Experimental design
Gel fabrication
Gel functionalization with TAMRA-RGD peptide
Silicone breast implant–derived materials
Mechanical characterization
Interfacial rheology measurements
Contact angle measurements
Steel ball indentation measurements
Gel preparation with Span85 surfactant treatment for cellular assays
Cell lines and culture
Antibodies and reagents
Cell morphology and spreading assays
Cell proliferation assays
Gene expression analysis
Isolation and culture of PBMCs
Preparation of a collagen master mix for 3D collagen I gels
PBMC-silicone interaction assay
PBMC—silicone droplets interaction assay
Immunofluorescence imaging
Hertz contact model with surface tension
Statistics
PA gels were functionalized with fibronectin using the cross-linker 6-((acryloyl)amino)hexanoic acid succinimidyl ester (Acryloyl-X SE; Thermo Fisher Scientific). The PA gel functionalization was adapted from a previous protocol (48). Briefly, desired amounts of 0.2% bis-acrylamide, 3% Irgacure 2959, 0.5 M Hepes (pH 6.0), and 0.3% Acryloyl-X SE were mixed and applied onto gels. Gels were overlaid with Sigmacote-treated coverslips and then placed under a UV source to activate photoinitiator for 10 min. The top coverslips were removed, and the gels were gently washed with 50 mM Hepes buffer (pH 6) for 5 min on ice three times. The gel substrates were then incubated in fibronectin (20 μg/ml) in 50 mM Hepes buffer (pH 8) overnight at 4°C. The PA gels were washed with phosphate-buffered saline (PBS). For silicone gel functionalization, the cured silicone gels were incubated in fibronectin (10 μg/ml) in PBS overnight at 4°C to allow fibronectin adsorption onto the gels and then washed with PBS.