급냉 동결법으로 제조된 요실금 치료용 폴리비닐알콜 하이드로겔 미세입자의 제조 및 분석

Poly (vinyl alcohol) (PVA) hydrogels having good biocompatibility, mechanical properties and high water content have been widely utilized as wound dressing, drug carrier, and bulking agent (or filler) materials. PVA hydrogels have been usually produced by chemical (using crosslinkers) or physical (using freeze-thawing technique) crosslinking of PVA chains. However, the residual toxic crosslinking agents in the hydrogel or long processing time are considered as practical limitations. In this study, we fabricated PVA hydrogel beads using a simple quenching technique, which does not need any toxic crosslinking agents and does not include time-consuming steps for the hydrogel formation. For the fabrication of the PVA hydrogel beads, the PVA/polyethylene glycol (PEG) mixture solution was directly sprayed into liquid nitrogen to form bead shapes and thawed out in room temperature. The prepared PVA hydrogels had good mechanical properties. From the X-ray diffraction study, the gelation mechanism and mechanical properties of the hydrogels could be explained by the phase separation between PEG/water and PVA, and thus the decreased inter-domain distance between PVA chains during the quenching process. The PVA hydrogel beads could be easily injected through 22G needle into the back of hairless mouse (subcutaneously) and stably located at the apply site for 12 weeks. From the results, we recognized that the prepared PVA hydrogel beads may be a potential candidate as an injectable filler or bulking agent for the treatment of urinary incontinence owing to its good mechanical properties, injectability, volume retention potential as well as biocompatibility.