2.1 Preparation of Silk Fibroin Methacryloyl
2.1.1 Preparation of
photoinitiator
LAP
The product of SilMA was purchased from Engineering For Life (Suzhou,
China). Firstly, we should prepare the solution of
LAP
according
to the instructions. In brief, 20 mL PBS was added into the brown bottle
containing 0.05 g photoinitiator LAP in solid state. The solution was
dissolved in 40-50
℃
water bath for 15 min, and be shaken several times during the period.
The standard solution of LAP was successfully prepared and stored in the
refrigerator (4 ℃), protected against exposure to light.
2.1.2 Preparation of SilMA hydrogel
As recommended,
the
SilMA with concentration of 10%, 15% and 20% were prepared. The
required mass of solid SilMA was taken and put into the centrifuge tube,
then the
corresponding
volume of standard solution of LAP was added. The SilMA solution was
dissolved at room temperature for 0.5-1 h, and be shaken several times
during the period (avoid violent ultrasound, high temperature and strong
shear). The sterile SilMA solution could be prepared by filtered with
syringe filter of 0.22 μM pore size (Biosharp, Hefei, China). The
mechanical properties, especially the hardness of hydrogel can be
readily adjusted by changing the UV
irradiation time to meet the needs of different tissues and experimental
requirements,[17] so is SilMA hydrogel. In this
study, the solution was irradiated with 405 nm light source for 1 min to
make SilMA hydrogel.