Research On Microfluidic Chip Based On Nanogold Signal Amplification Mode

Microfluidic devices had the advantages of low-cost, automation and excellent chemical compatibility. So it had been widely appied in biological molecules detection and disease diagnosis. The main purpose of this study was based on gold nanoparticles （AuNPs） functionalized with a high molar ratio of horseradish peroxidase （HRP） for signal amplification and combined the PDMS and paper microfluidic devices for detection of biological molecules, which aim to establish a rapid sensitive detection methods. This thesis is divided into two parts, the first part is the review, which summarized the property, application and detection method of the microfluidic devices. The second part is as follows:1. Polydimethylsiloxane Microfluidic Chemiluminescence Immunodevice based on Gold Nanoparticles Amplification for Sensitive detection of Human Immunoglobin GA polydimethylsiloxane （PDMS） microfluidic chemiluminescence （CL） immunodevice for sensitive detection of human immunoglobin G （IgG） with the signal amplification strategy was developed in this work. The immunodevice was prepared by covalently immobilizing capture antibodies （Abs） on the silanized microchannel of microfluidic chip. Gold nanoparticles （AuNPs） functionalized with a high molar ratio of horseradish peroxidase （HRP） were used as an Ab label for signal amplification. Using a sandwich immunoassay, the multi-HRP conjugated AuNPs can catalyze the luminol-H₂O₂ CL system to achieve the high sensitivity. In addition, the double spiral flow-channel was adopted here, which can still contribute to the high sensitivity. Based on signal amplification strategy, the performance of human IgG tests revealed a lower detection limit （DL） of 0.03 ng/mL and showed an increase of 7.4-fold in detection sensitivity compared to a commercial Ab-HRP conjugation. This microfluidic immunodevice can provide an alternative approach for sensitive detection of human IgG in the field of clinic diagnostic and therapeutic.2. Paper-based Microfluidic Devices based on Gold Nanoparticles Amplification for Sensitive detection of AdenosinePaper-based microfluidic devices for sensitive detection of adenosine based on sigal amplification of aptamer-gold nanoparticles-horseradish peroxidase （Apt2-AuNPs-HRP） was developed in this work. Gold nanoparticles （AuNPs） functionalized with a high molar ratio of horseradishperoxidase （HRP） were used as a caputure DNA （Apt2） label for signal amplification. The conformational transition of aptamer induced by targe-aptamer complex contributes to decreases the color intensity. In this approach, The multi-HRP conjugated AuNPs catalyzed 3,3’,5, 5’-tetramethylbenzidine （TMB）-H₂O₂ colorimetric detection method was achieved high sensitivity. Based on the signal amplification strategy, the developed method could discriminate adenosine at a lower detection limit of 3.3×10-14mol/L and showed an increase of 12.4-fold compared to a commercial Apt2-HRP conjugation. This paper-based calorimetric analytical devices showd a promising potential in small biological molecules detection and disease diagnosis.