A novel non-enzyme electrochemical biosensor for the rapid detection of Gram-positive bacteria has been constructed that relys on a stable and efficient combination between the peptidoglycan layer and platinum-nickel-copper nanocubes (Pt-Ni-Cu NCs). Briefly, bacteria were first captured by a specific antibody. Then, the electrochemical signal materials (Pt-Ni-Cu NCs) were bound to the bacteria peptidoglycan layer using specific structural and surface features. The rapid and sensitive bacterial detection was then achieved using intrinsic electrochemical characteristics and superoxidase-like activity of the Pt-Ni-Cu NCs. Moreover, the nature of peptidoglycan covering the whole bacteria provided the premise for signal amplification. Under optimal conditions, the electrochemical signal variation was proportional to the concentration of bacteria ranging from 1.5 × 102 to 1.5 × 108 CFU/mL with a detection limit of 42 CFU/mL using a working potential of − 0.4 V. This electrochemical biosensor has been successfully applied to detect bacteria concentrations in urine samples, and the recoveries range from 90.4 to 107%. The proposed biosensor could be applied for broad-spectrum detection of Gram-positive bacteria since most Gram-positive bacteria possess a thick peptidoglycan layer. The developed electrochemical biosensing strategy might be used as a potential tool for clinical pathogenic bacteria detection and point-of-care testing (POCT).

中文翻译：

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基于肽聚糖和铂-镍-铜纳米立方体的新型电化学生物传感器用于革兰氏阳性菌的快速检测

已经构建了一种用于快速检测革兰氏阳性菌的新型非酶电化学生物传感器，该传感器依赖于肽聚糖层和铂-镍-铜纳米立方体 (Pt-Ni-Cu NCs) 之间稳定有效的组合。简而言之，细菌首先被特定抗体捕获。然后，电化学信号材料（Pt-Ni-Cu NCs）使用特定的结构和表面特征与细菌肽聚糖层结合。然后利用 Pt-Ni-Cu NCs 的固有电化学特性和类超氧化物酶活性实现了快速灵敏的细菌检测。此外，覆盖整个细菌的肽聚糖的性质为信号放大提供了前提。在最佳条件下，电化学信号变化与细菌浓度成正比，范围为 1.5 × 102 至 1.5 × 108 CFU/mL，使用 - 0.4 V 的工作电位检测限为 42 CFU/mL。该电化学生物传感器已成功应用于检测尿样中的细菌浓度，回收率在 90.4% 到 107% 之间。由于大多数革兰氏阳性菌具有厚厚的肽聚糖层，因此所提出的生物传感器可用于革兰氏阳性菌的广谱检测。开发的电化学生物传感策略可用作临床病原菌检测和即时检测 (POCT) 的潜在工具。这种电化学生物传感器已成功应用于检测尿样中的细菌浓度，回收率范围为 90.4% 至 107%。由于大多数革兰氏阳性菌具有厚厚的肽聚糖层，因此所提出的生物传感器可用于革兰氏阳性菌的广谱检测。开发的电化学生物传感策略可用作临床病原菌检测和即时检测 (POCT) 的潜在工具。这种电化学生物传感器已成功应用于检测尿样中的细菌浓度，回收率范围为 90.4% 至 107%。由于大多数革兰氏阳性菌具有厚厚的肽聚糖层，因此所提出的生物传感器可用于革兰氏阳性菌的广谱检测。开发的电化学生物传感策略可用作临床病原菌检测和即时检测 (POCT) 的潜在工具。