Development Of Double-layer Hydrogel Microfluidic Chip And Application To Cell Culture And Metabolites Detection

The microfluidic chip (MC) is an important platform in the field of biomedical andbioengineering. MC with micron scale space can precisely match the physical size ofcell, which extremely contributes to realize biochemical experiment/analysis on singlecell level. This greatly facilitates cell research as they usually circulate in perfusionculture by oriented capturing, which is more close to the body’s physiological state sothat their realistic biological characteristics can be accurately monitored. Anotherbenefit of MC is that it only consumes little quantity of cells, which has substantialmeanings as many cells are not easily obtained, for example, primary cells and stemcells. MC with flexible network structure can further effectively mimic in vivomicroenvironment for cell research. Furthermore, multiple modules with different rolescan be integrated on a chip, so that related systematic research, such as cell seeding,cultivating, stimulating and fluorescence detection are programmed into a successiveprocess. MC can also carry out high-throughput analysis. The obtained a large amountof biological information is very important for cell functional analysis.Traditional MC fabrication techniques including: photolithography, wet etching,hot pressing, molding, injection molding, laser ablation, LIGA technology, softlithography, and so on. Lithography and molding method are commonly used. Softlithography and femtosecond laser technology possess superior performance as they areprone to form regular micro-nano structure. Although progress were made in chipfabrication techniques in the past decades, especially for chip in cell biology and tissueengineering, many defects, for example, the processing imprecision, high processingcost as well as sophisticated manufacturing procedure are still undesirable. It is keen tofind a more facile method and low-cost fabrication technique to meet the ongoingdemand. The hydrogel is hydrophilic and has capacity of perfect deformability.Compared with other synthetic biological material, it is more suitable to apply inbiological and medical engineering. Poly(ethylene glycol)(PEG) based hydrogel can begenerated by physical or chemical cross-linking method, for this reason, we can getdiverse structures and functions of hydrogels. To form PEG hydrogel, acrylated PEGderivates are often used because they can be easily polymerized usingphotopolymerization. Poly(ethylene glycol) diacrylate (PEGDA) hydrogel is anemerging scaffold for tissue engineering and regenerative medicine, which shows elastic character to preserve high content water, highly tunable and non-immunogenicfeatures. In the presence of photoinitiator and UV light, we can rapidly obtain thePEGDA hydrogel at room temperature with low energy input. Even more important,photopolymerization allows for spatial and temporal control of polymerization as wellas formation of complex shapes. Certainly, PEGDA can also be customized toincorporate a variety of biological molecules into the predetermined three-dimensionalstructure for particular use.Here, we take the above-mentioned merits of PEGDA, using photopolymerizationmethod, to fabricate desirable microstructure with advantages of fast, precision, andinexpensive for cell culture and metabolite detection. The experimental results showedthat the proposed method can achieve the fabrication of double-layer cell culture anddetection chip with short time treatment. Cells can be well captured and cultured in thehydrogel microfluidic chip with excellent activity. Chip integrated with porphyrincolorimetric sensor array system can effectively distinguish different types of tumor cellby metabolism characteristics detection. The hydrogel microfluidic chip has thepotential of practicable application once large-scale preparation is accomplished.