The Construction Of Integrated Drug Screen Chip For Interactions Between Concentration Gradient And Cell And Related Applications

Concentration gradient profile plays an important part in biomedical research.The in-depth study of biochemical molecules and related cellular responses will help us further understand the mechanism of life.However,the current methods for generating concentration gradients at the macro scale suffer the following two problems:first,it is hard to maintain the accuracy of the concentration gradient profile when the system of reactor is smaller than microliter scale;second,it is difficult to form special or complex concentration gradients profile.Microfluidics is mainly used for fluid control at the microscale.It has a smaller reaction system and faster detection speed.It can integrate multiple chemical and biological reactions on a single chip.Based on the microfluidic technology,this paper proposes an integrated drug testing chip based on the interaction of a wide range of concentration gradient and cell interaction based on microfluidic oscillation for the on-chip drug sensitivity of colon cancer cell line.In addition,this article also proposes a rapid mixing method based on ring-shaped microvalves and is used for bacterial susceptibility testing.The main content of this article is as follows:1.Anew type of pneumatic assisted ring mixer(PARM)with integrated on-chip isolation and rapid mixing was proposed and prepared.The classic Quake valve in the multilayer microfluidic chip can only control the fluid in the axial direction.We designed a ring-shaped pneumatic micro valve and used fluorescent dye experiments to perform qualitative and quantitative verification.As a proof of concept,we used PARM to capture GFP-tagged E.coli and determined its proliferation curves under 50,100,200,400?g·mL-1 concentrations of spectinomycin.This design enables fast mixing of different liquids in 4 nL systems in 2 seconds and can be used for on-chip cell or bacterial drug susceptibility testing.2.A large-scale concentration gradient chip based on micro-fluidic oscillation was proposed and prepared.The design can achieve a 2-fold or 5-fold serial dilution factor by changing the volume ratio of the sample chamber to the buffer chamber,and achieve a maximum range concentration of 1:56 by 6 step dilution.Downstream of the oscillating hybrid chip,we designed a static droplet array(SDA)structure to self-digitalize and store the resulting concentration gradients into microdroplets for further usage.3.Based on the above-mentioned large-scale concentration gradient generator,a microfluidic chip for tumor cell culture and drug testing was designed and fabricated.The chip integrates drug concentration gradient profile formation,cell culture and drug concentration cell interactions on a single chip.As an application validation,we use this chip to first achieve 24-hour incubation of Lovo and HT29 colon cancer cell lines.The concentration of fluorouracil(5-FU),a chemotherapeutic drug,is generated on the chip and stored in the reservoir.By on-chip drug sensitization,we found that Lovo significantly decreased when 5-FU concentration was higher than 750 ug.mL-1,while IR decreased significantly when HT29 was higher than 375?g.mL-1 with higher sensitivity to 5-FU than that of HT29.In summary,this paper proposes a drug testing chip with a wide range of concentration gradients and cell interactions,enabling the integration of drug concentration gradient formation,cell culture and drug concentration cell interactions on a single chip.In addition,a microfluidic chip for fast mixing based on a ring-shaped microvalve was designed in this paper and used for on-chip drug susceptibility testing.