Construction Of New Single-droplet Chip System And Application In Biochemical Analysis

The biochemical analysis of single droplet microfluidic chip has good application prospects in the field of biomedicine,and the analysis samples include cells,chemical standard samples,food pesticide residues,macromolecular proteins,etc.Among them,the analysis of single-cell heterogeneity is the current research hotspot.The analysis based on single-droplet chip has the following advantages: Firstly,the droplet can provide an independent reaction chamber to avoid the interference from the surrounding environment;Secondly,the small size of the droplets allows for rapid accumulation of samples to detectable levels,while also greatly reducing the consumption of reagents;Third,single droplet has good monodispersity,which can be used for accurate quantitative analysis,cell or drug screening.However,traditional microdroplet chip manufacturing process is complex,high cost,high requirements for the operator's academic background,Thus,exploiting convenient and universal strategies of singlecell preparation while maintaining high-throughput single-cell patterning remains a challenge.In this paper,a novel single-droplet chip platform with non-traditional significance was constructed.The use of ultrathin metal microtemplates(UTmS)provides a platform for singlecell heterogeneity studies and operator convenience without complex processes and high costs.High throughput single cells can be prepared in 20 min by gravity-induced natural deposition without additional fixation,reaction cell and centrifugation on a chip with a thickness of only5 ?m.The single-cell through-hole rate is approximately 88% and the viability of the cell on substrate is approximately 96±1.7%.Next,we explored the SERS technology with excellent performance in the analysis of single droplets.However,due to the pinning effect and coffeering effect,the trace analysis ability of the traditional SERS platform was limited and femtomolar level ultrasensitive biochemical substance analysis could not be achieved.This system creatively proposes a novel rolling strategy to perform continuous rolling-assisted evaporation on superhydrophobic surfaces(CRESH),which overcomes the inherent limitations of the pinning effect between droplets and interfaces,improves the enrichment efficiency,and achieves the detection of trace analytes at the femtomolar level in a synergistic manner.The detection limit has been greatly reduced.A 50 ?L droplet based on CRESH can be eventually condensed into 200 ?m aggregate,and final sizes is independent of the initial droplet volume which shows significant condensation efficiency and application potential of lower detection limit,and plays a role in effective,simple,economical,efficient and ultrasensitive SERS detection.