Green Synthesis and Biomedical Applications of Carbon Dots

Carbon dots are sub-10 nm fluorescent nanoparticles composed predominantly of carbon, oxygen and hydrogen, distinguished by strong photoluminescence, abundant surface functional groups and favourable biocompatibility. Green synthesis routes employ renewable biomass such as fruit peels, vegetable wastes and traditional herbal materials as carbon sources, using mild hydrothermal, microwave or calcination treatments that minimise toxic by-products and energy consumption. Tailoring surface chemistry through heteroatom doping or post-synthetic passivation enhances solubility, target specificity and optical properties. In biomedical contexts, carbon dots serve as bioimaging probes, drug-delivery vehicles, phototherapeutic agents and biosensors. Their intrinsic fluorescence facilitates real-time tracking in cells and small organisms, while surface functionalisation allows conjugation of drugs or targeting ligands. They exhibit catalytic, antioxidant and antimicrobial activities, enabling applications in wound healing, anti-inflammatory treatments and radical scavenging. Challenges include achieving standardised size distributions, understanding in vivo fate and ensuring long-term safety. Continued advances in green precursors and scalable production promise to underpin the clinical translation of carbon-dot platforms for diagnostics and therapy.

Research from Nature Portfolio

Recent studies have illuminated both safety considerations and advanced bioimaging applications. One investigation revealed that prolonged illumination of carbon dots can induce photodegradation into low-molecular-weight species that exhibit cytotoxic effects in normal and cancer cell lines. This finding underscores the importance of incorporating light-stability assessments into biocompatibility evaluations. Another report demonstrated the in vivo performance of hair- and skin-derived carbon dots in zebrafish. These naturally sourced particles exhibited high fluorescence quantum yields, exceptional photostability and negligible toxicity, enabling long-term imaging of developmental processes and clearance pathways. The work clarified how metabolic processing and ionic interactions govern fluorescence decay in living organisms, providing a framework for designing robust bioprobes.

Green Synthesis and Biomedical Applications of Carbon Dots publication trend

The graph below shows the total number of articles in green synthesis and biomedical applications of carbon dots across all publications each year (not limited to Nature Index journals).

Technical terms

Carbon dots (CDs): quasi-spherical nanomaterials (<10 nm) composed mainly of carbon atoms, exhibiting photoluminescence and versatile surface chemistry.

Green synthesis: preparation methods that use benign, renewable precursors and minimise toxic reagents and waste.

Photoluminescence quantum yield (QY): the ratio of emitted to absorbed photons, indicating fluorescence efficiency.

Theranostics: integration of therapeutic and diagnostic functions within a single nanoplatform.

ADME-T: pharmacokinetic processes of absorption, distribution, metabolism, excretion and toxicity governing nanomaterial fate in vivo.

References

1. Review on carbon dots: Synthesis and application in biology field. BMEMat (2023).
2. Photodegradation of carbon dots cause cytotoxicity. Nature Communications (2021).
3. In vivo characterization of hair and skin derived carbon quantum dots with high quantum yield as long-term bioprobes in zebrafish. Scientific Reports (2016).
4. Carbon Dot Therapeutic Platforms: Administration, Distribution, Metabolism, Excretion, Toxicity, and Therapeutic Potential. Small (2022).
5. Herbal medicine derived carbon dots: synthesis and applications in therapeutics, bioimaging and sensing. Journal of Nanobiotechnology (2021).