Ultrasensitive sensor arrays for multiplexed protein biomarker detection and disease diagnostics

This feature review article summarizes research activities in our laboratories over the past two decades developing microfluidic sensor arrays for disease biomarkers using nanomaterials and other advanced features to achieve unprecedented sensitivity in biomedical samples. We focus here mainly on detecting panels of protein biomarkers with high selectivity and sensitivity for diseases such as cancer and neurodegenerative disorders. These systems evolved from microfluidic systems with individual components such as pump, sample injector, detection array, etc. into 3-D printed arrays providing a single device with integrated sample, reagent and detection chambers. LODs at or below 1 fg mL^-1 were achieved in nearly all approaches by paying careful attention to incorporating nanoparticle-enhanced signal development on the sensors, and advanced reagents such as poly-HRP and femto-luminol that also enhance signal output.