Hybridization-based gold nanoprobe assay for the detection of candidemia in ICU patients - A novel method

Candidemia is a life-threatening infection in ICU patients, with mortality rates of 35-75%, yet current diagnostic methods such as blood culture and conventional Polymerase chain reaction (PCR) lack the sensitivity required for timely detection. Therefore, it is of interest to address this unmet diagnostic need, we developed a hybridization-based gold nanoprobe (AuNP) colorimetric assay for the direct detection of Candida DNA from 3 ml EDTA blood samples. AuNPs were functionalized with Candida-specific thiol-modified oligonucleotide probes using a modified salt-aging process and target DNA hybridization was performed at 56°C followed by visual colour assessment. The assay demonstrated 76% sensitivity, significantly outperforming conventional PCR at 24%, with positive results showing a distinct red-to-purple colour shift and a detection limit of 10 ng/µL. This rapid, low-cost, naked-eye-readable method using UV-Vis spectroscopy is particularly suitable for resource-limited ICU settings, offering a practical tool for earlier candidemia diagnosis and improved clinical outcomes.