(374d) Unraveling the Effect of Glucose on Candida Auris Using Dielectrophoresis

Candida auris is a rapidly emerging fungal pathogen recognized as a major global health threat. According to the CDC, over 2,300 clinical and nearly 5,800 screening cases were reported in the U.S. in 2022. Conventional diagnostic methods such as culture-based assays, often fail to accurately detect C. auris, resulting in misdiagnosis and inappropriate treatment. Molecular techniques, while more accurate, are expensive and require sophisticated equipment, highlighting the urgent need for rapid, precise, and accessible diagnostic alternatives. Given the critical role of glucose in C. auris metabolism, this study investigates how glucose availability influences the organism's ionic concentrations and enzyme activity—factors that, in turn, alter its dielectric properties. By characterizing dielectric changes under glucose-supplemented and glucose-limited conditions, we aim to develop a dielectrophoresis (DEP)-based label free, diagnostic tool for the rapid detection of C. auris.

In this study, we present a novel DEP-based approach for identifying C. auris by assessing its dielectric signatures. Strain CA1100 of C. auris was cultured in UFTYE media, washed in 145 mM sodium chloride, and resuspended in a low-conductivity buffer (80 μS/cm) composed of 8.5g sucrose and 0.3g dextrose. Using 3DEP technology, we quantified key electrical parameters including cytoplasm conductivity and permittivity, as well as specific membrane conductance and capacitance. For glucose-supplemented conditions, cells were exposed to 1% glucose for 40 minutes post-wash prior to being resuspended in the DEP buffer.

Our findings demonstrate that glucose exposure significantly alters the dielectric profile of C. auris, increasing the cytoplasmic conductivity, specific membrane conductance, and specific membrane capacitance. Notably, the glucose-supplemented cells exhibited a lower crossover frequency, suggesting enhanced dielectric activity at reduced frequencies. These dielectric shifts may serve as distinct biomarkers for DEP-based identification.

This approach offers a promising alternative to traditional diagnostic techniques, enabling rapid, label-free detection of C. auris suitable for point-of-care and resource-limited settings. Notably, C. auris is often multidrug-resistant, limiting the effectiveness of conventional antifungal treatments and complicating infection control. By improving both the speed and accuracy of detection, this DEP-based platform could play a vital role in early intervention, supporting more effective treatment decisions and enhancing screening efforts to contain the spread of resistant strains in healthcare environments.