Studies On Dual Concentration Gradient-microarray Chip And Its Application For The Synechococcus And Bacteria Co-culture

Compared to traditional concentration gradient generators,the concentration generator based on microfluidic chip technology has the advantages of precise and controllable,high stability,fast speed,less sample consumption,and small size,etc.,and therefore has received more and more attention.Array technology is an operation method that can be integrated in an orderly manner.It can process multiple samples at the same time or perform multiple processing on one sample in a short time.The combination of microfluidic chip technology and array technology can simultaneously demonstrate the advantages of both,and has important prospects for high-throughput screening.In this paper,based on the microfluidic chip platform,a novel concentration gradient-microarray chip is designed and fabricated,which can form a stable linear concentration gradient droplet array in a short time.When used in combination,two different concentration gradients can be generated at the same time to satisfy 100concentration combinations,and the droplets formed by each concentration combination exist in independent microchambers,and the effects of shear force can be avoided in the cultured cells.Long-term culture observations can be performed and the subsequent experimental operations can be completed.We also performed multi-condition optimization on the chip system,and finally determined that when the serpentine channel length is designed to be 16 mm,the channel width is designed to be 70μm,and the syringe pump used has a flow rate of 30μL/min,the linear relationship of the formed concentration gradient is optimal.The entire device is a general-purpose platform design that has compatibility and can be used in most experiments that require concentration gradients and has a high potential for application.Synechococcus sp.PCC 7002 cyanobacteria with Mesorhizobium sp.TAIHU and Pseudomonas stutzeri TAIHU two kinds of bacteria can form stable bacteria-cyanobacteria symbionts(BCS).In this paper,a concentration gradient-microarray chip was applied to the BCS and the appropriate osmotic pressure and media concentration range were screened.By observing the growth of the bacteria and analyzing the results,the required osmotic pressure range of 3817KPa to 8822KPa for the culture of the BCS with a unit number of 10~7cells/mL was obtained,and the concentration of the culture medium must be0.23 times that of the standard culture medium.Using this chip screening method,100different combinations of conditions can be performed in a short time,which greatly saves time.And only 25μL per droplet saves a lot of reagents and reduces the cost of the experiment.