After proper mixing, the PVA gel beads
were prepared by dropping PVA solution into a buffer solution containing
Na2HPO4 0.1 M, NaH2PO4 0.3 M, and H3BO3 70 g/L. After the
beads were formed, they were then washed using 4 C sterilized
water after 2 h of agitation and then stored in sterilized ice-water
for overnight.