Controllable Droplets Sliding Behaviors On Bio-inspired Slippery Surfaces And Their Biosensing Applications

Bio-inspired special wetted surfaces have been widely used in the fields of modern medicine,aerospace,industry,energy resource and other related fields due to their promising properties,such as self-cleaning,drag reduction,anti-wetting,anti-icing,antifouling,anti-reflection and so on.Recently,the biosensors based on wetting behavior have been attracted wide attention because of their potential application in the detection of cancer,small molecules,real time monitor biological warfare agent and other biomarkers,including protein,nucleic acid,toxic agent,et al.Under this background,we prepared series of slippery surfaces inspired by pitcher plant as substrate and biological droplet by rolling circle amplication(RCA)reaction triggered with detection molecule.The sequence of nucleic acid,type of lubricant and morphology of substrate were precisely designed.To investigate the adhesion between the droplet and the slippery surface,the sliding behavior of the droplet,such as sliding angle(SA),was introduced as output signal.Based on the difference of the sliding behavior of concentration dependent target on the bioinspired surface,the visual biochemical analysis and detection of the Point of Care Test(POCT)were realized.1.The manipulation on liquid phase regulation to tune the sliding behavior of droplet on slippery surface was developed.Six methods were explored to probe the mechanism between the droplet and lubricant.Critical sliding angles(CSA)were obtained for the detection of three kinds of cancer biomarkers and cells of cancer patients in viro.The chain length of DNA caused the hydrophobic exposure extent in the water-mediated system,then influenced the interfacial adhension between the droplet and lubricant,so SAs of biologocal droplet can be precisely controlled.It was first demonstrated that there was strong hydrophobic interaction between the short DNA fragments and lubricant than that long single strand DNA(ssDNA).The CSAs of droplets with targets,including hydrope biomarker adenosine triphosphates(ATP),cancer bioamarkers like microRNA and thrombin,and cells of prostate cancer(PC3),breast cancer(Hela)in viro were all provided when under specifically binding design.The mechanism of liquid phase regulation in this work was significance for the further design of liquid phase in droplet motion.Through designing DNA sequence of with different biomarkers,this detection with CSA as the signal output is of great significance for visual biosensing,especially for the people with color blindness or weak disease.2.The stragy for controlling liquid phase on droplet motion with temperature responsive was developed on Nepenthes inspired slippery surface.By manipulating the system of thermal induced the conformation of DNA in the liquid phase,then causing the exposure degree of the hydrophobic groups of ssDNA,the interface adhesion between droplets and SLIPs can be precisely and reversibly regulated,and it is observed that the droplets exhibit different SA on the lubricant slippery surface.This system with thermocontrol property provides a new idea for designing a more advanced antifouling system.It also provides a promising system for the controllability of liquids in biochips and microreactor devices.3.The bionic design strategy of solid phase and liquid phase control was proposed.Two theoretical models were adopted to fit the CSAs of dual control system,and the applicability of Dussan theory to CSA fitting was verified.It was verified that the interfacial adhesion between short DNA fragments was stronger than that long ssDNA.A dual-regulatory system was used to detect hydrope biomarker ATP,monitor the growth rate of cancer cells,and recognize 5 kinds of DNA with different strand length when adopting CSA as signal out.Because of the wide range detection and minimum detection limit of this dual-regulation detection system on biological droplet sliding behavior,it is of great significance for liquid directional transport,liquid printing,separation,microfluidic control equipment,biosensors and related researches that need to precisely control the directional movement of droplets.