Superwettable microchips with improved spot homogeneity toward sensitive biosensing.

The high-quality spots in microchips are prerequisites for sensitive and accurate detection of biomarkers. In this work, the superwettable micropattern was constructed by introducing superhydrophilic microwells onto a superhydrophobic substrate. The sample can distribute homogeneously within the well-designed superhydrophilic microwells after droplet evaporation and form homogeneous deposit spots, which can be ascribed to the enhanced Marangoni effect in superwettable micropattern and the suppressed outward flow by 3D nanodendritic silica structure. Based on the improved homogeneity of spots, sensitive and accurate fluorescence readout could be obtained. The free prostate-specific antigen (f-PSA) microchip based on the superwettable micropattern was developed. This superwettable f-PSA microchip exhibits high sensitivity, excellent specificity and long-term stability, and a limit of detection as low as 10fgmL-1 is achieved. Moreover, the superwettable f-PSA microchip can accurately detect human serum samples with excellent correlations with chemiluminescence immunoassay in the clinic, demonstrating its great potential as a sensitive and reliable sensing platform for biological analysis and clinical diagnosis.