Abstract: Physical cross-linked polyvinyl alcohol(PVA) hydrogel microspheres with high strength were prepared by a modified high-voltage electrostatic technique. The hydrogel microspheres were solidified and suspended in coagulation liquid composed of chloroform and acetone, then the microspheres in coagulation liquid were frozen and thawed to get PVA cross\|linked. The influence factors of PVA microspheres' diameter and morphology, such as, coagulation liquid, PVA solution concentration and flow rate, temperature and humidity and electrostatic field strength of high-voltage electrostatic system, the number of froze and thaw cycle of PVA were investigated. The results showed that high-voltage electrostatic system modified with atmospheric steam to control temperature and humidity  of PVA microsphere formation area was an effective method to overcome microfilament formation while PVA solution was in higher concentration, the optimized condition for prepare PVA hydrogel microspheres with high strength and controlled diameter was coagulation liquid of chloroform/acetone(2∶1, volume ratio), frozen at -20 ℃ and thawed at room temperature for five cycles, PVA solution concentration of 12% in weight, flow rate of 2 mL/h, electrostatic field strength of 12-15 kV, electrode distance of 3 cm, and the PVA hydrogel microsphere has a widely potential use in the field of tissue engineering.

Key words: High-voltage electrostatic, Physical cross-linking, Polyvingl alchol(PVA) hydrogel microsphere, Tissue engineering