volume-filling chemosensitivity arising in the modelling of morphogen spread during embryonic growth is considered. Existence and uniqueness of classical solutions to this novel system are established. Qualitat ... Full text Link to item Cite

New drug delivery approach for the treatment of prostate cancer (preclinical results and phase I study results).

Journal Article Journal of clinical oncology : official journal of the American Society of Clinical Oncology · July 2004 4661 Introduction: Treatment for localized prostate cancer includes observation, radiation and surgical therapy with or without androgen deprivation.. One potential relevant form of therapy is thermal therapy plus thermally sensitive liposomal encapsulated ... Cite

Test of the Epstein-Plesset model for gas microparticle dissolution in aqueous media: effect of surface tension and gas undersaturation in solution.

Journal Article Langmuir : the ACS journal of surfaces and colloids · March 2004 The gas from a free air bubble will readily dissolve in water, driven by two main factors: the concentration (undersaturation) of dissolved gas in the aqueous solution and the surface tension of the gas bubble-water interface via a Laplace overpressure in ... Full text Cite

The materials engineering of temperature-sensitive liposomes.

Journal Article Methods in enzymology · January 2004 Full text Cite

Mechanical properties and microstructure of polycrystalline phospholipid monolayer shells: Novel solid microparticles

Journal Article Langmuir · September 30, 2003 A polycrystalline phospholipid monolayer self-assembled at the surface of an air microbubble in aqueous solution represents a novel material structure: in essence, a solid shell of wax with micrometer-scale dimensions and a thickness of only a single molec ... Full text Cite

Disc formation in cholesterol-free liposomes during phase transition.

Journal Article Biochimica et biophysica acta · August 2003 Cryogenic transmission electron microscopy (cryo-TEM) images of lysolipid-containing thermosensitive liposomes (LTSL) revealed that open liposomes and bilayer discs appeared when liposomes were cycled through the gel (Lbeta') to liquid-crystalline (Lalpha) ... Full text Cite

Lipid Membranes: Biological Inspiration for Micro and Nano Encapsulation Technologies, Especially Drug Delivery

Journal Article Materials Research Society Symposium - Proceedings · January 1, 2003 Full text Cite

Evaluation of synthetic phospholipid ultrasound contrast agents.

Journal Article Ultrasonics · November 2002 The echogenic properties of synthetic, phospholipid encapsulated, air-filled microbubbles with various carbon-chain length as ultrasound contrast agents are investigated through the use of a flow-through laboratory ultrasound system. Specifically, we inves ... Full text Cite

From soft materials to rational design of active carrier delivery systems.

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · August 18, 2002 Link to item Cite

Evaluation of the effectiveness of UK community pharmacists' interventions in community palliative care.

Journal Article Palliative medicine · May 2002 IntroductionIn 1997, the Royal Pharmaceutical Society of Great Britain Working Party reported that UK community pharmacists had a crucial role in effective medicines management and effective symptom control for those receiving palliative care in t ... Full text Cite

Interactions of pH-sensitive peptides and polymers with lipid bilayers: Binding and membrane stability

Journal Article Current Topics in Membranes · January 1, 2002 The controlled release of content from liposomes is critical for their successful use as drug delivery systems. The most commonly used triggering mechanisms for content release are changes in the environment, such as a change in temperature or pH. In this ... Full text Cite

The development and testing of a new temperature-sensitive drug delivery system for the treatment of solid tumors.

Journal Article Advanced drug delivery reviews · December 2001 Featured Publication Our laboratories have been working together in close collaboration for over 10 years concerning the design and performance of lipid-based drug delivery systems. Over the past 3 years we have conceived of, developed, and tested pre-clinically, a new liposom ... Full text Cite

Equilibrium and dynamic interfacial tension measurements at microscopic interfaces using a micropipet technique - 2. Dynamics of phospholipid monolayer formation and equilibrium tensions at the water-air interface

Journal Article Langmuir · September 4, 2001 Equilibrium and dynamic interfacial tension measurements were performed using micropipet technique. Dynamics of phospholipid monolayer formation and equilibrium tensions at the water-air interface were studied. Results showed that the surface tension and t ... Full text Cite

Equilibrium and Dynamic Interfacial Tension Measurements at Microscopic Interfaces Using a Micropipet Technique. 1. A New Method for Determination of Interfacial Tension

Journal Article Langmuir · September 4, 2001 A new micropipet technique has been developed to measure the equilibrium and dynamic interfacial tensions of microscopic liquid-gas and liquid-liquid interfaces. In this technique, a liquid-gas or liquid-liquid interface with a radius of curvature ranging ... Full text Cite

Interaction of synthetic HA2 influenza fusion peptide analog with model membranes.

