Applications for a single-cell study: improving cell viability in experimental setups and designing of a single cell releasing device

Abstract

In the first phase, it was about an investigation of cell viability of white blood cells during the sorting process in a spiral microchannel with three methods including Trypan Blue staining, Scanning Electron Microscopy (SEM) and Wright’s staining. After the white blood cells were injected through the setup, the outcome showed that in a feeding system, between a syringe and needle, despite of high shear and extensional stresses induced in fluid stream, no effects of these stresses on cell viability was found. Despite of that, cells were more likely to be deformed in the case with maximum stresses, in which flow passing through 5 ml syringe at 8 ml/min. Normal cells was decreased about 12% under SEM and about 16% with Wright’s stain testing. Finally, a whole setup of spiral microchannel was also experimented using Trypan Blue staining. About 70% of cells could survive after passing through a whole setup with a 1 ml syringe at 1 ml/min. This suggested that majority of cell death occurred in the spiral channel not in the feeding system. For the second phase, it was about designing of a releasing device which is used to discharge a specific cell for a further biological testing. The idea is that the releasing device is designed as the main channel located over the wells and the second channels (buffer channels) located at the bottom of the wells. During immobilization, the fluid in the main channel will flow over the wells, while the fluid from buffer channels will slowly be injected to keep the cells floating. In the releasing process, the fluid flow in the main channel will be slowed down. Meanwhile, the stronger fluid flow is injected from the buffer channels to push the cells out of the wells. Using computational software, the results showed that when the cell size was increased, the required flow rate was increased as well until the cell size of around 14 µm. At this size, the required flow rate was around 1.2 nl/hr. For the cell size bigger than 14 µm, the required flow rate gradually reduced.