Numbers of UV crosslinkable chitosan hydrogels through chemical modification had drawn increasing attention, however most of these chitosan hydrogels lost the pH-responsive performance because plenty of amino groups (‒NH₂) in chitosan were consumed by reacting with other functional groups. To construct a pH-responsive UV-crosslinkable chitosan hydrogel for active modulating drug release with desired behavior, C₆-OH selectively modified chitosan via protection/deprotection strategy to amino groups was synthesized, the allyl groups on C₆ site and amino groups on C₂ site endowed chitosan with UV crosslinking capability and pH responsiveness, respectively. Rapid UV crosslinking gelation (30 s) with low-dose UV irradiation (4 mW/cm²) via “thiol-ene” click chemistry were demonstrated for the patterned microgel and in-situ formed hydrogel in vivo. The swelling and shrinkage of hydrogel could active modulate the opposite release behaviors of doxorubicin (DOX) and bovine serum albumin (BSA) in different pH medium. The smart UV-crosslinkable chitosan hydrogel via click chemistry might provide a new drug carrier for active modulating opposite drug release behaviors.

通过化学修饰的UV可交联壳聚糖水凝胶的数量已引起越来越多的关注，但是大多数这些壳聚糖水凝胶失去了pH响应性能，因为壳聚糖中的大量氨基（‒NH ₂）与其他官能团反应而被消耗掉了。为了构建pH响应型可交联的壳聚糖水凝胶，以主动调节具有所需行为的药物释放，合成了通过保护/去保护策略对氨基进行C ₆ -OH选择性修饰的壳聚糖，C ₆位上的烯丙基和C上的氨基₂该位点赋予壳聚糖分别具有UV交联能力和pH响应性。通过图案化的微凝胶和体内原位形成的水凝胶，证明了通过“硫醇-烯”点击化学技术以低剂量紫外线照射（4 mW / cm ²）进行快速紫外线交联凝胶化（30 s）。水凝胶的溶胀和收缩可以在不同的pH介质中调节阿霉素（DOX）和牛血清白蛋白（BSA）的相反释放行为。通过点击化学的智能的紫外线可交联的壳聚糖水凝胶可能为主动调节相反的药物释放行为提供一种新的药物载体。