Green-Synthesized Hyaluronic Acid-Conjugated Fluorescent Graphene Quantum Dots for Bioimaging and Cancer Theranostics: Synthesis, Characterization, and Cytotoxicity Assessment.

Designing of fluorescent materials in biomedical sciences is gaining attention due to unique characteristics like imaging driven by diagnosis and treatment. The exploration of fluorescent materials from green sources with highlights its application arena in cancer theranostic gained significant attention of oncology researchers. Outwards to the bioimaging techniques, fluorescent graphene quantum dots (fGQDs) grasp a potential place in biomedical research. Additionally, fGQDs have tuneable surface characteristics with high fluorescence, high loading and permeation capability. The present investigation explored the green synthesis of fGQDs using star anise fruit as precursor followed by surface decorated hyaluronic acid (HA) to form conjugated HA - GQD. The advance spectral characterization was used to confirm the synthesis of fGQDs and HA-GQD. The emission at 338 nm with excitation at 576 nm promise strong fluorescence with quantum yield of 16.52%. The conjugated HA-GQDs shows prominent bioimaging capability and lower cytotoxic potential at concentration less than 40 µg/ml. While cell inhibition against MCF-7 was dramatically increases at concentration above 100 µg/mL suitable to promote synergistic inhibition with other anticancer agents. This work demonstrates a sustainable route for developing multifunctional nanomaterials with promising application in cancer theranostics.