Design Of Nerve Cell Microfluidic Chip And Its Electrical Signal Detection

The neural system realizes the perception,transmission,and coding of information through the collaborative activities of network groups.According to the morphological study of neuropathology,the loss of cognitive function is closely related to the dysfunction of synaptic structure and abnormal activity of the neural circuit.Microfluidic technology can simulate a complex microenvironment in a simple device,and its combination with microelectrode technology can monitor the activity of neurons in a neural network in the form of electrical signals,which can improve the accuracy of in vitro prediction,and provide a new method for the study of cell physiology of nervous system and pathophysiology of many congenital and acquired neurodegenerative diseases.At present,there are few chips for the study of different cell culture zones.At the same time,the operation of the detection device is complex and expensive,and it is inconvenient to bond the commercial electrode with the chip.Therefore,based on microfluidic technology and microelectrode technology,this study aims to provide a fast and simple method for cell electrical signal detection.In this paper,we first designed a microfluidic chip for culturing nerve cells.On the chip,neurons and glial cells can be inoculated according to the needs for regional culture.The flow direction of culture medium can be controlled by the micro valve on the chip to achieve indirect co culture of cells.Comsol simulation software is used to simulate the chip:through the comparison of different inlet flow rates,the inlet flow rate of the chip is determined to be0.5μL/min;The velocity distribution in the cell culture chamber on the chip was simulated,which showed that the fluid in different cell culture chambers could be evenly distributed and the velocity did not fluctuate greatly;The distribution of cells in the chip was simulated,which showed that the cells could be evenly distributed in the culture chamber;And the diffusion rate of CO₂in the chip was simulated,and the casting thickness of PDMS was 2-3mm.Combined with the current machining accuracy,the chip is processed locally.Next,the PMMA chip was processed by laser ablation,and the bottom of the PMMA chip culture chamber was rough,which was not conducive to the follow-up observation of cells.The soft lithography method with PDMS as the processing material was used to process the chip,and the processed chip was bonded and packaged to complete the process from design to implementation.The sealing performance of the chip after bonding was tested,which proved that the chamber had good sealing performance;The contact angle of the chip surface is 106.45°,The hydrophilicity is poor;The width of microchannel on the chip is 200μm.The height is 40μm.The width of the micro column is 500μm is consistent with the design width.Finally,the growth curve of PC12 cells was drawn.The results showed that the best adherent density of PC12 cells was 8×10³cells/cm²and passaged on 3-4 day;When PC12cells were seeded on the microchip,it was observed that the cells grew well on the microfluidic chip,and the processes extended and connected with each other;The results showed that K⁺decreased the extracellular potential,while Ca²⁺increased the extracellular potential,which was consistent with the effect of high concentration of K⁺and Ca²⁺on the membrane potential,It shows that the simple device can detect the changes of extracellular potential of cells,and indirectly reflect the changes of extracellular potential through the changes of potential difference.To sum up,a microfluidic chip for culturing nerve cells is designed in this paper.The designed chip is simulated,and the chip is simplified according to the requirements of processing accuracy.Finally,PC12 with good cell activity is selected to be inoculated on the chip to detect the electrical signal of cell population,and the effect of different ions on the extracellular potential is observed,It provides a new experimental method for the simple experiment of drugs.