Isolation method of Saccharomyces cerevisiae from red blood cells based on the optically induced dielectrophoresis technique for the rapid detection of fungal infections.

Saccharomyces cerevisiae (S. cerevisiae) has been classically used to treat diarrhea and diarrhea-related diseases. However, in the past two decades, fungal infections caused by S. cerevisiae have been increasing among immunocompromised patients, and it takes too long to isolate S. cerevisiae from blood to diagnose it in time. In this paper, a new method for the isolation and selection of S. cerevisiae from red blood cells (RBC) is proposed by designing a microfluidic chip with an optically-induced dielectrophoresis (ODEP) system. It was verified by theory and experiments that the magnitude and direction of the dielectrophoresis force applied on RBCs and S. cerevisiae are different, which determine that the S. cerevisiae can be isolated from RBCs by the ODEP system. By designing the specific light images and the dynamic separation mode, the optimal operating conditions were experimentally achieved for acquiring higher purity of S. cerevisiae. The purity ranges were up to 95.9%-97.3%. This work demonstrates a promising tool for efficient and effective purification of S. cerevisiae from RBCs and provides a novel method of S. cerevisiae isolation for the timely diagnosis of fungal infections.

Label-free rapid isolation of saccharomyces cerevisiae with optically induced dielectrophoresis-based automatic micromanipulation.

Saccharomyces cerevisiae is well-known in the baking and brewing industries and always used for the preparation of probiotics, especially its subtype, Saccharomyces boulardii, to prevent and treat various diarrhea and intestinal diseases. However, case reports on the side effects of a wide range of serious infections for the elderly, immunocompromised and critically ill patients after treatment with the S. cerevisiae have been increasing in recent years. The existing diagnose methods of the invasive S. cerevisiae infections in clinical, especially, the key step of the method-cell isolation, is time-consuming that always miss timey diagnose and early prevention. Here, we propose a new automatic micromanipulation method to label-free rapid isolation of S. cerevisiae based on the optically-induced dielectrophoresis (ODEP) technology, combining with image processing and recognition. S. cerevisiae is firstly identified by the image recognition method and then, automatically captured and moved to the target location by designing optical patterns. The results indicate the method can flexibly and automatically manipulate multiple S. cerevisiae cells simultaneously, such as, arranging S. cerevisiae cells, moving an array of the cells at any directions, aggregating the cells, and separating S. cerevisiae from the solution mixed with impurities. This work represents a step toward the use of automatic micromanipulation of ODEP technology to automatically and rapidly isolate S. cerevisiae for the detection of the invasive S. cerevisiae infections.

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.