Department of Analytical Chemistry, Faculty of Pharmacy, "Iuliu Hatieganu" University of Medicine and Pharmacy, 4 Pasteur Street, 400349 Cluj-Napoca, Romania.
Department of Infectious Diseases and Preventive Medicine, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Calea Manastur 3-5, 400372 Cluj-Napoca, Romania.
Biosensors (Basel). 2022 Jun 22;12(7):440. doi: 10.3390/bios12070440.
, an opportunistic Gram-negative bacterium, is one of the main sources of infections in healthcare environments, making its detection very important. N-3-oxo-dodecanoyl L-homoserine lactone (3-O-C-HSL) is a characteristic molecule of quorum sensing-a form of cell-to-cell communication between bacteria-in . Its detection can allow the determination of the bacterial population. In this study, the development of the first electrochemical aptasensor for the detection of 3-O-C-HSL is reported. A carbon-based screen-printed electrode modified with gold nanoparticles proved to be the best platform for the aptasensor. Each step in the fabrication of the aptasensor (i.e., gold nanoparticles' deposition, aptamer immobilization, incubation with the analyte) was optimized and characterized using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Different redox probes in solution were evaluated, the best results being obtained in the presence of [Fe(CN)]/[Fe(CN)]. The binding affinity of 106.7 nM for the immobilized thiol-terminated aptamer was determined using surface plasmon resonance. The quantification of 3-O-C-HSL was performed by using the electrochemical signal of the redox probe before and after incubation with the analyte. The aptasensor exhibited a logarithmic range from 0.5 to 30 µM, with a limit of detection of 145 ng mL (0.5 µM). The aptasensor was successfully applied for the analysis of real samples (e.g., spiked urine samples, spiked microbiological growth media, and microbiological cultures).
铜绿假单胞菌是一种机会性革兰氏阴性菌，是医疗环境中感染的主要来源之一，因此对其进行检测非常重要。N-3-氧代-十二烷酰基-L-高丝氨酸内酯（3-O-C-HSL）是细菌群体感应的特征分子——一种细菌之间的细胞间通讯形式。它的检测可以确定细菌种群。在本研究中，报道了用于检测 3-O-C-HSL 的首个电化学适体传感器的开发。经证实，经金纳米粒子修饰的碳基丝网印刷电极是适体传感器的最佳平台。使用循环伏安法、差分脉冲伏安法和电化学阻抗谱对适体传感器的各个制造步骤（即金纳米粒子沉积、适体固定化、与分析物孵育）进行了优化和表征。评估了溶液中的不同氧化还原探针，在存在 [Fe(CN)]/[Fe(CN)]时获得了最佳结果。使用表面等离子体共振法确定了固定化硫醇末端适体的结合亲和力为 106.7 nM。通过在与分析物孵育前后使用氧化还原探针的电化学信号对 3-O-C-HSL 进行定量。该适体传感器的对数范围为 0.5 至 30 µM，检测限为 145 ng mL（0.5 µM）。该适体传感器成功应用于实际样品的分析（例如，尿液样品加标、微生物生长培养基加标和微生物培养物）。
