Advances in virus detection using carbon and quantum dot technologies: a review.

BACKGROUND: The diagnosis of viral infections still depends largely on traditional lab methods like PCR and ELISA, which are often costly, time-consuming, and unsuitable for large-scale or low-resource testing. Because of these issues, researchers are exploring new approaches using nanotechnology. Quantum dots (QDs) and carbon dots (CDs) are two types of fluorescent nanodots with special optical and surface properties, becoming promising tools for detecting viruses. However, their different physical and chemical characteristics, biocompatibility, and integration potential lead to distinct analytical performances, highlighting the need for a comparative assessment of their applicability in viral biosensing. RESULTS: This review systematically analyses recent advances in QD- and CD-based biosensors for viral detection, covering both nucleic acid- and protein-based assays. QDs show advanced techniques, with integration into fluorescence, FRET, ECL, PEC, and lateral-flow formats, enabling multiplexed detection of several viruses, including dengue, HAV, HBV, and SARS-CoV-2. In contrast, CDs are mainly used for single-target fluorescence or electrochemical assays, indicating they are in an earlier stage of development. Comparative studies reveal that QDs-based viral assays can detect targets such as HIV-1 nucleic acids at levels as low as 6.5 × 10 M, which is generally one order of magnitude lower than CDs, though the latter show better biocompatibility and stability. QDs offer a wider range of sensitivity and performance, while CDs provide safer, simpler, and more sustainable sensing options. These differing features define their unique analytical roles and potential for practical use. SIGNIFICANCE: By bringing together findings from recent literature studies, this review bridges fundamental nanochemistry with practical virus diagnostics. It explains how QDs and CDs contribute differently to sensitivity, multiplexing, and biosensor integration, providing guidance for selecting suitable nanomaterials in analytical design. The comparative insights highlight pathways for developing cost-effective, safe, and portable viral detection platforms, supporting the transition of nanodot-based assays from the laboratory to clinical and field applications.