Carbon-based quantum dots in oncology: Properties and applications in cancer therapy and diagnosis

Carbon dots (CDs) are emerging as transformative nanomaterials in the field of cancer diagnostics due to their unique photoluminescence, high biocompatibility, aqueous solubility, and facile surface functionalization. This review presents a comprehensive synthesis of recent advancements in the application of multifunctional CDs for cancer diagnosis. Emphasis is placed on their potential as optical probes for non-invasive bioimaging, fluorescence-guided tumor identification, and early-stage cancer detection. The photophysical properties of CDs- including excitation-dependent emission and size-tunable fluorescence enable high-contrast imaging with reduced photobleaching, which is critical for real-time monitoring of tumor microenvironments. Additionally, CDs offer significant promise in biosensing platforms for detecting cancer biomarkers such as nucleic acids, proteins, and specific antigens with high sensitivity and specificity. Their functionalized surfaces facilitate conjugation with targeting ligands, enabling selective cellular uptake and tumor localization. This review also highlights the advantages of CDs over conventional contrast agents, including reduced toxicity, deeper tissue penetration in the near-infrared range, and the capability for multimodal imaging. Key synthetic routes are compared in terms of yield, scalability, and control over optical properties. Despite these advantages, translational challenges remain, particularly in terms of standardizing synthesis, ensuring reproducibility, and evaluating long-term biocompatibility. Overall, CDs represent a promising frontier in precision diagnostics, offering the potential for integration into next-generation diagnostic nanoplatforms that aim for early, accurate, and minimally invasive cancer detection. • CDs enable customizable fluorescence for cancer imaging and early detection. • CDs are suitable for biological applications due to their biocompatibility and low toxicity levels. • Functionalized CDs allow for controlled drug delivery and tumor identification. • CDs act as both photothermal and photodynamic agents in cancer therapy. • Machine learning improves CD synthesis for precise medicinal applications.