Journal Article Biophysical journal · July 2001 The interaction of the synthetic 21 amino acid peptide (AcE4K) with 1-oleoyl-2-[caproyl-7-NBD]-sn-glycero-3-phosphocholine membranes is used as a model system for the pH-sensitive binding of fusion peptides to membranes. The sequence of AcE4K (Ac-GLFEAIAGF ... Full text Cite

Efficacy of liposomes and hyperthermia in a human tumor xenograft model: importance of triggered drug release.

Journal Article Cancer Res · December 15, 2000 The tumor drug concentrations, drug distributions, and therapeutic efficacies achieved by three fundamentally different liposomes, nonthermosensitive liposome (NTSL), traditional thermosensitive liposome (TTSL), and low temperature sensitive liposome (LTSL ... Link to item Cite

PEG-covered lipid surfaces: bilayers and monolayers.

Journal Article Colloids and surfaces. B, Biointerfaces · October 2000 In this review paper we survey the ways in which various micropipet techniques have been used to study the mechanochemical and interactive features of lipid bilayer vesicles and monolayer-coated gas bubbles. Special emphasis will be made on characterizing ... Full text Cite

Hyperthermia increases accumulation of technetium-99m-labeled liposomes in feline sarcomas.

Journal Article Clin Cancer Res · September 2000 The effect of hyperthermia on the accumulation of technetium-99m-labeled liposomes was studied in feline sarcomas. Each cat received two separate injections of liposomes. The first was used to quantify the amount of technetium-99m-labeled liposomes within ... Link to item Cite

AnkB, a periplasmic ankyrin-like protein in Pseudomonas aeruginosa, is required for optimal catalase B (KatB) activity and resistance to hydrogen peroxide.

Journal Article Journal of bacteriology · August 2000 In this study, we have cloned the ankB gene, encoding an ankyrin-like protein in Pseudomonas aeruginosa. The ankB gene is composed of 549 bp encoding a protein of 183 amino acids that possesses four 33-amino-acid ankyrin repeats that are a hallmark of eryt ... Full text Cite

Water permeability and mechanical strength of polyunsaturated lipid bilayers.

Journal Article Biophys J · July 2000 Featured Publication Micropipette aspiration was used to test mechanical strength and water permeability of giant-fluid bilayer vesicles composed of polyunsaturated phosphatidylcholine PC lipids. Eight synthetic-diacyl PCs were chosen with 18 carbon chains and degrees of unsat ... Full text Link to item Cite

Effect of chain length and unsaturation on elasticity of lipid bilayers.

Journal Article Biophys J · July 2000 Featured Publication Micropipette pressurization of giant bilayer vesicles was used to measure both elastic bending k(c) and area stretch K(A) moduli of fluid-phase phosphatidylcholine (PC) membranes. Twelve diacyl PCs were chosen: eight with two 18 carbon chains and degrees o ... Full text Link to item Cite

Lipid-coated microgels for the triggered release of doxorubicin.

Journal Article Journal of controlled release : official journal of the Controlled Release Society · July 2000 We have systematically engineered a polymeric, multi-component drug delivery system composed of a lipid-coated hydrogel microparticle (microgel). The design of this delivery system was motivated by the recent elucidation of the mechanism of regulated secre ... Full text Cite

Alkali earth metal binding properties of ionic microgels

Journal Article Macromolecules · May 30, 2000 Spherical micron-sized (4-10 μm in diameter) poly(methacrylic acid-co-acrylic acid) microgels were synthesized by precipitation polymerization, and their chelation reactions with chloride salts of Mg2+, Ca2+, Sr2+, and Ba2+ were investigated by isothermal ... Full text Cite

The influence of tiered layers of surface-grafted poly(ethylene glycol) on receptor-ligand-mediated adhesion between phospholipid monolayer-stabilized microbubbles and coated glass beads

Journal Article Langmuir · March 21, 2000 The goal of the current study is to measure the strength of specific adhesion between a prototypical phospholipid-stabilized ultrasound contrast agent, the surface of which has been derivatized with a ligand molecule, and a glass bead surface coated with t ... Full text Cite

A new temperature-sensitive liposome for use with mild hyperthermia: characterization and testing in a human tumor xenograft model.

