加拿大滑铁卢大学Juewen Liu团队通过冷冻辅助将未修饰的二嵌段DNA接合到水凝胶纳米颗粒和整体上，用于DNA和Hg²⁺检测。 相关研究成果于2021年4月1日发表于国际顶尖学术期刊《德国应用化学》。

丙烯酸盐修饰的DNA是制备DNA功能化水凝胶最常用的试剂。

在聚丙烯酰胺水凝胶中，未改性的五腺嘌呤（A5）在冷冻聚合条件下8h内可达到75%的共轭效率。通过形成双链或其他折叠结构以及去除冷冻条件，降低了DNA掺入效率。通过设计含有A5片段的二嵌段DNA，连接了多种功能DNA序列。

这种水凝胶被设计用于超灵敏的DNA杂交和Hg2+检测，检测限分别为50μm和10 nM，证明了使用未修饰的DNA代替丙烯酰化物-DNA的可行性。同样的方法也适用于凝胶纳米颗粒和整体。

研究工作通过冷冻技术揭示了有趣的反应产物，并提供了一种将DNA连接到水凝胶上的经济有效方法。

附：英文原文

Title: Freezing‐assisted Conjugation of Unmodified Diblock DNA to Hydrogel Nanoparticles and Monoliths for DNA and Hg2+ Sensing

Author: Yuqing Li, Hang Gao, Zengyao Qi, Zhicheng Huang, Lingzi Ma, Juewen Liu

Issue&Volume: 2021-04-01

Abstract: Acrydite‐modified DNA is the most frequently used reagent to prepare DNA‐functionalized hydrogels. Herein, we show that unmodified penta‐adenine (A5) can reach up to 75% conjugation efficiency in 8 h under a freezing polymerization condition in polyacrylamide hydrogels. DNA incorporation efficiency was reduced by forming duplex or other folded structures and by removing the freezing condition. By designing diblock DNA containing an A5 block, various functional DNA sequences were attached. Such hydrogels were designed for ultrasensitive DNA hybridization and Hg2+ detection, with detection limits of 50 pM and 10 nM, respectively, demonstrating the feasibility of using unmodified DNA to replace acrydite‐DNA. The same method worked for both gel nanoparticles and monoliths. This work revealed interesting reaction products by exploiting freezing and has provided a cost‐effective way to attach DNA to hydrogels.

DOI: 10.1002/anie.202102330

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202102330