Study On Electrophoresis Biochip For Fast Separation Of DNA

Electrophoresis is the migration of charged particles(e.g.,nucleic acids)to the electrode with an opposite charge under the influence of electric field.It is widely applied in the fields of agriculture science,medical medicine,etc.Nucleic acid electrophoresis mainly includes capillary electrophoresis(CE)and gel electrophoresis(SGE).Compared with CE,SGE is adopted in the adopted by most of laboratories,research institutes and hospitals because of its low cost.However,traditional SGE requires tedious experimental operations with various equipment,high chemical consumption,and long experiment time.To overcome these drawbacks,we studied the electrophoresis biochip which can realize fast DNA separation.Combining with the polymerase chain reaction technology,we performed the identification of periodontal pathogens(e.g.,Porphyromonas gingivalis(P.g),Tannerela forsythia(T.f),and Treponema denticola(T.d))based on the self-built SGE system.This thesis mainly consists of four parts as the follows.(1)We compared the advantages and disadvantages of the separation of DNA ladder by polyacrylamide and agarose gel electrophoresis in terms of experimental operations,separation performance,and the appropriate separation range of DNA.We investigated the influence of fluorescence dyes,separation voltage,and electrophoresis buffer on the separation performance of DNA,and finally we concluded the optimal experimental conditions for DNA separation.(2)We proposed the electrophoresis biochip for separation of DNA,and optimized the geometrical dimensions(e.g.,length,width and height)of the channel in the chip by series of experiments.We also made the chips after analyzing the materials and processing technique.(3)We tested the chips based on the self-built SGE system.According to the experimental results,we further optimized the experimental conditions to realize best separation performance.Moreover,validated the stability and reproducity of the instruments and the biochip.(4)We amplified the DNA fragments of P.g,T.f,T.d with PCR and carried out electrophoresis in the chip and analyzed the results.Electrophoresis of PCR products of P.g with different amplification cycles was performed in the chip.Such a work indicates that performing electrophoresis in the chip can offer separation of DNA ladder with high resolution and effective identification of PCR products of periodontal pathogens.The method proposed in this work can greatly save the chemical consumption and thus reduce the experimental cost.It can also significantly improve the speed of electrophoresis.Therefore,the biochip designed in this work has great value for the development of portable gel electrophoresis apparatus.