Lim Hyunjung, Kim Jae Young, Choo Seunghee, Lee Changseok, Han Byoung Joe, Lim Chae Seung, Nam Jeonghun
School of Biomedical Engineering, Korea University, Seoul 02841, Republic of Korea.
Research Institute for Skin Image, Korea University College of Medicine, Seoul 08308, Republic of Korea.
Micromachines (Basel). 2023 Mar 23;14(4):712. doi: 10.3390/mi14040712.
An early and accurate diagnosis of Candida albicans is critical for the rapid antifungal treatment of candidemia, a mortal bloodstream infection. This study demonstrates viscoelastic microfluidic techniques for continuous separation, concentration, and subsequent washing of Candida cells in the blood. The total sample preparation system contains two-step microfluidic devices: a closed-loop separation and concentration device and a co-flow cell-washing device. To determine the flow conditions of the closed-loop device, such as the flow rate factor, a mixture of 4 and 13 μm particles was used. Candida cells were successfully separated from the white blood cells (WBCs) and concentrated by 74.6-fold in the sample reservoir of the closed-loop system at 800 μL/min with a flow rate factor of 3.3. In addition, the collected Candida cells were washed with washing buffer (deionized water) in the microchannels with an aspect ratio of 2 at a total flow rate of 100 μL/min. Finally, Candida cells at extremely low concentrations (Ct > 35) became detectable after the removal of WBCs, the additional buffer solution in the closed-loop system (Ct = 30.3 ± 1.3), and further removal of blood lysate and washing (Ct = 23.3 ± 1.6).
白色念珠菌的早期准确诊断对于念珠菌血症（一种致命的血流感染）的快速抗真菌治疗至关重要。本研究展示了用于在血液中连续分离、浓缩并随后洗涤念珠菌细胞的粘弹性微流控技术。整个样品制备系统包含两步微流控装置：一个闭环分离浓缩装置和一个共流细胞洗涤装置。为了确定闭环装置的流动条件，如流速因子，使用了4和13μm颗粒的混合物。在流速因子为3.3、流速800μL/min的情况下，念珠菌细胞在闭环系统的样品池中成功地从白细胞（WBC）中分离出来，并浓缩了74.6倍。此外，收集到的念珠菌细胞在纵横比为2的微通道中用洗涤缓冲液（去离子水）以100μL/min的总流速进行洗涤。最后，在去除白细胞、闭环系统中的额外缓冲液（Ct = 30.3±1.3），并进一步去除血液裂解物和洗涤后（Ct = 23.3±1.6），极低浓度（Ct > 35）的念珠菌细胞变得可检测到。