Journal Article Cancer Res · March 1, 2000 Featured Publication The single biggest challenge now facing drug delivery (for liposomes and indeed other carriers) is to initiate and produce release of the encapsulated drug only at the diseased site and at controllable rates. Our efforts have focused on developing a new th ... Link to item Cite

Design and performance of poly(HPMA) hydrogels containing symmetrical biodegradable crosslinkers composed of oligo-lactate and oligo-glycolate esters

Journal Article American Chemical Society, Polymer Preprints, Division of Polymer Chemistry · March 1, 2000 The synthesis and testing of the first symmetrical based on vinylic oligomers of α-hydroxy acids are described. Biodegradable gel networks with chemically defined crosslinks were made and studied and were shown to degrade at a defined rate in response to t ... Cite

An IDL to Ada95 mapping to support propagation modeling

Journal Article Ada Lett. (USA) · 2000 Representing dynamic interdependencies between design objects is an essential part of modeling the critical software communications found in complex software systems. This paper investigates the modeling of propagations (our term for dynamic interdependenc ... Cite

Use of hyperthermia to augment liposomal drug delivery to tumours

Conference RADIATION RESEARCH, VOL 2, CONGRESS PROCEEDINGS · January 1, 2000 Link to item Cite

Investigation of the swelling response and drug loading of ionic microgels: The dependence on functional group composition

Journal Article Macromolecules · December 28, 1999 Spherical micron-sized (4-7 μm diameter) poly(methacrylic acid-co-nitrophenyl acrylate) microgels were synthesized by precipitation polymerization and selectively derivatized with carboxylic acid, glutamic acid, hydroxamic acid, sulfonic acid, and ethanol ... Full text Cite

Targeted drug delivery

Journal Article Expert Opinion on Therapeutic Patents · November 17, 1999 Creating effective targeted drug delivery strategies is an integral component of the overall process of drug development. The four key requirements of an effective drug delivery system are retain, evade, target and release. Increasing the therapeutic index ... Full text Cite

Investigation of the swelling response and loading of ionic microgels with drugs and proteins: the dependence on cross-link density

Journal Article Macromolecules · July 27, 1999 The pH and NaCl induced swelling response and drug and protein loading of poly(methacrylic acid-co-acrylic acid) microgels (4-10 μm diameter) were measured as a function of cross-link density. The swelling ratio (Q) of the microgels increased linearly from ... Full text Cite

Materials engineering of lipid bilayers for drug carrier performance

Journal Article MRS Bulletin · January 1, 1999 An account is given on recent advances in the design and characterization of liposomes. Focus is on connecting the the performance of liposomes to their properties and composition. The important of research in drug transport and release is stressed in view ... Full text Cite

Effect of bilayer cholesterol and surface grafted poly(ethylene glycol) on pH-induced release of contents from liposomes by poly(2-ethylacrylic acid)

Journal Article Journal of Liposome Research · January 1, 1999 Liposomal delivery systems have yet to reach the levels of burst release of drug at a diseased site necessary to achieve high local therapeutic levels. A pH sensitive, triggered release system, is one mechanism which shows great promise, especially for use ... Full text Cite

Enhancement of the phase transition permeability of DPPC liposomes by incorporation of MPPC: A new temperature-sensitive liposome for use with mild hyperthermia

Journal Article Journal of Liposome Research · January 1, 1999 The present study describes a novel method of preparing thermosensitive liposomes by compositional modification, incorporating a highly bilayer compatible lysolipid, 1-Palmitoyl-2-Hydroxy-sn-Glycero-3-Phosphocholine (MPPC) into the gel phase liposomes comp ... Full text Cite

Attachment of ligands to gas-filled microbubbles via PEG spacer and lipid residues anchored at the interface

Journal Article Proceedings of the Controlled Release Society · January 1, 1999 Cite

Environmental response of anionic microgels.

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · August 23, 1998 Link to item Cite

Nanomechanics of the neutrophil interface: Cell surface compliance.

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · August 23, 1998 Link to item Cite

pH and NaCl triggered response of anionic microgels

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · August 23, 1998 Link to item Cite

pH and Ion-Triggered Volume Response of Anionic Hydrogel Microspheres.

Journal Article Macromolecules · July 28, 1998 Micrometer-sized (4-7 µm diameter) poly(methacrylic acid) (PMAA) hydrogel microspheres were synthesized by precipitation polymerization. Individual microspheres were held in a micropipet and visualized by interference contrast microscopy. They were charact ... Full text Link to item Cite

A synthetic mimic of the secretory granule for drug delivery.

Journal Article Nature · July 1998 Secretory cells contain submicroscopic granules composed of a polyanionic polymer network that is collapsed owing to the presence of hydronium ions and weak base cations. The network is encapsulated within a lipid membrane, and functions as a vehicle for t ... Full text Cite

Centre families in two-dimensional complex holomorphic dynamical systems

Journal Article Proc. R. Soc. Lond. A, Math. Phys. Eng. Sci. (UK) · 1998 We consider a two-dimensional complex holomorphic dynamical system. In particular, we use the singular point theory of C.H. Briot and J.C. Bouquet to establish the existence of complex holomorphic invariant manifolds of the system in the neighbourhood of a ... Full text Link to item Cite

Adsorption, molecular exchange and defect formation in membranes

Journal Article Current Opinion in Colloid and Interface Science · January 1, 1998 The past year has seen significant advances in our understanding of the key factors involved in determining whether a macromolecule or colloidal particle can reach, bind to, and absorb into lipid bilayer membranes. The highlights include the need to combin ... Full text Cite

Interactions between poly(2-ethylacrylic acid) and lipid bilayer membranes: effects of cholesterol and grafted poly(ethylene glycol).

