A simple single‐step fabrication of a novel biocomposite electrode was used for cholesterol sensing through direct electron transfer. The bio‐composite was prepared by polypyrrole, green reduced graphene oxide (gRGO) and cholesterol oxidase (ChOx). The graphene oxide (GO) was “green” reduced, with the Paederia foetide (PFL) plant extract at 60 °C to improve its biocompatibility. The adherence of gRGO to the electrode surface was improved through its co‐deposition during electro‐polymerization of pyrrole. Interestingly, the enzyme ChOx also could be immobilized during this co‐deposition process, resulting in one step biosensor fabrication. The optimization of electrochemical deposition parameters on glassy carbon electrode for this enzymatic bioelectrode (ChOx‐gRGO‐PPy/GCE) has resulted in excellent sensitivity (1095.3 μA mM⁻¹ cm⁻²), wide linear range (0.01–6 mM), and low detection limit (3.78 μM) of cholesterol. Also, the Dubinin‐Radushkevitch (D−R) adsorption study revealed the occurrence of physisorption (ϵ=3.35) process in this bioelectrode, confirming diffusion‐controlled reaction. Reproducibility of electrodeposition procedure, impeccable selectivity in the presence of interferrants, repeatability for multiple use and long‐term stability for practical use were also ensured. This could be used to construct the cost‐effective device for cholesterol diagnosis.

中文翻译：

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基于聚吡咯，绿色还原氧化石墨烯和胆固醇氧化酶的复合电极直接电子转移胆固醇生物传感器的一步制备

一种新颖的生物复合电极的简单一步制造用于通过直接电子转移进行胆固醇感测。该生物复合材料由聚吡咯，绿色还原氧化石墨烯（gRGO）和胆固醇氧化酶（ChOx）制备。氧化石墨烯（GO）被Paederia foetide还原为“绿色”（PFL）植物提取物在60°C时可改善其生物相容性。通过在吡咯的电聚合过程中进行共沉积，可以改善gRGO在电极表面的附着力。有趣的是，在共沉积过程中也可以固定酶ChOx，从而一步完成了生物传感器的制造。对于此酶促生物电极（ChOx-gRGO-PPy / GCE）在玻璃碳电极上的电化学沉积参数的优化产生了出色的灵敏度（1095.3μAmM ^-1  cm ^-2），宽线性范围（0.01–6 mM）和低胆固醇检测限（3.78μM）。同样，Dubinin-Radushkevitch（DR）吸附研究表明在该生物电极中发生了物理吸附（ϵ = 3.35）过程，证实了扩散控制的反应。还确保了电沉积程序的可重复性，存在干扰物时无可挑剔的选择性，多次使用的可重复性以及实际使用的长期稳定性。这可用于构建具有成本效益的胆固醇诊断设备。