Experimental design
Gel fabrication
Gel functionalization with fibronectin
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
Immunofluorescence imaging
Hertz contact model with surface tension
Statistics
PBMCs were cultured and used as described above. Silicone droplets containing media was prepared as follows: 100 μl of silicone liquid (SYLGARD 184, Dow Corning) was added to 3 ml of cell media into a 10-ml syringe barrel and further mixed by pushing and pulling the plunger in the barrel three times. Cells were embedded with silicone microdroplets in a 3D collagen I gel with a final concentration of 1.6 mg/ml. A total of 18,000 cells per condition were gently mixed with 22.5-μl silicone droplets containing media and added to 45 μl of the previously prepared collagen I master mix in a sterile tube on ice. The cell-containing collagen I solution was gently mixed until a homogeneous bright pink color was obtained and subsequently transferred to a 96-well plate. Polymerization of the collagen gel and equilibration of gas conditions within the collagen matrix took place for 20 to 30 min at 37°C and 5% CO2 to obtain a final pH of 7.4 to 7.5 (fig. S10B). The pH values were determined using indicator paper strips. Cells embedded in the silicone droplet containing collagen matrices were maintained for 3 days with medium replacement every 1 to 2 days.