Research Of TdT Enzymatic DNA Synthesis Chip Based On Information Storage

With the rapid development of science and technology as well as information industry,the total amount of information in the world is growing explosively,and the existing storage equipment is difficult to satisfy the requirement of information storage at this stage.As a kind of information storage medium with high density,security and stability,DNA is suitable for future information storage.As the basic of information storage in DNA,the development of DNA synthesis technology with high accuracy and high throughput is of great significance.However,the traditional chemical DNA synthesis has a high synthesis error rate and is easy to produce chemical pollution.Enzymatic DNA synthesis has great potential to substitute for the existing chemical methods in terms of synthesis accuracy,synthesis length and environmental friendliness,so it is of great significance to develop information storage technology based on enzymatic DNA synthesis.In order to meet the demand of automatic DNA synthesis,a microfluidic chip for enzymatic DNA synthesis is designed in this paper.The bifurcation structure is used to control the parallel enzymatic synthesis of DNA in multi region.This paper mainly focuses on the following three aspects.Firstly,the aldehyde modified glass slide was selected as the solid phase carrier,and the initiator oligonucleotide modified with amino group at the 5' end was immobilized on the glass slide by the chemical reaction of aldehyde-ammonia condensation to form Schiff base.And the DNA chain was extended on the immobilized initiator oligonucleotide through enzymatic DNA synthesis by manual operation.Using the uracil nucleotides added in the initiator oligonucleotide,the DNA chain was cut off by endonuclease VIII and uracil-DNA glycosylase(UDG),which can specifically recognized the uracil bases,then the synthesized DNA was released.The performance of initiator oligonucleotide immobilization,enzymatic DNA synthesis and DNA strand cleavage were tested by fluorescence in situ hybridization and mass spectrometry.Secondly,a microfluidic chip which can realize automatic DNA synthesis was designed.The chip consists of three parts: liquid entry ports,bifurcation structure for liquid distribution and DNA synthesis regions.The structure parameters of each part of the chip were designed by simulation,and the chip with three layers was fabricated by soft lithography.The peristaltic pump was used to drive the liquid flow,and the pneumatic valves were used to control the flow direction of the liquid.The peripheral control system of the chip was optimized and improved through experiments.Finally,the DNA synthesis chip was fabricated by bonding the initiator oligonucleotide modified slide with the PDMS layers.On the basis of connecting the synthesis chip with the peripheral control system,the parallel and automatic extension of DNA chains in different synthesis regions was realized by setting the sequential flow of the valve control system,which lays a foundation for information storage in DNA.