The Study On Microfluidic Cell Chip By Bio-functionalization

As a novel analytical technology,microfluidic chip develops very fast in terms of its reaction speed,reagent consumption,miniaturization,cost and automation.It is an emerging technology for advanced analytical chemistry,biology and medicine.Advances in microfabrication technology have led to the appearance and booming of microfluidic chip in bio-medicine,especially in the cell study.Bio-functionalization is the forefront of microfluidic chip development.This method is based on covalently bonding or non-specific adsorption of antibodies which recognise antigens on microfluidic channel surfaces.At present,the macromolecule protein is used to finish bio function alization of the microfluidic chip.Because of its complexity,the protein structure has to maintain a specific three-dimensional conformation to have function and biological activity.If protein's active site is obscured or damaged,its sensitivity and specificity will be lowered when proteins are covalently attached to the microchannel. Therefore,the most important question is how to maintain the protein's activity and specificity in the microchannel.In order to improve bio-functionalizition,this study selected RGD peptide as the object to complete bio-functionalizition on the microchannel surface.Through RGD immobilization,the microfluidic cell chip including cell selection / capture,culture and analysis was established.Firstly,in order to determine the voltage reference and the corresponding pressure time, the electrical properties of PBS buffers,TE buffer and RPMI 1640 medium have been examined experimentally in this work.And then the PBS buffer was chosen as optimal buffer in this study.In addition,the velocity of electroomistic flow(EOF) was measured by the low concentration PBS buffer displacing the high concentration PBS.By comparing the theoretical and actual values of the times of EOF caused by the pulse voltage and through the entire microchannel,the system operating parameters were determined.Secondly,the bio-functionalization of microfluidic chip was completed by silane modified and RGD covalently bonded.The results showed the saturated concentration of RGD peptide is 0.1mg/ml.The bio-functionalization was finished by the covalently-linked method,which resulted in solid RGD peptide binding as well as RGD uniform layer.Finally,the performance of microfluidic chip was evaluated by the ability of capturing target cells and biocompatibility of microfluidic chip.The RGD bio-functionalization microfluidic chip could effectively capture the A549 cells.When the incubation time was 20 minutes,the capture rate was 100%.The result of cell culture showed that the cells could survive up to 12 hours in the microchannel at room temperature without CO₂ and the relative humidity.It illuminated the microfluid chip had better biocompatibility.In summary,this study used self-assembled molecular layers technology to build the RGD bio-functionalizied microfluidic chip successfully.It provided a high sensitivity and specificity technology platform for cell systems biology research,clinical diagnosis and drug screening,etc.This microfluidic chip would have important applications for the development of microfluidics in bio-analysis,cell sorting and cell culture.