Journal Article Faraday discussions · January 1998 The exchange of the protonatable polymer, poly(2-ethylacrylic acid) (PEAA), has been studied with vesicle membranes containing cholesterol from 0 to 60 mol% or PEG2000-lipid (5 mol%). The release of an entrapped dye from 100 nm extruded liposomes was used ... Full text Cite

Binding of paclitaxel to lipid interfaces: Correlations with interface compliance

Journal Article Journal of Liposome Research · January 1, 1998 In the present work, we have studied the paclitaxel loading efficiency of lipid bilayers with respect to their compositional behavior, which in turn determines their mechanical properties. We have found that, if a drug with a low water solubility like pacl ... Full text Cite

Exchange of monooleoylphosphatidylcholine as monomer and micelle with membranes containing poly(ethylene glycol)-lipid.

Journal Article Biophysical journal · November 1997 Surface-grafted polymers, such as poly(ethylene glycol) (PEG), provide an effective steric barrier against surface-surface and surface-macromolecule interactions. In the present work, we have studied the exchange of monooleoylphosphatidylcholine (MOPC) wit ... Full text Cite

Biomembrane templating of nanometer-scale polymer patterns

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · September 7, 1997 Link to item Cite

Barrier properties of surface-grafted PEG for macromolecule-surface interactions.

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · April 13, 1997 Link to item Cite

Barrier properties of surface-grafted PEG for macromolecule-surface interactions

Journal Article American Chemical Society, Polymer Preprints, Division of Polymer Chemistry · April 1, 1997 Cite

Mimicking the smart polymer matrix of the secretory granule: a new concept in controlled release drug delivery

Journal Article Polymeric Materials Science and Engineering, Proceedings of the ACS Division of Polymeric Materials Science and Engineering · January 1, 1997 Regulated secretion of biological molecules is controlled by specialized secretory cells. The design of a multi-component drug delivery system which can closely mimic the properties of the secretary granule will have utility for triggered release of drugs. ... Cite

Pore formation and pore dynamics in bilayer membranes

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · December 1, 1996 Cite

Biomembrane templates for nanoscale conduits and networks.

Journal Article Science (New York, N.Y.) · August 1996 Long nanotubes of fluid-lipid bilayers can be used to create templates for photochemical polymerization into solid-phase conduits and networks. Each nanotube is pulled from a micropipette-held feeder vesicle by mechanical retraction of the vesicle after mo ... Full text Cite

Nanometer-scale polymeric patterns and networks.

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 24, 1996 Link to item Cite

Avidin-biotin interactions at vesicle surfaces: adsorption and binding, cross-bridge formation, and lateral interactions.

Journal Article Biophysical journal · March 1996 Densely packed domains of membrane proteins are important structures in cellular processes that involve ligand-receptor binding, receptor-mediated adhesion, and macromolecule aggregation. We have used the biotin-avidin interaction at lipid vesicle surfaces ... Full text Cite

PORE FORMATION AND PORE DYNAMICS IN BILAYER MEMBRANES.

Conference ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) · January 1, 1996 Full text Cite

Nanometer-scale polymeric patterns and networks

Journal Article Polymeric Materials Science and Engineering, Proceedings of the ACS Division of Polymeric Materials Science and Engineering · 1996 Cite

Reaction-diffusion model for autocatalytic polymerization: II. The initial value problem

Journal Article IMA Journal of Applied Mathematics (Institute of Mathematics & Its Applications) · 1996 An initial-boundary value problem arising from a simple model for radical chain polymerization is discussed in detail. General properties of the solution are derived first and it is shown that a moving interface develops. This separates a region where the ... Cite

EXPERIMENTAL TESTS FOR MOLECULAR PROTRUSIONS AND UNDULATIONS IN LIPID BILAYERS

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · August 20, 1995 Link to item Cite

Experimental tests for protrusion and undulation pressures in phospholipid bilayers.

