Viscoelastic Separation and Concentration of Fungi from Blood for Highly Sensitive Molecular Diagnostics

Sci Rep. 2019 Feb 28;9(1):3067. doi: 10.1038/s41598-019-39175-5.

Abstract

Isolation and concentration of fungi in the blood improves sensitivity of the polymerase chain reaction (PCR) method to detect fungi in blood. This study demonstrates a sheathless, continuous separation and concentration method of candida cells using a viscoelastic fluid that enables rapid detection of rare candida cells by PCR analysis. To validate device performance using a viscoelastic fluid, flow characteristics of 2 μm particles were estimated at different flow rates. Additionally, a mixture of 2 μm and 13 μm particles was successfully separated based on size difference at 100 μl/min. Candida cells were successfully separated from the white blood cells (WBCs) with a separation efficiency of 99.1% and concentrated approximately 9.9-fold at the center outlet compared to the initial concentration (~2.5 × 107 cells/ml). Sequential 1st and 2nd concentration processes were used to increase the final number of candida cells to ~2.3 × 109 cells/ml, which was concentrated ~92-fold. Finally, despite the undetectable initial concentration of 101 CFU/ml, removal of WBCs and the additional buffer solution enabled the quantitative reverse transcription (RT)-PCR detection of candida cells after the 1st concentration (Ct = 31.43) and the 2nd concentration process (Ct = 29.30).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Candida / genetics
  • Candida / isolation & purification*
  • Candidiasis / diagnosis
  • Candidiasis / microbiology*
  • Cell Separation / instrumentation*
  • Elasticity
  • Equipment Design
  • Humans
  • Lab-On-A-Chip Devices*
  • Microfluidic Analytical Techniques / instrumentation
  • Polymerase Chain Reaction
  • Viscosity