Microfluidic-based plasmonic microneedle biosensor for uric acid ultrasensitive monitoring

Uric acid (UA) is considered a potential risk factor in the causation or progression of kidney disease. Capabilities in personalized health monitoring enabled by capture and quantitative analysis of uric acid in the interstitial fluid could make up for the limitations of approach assessment of blood samples. Herein, we report a microfluidic−based wearable plasmonic microneedle sensor for interstitial fluid (ISF) sampling and minimally invasive uric acid monitoring. Under the force of the negative pressure generated by finger push. The hollow microneedle array could extract and deliver subcutaneous fluids to the sensing chamber by a microfluidic channel for SERS detection. The SERS sensing chip based on three-dimensional (3D) gold nanoarrays was found to have excellent reproducibility with 5.96% RSD. This high−density microarray showed ultrasensitive and label-free detection of uric acid molecules with a detection limit of 0.51 µM and enable fast identification of target molecules by integration with a handheld Raman spectrometer. The sensing platform may help bring unlimited possibilities for efficient medical healthcare and early disease prevention in daily life.