Journal Article Biochemistry · July 11, 1995 Theoretical treatments predict that strong entropic pressures between adjacent bilayer membranes can arise from out of plane motions caused by either thermally induced bending undulations of the entire bilayer [Harbich, W., & Helfrich, W. (1984) Chem. Phys ... Full text Link to item Cite

Phase Behavior of a Lipid/Polymer-Lipid Mixture in Aqueous Medium

Journal Article Macromolecules · July 1, 1995 The phase behavior of a mixture of bilayer forming lipids and polymer-lipids (lipids with covalently attached polymer to their hydrophilic moieties) in excess water is studied theoretically. The mixture is predicted to exhibit complex phase behavior for po ... Full text Cite

Range and magnitude of the steric pressure between bilayers containing phospholipids with covalently attached poly(ethylene glycol).

Journal Article Biophys J · May 1995 The interactive properties of liposomes containing phospholipids with covalently attached poly(ethylene glycol) (PEG-lipids) are of interest because such liposomes are being developed as drug delivery vehicles and also are ideal model systems for measuring ... Full text Link to item Cite

Lysolipid exchange with lipid vesicle membranes.

Journal Article Annals of biomedical engineering · May 1995 While the aqueous solubility for bilayer phospholipids is less than 10(-10) M--keeping lipid membranes at essentially constant mass, single chain surfactants can have a significant aqueous solubility. Thus, in surfactant solutions, both monomer and micelle ... Full text Cite

Influence of bilayer fluctuations on the steric interactions between polymer-grafted bilayers

Journal Article Liquid Crystals · January 1, 1995 We propose a mechanism, through which the low membrane bending rigidity changes the steric polymer repulsion between polymer-grafted bilayers. We calculate the energy of a polymer chain trapped between two thermally undulating surfaces. The proposed treatm ... Full text Cite

Centre theorem for two-dimensional complex holomorphic systems and its generalization

Journal Article Proceedings of The Royal Society of London, Series A: Mathematical and Physical Sciences · 1995 Cite

The "Stealth" liposome: A prototypical biomaterial

Journal Article Chemical Reviews · 1995 Featured Publication Cite

Adsorption and adhesion at vesicle surfaces: the influence of grafted polymer on avidin-biotin binding and tests of receptor-mediated adhesion

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · January 1, 1995 Micropipette techniques coupled to fluorescence video microscopy are used to carry out two kinds of experiments on adsorption and adhesion at vesicle surfaces. The model system of biotinylated lipid vesicles with avidin is also used. The binding of avidin ... Cite

A novel micropipet method for measuring the bending modulus of vesicle membranes.

Journal Article Biophysical journal · August 1994 A theoretical model and an experiment are presented for determining the bending modulus of a bilayer vesicle membrane. The vesicle is held with a pipet having a radius between 1 and 2 microns, and the tension in the membrane is changed by changing the suct ... Full text Cite

Role of the membrane cortex in neutrophil deformation in small pipets.

Journal Article Biophysical journal · August 1994 The simplest model for a neutrophil in its "passive" state views the cell as consisting of a liquid-like cytoplasmic region surrounded by a membrane. The cell surface is in a state of isotropic contraction, which causes the cell to assume a spherical shape ... Full text Cite

Increased adhesion between neutral lipid bilayers: interbilayer bridges formed by tannic acid.

Journal Article Biophys J · June 1994 Tannic acid (TA) is a naturally occurring polyphenolic compound that aggregates membranes and neutral phosolipid vesicles and precipitates many proteins. This study analyzes TA binding to lipid membranes and the ensuing aggregation. The optical density of ... Full text Link to item Cite

The Influence of polymer-grafted lipids on the physical properties of lipid bilayers: A theoretical study

Journal Article Journal of Colloid And Interface Science · January 1, 1994 Experimental studies of bilayers containing polymer-grafted lipids have been underway for some time now. Modeling the physical properties of these bilayers, however, is not trivial because of the complexities in the self-assembling polymer-lipid/lipid bila ... Full text Cite

Measurement of material extravasation in microvascular networks using fluorescence video-microscopy.

Journal Article Microvasc Res · September 1993 We have developed a new method using fluorescence videomicroscopy to quantitate the extravasation of intravenously injected materials. This method can measure the relative plasma concentration of, and the vascular permeability to, these materials in microc ... Full text Link to item Cite

Increased microvascular permeability contributes to preferential accumulation of Stealth liposomes in tumor tissue.

Journal Article Cancer Res · August 15, 1993 Stealth liposomes have recently emerged as a promising antitumor drug delivery system, yet no studies have been reported to examine their dynamic behavior at the microcirculatory level. In this investigation, we have used in vivo fluorescence videomicrosco ... Link to item Cite

Viscosity of passive human neutrophils undergoing small deformations.

Journal Article Biophysical journal · May 1993 At issue is the type of constitutive equation that can be used to describe all possible types of deformation of the neutrophil. Here a neutrophil undergoing small deformations is studied by aspirating it into a glass pipet with a diameter that is only slig ... Full text Cite

Volume and osmotic properties of human neutrophils.

