Construction And Biosensing Applications Of Bioinspired Superwettable Interfaces

Biosensing technology is vital for early diagnosis of disease and clinical application.The last decades witnessed major advances in the development of biosensors.However,the accurate and sensitive detection of small-volume and low-concentration samples used for the disease diagnosis remains one of the challenges in the biosensing field.In addition,the spot with poor homogeneity and stability,the spreading-loss and cross-contamination of sample,the energy consumption of sample droplet transportation and other common problems in biosensors also restrict their development.The exploitation and construction of high-performance sensing interfaces are the key to the development of biosensor technology.Based on the above background,bioinspired superwettable interfaces were prepared through nanofabricating and controlling surface wettability.The basic science problems and properties of bioinspired superwettable interfaces were analysis theoretically.Their feasibility in biosensing and suitability in clinical diagnosis were investigated.The main contents are as follows,1)The high-quality spots in microchips are prerequisites for sensitive and accurate detection of biomarkers.Inspired by the structure of desert beetle,superwettable microarray chip was fabricated.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.Moreover,the superwettable f-PSA microchip can accurately detect human serum samples with excellent correlations with chemiluminescence immunoassay in the clinic.The as-designed superwettable microarray chips have great potential for early cancer diagnosis,multi-component detection and high-throughput analysis.2)Traditional fluorophores often suffer from the aggregation-caused quenching(ACQ)problem at high concentration or in aggregated state.Here,we developed an AIE-based superwettable microchip by combining the evaporation-induced enrichment of superwettable microchips and the aggregation-induced emission of AIEgens together into one chip.Benefitting from the synergistic effect of the above two mechanisms,the AIE molecules were enriched from the diluted solution via evaporation and aggregated and then realized the fluorescence enhancement.Based on the dual enhancement effect of the AIE-based superwettable microchip,microRNA-141(miR-141)can be detected with excellent reproducibility,sensitivity and specificity.The proposed AIE-based superwettable microchip will provide a simple fluorescence enhancement biosensing platform for rapid,multiplexed and high-throughput analysis of specific targets in environmental monitoring,food safety,medical diagnosis and related research areas,3)Directional transportation of liquid without energy input remains a challenge in microfluidic biochips for clinical detections.Bioinspired by the water-collecting behaviors of the cactus spine,superwettable asymmetrical microfluidic(SAM)chips were fabricated by integrating surface superwettability with geometric asymmetry.The SAM chips are capable of spontaneously,directionally transporting the droplet without need of any external energy input,even anti-gravity.The gradient of the Laplace pressure arising from the geometric asymmetry of SAM chip is the main driving force.The multi-microchannel SAM chips with parallel detection zones realize the sensitive PSA detection.Moreover,the accurate PSA detection in clinical serum samples from prostate cancer patients was also achieved.This work unravels the mechanism of directional liquid transportation without energy input,provides new insights for the fabrication of simple microfluidic devices and have great potential in multicomponent biosensing and clinical diagnosis.