Cell Culture and Biocompatibility
Ability of A. atlas fibers to support the attachment and growth of mouse fibroblast cells was studied in compar- ison to the common B. mori silk. Silk fibers were com- pressed into a sheet and sterilized in an autoclave at
120 °C. Samples were accurately weighted and placed in a 24-well culture plate and incubated with NIH3T3 mouse fibroblast cells at a concentration of 1.5 × 105 cells mL−1 DMEM media containing 4 mM l-glutamine,
10 % calf serum, and 1.0 % of 104 μg/mL penicillin/ streptomycin were added into each well and the plates were incubated at 37 °C and 5 % CO2 up to 11 days. Me- dia was refreshed every 3 days. After the desired length of incubation, the samples were transferred to a new culture plate and the unattached cells were removed by rinsing with phosphate buffered saline. Metabolic ac- tivities of the cells on the silk fibers were measured us- ing a MTS assay. To perform the assay, about 0.5 mL per well of 20 % MTS solution in DMEM media was added into each well and incubated for 3 h. After 3 h, 150 μL of DMEM was collected into a 96-well plate and the ab- sorbance of the solution was read on a Mutiwell plate reader (Thermoscientific Model: Multiskan) at a wave- length of 490 nm to obtain the optical densities. Blank samples without any cells were also tested and used as control. At least four samples were tested for each time point and the experiments were repeated twice. The av- erage optical density of the cells with ± one standard de- viation are reported.