Journal Article Blood · May 1993 Quantitative models describing the dynamics of human neutrophils in the microcirculation require accurate morphometric parameters such as volume and surface membrane area. Using both a micropipette technique and video light microscopy (LM) to measure the d ... Cite

The effect of flunarizine on erythrocyte suspension viscosity under conditions of extreme hypoxia, low pH, and lactate treatment.

Journal Article Br J Cancer · April 1993 Flunarizine is a class IV calcium channel blocker which increases oxygen delivery to hypoxic regions in solid tumours, exerting a radiosensitising effect in vivo in animal tumour models. Precisely how the drug improves oxygenation is not well understood. W ... Full text Link to item Cite

Tension-stabilized pores in giant vesicles: determination of pore size and pore line tension.

Journal Article Biochimica et biophysica acta · April 1993 We present the first observations of giant, long-existing, stabilized pores in vesicle membranes. Using a new experimental technique for studying the electro-permeabilization of lipid membranes, giant liposomes (from 25 to 56 microns in diameter) were subj ... Full text Cite

RECOVERY OF PASSIVE HUMAN NEUTROPHILS AFTER SMALL DEFORMATIONS

Conference BIOPHYSICAL JOURNAL · February 1, 1993 Link to item Cite

THEORETICAL-STUDIES OF MODEL BIOSURFACE PROPERTIES

Conference BIOPHYSICAL JOURNAL · February 1, 1993 Link to item Cite

Measurement of interbilayer adhesion energies.

Journal Article Methods in enzymology · January 1993 Full text Cite

Pentoxifylline modulates deformability, F-actin content, and superoxide anion production of polymorphonuclear leukocytes from diabetic cats.

Journal Article Exp Eye Res · December 1992 Capillary occlusion is an early event in the development of diabetic retinopathy, and white blood cells have recently been shown to be involved. We have shown previously that pentoxifylline improves deformability and decreases F-actin content of unstimulat ... Full text Link to item Cite

Repulsive interactions and mechanical stability of polymer-grafted lipid membranes.

Journal Article Biochim Biophys Acta · July 8, 1992 Liposome membranes containing lipids with covalently attached poly(ethylene glycol) (PEG-lipid) are currently being developed as drug delivery systems. These, so called, 'Stealth' liposomes have a relatively long half life (approximately 1 day) in blood ci ... Full text Link to item Cite

A sensitive measure of surface stress in the resting neutrophil.

Journal Article Biophysical journal · June 1992 The simplest parameterized model of the "passive" or "resting receptive" neutrophil views the cell as being composed of an outer cortex surrounding an essentially liquid-like highly viscous cytoplasm. This cortex has been measured to maintain a small persi ... Full text Cite

GRAFTED POLYMER (STEALTH) LIPOSOMES

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · April 5, 1992 Link to item Cite

Modulation of the interbilayer hydration pressure by the addition of dipoles at the hydrocarbon/water interface.

Journal Article Biophys J · March 1992 The effects of the cholesterol analog 5 alpha-cholestan-3 beta-ol-6-one (6-ketocholestanol) on bilayer structure, bilayer cohesive properties, and interbilayer repulsive pressures have been studied by a combination of x-ray diffraction, pipette aspiration, ... Full text Link to item Cite

Structure and cohesive properties of sphingomyelin/cholesterol bilayers.

Journal Article Biochemistry · February 25, 1992 Thermal, structural, and cohesive measurements have been obtained for both bovine brain sphingomyelin (BSM) and N-tetracosanoylsphingomyelin (C24-SM) in the presence and absence of cholesterol. A goal of these experiments has been to clarify the mechanisms ... Full text Link to item Cite

Interbilayer interactions between sphingomyelin and sphingomyelin/cholesterol bilayers.

Journal Article Biochemistry · February 25, 1992 Pressure versus fluid spacing relations have been obtained for sphingomyelin bilayers in the gel phase and equimolar sphingomyelin/cholesterol in the liquid-crystalline phase by the use of X-ray diffraction analysis of osmotically stressed aqueous dispersi ... Full text Link to item Cite

Formal theory concerning the generation and propagation of travelling wave-fronts in reaction-diffusion equations

Journal Article Quarterly Journal of Mechanics and Applied Mathematics · 1992 In this paper we develop a formal approach to examining the long-time asymptotic form of propagating wave-fronts which can develop in initial boundary-value problems for partial differential equations of the reaction-diffusion type. Particular attention is ... Cite

Polymer-grafted liposomes: Physical basis for the "stealth" property

Journal Article Journal of Liposome Research · January 1, 1992 Polymer-bearing lipids have recently been incorporated into liposomes that are used in in vivo drug delivery. This strategy has improved the liposome's ability to avoid the reticuloendothelial system and has thereby increased its circulation time in the bl ... Full text Cite

