Resistive sensing techniques have recently emerged as a powerful tool to sensitively detect proteins of interest. However, detecting intracellular proteins present in cell-derived lysates remains largely unexplored. Here, a resistive sensing technique was utilized to develop a biosensor for the detection of the autophagy-related LC3 protein using three different resistive transducers. Microfiber-, paper- and carbon nanofiber-based transducers were compared to determine optimal sensitivity. The microfiber- and paper-based transducers utilized a conductive poly-pyrrole, co-polymerized with carboxylic acid functional 3-thiopheneacetic acid, allowing for effective cross-linking between the conductive coated substrates and LC3 antibodies using glutaraldehyde as the cross-linking agent. Anti-LC3 antibodies were immobilized on the highly conductive carbon nanofiber using adsorbed 1-pyrenebutyric acid and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride as the cross-linking agent. A resistive sensor capable of mediating the protein-antibody binding and accurately measuring a change in conductivity of the transducers was designed and manufactured. The portable sensor was integrated with a computer to generate and display measured results via a user-friendly interface. The various transducing elements were added to the sensor where LC3 detection took place. All three transducers proved effective at detecting LC3 protein in the solution buffer and were capable of distinguishing between different concentrations of LC3 protein in a highly sensitive manner. The results highlight how the unique combination of transducer- and system design, in combination with resistive sensing enables the rapid, robust and accurate detection of the LC3 protein, reporting on a critical biological process, here autophagy.

中文翻译：

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用于检测自噬中 LC3 蛋白的电阻式生物传感器

电阻传感技术最近已成为灵敏检测目标蛋白质的有力工具。然而，检测细胞衍生的裂解物中存在的细胞内蛋白质在很大程度上仍未得到探索。在这里，利用电阻传感技术开发了一种生物传感器，用于使用三种不同的电阻传感器检测自噬相关的 LC3 蛋白。对基于微纤维、纸和碳纳米纤维的换能器进行了比较，以确定最佳灵敏度。超细纤维和纸基换能器利用导电聚吡咯，与羧酸官能 3-噻吩乙酸共聚，允许使用戊二醛作为交联剂在导电涂层基材和 LC3 抗体之间进行有效交联。使用吸附的 1-芘丁酸和 1-乙基-3-（3-二甲基氨基丙基）碳二亚胺盐酸盐作为交联剂，将抗 LC3 抗体固定在高导电性碳纳米纤维上。设计并制造了一种能够介导蛋白质-抗体结合并准确测量换能器电导率变化的电阻传感器。便携式传感器与计算机集成，通过用户友好的界面生成和显示测量结果。各种换能元件被添加到发生 LC3 检测的传感器中。所有三种传感器都证明在检测溶液缓冲液中的 LC3 蛋白方面是有效的，并且能够以高度灵敏的方式区分不同浓度的 LC3 蛋白。