Characterization of the Dielectrophoretic Response of Different Candida Strains Using 3D Carbon Microelectrodes

Abstract

Bloodstream infection with Candida fungal cells remains one of the most life-threatening complications among hospitalized patients around the world. Although most of the cases are still due to Candida albicans, the rising incidence of infections caused by other Candida strains that may not respond to traditional anti-fungal treatments merits the development of a method for species-specific isolation of Candida. To this end, here we present the characterization of the dielectrophoresis (DEP) response of Candida albicans, Candida tropicalis and Candida parapsilosis. We complement such characterization with a study of the Candida cells morphology. The Candida strains exhibited subtle differences in their morphology and dimensions. All the Candida strains exhibited positive DEP in the range 10–500 kHz, although the strength of the DEP response was different for each Candida strain at different frequencies. Only Candida tropicalis showed positive DEP at 750 kHz. The current results show potential for manipulation and enrichment of a specific Candida strain at specific DEP conditions towards aiding in the rapid identification of Candida strains to enable the effective and timely treatment of Candida infections.

Review: Dielectrophoresis in cell characterization

“…The authors cited leakage of the intracellular ions due to the low conductivity medium; a challenge that the DEP community is still working to meet. While this study did not characterize cell parameters, Islam et al used 3D carbon microelectrodes to characterize unique trapping responses of various Candida fungal strains [98]. The significance here was the greatest differences in cell trapping across the strains occurred at higher frequencies, followed by minimal trapping (net zero force).…”

Electrospun carbon nanofibre-assisted patterning of metal oxide nanostructures

“…The stabilized electrospun AuCl 3 /PAN nanofibres were carbonized in a horizontal tube furnace (Carbolite Giro) to obtain the template AuNP/carbon nanofibres. The carbonization recipe used in our work was adapted from a process popularly used in carbon microelectromechanical systems (C-MEMS) technology 76 – 80 . Briefly, the process involved three steps: heating from room temperature to 900 °C with a heating rate of 5 °C min −1 , dwelling at 900 °C for 1 h, and cooling down to room temperature with natural cooling.…”

Evaluating carbon-electrode dielectrophoresis under the ASSURED criteria

“…This is promising in the species-specific separation of Candida cells for sample preparation toward the diagnosis of candida infection. Reprinted with permission from Islam et al ( 50 ), Copyright 2020 Multidisciplinary Digital Publishing Institute. (D) Rapid and continuous separation of 1 and 10 μm polystyrene microparticles using 3D carbon streaming dielectrophoresis.…”

“…Cell membrane potential differs with phenotype; therefore, phenotypical cell separation is possible using DEP. 3D carbonDEP was implemented for different strains of Candida to characterize the dielectrophoretic behavior of Candida cells ( 50 ). The three most common strains, C. albicans, Candida tropicalis , and Candida parapsilosis were investigated, which showed that the strains indeed showed different dielectrophoretic responses, as shown in Figure 2C .…”