EG-FETs Equipped with Selected Aptamers as Specificity Determinants for Sensitive Quantification of the WHO Priority Pathogenic Yeast Cryptococcus neoformans
Description
According to the WHO, Cryptococcus neoformans is one of the most critical fungal pathogens worldwide, causing severe and often life-threatening infections, particularly in HIV or other immuno-compromised patients. While current diagnostic methods are generally reliable, misidentification with morphologically related fungi can occur in certain settings, potentially leading to severe consequences. In this study, we developed an aptamer-based biosensing strategy for the specific detection of C. neoformans. Using six rounds of FluCell-SELEX with counter selection against Candida albicans, Candidozyma auris, and Candida parapsilosis, three individual aptamers (Anti-CN-1, Anti-CN-2, and Anti-CN-3) were identified from an enriched oligonucleotide-based library. Fluorescence-based assays confirmed high specificity of all aptamers toward C. neoformans, even in complex fungal environments. Moreover, binding affinity analysis revealed low nanomolar dissociation constants ranging from 3.05–5.60 nM, demonstrating strong and reliable target interaction. Integration of the aptamers into reduced graphene oxide electrolyte-gated field-effect transistor (EG-FET) biosensors, enabling label-free electrical detection of C. neoformans with limits of detection as low as 10 cells/mL. Collectively, these findings demonstrate that the tested aptamer-functionalized EG-FET biosensors provide a sensitive and selective platform for a rapid, label-free and user-friendly detection of C. neoformans, highlighting their potential for future point-of-care diagnostic applications.
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Institutions
- Universität UlmBaden-Wurttemberg, Ulm