Morphology, geometry and mechanical properties of GAP A3 hybridoma cells as a function of the cell cycle

Journal Article Annals of Biomedical Engineering · December 1, 1991 The sensitivity of animal cells in bioreactor culture to hydrodynamic shear and abrasion results in reduced cell growth rate and viability and is widely perceived as a barrier to scale-up in processing. Cell shear- and abrasion-sensitivity is also importan ... Cite

Mechanical and interactive properties of lipid membranes containing surface-bound polymer

Journal Article Annals of Biomedical Engineering · December 1, 1991 The rapid clearance, from the blood stream, of liposomes used in delivery systems is one of the major obstacles to advancing many applications of liposomes in medical technologies. The incorporation of glycolipids or a lipid that contains a large polymeric ... Cite

Deformation and flow of neutrophils and monocytes

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · December 1, 1991 The deformation and flow of neutrophils and monocytes in the smallest vessels is studied experimentally. The preparation of cells, micropipet manipulation, measurement of cortical tension, measurement of viscosity and of the rate of recovery is described. ... Cite

Recovery of passive neutrophils after large deformation. Liquid drop model

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · December 1, 1991 The validity of the Neutonian liquid model as a description of the recovery of a neutrophil after large deformation is investigated. In the first part, we report the results of experiments in which cells are deformed from their resting spherical geometry, ... Cite

Deformation and flow of neutrophils in micropipets

Journal Article Annals of Biomedical Engineering · December 1, 1991 The undeformed human neutrophil in the resting, passive state is shaped like a sphere with a diamter of about 8 μm. Thus, it must deform significantly in order to flow through the small capillaries (approximately 4 μm) of the body. To model and understand ... Cite

A physical characterization of GAP A3 hybridoma cells: morphology, geometry, and mechanical properties.

Journal Article Biotechnology and bioengineering · October 1991 Morphological, geometrical, and rheological properties of the GAP A3 hybridoma cell line have been evaluated as a function of the cell cycle. Interference contrast video microscopy and scanning electron microscopy (SEM) showed that a sample of cells taken ... Full text Cite

Time-dependent recovery of passive neutrophils after large deformation.

Journal Article Biophysical journal · October 1991 Experiments are performed in which a passive human neutrophil is deformed into an elongated "sausage" shape by aspirating it into a small glass pipette. When expelled from the pipette the neutrophil recovers its natural spherical shape in approximately 1 m ... Full text Cite

Possible role of cell cycle-dependent morphology, geometry, and mechanical properties in tumor cell metastasis.

Journal Article Cell biophysics · April 1991 Studies that examine the shear- and abrasion-sensitivity of proliferating cells are important in order to understand the behavior of hybridoma cells in bioreactor culture and metastasizing cancer cells in the bloodstream. Little is known about the link bet ... Full text Cite

Morphology and mechanical properties of gap A3 hybridoma cells as related to cell cycle

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · December 1, 1990 The morphological and rheological properties of a hybridoma cell line namely, GAP A3, have been evaluated as a function of its cell cycle. Results show that a hybridoma cell line cannot be characterized by a single value for any one property, and that prop ... Cite

Elastic deformation and failure of lipid bilayer membranes containing cholesterol.

Journal Article Biophys J · October 1990 Featured Publication Giant bilayer vesicles were reconstituted from several lipids and lipid/cholesterol (CHOL) mixtures: stearolyloleoylphosphatidylcholine (SOPC), bovine sphingomyelin (BSM), diarachidonylphosphatidylcholine (DAPC), SOPC/CHOL, BSM/CHOL, DAPC/CHOL, and extract ... Full text Link to item Cite

Rapid flow of passive neutrophils into a 4 microns pipet and measurement of cytoplasmic viscosity.

Journal Article Journal of biomechanical engineering · August 1990 Neutrophils from five different individuals are isolated with a density separation technique. A total of 151 unactivated (passive) cells are rapidly aspirated at constant suction pressure and at room temperature into a pipet with a diameter of 4 microns. T ... Full text Cite

Effect of pentoxifylline on the flow of polymorphonuclear leukocytes through a model capillary.

Journal Article Angiology · April 1990 Pentoxifylline is a methylxanthine derivative used to increase blood flow in peripheral atherosclerosis. Pentoxifylline is known to increase whole blood filtration rate, and recent evidence suggests that pentoxifylline increases the filtration rate of poly ... Full text Link to item Cite

The viscosity of neutrophils and their transit times through small pores.

