Research

Diagnostic tool for tick-borne infections

Funded by NIH 1R01AI174300-01: The incidence of tick-borne diseases (TbD) is increasing and is expected to continue to increase, in large part due to global climate change. Our goal is to create a continuous, rapid, sensitive, and label-free diagnostic tool for tick-borne diseases (TbD). Our hypothesis is based on our previously published studies showing that differential expression of proteins on bioparticles can be leveraged to detect infections and parasites via an electrokinetic technique, dielectrophoresis (DEP) Two main reasons are: (1) people are encroaching more into the habitats where ticks live, and (2) as climate changes, tick ranges are expanding; thus, TbD cases are expected to increase in the future, becoming an even greater problem. Currently, Lyme disease is the most prevalent vector-borne disease in the US, with estimates of ~476,000 cases/year.

Additionally, we are also evaluating if Rickettsia spp. could be detected early on through an internal RSA grant

Extraction of rare earth elements (REE) using biosorbent

Funded by NSF 1500815: This work presents the dielectric characterization of rare earth elements (REEs) biosorption by Cupriavidus necator using dielectrophoretic crossover frequency measurements. Traditional means of characterizing biomass for biosorption are limited and time-consuming. In this research, for the first time, we present an electrokinetic method termed dielectrophoresis (DEP) for the characterization of biosorption (uptake) of rare earth elements (REEs) by gram-negative bacteria - Cupriavidus necator. Quantified dielectric properties of native Cupriavidus necator (REE-) and those exposed to rare earth elements (REE+), europium, neodymium, and samarium revealed a substantial change in the surface characteristics of the Cupriavidus necator after exposure to the REE solution. The response of C. necator to changes in REE exposure is substantially different for europium but similar between neodymium and samarium. Statistically, the dielectric signatures of both the REE+ and REE- groups were significantly different, proving that the REEs were absorbed by the bacteria. This research will revolutionize and impact the researchers and industrialists in the field of biosorption, seeking economical, greener, and sustainable means to recover REEs.

Breast cancer detection via liquid biopsy

Noncommunicable diseases (NCDs) kill more than 36 million people annually, representing 63% of global deaths 1. Breast cancer, a subset of NCDs, accounts for over 500,000 of these deaths 2, with an incidence of about 1.1 million new cases being reported per year. The dielectrophoretic separation of infiltrating ductal adenocarcinoma cells (ADCs) from isolated peripheral blood mononuclear cells (PBMCs) in a ~1.4 mm long Y-shaped microfluidic channel with semi-circular insulating constrictions was numerically investigated. Here, ADCs (breast cancer cells) and PBMCs electrophysiological properties were iteratively extracted through the fitting of a single-shell model with the frequency-conductivity data obtained from AC microwell experiments. The radius of the semi-circular constrictions at which the effective potential difference was swept to obtain the optimum constriction size was also found. The numerical results, which were obtained by the integration of fluid flow, electric current, and particle tracing module in COMSOL v5.3, reveal that PBMCs can be maximally separated from ADCs using a DC power source of 50 V. This result is the first step towards the production of a supplementary or confirmatory test device to diagnose early-stage breast cancer and its progression non-invasively.

Tenogenically differentiating mesenchymal stem cells.

Tendons are collagenous musculoskeletal tissues that connect muscles to bones and transfer the forces necessary for movement. Tendons are susceptible to injury and heal poorly, with long-term loss of function. Mesenchymal stem cell (MSC)-based therapies are a promising approach for treating tendon injuries but are challenged by the difficulties of controlling stem cell fate and of generating homogenous populations of stem cells optimized for tenogenesis (differentiation toward tendon). To address this issue, we aim to explore methods that can be used to identify and ultimately separate tenogenically differentiated MSCs from non-tenogenically differentiated MSCs. In this study, baseline and tenogenically differentiating murine MSCs were characterized for dielectric properties (conductivity and permittivity) of their outer membrane and cytoplasm using a dielectrophoretic (DEP) crossover technique. Experimental results showed that unique dielectric properties distinguished tenogenically differentiating MSCs from controls after three days of tenogenic induction. Together, cell responses at the crossover frequency, cell morphology, and shell models showed that changes potentially indicative of early tenogenesis could be detected in the dielectric properties of MSCs as early as three days into differentiation. Differences in dielectric properties with tenogenesis indicate that the DEP-based label-free separation of tenogenically differentiating cells is possible and avoids the complications of current label-dependent flow cytometry-based separation techniques. Overall, this work illustrates the potential of DEP to generate homogeneous populations of differentiated stem cells for applications in tissue engineering and regenerative medicine.