Carbon Dots in Cancer Diagnosis: A Review of Recent Advances and Clinical Perspectives

Abstract

Early and accurate diagnosis is crucial for effective therapy and improved patient outcomes in cancer. Conventional diagnostic tools such as magnetic resonance imaging, computed tomography, and positron emission tomography scan often face challenges including limited sensitivity, specificity, and responsiveness, particularly in early-stage cancers. Carbon dots (CDs), an emerging class of carbon-based nanomaterials, may serve as an alternative owing to their unique optical properties, excellent biocompatibility, low cytotoxicity, and versatile surface chemistry. Typically, less than 10 nm in size, CDs display excitation-dependent photoluminescence spanning visible to near-infrared wavelengths, allowing deep-tissue, high-contrast imaging with reduced background interference. Their functionalized surfaces enable conjugation with antibodies, aptamers, and ligands, enhancing targeted bioimaging, biosensing, and image-guided surgical or therapeutic interventions. Beyond imaging, CDs have evolved into multifunctional theranostic platforms capable of integrating diagnostics with drug delivery, photodynamic, and photothermal therapy, enzymatic tumor modulation, and microenvironment-responsive activation. Advances in green synthesis and scalable bottom-up fabrication have further strengthened their translational potential, offering eco-friendly routes to clinically relevant CD formulations. Nonetheless, key challenges persist, including long-term biosafety, reproducibility, and regulatory approval. This review summarizes recent progress, clinical relevance, and future perspectives of CDs in cancer bioimaging, biosensing, and theranostics, underscoring their promise in precision oncology.