Elecrchemical Detection Of Glucose And Dissolved Oxygen Based On Microfluidic Chip

Assisted Reproductive Technology（ART）offers the possibility of treating infertility but still faces problems such as low fertility and low fertility.The key to solve this problem is to select single embryo with high quality and development potential for transplantation.Current screening methods rely on the subjectivity of the physician and are difficult to standardize.Embryo metabolism is directly related to embryo quality and embryo development potential,which can be used as a new standard for embryo screening.The microfluidic chip can detect the metabolites of embryos quantitatively and precisely,and can establish stable embryo culture and detection environment in the channel.Electrochemical technology has the advantages of portability and high precision,so it can be used for the detection of embryonic metabolites.In this dissertation,a microfluidic system with a valve was developed to replace the embryo with human umbilical vein endothelial cells（HUVEC）to establish a biochemical sensor for cell culture and electrochemical detection.In this dissertation,a microfluidic system for cell culture and detection is developed by combining normally closed valves with microfluidics.HUVEC cells were cultured on a microfluidic chip,which consisted of a cell culture chamber,a normally closed valve,a branch fluid circuit,a mixing zone and a testing zone.The normally closed valve is used to separate the cell culture area and electrode detection area to prevent the interference between the cell culture area and electrode detection area.The surface modification and characterization of polydimethylsiloxane（PDMS）flexible base were carried out by using gold film coating material.Glucose electrodes were modified with graphene and copper nanoparticles,and dissolved oxygen electrodes were modified with platinum nanoparticles and Nafion thin films.The model of oxygen uptake by cells in the chip was established by numerical simulation,and the diffusion of substances in cells was investigated.The advantages of the valve scheme are obtained by comparing the two schemes.At the same flow rate v=1.66×10^-4m/s,at least 60s is needed for detection without valve scheme.The concentration of oxygen arriving at the electrode area is 185.16μM,and the concentration of oxygen arriving at the electrode area is 110μM with valve scheme 6s,which is closer to the true value.An enzyme-free glucose sensor and a dissolved oxygen sensor based on a microfluidic chip were prepared.The detection range of the enzyme-free glucose sensor was 50μM～10mM,and the sensitivity was 0.17μA·mM^-1·mm^-2.The detection accuracy was high and the detection range was wide,with a wide application prospect.The detection range of the dissolved oxygen sensor was 7.5～281.25μM,and the sensitivity was 0.23μA·mM^-1·mm^-2.A microfluidic chip for cell culture and electrochemical detection of glucose was designed.A system consisting of an electric inverted fluorescence microscope,an electrochemical workstation,a cell culture device and a circuit control unit was established to detect glucose consumption during cell culture.The cells were cultured in a flow-stop mode and glucose uptake in HUVEC cells within 2h was determined.In this dissertation,an enzyme-free sensor was first applied to the detection of microfluidics cells.