Yin Mengyuan, Zhang Yaxing, Liang Hanxue, Liu Chang, Bi Yanhui, Sun Juanjuan, Guo Weiwei
Research Center for Analytical Sciences, Tianjin Key Laboratory of Molecular Recognition and Biosensing, College of Chemistry, Nankai University, Tianjin 300071, China.
Anal Chem. 2024 Apr 2;96(13):5215-5222. doi: 10.1021/acs.analchem.3c05562. Epub 2024 Mar 20.
Stimuli-responsive DNA hydrogels have shown great potential in sensing applications due to their attractive properties such as programmable target responsiveness, excellent biocompatibility, and biodegradability. In contrast to the extensively developed DNA hydrogel sensing systems based on the stimuli-responsive hydrogel-to-solution phase transition of the hydrogel matrix, the quantitative sensing application of DNA hydrogels exhibiting smart shape deformations has rarely been explored. Moreover, bulk DNA hydrogel-based sensing systems also suffer from high material cost and slow response. Herein, free-standing bilayer polyacrylamide/DNA hybrid hydrogel films with programmable responsive properties directed by the sequence of functional DNA units have been constructed. Compared with bulk DNA hydrogels, these DNA hydrogel films with a thickness at the micrometer scale not only greatly reduce the consumption of DNA materials but also facilitate the mass transfer of biomacromolecular substances within the hydrogel network, thus favoring their sensing applications. Therefore, a target-responsive smart DNA hydrogel film-based sensor system is further demonstrated based on the large amplitude macroscopic shape deformation of the film as a visual signal readout. As a proof of concept, Pb or UO ion-responsive DNA units were introduced into the active layer of the bilayer hydrogel films. In the presence of Pb or UO ions, the occurrence of a cleavage reaction within the DNA units leads to the release of DNA segments from the hydrogel film, inducing a dramatic shape deformation of the film, and thus sensing of Pb or UO ions with high specificity is achieved based on measuring the bending angle changes of these smart free-standing films. These smart DNA hydrogel film sensors with target-programmable responsiveness, simple operation, and ease of storage may hold promise for future rapid on-site testing applications.
刺激响应性DNA水凝胶因其具有可编程的靶标响应性、优异的生物相容性和可生物降解性等吸引人的特性，在传感应用中显示出巨大潜力。与基于水凝胶基质的刺激响应性水凝胶到溶液相变而广泛开发的DNA水凝胶传感系统不同，对表现出智能形状变形的DNA水凝胶的定量传感应用很少被探索。此外，基于块状DNA水凝胶的传感系统还存在材料成本高和响应缓慢的问题。在此，构建了具有由功能性DNA单元序列指导的可编程响应特性的独立双层聚丙烯酰胺/DNA混合水凝胶膜。与块状DNA水凝胶相比，这些厚度在微米级的DNA水凝胶膜不仅大大减少了DNA材料的消耗，还促进了生物大分子物质在水凝胶网络内的传质，从而有利于它们的传感应用。因此，基于膜的大幅度宏观形状变形作为视觉信号读出，进一步展示了一种基于目标响应的智能DNA水凝胶膜传感器系统。作为概念验证，将Pb或UO离子响应性DNA单元引入双层水凝胶膜的活性层中。在存在Pb或UO离子的情况下，DNA单元内发生切割反应，导致DNA片段从水凝胶膜中释放出来，引起膜的剧烈形状变形，从而基于测量这些智能独立膜的弯曲角度变化实现对Pb或UO离子的高特异性传感。这些具有目标可编程响应性、操作简单且易于存储的智能DNA水凝胶膜传感器可能在未来的快速现场测试应用中具有前景。
