A bipolar Electrode-Electrochemiluminescence sensor for Salmonella typhimurium detection based on β-cyclodextrin Host-Guest recognition

• Published in: Microchemical journal 2023-10, Vol.193, p.109191, Article 109191
• Main Authors: Xu, Mingyao, Chen, Yin, Fei, Yunjie, Lv, Fenglan, Xiong, Xiaohui, Liu, Yuanjian
• Format: Article
• Language: English
• Subjects: BPE-ECL; Host–guest recognition; S. typhimurium; β-CD
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2023.109191

Schematic diagram of BPE-ECL biosensor for S. typhimurium detection based on β-CD host–guest identification. [Display omitted] •A BPE-ECL sensor was constructed for S. typhimurium detection based on β-CD host–guest recognition.•The host–guest molecular recognitions are dependent on their molecular structure but not covalent bonds.•The BPE-ECL sensor has a low detection limit of 10 CFU mL−1 and a detection range of 10–105 CFU mL−1. A bipolar electrode electrochemiluminescence (BPE-ECL) with β-cyclodextrin (β-CD) host–guest recognition was constructed for the rapid detection of Salmonella typhimurium (S. typhimurium). Firstly, the sulfhydryl β-CD (SH-β-CD, with inner diameter size: 6.0–6.5 Å) was assembled on the gold-plated cathode of BPE. Ferrocene (Fc, length: 3.5 Å; width: 4.4 Å) labelled signal probe and parts Fc-aptamer complement each other to form a double-stranded DNA (dsDNA). Due to its large size, the dsDNA with a double Fc (width > 8.8 Å) could not be embedded into the cavities of β-CD. In the presence of S. typhimurium, Fc-aptamer bond specifically to S. typhimurium, and the signal probe was shed from the dsDNA. Then, the signal probe (guest) was captured by the SH-β-CD (host) on the surface of the BPE. Due to the principle of spatial matching between Fc and SH-β-CD, a stable inclusion complex could be formed, which made Fc close to the cathode surface of the BPE. When a certain driving voltage was applied, Fc was oxidized to Fc+. The cathode surface of Fc+ would promote electron transfer, causing the [Ru(bpy)3]2+ at the anode emit light, and effectively convert the electrochemical signal into an ECL signal. 101-105 CFU mL−1S. typhimurium was positively correlated with Fc+ and ECL intensity, with a detection limit of 101 CFU mL−1. Therefore, S. typhimurium can be quantitatively detected by the electron transfer rate of the BPE.