Discriminating dengue‐infected hepatic cells (WRL‐68) using dielectrophoresis

Abstract

Dielectrophoresis (DEP), the induced movement of dielectric particles placed in a nonuniform electric field, has been used as a potential technique for manipulation and separation of many biological samples without destructive consequences to the cell. Cells of the same genotype in different physiological and pathological states have unique morphological and structural features, therefore, it is possible to differentiate between them using their DEP responses. This paper reports the experimental discrimination of normal and dengue-infected human hepatic fetal epithelial cells (WRL-68 cells) based on their DEP crossover frequency, at which no resultant movement occurs in the cells in response to the DEP force. A microarray dot electrode was used to conduct the DEP experiments. The DEP forces applied to the cells were quantified by analyzing the light intensity shift within the electrode's dot region based on the Cumulative Modal Intensity Shift image analysis technique. The differences in dielectric properties between infected and uninfected cells were exploited by plotting a unique DEP spectrum for each set of cells. We observed that the crossover frequency decreased from 220 kHz for the normal WRL-68 cells to 140 kHz after infection with the dengue virus in a medium conductivity of 100 μS/cm. We conclude that the change in the DEP crossover frequency between dengue-infected cells and their healthy counterparts should allow direct characterization of these cell types by exploiting their electrophysiological properties.

Dielectrophoresis for Biomedical Sciences Applications: A Review

“…The microarray dot electrode used in [18], was chosen because of the confined area for the DEP manipulation. Induced cells were either collected at the dot center in the case of n-DEP, or travel toward the dot edge in the case of p-DEP.…”

“…Recently, researchers have used microarray dot electrodes to discriminate dengue-infected cells [18]. The cells’ dielectric properties were quantified by analyzing the light intensity shift within the electrode’s dot region based on the Cumulative Modal Intensity Shift image analysis technique.…”

“…Currently, the normal standard of dengue infection detection is by using protein expression of antibody and antigen such as ELISA, Haemaaggluitination Inhibition (HAI) and reverse transcriptase- polymerase chain reaction (RT-PCR) techniques [191,192,193,194,195]. However, recently the DEP techniques have shown to be promising diagnostic tools by manipulating the dielectric properties of the cell cytopathic effect in infection [18,196]. Conversely, the DEP techniques also provide a great advantages by preserving the correlation of specificity and sensitivity forcing the compromise of high-throughput and highly specific isolation of bio particles label free applications with minimal sample preparations [197].…”

“…The CM factor K(ω) can be positive or negative depending on the relative polarizability between the cell and suspending medium, creating the pDEP and nDEP effect. This can be controlled by selecting the appropriate frequency of the applied electric field [18]. In most DEP experiments, the typical media used in cell culture techniques (i.e., phosphate-buffered saline (PBS); Dulbecco’s Modified Eagle Medium (DMEM)) cannot be used in DEP experiments due to their high conductivity, and a low-conductivity medium or buffer is usually used as the suspending medium; however, the medium was reported to have a notable influence in decreasing cell viability after 6 h of incubation [112].…”

“…Distinguishing the properties between a healthy and pathological state of cells has become the major interest of study to researchers to unravel the mystery of the disease and deliver the unmet rapid disease treatment [17]. Recently, a few researchers have directed their efforts to distinguish between healthy and infected/unhealthy cells utilizing a technique called dielectrophoresis (DEP) [18,19,20]. DEP is the movement of particles by a trapping force in a non-uniform electric field when the particles and surrounding medium have different polarizabilities.…”