Qu Fengjin, Ma Xiaoyan, Gautrot Julien E
Center for Regenerative and Reconstructive Medicine, Med-X Institute, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China; Department of Applied Chemistry, School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an, 710072, China; Institute of Bioengineering, Queen Mary University of London, Mile End Road, London, E1 4NS, UK; School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
Department of Applied Chemistry, School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an, 710072, China.
Biosens Bioelectron. 2021 May 1;179:113045. doi: 10.1016/j.bios.2021.113045. Epub 2021 Feb 18.
The ability to reversibly switch bioelectrocatalytic sensors is attractive for the design of biomonitoring platforms displaying a complex environmental response, or for the protection of biosensors. However, the retention of reversible biocatalytic properties upon multiple environmental cycles, with broad detection range, low signal-to-noise and limit of detection remains challenging. In this report, we demonstrate the precise positioning of the enzyme glucose oxidase within block-copolymer brush nanostructures, via the re-initiation of N-isopropylacrylamide (NIPAM) polymerisation from enzyme-decorated poly(dimethylaminoethyl methacrylate) (PDMAEMA) blocks. We find that the precise design of polymer brush grafting density, thickness and crosslinking of the PNIPAM block enables the stable positioning of biocatalytic sites close to electrode surfaces. The control of the polymer brush nanostructure, its conformation and the distribution of biocatalytic sites is characterised via a combination of in situ ellipsometry, X-ray photoelectron spectroscopy, grazing angle FTIR and surface plasmon resonance. In turn, cyclic voltammetry and electrochemical impedance spectroscopy demonstrate that such control of the polymeric nanostructures confers a unique combination of low limit of detection (23.9 μM), a broad dynamic range of glucose sensing (0.05-12.8 mM) and true "OFF" state upon pH or thermal stimulation, whilst retaining excellent performance over repeated switching cycles of the sensor. Therefore, hierarchical biocatalytic polymer brushes display unique properties for the design of responsive biosensors and complex multi-functional gating platforms.
对于设计能够呈现复杂环境响应的生物监测平台或用于生物传感器的保护而言，可逆切换生物电催化传感器的能力颇具吸引力。然而，在多个环境循环中保持具有宽检测范围、低信噪比和检测限的可逆生物催化特性仍然具有挑战性。在本报告中，我们通过从酶修饰的聚（甲基丙烯酸二甲氨基乙酯）（PDMAEMA）嵌段重新引发N-异丙基丙烯酰胺（NIPAM）聚合反应，证明了葡萄糖氧化酶在嵌段共聚物刷纳米结构中的精确定位。我们发现，PNIPAM嵌段的聚合物刷接枝密度、厚度和交联的精确设计能够使生物催化位点稳定地定位在靠近电极表面的位置。通过原位椭偏仪、X射线光电子能谱、掠角傅里叶变换红外光谱和表面等离子体共振相结合的方法，对聚合物刷纳米结构、其构象以及生物催化位点的分布进行了表征。反过来，循环伏安法和电化学阻抗谱表明，这种对聚合物纳米结构的控制赋予了低检测限（23.9 μM）、宽葡萄糖传感动态范围（0.05 - 12.8 mM）以及在pH或热刺激下真正的“关闭”状态的独特组合，同时在传感器的重复切换循环中保持优异性能。因此，分级生物催化聚合物刷在设计响应性生物传感器和复杂的多功能门控平台方面具有独特性能。
