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영어

Surface enhanced Raman scattering (SERS) sensing has attracted considerable attention for ultrasensitive, highly specific and multiplex biomolecular assays. Recently, new optofluidic approaches have been developed for the reliable and reproducible on-chip SERS detection. These optofluidic systems have opened up possibilities of small sample requirements, fast mixing, and enhanced sensing signals. In accordance with these requirements, we here describe the development of an electrokinetic optofluidic SERS chip using the electro-active microwell for sensitive and multiplex SERS detection. This device allows for both efficient mixing to enhance the rate of binding between the SERS enhancers and the biomolecular targets and sample enrichment to improve detection sensitivity through the use of electroactive microwells. As another approach, we here present an optofluidic surface enhanced Raman spectroscopy (SERS) device for on-chip detection of vasopressin using an aptamer based binding assay. To create the SERS-active substrate, densely packed, 200 nm diameter, metal nanotube arrays were fabricated using an anodized alumina nanoporous membrane as a template for shadow evaporation. We explore the use of both single layer Au structures and multilayer Au/Ag/Au structures and also demonstrate a facile technique for integrating the membranes with all PDMS microfluidic devices. Using the integrated device, we demonstrate a linear response in the main detection peak intensity to solution phase concentration and a limit of detection on the order of 50 ng/mL. This low limit of detection is obtained with device containing the multilayer SERS substrate which we show exhibits a stronger Raman enhancement while maintaining biocompatibility and ease or surface reactivity with the capture probe.