Localized hydrodynamic flow confinement assisted nanowire sensor for ultrasensitive protein detection.

Affordable methods for ultra-sensitive biomarkers detection may improve the standard of living in resource-constrained countries. Nanowire biosensor is preponderant in ultra-sensitive protein detection. However, current strategies for nanowire sensor (NWS) fabrication often require sophisticated instruments, being inaccessible in less-resourced laboratories. Herein, we circumvent this challenge by developing a simple methodology, localized hydrodynamic flow confinement assisted nanowire sensor fabrication, enable the detection with limits of detection (LOD) for IgA and IgG measurement were 0.089 fg/mL and 0.93 fg/mL, respectively, demonstrating a 10-fold increase in detection sensitivity compared with the published NWS. Noteworthy, an X-Y positioner combined with a homemade microchemical pen (MCP) for tunable chemical deposition were sufficient to complete the fabrication of the nanowire biosensor without other expensive and demanding equipment. Overall, a particularly accessible, competitive, and low-cost approach of nanowire sensor fabrication for ultra-sensitive protein detection was developed, which could widely facilitate the application of nanowire biosensors. Besides, the nanowire sensor can also be employed to detect other analytes of interest by the use of different stimuli-responsive biosystems.