Hydrogel Micropattern Incorporating Nanostructures for Fluorescence-based Biosensing

Different fluorescence biosensor based on hydrogel microstructures incorporating different nanostructures are introduced in this symposium. First, the quantum dot (QD)–enzyme conjugates were entrapped within the... [ view full abstract ]

Different fluorescence biosensor based on hydrogel microstructures incorporating different nanostructures are introduced in this symposium. First, the quantum dot (QD)–enzyme conjugates were entrapped within the poly(ethylene glycol) (PEG)-based hydrogel microstructures. Glucose oxidase (GOX) and alcohol oxidase (AOX) were chosen as the model oxidase enzymes, conjugated to carboxyl-terminated CdSe/ZnS QDs, and entrapped within the hydrogel microstructures, which resulted in a fluorescent hydrogel microarray that was responsive to glucose or alcohol. The hydrogel-entrapped GOX and AOX were able to perform enzyme-catalyzed oxidation of glucose and alcohol, respectively, to produce H2O2, which subsequently quenched the fluorescence of the conjugated QDs. Second, we developed a novel silver-based MEF biosensing platform that consisted of poly(ethylene glycol)(PEG) hydrogel microstructures entrapping silica-coated AgNPs (Ag@SiO2). AgNPs were coated with different thickness of silica to optimize the MEF effects. As a model system, the fluorescence detection of glucose by a sequential bi-enzymatic reaction was chosen. For this analysis, hydrogel microstructures entrapping glucose oxidase (GOX), peroxidase (POD) and Ag@SiO2 were prepared by a simple photopatterning process. We took advantage of the MEF from Ag@SiO2 within the hydrogel microstructures to improve the performance of the fluorescence detection device. Finally, describes the design and fabrication of a microdevice as a new platform for highly sensitive MMP-9 detection. For enhanced MMP-9 detection, fluorescently labeled MMP-9-specific peptides were immobilized onto an electrospun nanofiber matrix that was framed with hydrogel micropatterns via photolithography. Due to the huge surface area of the nanofiber and small dimensions of the microsystem, a faster response time (30 minutes) and lower detection limit (10 pM) could be achieved.