Journal Article Biorheology · January 1990 Passive neutrophils from five different individuals are rapidly aspirated at constant suction pressure and at room temperature into a pipet with a diameter of 4 microns. The excess suction pressures (i.e., the pressures in excess of the small threshold pre ... Full text Cite

Rapid deformation of "passive" polymorphonuclear leukocytes: the effects of pentoxifylline.

Journal Article J Cell Physiol · September 1989 Entry times for spherical (no pseudopods) polymorphonuclear leukocytes (PMNs) into a 4 microns micropipet have been measured as a function of pipet suction pressure (2,500-20,000 dyn/cm2) and concentration of the drug pentoxifylline (PTX, 0.1-10.0 mM). For ... Full text Link to item Cite

Electro-mechanical permeabilization of lipid vesicles. Role of membrane tension and compressibility.

Journal Article Biophysical journal · May 1989 A simple micropipet technique was used to determine the critical electric field strength for membrane breakdown as a function of the applied membrane tension for three different reconstituted membranes: stearoyloleoylphosphatidylcholine (SOPC), red blood c ... Full text Cite

Structure and mechanical properties of giant lipid (DMPC) vesicle bilayers from 20 degrees C below to 10 degrees C above the liquid crystal-crystalline phase transition at 24 degrees C.

Journal Article Biochemistry · October 1988 We have used micromechanical tests to measure the thermoelastic properties of the liquid and gel phases of dimyristoylphosphatidylcholine (DMPC). We have found that the rippled P beta' phase is only formed when a vesicle is cooled to temperatures below the ... Full text Cite

Thermomechanical and transition properties of dimyristoylphosphatidylcholine/cholesterol bilayers.

Journal Article Biochemistry · June 28, 1988 Mixtures of dimyristoylphosphatidylcholine (DMPC) and cholesterol (Chol) have been used to examine the effects of cholesterol on the chain crystallization transitions and thermomechanical properties in phospholipid bilayer membranes. The mechanical propert ... Full text Link to item Cite

Attraction between Lipid Bilayer Membranes in Concentrated Solutions of Nonadsorbing Polymers: Comparison of Mean-Field Theory with Measurements of Adhesion Energy

Journal Article Macromolecules · January 1, 1988 Recent experimental advances have made quantitation of weak membrane attraction possible in concentrated solutions of macromolecules. Here, we report direct measurements of the free energy potential for adhesion of synthetic lipid bilayers in aqueous solut ... Full text Cite

Physical properties of surfactant bilayer membranes: Thermal transitions, elasticity, rigidity, cohesion, and colloidal interactions

Journal Article Journal of Physical Chemistry · 1987 Featured Publication Simple micromechanical methods provide direct measurements of surface cohesion, elasticity, rigidity, and mutual attraction properties of surfactant double-layer membranes in aqueous media. Temperature-dependent tests yield explicit data for thermal phase ... Cite

Inactivation of the sodium current in squid giant axons by hydrocarbons.

Journal Article Biophysical journal · October 1985 The voltage dependence of the steady state inactivation parameter (h infinity) of the sodium current in the squid giant axon is known to be shifted in the hyperpolarizing direction by hydrocarbons and it has been suggested that the shifts arise from thickn ... Full text Cite

A quantitative explanation of the effects of some alcohols on gramicidin single-channel lifetime.

Journal Article Biochimica et biophysica acta · April 1985 The effects of n-decanol, n-hexadecanol, n-octyl(oxyethylene)3 alcohol and cholesterol on gramicidin single-channel lifetime in planar lipid bilayers have been determined. The bilayers used were formed from a solution of monoolein in squalene. Measurements ... Full text Cite

HYDRIDIZATION AND CATALYSIS BY LANTHANIDE FILMS.

Journal Article Proceedings of The Royal Society of London, Series A: Mathematical and Physical Sciences · 1984 Hydrogen absorption to give the dihydrides MH//2// plus //i containing interstitial hydrogen H//i has been studied for the metals Gd, Dy, Er, Yb and Lu in the form of films deposited in ultra-high vacuum on glass. Film areas were determined by Kr adsorptio ... Cite

The effects of bilayer thickness and tension on gramicidin single-channel lifetime.

Journal Article Biochimica et biophysica acta · October 1983 Measurements have been made of gramicidin single-channel lifetimes in monoacylglycerol bilayers chosen so that their thickness ranged from above to below the length of the gramicidin channel. Contact angles, electrical capacities and bulk-phase interfacial ... Full text Cite

Tensions and free energies of formation of "solventless" lipid bilayers. Measurement of high contact angles.

Journal Article Biophysical journal · March 1983 A method is described for the accurate measurement of the interfacial tension of lipid bilayer membranes containing little or no solvent. The tensions were obtained from the interfacial tensions of the equilibrium film-forming solution in the Plateau-Gibbs ... Full text Cite