Injectable, Dual-Cross-Linked, Dynamic Hydrogel for Tissue Separation and Thermal Shielding during Percutaneous Cryoablation.

PURPOSE: To develop a biocompatible hydrogel for hydrodissection to facilitate percutaneous cryoablation. MATERIALS AND METHODS: A hydrogel was created by cross-linking alginate, calcium ions, and polyethylene glycol conjugated with boronic acid. Stability of the gel and maintenance of structural integrity were assessed utilizing serum-containing cell culture media. Mechanical properties of the hydrogel were studied using rheometric analysis, and insulation was assessed during repeat freeze-thaw cycles. Cytotoxicity was examined through direct and indirect contact tests using human fibroblasts. Cytokine tumor necrosis factor-α (TNF-α) release from mouse macrophages was measured as a surrogate for inflammatory effects. Tissue displacement, migration, and resorption of the hydrogel were explored following intraperitoneal instillation in mice using serial ultrasound (US) and magnetic resonance (MR) imaging. RESULTS: The hydrogel exhibited shear-thinning behavior upon injection and self-healing properties upon repeated mechanical manipulation. Additionally, the gel maintained its insulative properties during consecutive freeze-thaw cycles. Viability of human fibroblasts was similar when cultured with and without the hydrogel for 3 days (100% vs 92%, P = .65). In addition, TNF-α secretion from macrophages in the presence of the gel (123.8 pg/mL [SD ± 99.4]) was comparable to a no-treatment control (47.5 pg/mL [SD ± 15.6], P = .98). Gel injection into the mouse peritoneum achieved durable bowel displacement for 6 hours. Half of the gel remained at 24 hours, with nearly all the gel (95%) resorbed by 72 hours. CONCLUSIONS: This novel hydrogel demonstrated favorable biocompatibility and physical properties for achieving prolonged tissue separation and thermal shielding during cryoablation.

Duke Scholars

Author Eric Mastria Radiology, Interventional Radiology