(449e) Label-Free Detection of Babesiosis Via Dielectrophoretic Profiling of Babesia Microti-Infected Red Blood Cells

Babesia microti, the primary causative agent of human babesiosis in the United States, is a tick-borne parasite that invades and replicates within red blood cells (RBCs). With rising cases, especially among immunocompromised individuals and blood transfusion recipients, early and accurate detection of babesiosis is becoming increasingly critical. Current diagnostic methods including Giemsa-stained blood smear microscopy, PCR, and serological assays are time-intensive, reagent-dependent, and poorly suited for point-of-care applications. Thus, there is a pressing need for rapid, label-free diagnostic techniques capable of detecting infected RBCs at the single-cell level.

In this study, we present a novel approach for detecting B. microti-infected RBCs using dielectrophoresis (DEP), a label-free technique that distinguishes cells based on their unique dielectric properties. We hypothesize that the intracellular infection alters the electrical characteristics of the host RBC, such as membrane capacitance and cytoplasmic conductivity, due to changes in cell morphology, ion distribution, and metabolic activity. These changes, in turn, result in a distinct DEP response compared to uninfected RBCs.

To test this, we used 3DEP technology to obtain the dielectric profile of healthy and B. microti-infected RBCs. Blood samples from both healthy and B. microti-infected BALB/c mice, collected via cardiac puncture, were gravity separated to collect packed RBCs. The packed RBCs were suspended in a DEP medium at various conductivities ranging from 0.01-0.05 S/m and introduced into the device. Cells were subjected to an AC frequency sweep ranging from 0.5 kHz to 45 MHz at a fixed voltage of 10 _Vpp to evaluate their crossover frequency, the point at which the DEP force transitions from positive to negative or vice versa.

Our previous study revealed significant alterations in the dielectric properties and crossover frequency of RBCs infected with Babesia bovis, highlighting the potential of dielectrophoresis for detecting intracellular parasite infections. Although data collection and analysis for B. microti are ongoing, this study aims to lay the groundwork for a rapid, portable diagnostic tool for babesiosis. The proposed platform offers a cost-effective alternative for early screening and disease management, particularly in low-resource or blood bank settings. Moreover, our approach holds promise for broader applications in the label-free detection of other intracellular pathogens.

In conclusion, this study presents the first dielectrophoretic characterization of Babesia microti-infected RBCs and establishes the biophysical signatures that can be leveraged for rapid diagnostic development. Our work demonstrates the potential of integrating biomedical microdevices with infectious disease diagnostics, representing a significant step forward in non-invasive, label-free screening technologies for parasitic infections.