Surface Modification Of Functional Materials For Microchip Application

Microfluidic chips are widely used in chemistry,biology,medicine and other fields by controlling the fluids in devices to achieve different functions.Based on microfluidic chip,surface modification of functional materials can realize physical or chemical changes of materials and expand material applications.Polydimethylsiloxane(PDMS)is characterized by stable properties,low price and easy curing.Therefore,PDMS is chosen as the material for fabricating microfluidic chips.By designing the chip channel,the physical performance of the chip can be changed.Then chemical modification is realized by chemical modification of the internal structure of the chip.Based on microfluidic technology,this paper has carried out the following three aspects through surface modification of modified materials.1.Based on the microfluidic chip,the preparation material PDMS is regulated to change the shape of the channel structure,thereby affecting the droplet behavior.The effect of channel structure on microdroplets was investigated by applying an electric field to the microfluidic device.By designing different rectangular channel structures,water-in-oil droplets are generated by flow focusing method,and observed different trajectories of droplets in electric field.It is found that the charged quantity of droplets is related to the channel structure.By changing the water phase to NaCl solution,it was found that the ion concentration of solution was negatively correlated with the channel flow potential.Then the gold-plated chip was modified by chemical method.It was found that the flow potential increased and the droplet deflection became more obvious after the modification of the gold-plated channel.2.A micro-column PDMS chip was designed.The three-dimensional network scaffolds with both micro-structure and nano-structure were prepared by electrospinning the meshed Polylactic-co-glycolic acid(PLGA)nanofibers on the microcolumns.The surface modification of the nanofibers was carried out by chemical method to connect antibodies.It was found that the capture time was 30 minutes on the PDMS substrates with both spinning and micro-pillars,and the capture effect was the best.When the spinning time is 4 min,the density of the nanofibers also facilitates cell capture.3.The microcolumn channel is etched inside the microfluidic chip,and the surface of the microcolumn is still coupled with PLGA nanofibers.The antibodies were chemically modified on the surface of nanofibers.Simulate the blood flow to capture the mobile cells from static to dynamic.The three-dimensional network fiber structure of microcolumn shows a good capturing effect on MCF-7 in microfluidic chip.The capturing efficiency reaches 91.53%.The morphology of the captured cells was characterized by scanning microscope,and it was found that the captured cells had pseudopodia and interacted with the spinning substrate.This is of great significance to the study of the interaction between cells and materials and the establishment of cell detection platform.It also provides certain research value for the diagnosis and clinical analysis of cancer diseases.