| Swine transmissible gastroenteritis virus（TGEV）is characterized by short incubation period,rapid transmission and 100%mortality rate of infected piglets.Therefore,it is of great significance to develop a fast,sensitive,reliable and inexpensive detection method to realize early screening of TGEV,which can reduce the loss of pig industry.Loop-mediated isothermal amplification（LAMP）technique can amplify nucleic acid samples with low concentration at the early stage of infection.The novel electrochemical sensing technology has the advantages of fast analysis speed,sensitive detection and simple operation,which is an effective method for quantitative detection of LAMP products.In view of the above advantages,in this thesis,a series of new photoelectrochemical（PEC）sensing platforms that can quantitatively detect TGEV are designed based on LAMP technology to realize in-situ signal amplification.The main research work is as follows:1.Firstly,the electrochromic（EC）region,electron injection（EI）region and conductive channel are integrated on a chip doped indium tin fluoride（FTO）by laser etching technology.A specially designed TGEV primer was fixed in the EI region,which had been modified with Zn O nanords（Zn O NRs）,and the target gene was multiplied within 40 min by in-situ LAMP reaction.Under light conditions,the photogenerated electrons generated by Zn O NRs will flow to the EC region that has been modified electrodeposited Prussian Blue（PB）,resulting in the reduction of PB to Prussian White（PW）,which produces a significant visual difference.In other words,semi-quantitative detection is completed by observing PB color with naked eyes,and its gray value is read for quantitative detection.In the range of 7.5 fg/μL～0.75μg/μL,the gray value of EC detection region showed a good linear relationship with the logarithm of TGEV concentration,and the detection limit was 2.5 fg/μL（S/N=3）.The in-situ LAMP-photo-electrochromic sensing platform realizes the visual quantitative detection of TGEV.2.To further improve the sensitivity of TGEV detection,this work used Cd S hollow spheres（Cd S HS）with excellent photoelectric performance as photoanode material,Cu2O/Cu O as photocathode material,and fixed specific TGEV primers on the photoanode,to construct a photoassisted bipolar fuel cell（PFC）self-powered supply sensing platform.Then in-situ LAMP reaction was performed.In the range of 0.075 fg/μL to 7.5 ng/μL,the output power density showed a good linear relationship with the logarithm of TGEV concentration,and the detection limit was as low as 0.025 fg/μL（S/N=3）.The quantitative detection range and detection limit of the in-situ LAMP-photoassisted bipolar PFC self-powered sensing platform for TGEV are significantly better than those in the previous chapter,and it has high detection sensitivity.3.Based on the above studies,in this work,combined with the simple and intuitive characteristics of photo-electrochromic and the advantages of PFC self-powered sensing platform without external power supply and high sensitivity,the in-situ LAMP-visualization/PFC self-powered dual-mode output sensing platform was constructed.Cd S nanoparticles（Cd S/Zn O NRs）modified with highly photoactive Zn O NRs were used as photoanodes and PBs as cathodes to construct PFC sensing substrates.Two kinds of signal output can be achieved after in-situ LAMP reaction on the photoanode.One is the semi-quantitative detection of visual signal caused by the discoloration of PB.The other is the PFC power density electrical signal collected by electrochemical workstation.The output power density and the logarithm of TGEV concentration show a good linear relationship in the detection range of 0.075 fg/μL～7.5 ng/μL,and the detection limit is 0.025 fg/μL（S/N=3）.This multi-signal output sensing platform provides more options for quantifying the detection results.Moreover,the two methods can verify each other,which meets the needs of different scenarios and improves the reliability of detection. |
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