Research Center for Analytical Sciences, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin, 300071, PR China.
Research Center for Analytical Sciences, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin, 300071, PR China.
Biosens Bioelectron. 2022 Aug 15;210:114290. doi: 10.1016/j.bios.2022.114290. Epub 2022 Apr 19.
A portable, cost-effective and storable DNA-gold nanoparticle (AuNP) hybrid hydrogel film based biosensing system was developed, with AuNPs serving as both the crosslinking units of the film and the signaling units. Using a layer-by-layer assembly method, hydrogel film composed of three-dimensional hydrophilic network of densely packed AuNPs interconnected by responsive DNA structures was constructed onto a glass slide. By programming the sequence of DNA structures, target-responsive hybrid films were constructed. As a proof of concept, the sequence of a substrate DNA which can be identified and cleaved by Pb-dependent DNAzyme was encoded to construct Pb-responsive DNA-AuNP hybrid hydrogel film. The high-density packing of AuNPs as signal substances significantly improved the sensitivity of the ultrathin film biosensing system while reduced the cost of expensive DNA materials. A hydrogel film composed of 10 layers of assembled DNA-AuNP structures generated sufficient visual colorimetric signals for Pb detection, with a detection limit of 2.6 nM. By introducing UO-dependent DNAzyme, the system could be further applied in the sensitive and selective detection of UO, with a detection limit of 10.3 nM. Compared with bulk-sized DNA hydrogel biosensing systems, the DNA-AuNP hydrogel film biosensing system exhibited faster response thanks to the sub-micrometer ultrathin film structures. Moreover, the protection of fragile non-covalently crosslinked DNA films with solid slides also facilitated the portable application and long-term storage of the resulting biosensing system, with 95% of the response signal retained after three months of storage. The DNA-AuNPs hydrogel film biosensing system is highly promising for future rapid on-site detection applications.
一种便携式、经济高效且可储存的 DNA-金纳米粒子 (AuNP) 混合水凝胶薄膜基生物传感系统已被开发出来，其中 AuNP 既作为薄膜的交联单元，也作为信号单元。通过层层组装方法，构建了由通过响应性 DNA 结构相互连接的密集堆积 AuNP 的三维亲水网络组成的水凝胶薄膜。通过对 DNA 结构的序列进行编程，可以构建目标响应性混合薄膜。作为概念验证，编码了可以被 Pb 依赖性 DNA 酶识别和切割的底物 DNA 的序列，以构建 Pb 响应性 DNA-AuNP 混合水凝胶薄膜。作为信号物质的高密度 AuNP 包封显著提高了超薄薄膜生物传感系统的灵敏度，同时降低了昂贵 DNA 材料的成本。由 10 层组装的 DNA-AuNP 结构组成的水凝胶薄膜产生了足够的用于 Pb 检测的可见比色信号，检测限为 2.6 nM。通过引入 UO 依赖性 DNA 酶，该系统可以进一步应用于 UO 的灵敏和选择性检测，检测限为 10.3 nM。与块状 DNA 水凝胶生物传感系统相比，由于亚微米级超薄薄膜结构，DNA-AuNP 水凝胶薄膜生物传感系统表现出更快的响应速度。此外，通过将易碎的非共价交联 DNA 薄膜固定在固体载玻片上，也便于便携式应用和长期储存，经过三个月的储存，响应信号保留了 95%。DNA-AuNPs 水凝胶薄膜生物传感系统具有广阔的应用前景，非常适合未来的快速现场检测应用。
