Hydrogels have been used extensively to deliver functional molecular cargos in response to external mechanical force. However, the intrinsic brittleness of gels restricts the applicable range of strain to 0.1, thus limiting the range of molecular release rate that may be controlled. Also, uncontrollable molecular diffusion, which is especially prominent in small molecules, reduces the role of mechanical stimulus on the release rate. As such, we hypothesized that these challenges would be resolved by combining cyclodextrin, which may form guest-host complexes with small molecular cargos, with a stretchable hydrogel system. We examined this hypothesis by synthesizing cyclodextrin acrylate and incorporating it into a polyacrylamide gel that can be stretched by 100% of its original length. In the absence of external stretching, hydrogels containing cyclodextrin acrylate with a degree of acryloyl group substitution (DS_A) of 2.3 presented a lower molecular release rate than hydrogels without cyclodextrin acrylate. More interestingly, the polyacrylamide-cyclodextrin hydrogel system displayed an increased molecular release rate corresponding to the degree of stretching, particularly in the gels containing cyclodextrin acrylate with a DS_A of 2.3. As such, this stretchable gel loaded with quinine was used to inhibit the growth of E. coli in lysogeny broth only when the gel was stretched. We believe the results of this study would be valuable for improving the quality of controlled molecular delivery and subsequent efficacy of molecular cargos.

水凝胶已被广泛用于响应于外部机械力而递送功能性分子货物。然而，凝胶的固有脆性将应变的适用范围限制为0.1，从而限制了可以控制的分子释放速率的范围。同样，不可控的分子扩散（在小分子中尤为突出）降低了机械刺激对释放速率的作用。因此，我们假设将环糊精与可伸展的水凝胶系统结合起来可以解决这些挑战，环糊精可能与小分子货物形成客体-宿主复合物。我们通过合成丙烯酸环糊精并将其并入可以拉伸其原始长度100％的聚丙烯酰胺凝胶中，检验了这一假设。在没有外部伸展的情况下，与没有环糊精丙烯酸酯的水凝胶相比，2.3的_A）呈现出更低的分子释放速率。更有趣的是，聚丙烯酰胺-环糊精水凝胶体系显示出与拉伸程度相对应的增加的分子释放速率，特别是在含有DS _A为2.3的环糊精丙烯酸酯的凝胶中。这样，仅当凝胶被拉伸时，这种装载有奎宁的可拉伸凝胶才被用来抑制大肠杆菌在溶菌性肉汤中的生长。我们相信这项研究的结果对于改善可控分子传递的质量和分子货物的后续功效将是有价值的。