Improved detection of Candida albicans with carbon nanotube field-effect transistors

A biosensor for detecting Candida albicans has been developed to improve the performance characteristics of the currently available methods. It is based on a field-effect transistor (FET) in which a network of single-walled carbon nanotubes (SWCNTs) acts as the conductor channel. Monoclonal anti-Candida antibodies were adsorbed onto the SWCNT to provide specific binding sites for fungal antigens. Tween 20 at 0.5% was used as a blocking agent to prevent the non-specific binding of other yeasts or proteins. Our FET devices were exposed to increasing concentrations of C. albicans and were able to detect at least 50 cfu/mL in only 1 h. The sensor response remained stable for more than 10 days. To evaluate the selectivity of our FET devices, Cryptococcus albidus and Saccharomyces cerevisiae were tested as potential competing yeasts for C. albicans. The results showed that biosensors based on a carbon nanotube field-effect transistor are useful tools to detect pathogenic yeasts like C. albicans at low concentrations displaying high selectivity.