| Multiplexed immunoassay of biomarkers has recently attracted considerable interest dueto its advantages in early screening of diseases, evaluating the extent of diseases, andmonitoring the response of diseases to therapy. To date, however, the primary and scantyimmunoassay for the qualitative analysis of multiplex analytes on μ-PADs is colorimetricmethod. Sensitive and quantitative immunoassay is still needed when a “yes”or “no” answeris insufficient and the level of an analyte in real biological sample is important for simple,rapid, low-cost POCT, public health and environmental monitoring. However, they are oftennot applicable in developing countries and resource-poor countries and regions, because theseanalytical systems are too expensive, large, complicated, and dependent on specificinfrastructures and professional operation personnel. Therefore, it is of considerable interestto the further research for rapid, simple, sensitive and accurate alternative methodology fordetermination of tumor markers.In this paper, to reliaze the point of care testing, rapid and portable determination ofcancer markers in the body fluid, we combine the applications of photoelectrochemical withmicrofluidics in the bioanalysis to develop microfluidic photoelectrochemical immunodevices.According to the construction study of the microfluidic photoelectrochemical immunodevices,the main research is as follows:(1) A favorable selective PEC sensor was fabricated on highly ordered and verticallyaligned AuNPs-modied TiO2NTs, utilizing a molecularly imprinted PoPD film as therecognition element. This strategy largely reduces the destructive effect of UV light and thephotogenerated h+of illuminated TiO2to template molecules. A detailed exploration of thestructural, optical, and PEC properties was carried out to gain some new insights into thefundamental mechanisms. The new PoPD and AuNPs-functionalized TiO2NTs has beensynthesized for application to PEC organophosphate pesticides sensing.(2)A novel lab-on-paper device, combining the sensitivity and low-cost of microfluidic PECanalytical origami device and the low-cost, stability, and selectivity of molecular imprintingtechnique, was developed. The construction of this PEC assay in the3D macro porous PWEshowed an enhanced PEC response under an external light source compared with the traditional at electrode. The proposed MPANI-Au-PWE on them-MPECOD could not only beimprinted as an artificial receptor for the selective recognition of other pesticides, drugs andproteins, but also be readily integrated with other signal reporting mechanisms on μ-PADs.(3) To fabricate a low-cost immunodevice, chromatographic paper and polymer film wereused as the substrate to develop electrochemical microfluidic paper-based analyticalimmunodevice to detect multiple cancer markers, and the principle for the determination wasinvestigated.(4) An ultrasensitive photoelectrochemical immunoassay was introduced into microfluidicpaper-based analytical devices based on a multiple electron transfer system for the first time,which was constructed using narrow-band-gap semiconductor nanoparticles (NPs),wide-band-gap semiconductor NPs, and an electron-accepting medium. With the aids of asimple home-made device-holder, the concentrations of carcinoembryonic antigenin realhuman serum samples was detected sensitively.(5) A photoelectrochemical immunoassay was introduced into a microfluidic paper-basedanalytical device equipped with a paper supercapacitor, based on a chemiluminescence lightsource and a digital multi-meter（DMM）. Furthermore, the photocurrent generated from thePWE could be detected sensitively by a DMM through the amplification of PSC, providing alow-cost, simple, portable, and disposable approach for detection and diagnosis in developingcountries, resource-limited and remote regions and allowing the expensive and sophisticatedelectrochemical workstation or lock-in amplifier to be abandoned. |
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