Rapid isolation method of Saccharomyces cerevisiae based on optically induced dielectrophoresis technique for fungal infection diagnosis.

Saccharomyces cerevisiae(S. cerevisiae) has been classically used as a treatment for diarrhea and diarrhea-related diseases. However, cases of the fungal infections caused by S. cerevisiae have been increasing in the last two decades among immunocompromised patients, while a long time was spent on S. cerevisiae isolation clinically so it was difficult to achieve timely diagnosis the diseases. Here, a novel approach for isolation and selection of S. cerevisiae is proposed by designing a microfluidic chip with an optically induced dielectrophoresis (ODEP) system. S. cerevisiae was isolated from the surroundings by ODEP due to different dielectrophoretic forces. Two special light images were designed and used to block and separate S. cerevisiae, respectively, and several manipulation parameters of ODEP were experimentally optimized to acquire the maximum isolation efficiency of S. cerevisiae. The results on the S. cerevisiae isolation declared that the purity of the S. cerevisiae selected by the method was up to 99.5 % ±0.05, and the capture efficiency was up to 65.0 % ±2.5 within 10 min. This work provides a general method to isolate S. cerevisiae as well as other microbial cells with high accuracy and efficiency and paves a road for biological research in which the isolation of high-purity cells is required.