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The detection of transmissible gastroenteritis virus (TGEV) is of great significance to reduce the loss of pig industry. A LAMP-visualization/PFC self-powered dual-mode output sensor platform was constructed to detect TGEV by combining a simple and intuitive photoelectrochromic material with a highly sensitive PFC self-powered sensing platform without external power supply. The PFC sensing substrate was constructed using CdS nanoparticles modified ZnO NRs (CdS/ZnO NRs) as the photoanode, which exhibited high photoactivity, and Prussian blue (PB) as the cathode. After LAMP reaction on the optical anode, visual signals caused by PB discolorimetry can be detected semi-quantitatively, or PFC power density electrical signals collected by electrochemical workstation can be used. The output power density value is logarithm of TGEV concentration. The linear relationship was good within the detection range of 0.075 fg/μL-7.5 ng/μL, with a detection limit of 0.025 fg/μL (S/N = 3). This multi-signal output sensing platform provides more choices for quantifying TGEV detection results, and the two methods can be mutually verified, which meets the needs of different scenarios and improves the reliability of detection. It has a good effect in the actual sample detection, without the use of expensive and complex instruments, and has a broad application prospect. [Display omitted] • Dual-mode output sensor platform for TGEV detection was constructed. • Combination of visualization/PFC self-powered sensors and nucleic acid amplification. • Simple and intuitive visual color change without external power supply. • The chip with detection limit of 0.025 fg/μL, good selectivity and stability. [ABSTRACT FROM AUTHOR]

The outbreak of transmissible gastroenteritis virus (TGEV) will cause huge economic losses to the whole pig industry. Hence, there is urgent need to develop a rapid and ultrasensitive method for detection of TGEV. As a nucleic acid detection technique, loop-mediated isothermal amplification (LAMP) can achieve quantitative detection of targeted nucleic acids with high sensitivity and selectivity. Nevertheless, the signal outputs of LAMP method must be acquired by complicated instruments. In this work, we firstly developed a LAMP photochromic sensing chip for porcine TGEV detection by combination of the photochromic sensing chip and nucleic acid amplification. The detection signal was based on color change of electrochromic material rather than electrical signal, and thus the detection signal can be obtained by visualization without relying on complicated instrument. The entire test was performed with small fluorinated indium tin oxide electrodes modified with zinc oxide (ZnO) (a photocatalytic material) and Prussian blue (PB) (an electrochromic material). When photoinduced electrons produced by ZnO were injected into PB under light, the PB was reduced to Prussian white. The higher the concentration of TGEV, the more double-stranded DNA was produced after amplification. The amplified product produced greater impedance, and fewer electron was transferred, which affect the corresponding color change of PB. The sensing chip also showed highly sensitive response to TGEV, with the minimum limit of detection was determined to be 2.5 fg/μL. The sensing chip developed herein will provide a new avenue for DNA amplification detection by visualization. [ABSTRACT FROM AUTHOR]

• CdS hollow spheres as photoanode and Cu 2 O/CuO as photocathode materials. • Dual-photoelectrode photocatalytic fuel cell based self-powered biosensor. • In-situ loop-mediated isothermal amplification of TGEV. • No complex thermal cycles, no need for expensive instruments. • LAMP PFC-SPBs with a lower detection limit of 0.025 fg μL−1. Loop-mediated isothermal amplification (LAMP) as a nucleic acid detection technology has many advantages than conventional polymerase chain reaction in terms of sensitivity, specificity, and equipment requirements. And combining photocatalytic fuel cell (PFC) power density readout with high sensitivity, we developed a LAMP-based dual-photoelectrode photocatalytic fuel cell based self-powered biosensors (LAMP PFC-SPBs) for the ultra-sensitive detection of transmissible gastroenteritis virus (TGEV). In this sensor, the specially designed primers were immobilized on the photosensitive material CdS-modified sensing substrate with a distinct electrochemical signal and amplified TGEV within 1 h. A wide detection range of the LAMP PFC-SPBs was demonstrated, ranging from 0.075 fg μL−1 to 7.5 ng μL−1, with a lower detection limit of 0.025 fg μL−1. In-situ LAMP PFC-SPBS had great merits in simplicity (no complex thermal cycles, no need for expensive instruments), sensitivity, specificity, and provides a new perspective on the combination of nucleic acid amplification and electrochemistry. [ABSTRACT FROM AUTHOR]