Microfluidic Assays to Enhance Biodetection and Diabetes Research

Microfluidic;Porous hydrogel;Biodetection;High sensitivity;Diabetes;Autoantibodies;Biomedical engineering;Bioengineering, College of Engineering and Computer Science

Duan, KaiYi, Yasha ;

University of Michigan

关键词: Microfluidic;    Porous hydrogel;    Biodetection;    High sensitivity;    Diabetes;    Autoantibodies;    Biomedical engineering;    Bioengineering, College of Engineering and Computer Science;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/143525/Microfluidic%20Assays%20to%20Enhance%20Biodetection%20and%20Diabetes%20Research%20%28Kai%20Duan%29.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Expansion of biomarker detections with nuanced monitoring of disease states can deliver more effective, personalized medicine. Leveraging novel biomarkers in clinical settings requires higher sensitivity, shorter assay times, and increased specificity in protein detection. Standard ELISA involves multi-step preparations that extends the length and complexity of its protocol. Newer techniques using nanoplasmonics, fluorescence resonance energy transfer, single molecule detections, among others require specialized equipment and techniques. Here I report a novel method using immuno-functionalized, porous poly (ethylene) glycol diacrylate (PEGDA) hydrogel microspheres to enable rapid, high sensitivity antigen detection in arrayed microfluidics. I applied these microfluidic techniques to wound healing and diabetes motivated applications that illustrate their future potentials. In wound healing, Vascular endothelial growth factor (VEGF) promotes wound revascularization by stimulating angiogenesis, in addition to stimulatory effects on other wound cells. In our arrayed microfluidics, the technique incorporates antibody encapsulation, trapping, and flow perfusion on a single device to allow an integrated assay. The result showed that the convergence of tunable porous hydrogel with efficient microfluidics improved the sensitivity of the assay. The detection limit of this microfluidic porous microgel based assay was 0.9 pg/mL, with only 1+ hour of assay time, demonstrating a novel assay that exceed conventional technologies in terms of sensitivity and speed. In the multifaceted disease of diabetes, sensitive, single volume detections ofmultiple antibodies can provide immunoprofiling and early screening of at-risk patients. To advance the state-of-the-art suspension assays for diabetes antibodies, porous hydrogeldroplets were multiplexed in microfluidic serpentine arrays to enhance the detection of antibodies against insulin, glutamic acid decarboxylase (GAD), and insulinoma-associatedprotein 2 (IA-2). Optimization of assay protocol resulted in a shortened assay time of 2 h, with better than 20 pg mL detection limits across all three antibodies. Specificity and cross-reactivity tests showed negligible background, nonspecific antibody–antigen, andnonspecific antibody–antibody bindings. Multiplexed detections were able to measure within 15% of target concentrations at both low and high ranges. The technique enabled quantifications of as little as 8000 molecules in each 500 μm droplet using a singlevolume, multiplexed assay format, a breakthrough necessary for the adoption of diabetes panels for clinical screening and monitoring in the future. Also, the PEGDA hydrogel sensors is being applied in our latest diabetes project: Hypoxia-FFA synergy in beta cell impairment via multimodal microfluidics. To achieve the beta cell culture and precise detection of insulin, a porous PEGDA hydrogel biosensor thin film was developed for coating on microfluidic devices. This new spatial sensor is able to enhance the detection of secreted insulin transport, while mapping their release in beta cells cultured atop a gradient of oxygen concentrations. The optimization of this multimodal device resulted in a 200 um thickness sensor, shorten assay time of 2 hours, better than 50 pg/mL detection limits, and capable of sustaining better than 90% viability of beta cells.