Microfluidic technology is regarded as one of the most capable technologies to change human beings in the 21st century, and its main application field is the biomedical field related to human fate.
Application of Microfluidic Chip Technology in Gene Detection
In gene detection, microfluidic chip technology is mainly used in nucleic acid amplification, separation, sequencing and polypeptide detection. Polymerase chain reaction (Polymerase Chain Reaction,PCR) is widely used in molecular biology. It can amplify DNA molecules in vitro. The conventional PCR process takes about 1-2 hours, and requires more reagents, which is time-consuming and laborious. When microfluidic chip technology is used in PCR amplification and related detection, it can not only simplify the operation steps, but also significantly improve the detection efficiency. In 1998, Kopp et al proposed a continuous flow microfluidic PCR amplification chip, in which the reaction solution circulates through different temperature regions to complete the PCR amplification reaction, and the whole amplification reaction is completed in flow, which shortens the amplification time and reduces the reagents needed for the reaction. Since then, on the basis of this research, many scientists have made further improvements to the continuous mobile PCR technology to make it more miniaturized. With the continuous improvement and development of microfluidic chip technology, the length of DNA fragments that can be separated by microfluidic analysis technology is gradually expanding, which can complete the sequencing of DNA fragments and the separation and analysis of genetic material, and there are multi-channel microfluidic chips that can carry out parallel analysis at the same time. The effective separation length of 3.5cm was studied by Mathies, and the sequence of 150~200bp with length of 150~200bp was completed by 7min on a single channel glass chip. Later, they extended the separation channel to 7.5cm, and used a four-color fluorescence detector to complete the sequence analysis of 500bp for 20 minutes, with an accuracy of 99.4%. Single nucleotide polymorphism (single nucleotide polymorphism,SNP) is an ideal genetic marker for the physical map of the human genome, which can meet the mapping of genes related to metabolism, growth and disease. Gene polymorphism is a common phenomenon in various heritable variations of human beings. SNP detection method is mainly based on PCR, through electrophoresis technology to distinguish the differences of DNA fragments caused by base differences for genotyping. Taylor et al designed a cross microfluidic chip to analyze it and discussed the correlation between a variety of diseases and their variation. The whole analysis process is shortened from a few days of traditional methods to 45min.
Application of Microfluidic Chip Technology in protein Analysis.
Protein is the most basic bioactive substance of organism. The separation and determination of protein can help people understand the role of protein in biological function and is of inestimable value in discovering new diagnosis and treatment methods. The traditional protein analysis steps are carried out by hand, these methods are too cumbersome, large sample consumption and low sensitivity, which can not meet the needs of proteomics for fast, integrated, high-throughput and high sensitivity analysis system. The microfluidic analysis chip system is used to analyze protein samples, protein structure, function and protein interaction. The analysis steps are carried out on a few square centimeters of analysis chip, with fast reaction speed and high sensitivity. In addition, the amount of reagents and reactants needed by microfluidic chip detection technology is less, which can greatly reduce the reagent consumption. Hofmann et al used isoelectric focusing capillary electrophoresis chip technology to label peptides with Cy5 to separate and detect the mixture of cytochrome C, ribonuclease An and myoglobin, and completed the whole detection process in 5 min.
Application of Microfluidic Chip Technology in Cell Analysis.
With the rapid development of life science, the analysis and detection of the composition and morphological changes of single cell and intracellular has become the focus of research. Because the microchannel width (10 ~ 50 μ m) of microfluidic chip is similar to that of biological cells, biological cells are easy to manipulate, observe and detect in microchannels. Single cell research with microfluidic chip has unique advantages. Shin et al. constructed a kind of electroporation cell chip. They carried out the electroporation experiment on the cells in the fluid channel through the exponential decay pulse generator, and measured various parameters of the cell electroporation. In recent years, a lot of studies have been carried out on the time and space control of chemical concentration gradient in cell microenvironment, cell culture and so on. It is believed that with the continuous update of microfluidic technology, this technology is expected to become the main tool for cell research.
