Microfluidic Chip For Preparing Microbubble And Its Application In Biology

With small volume, mobile flexibly, microbubble can realize the function of micropump, mixing, gate control and is widely used in some biochemical research. But it has the property of strong scalability, moving quickly, even interfering in some traditional biological experiment. So it is necessary to realize the possibility of microbubble being handled. Microfluidic chip platform has the advantages of miniaturization, automation, low cost, high throughput, high efficiency and provides a powerful platform for the study of microbubble which greatly increases the capability of handling microbubble. In microfludic chip, microbubble could be easily generated, removed and transported which is hard to achieve using the conventional methods.Based on the permeability of polydimethylsiloxane(PDMS) membrane, we designed a new bubble forming structure which could reduce the speed of gas into chip and realize the controllability of bubble. We applied the new structure to control the microbubble in biological experiments. First, we started with vascular air embolism as the prototype and in real time monitored the influence of microbubble forming process on human umbilical vein endothelial cells(HUVEC). We set the cell fluorescence change rate as the statistical data. In addition to observing calcium response from the adjacent cells, we also observed calcium signal change in the downstream cells. We treated cells by using 1-octyl alcohol, Suramin, antagonized ATP, UTP and ADP, respectively and observed an obvious decline in calcium response. In addition, we used PI-Calcein-AM staining assay for cell staining, showing that after contacting with microbubble, the cells were still in a state of survival. Therefore, we concluded that microbubble could damage cells in a different degree, which provided a new platform for further research on vascular air embolism.Taking advantage of the microfluidic microbubble formation platform, we also investigated the gas chemotaxis behavior of C.elegans. Due to the low solubility of nitrogen, oxygen in water and the relative stability of the bubble, a two way gas system was stably formed, which allowed C. elegans having plenty of time to choose gas preferences. The results showed that the nematode had an obvious escape behavior to carbon dioxide; compared to air that is 21% O2, nematode is much more like 11% O2 which consistented with literature reports. It offered a powerful proof that the system was feasible to study the gas chemotaxis and laid the foundation for the further research on the mechanism of gas chemotaxis and three way gas chemotaxis.