Highly Localized Enrichment of Trypanosoma brucei Parasites Using Dielectrophoresis

Abstract

Human African trypanosomiasis (HAT), also known as sleeping sickness, is a vector-borne neglected tropical disease endemic to rural sub-Saharan Africa. Current methods of early detection in the affected rural communities generally begin with general screening using the card agglutination test for trypanosomiasis (CATT), a serological test. However, the gold standard for confirmation of trypanosomiasis remains the direct observation of the causative parasite, Trypanosoma brucei. Here, we present the use of dielectrophoresis (DEP) to enrich T. brucei parasites in specific locations to facilitate their identification in a future diagnostic assay. DEP refers to physical movement that can be selectively induced on the parasites when exposing them to electric field gradients of specific magnitude, phase and frequency. The long-term goal of our work is to use DEP to selectively trap and enrich T. brucei in specific locations while eluting all other cells in a sample. This would allow for a diagnostic test that enables the user to characterize the presence of parasites in specific locations determined a priori instead of relying on scanning a sample. In the work presented here, we report the characterization of the conditions that lead to high enrichment, 780% in 50 s, of the parasite in specific locations using an array of titanium microelectrodes.

Dielectrophoresis applications in biomedical field and future perspectives in biomedical technology

“…In a recent study, Keck et al. [126] describe the use of DEP to selectively trap and enrich T. brucei parasites in a specific region of semicircular titanium electrodes array. The percentage of parasites that were attracted to the electrodes in 50 s was used to evaluate the DEP response of the parasites.…”

Analysis of microorganisms with nonlinear electrokinetic microsystems

“…Inset shows what the parasite would look like if viewed with a specialty microscope. Adapted from [51], open access article under the Creative International Public License 4.0 (2020).…”

“…All of work done in parasite identification using DEP and other similar processes culminates in the technology being used diagnostically in the real‐world. Researchers from Clemson University have very recently begun testing of DEP as an enrichment and trapping device of Trypanosoma brucei , a parasite that is a vector for the lethal Human African trypanosomiasis (HAT) disease [51]. Traditionally, testing for the disease starts with a general serological test, but the best confirmation for the disease is direct observation of the parasite, T. brucei .…”

“…Traditionally, testing for the disease starts with a general serological test, but the best confirmation for the disease is direct observation of the parasite, T. brucei . Having a reliable and robust testing technique is critical for this disease as the first stage can be treated effectively and is safer than second‐stage treatment that requires expensive and/or toxic therapy methods [51]. An example of this technology is illustrated in Fig.…”

“…To explain once again, finding evidence of T. brucei early is key to safe, effective, and affordable treatment. Reading more about the work, the reader will discover the significance of zone three and four as they are primary areas of parasitic aggregation [51] The group attributes the success of the region to a large ∇E 2 magnitude reached in that location on the electrode. The work done by this group shows how DEP and similar nonlinear EK methods are advancing to have a more substantial basis within the healthcare field.…”