Mao Xiaoxia, Chen Guifang, Wang Zihan, Zhang Yuanguang, Zhu Xiaoli, Li Genxi
Center for Molecular Recognition and Biosensing , School of Life Sciences , Shanghai University , Shanghai 200444 , China . Email:
School of Life Sciences , Anqing Normal University , Anqing 246011 , China.
Chem Sci. 2017 Nov 22;9(4):811-818. doi: 10.1039/c7sc03716c. eCollection 2018 Jan 28.
Hydrogels are of great interest in the field of biosensing for their good biocompatibility, plasticity, and capability of providing 3D scaffolds. Nevertheless, the application of hydrogels has not been linked with broad surface biosensing systems yet. To overcome the limitations, here for the first time, surface-immobilized pure DNA hydrogels were synthesized using a surficial primer-induced strategy and adopted for biosensing applications. The DNA hydrogel 3D scaffold is successfully constructed on a transparent ITO electrode, which facilitates both colourimetric and electrochemical measurements. Results show that the hydrogel is able to wrap enzymes solidly and exhibits favourable stability under different conditions. Owing to the free diffusion of the micromolecular targets throughout the hydrogel, while isolating the enzymes from the macromolecular interferences outside the hydrogel, the direct colourimetric and electrochemical detection of hydrogen peroxide and bilirubin in serum is achieved. The detection limit of hydrogen peroxide in serum is 22 nM by colourimetric analysis and 13 nM by electrochemical measurement. The detection limit of bilirubin is 32 nM, a favourable limit that could be used in jaundice diagnosis. In addition, the enzyme@hydrogel can be easily regenerated and the catalytic activity is retained for a few cycles, thus allowing the recycling of the hydrogel-based biosensing system. The successful integration of DNA hydrogels with surface biosensing systems will greatly expand the applications of hydrogels for diagnostic and environmental monitoring purposes.
水凝胶因其良好的生物相容性、可塑性以及提供三维支架的能力，在生物传感领域备受关注。然而，水凝胶的应用尚未与广泛的表面生物传感系统相关联。为了克服这些限制，本文首次采用表面引物诱导策略合成了表面固定的纯DNA水凝胶，并将其应用于生物传感。DNA水凝胶三维支架成功构建在透明ITO电极上，便于比色和电化学测量。结果表明，该水凝胶能够牢固包裹酶，并在不同条件下表现出良好的稳定性。由于小分子靶标在整个水凝胶中自由扩散，同时将酶与水凝胶外的大分子干扰物隔离开来，实现了血清中过氧化氢和胆红素的直接比色和电化学检测。血清中过氧化氢的比色分析检测限为22 nM，电化学测量检测限为13 nM。胆红素的检测限为32 nM，这是一个可用于黄疸诊断的良好限值。此外，酶@水凝胶易于再生，催化活性可保留几个循环，从而实现基于水凝胶的生物传感系统的循环利用。DNA水凝胶与表面生物传感系统的成功整合将极大地扩展水凝胶在诊断和环境监测方面的应用。
