Carbon dots derived from edible fern (Stenochlaena palustris (Burm. fil.) Bedd.) for heavy metal sensing and biomedical applications

Carbon dots, a new family of nanoparticles that emit light, have lately garnered notable attention for their prospective use in nanobiotechnology, biomedical, and energy applications. The study presented a simple, useful, and eco-friendly technique for creating fluorescent carbon dots of Stenochlaena palustris utilizing a low-cost, natural hydrothermal synthetic process. The solution exhibits light blue fluorescence under UV irradiation. The UV Vis spectrophotometer peaks were seen at 280nm and 225nm resulting in n-π*(C=O) and π-π*(C=C) transitions respectively. FTIR revealed the presence of functional groups such as O-H, C-N, -NH 2 , C-O, C-O-C, C=C and aromatic rings. The crystallinity of CDs was elucidated by the X-ray diffraction pattern which showed a peak at 28˚ corresponding to the (002) plane of graphitic carbon indicating the presence of sp 2 hybridized carbon. High resolution TEM images revealed the presence of the lattice fringes of graphitic carbon, with an interplanar spacing of approximately 0.19 nm. In terms of their ability to detect heavy metal ions, carbon dots could detect Cd 2+ at the lowest concentration of 0.3 ppm. Carbon dots demonstrated 83% suppression of their radical scavenging capacity at the lowest volume of 1 μL. The maximum cytotoxicity was observed with 100 μL of the sample (%Viability-95.78%). Green fluorescence was emitted by the sample while observed under the blue filter of the inverted phase contrast fluorescence microscope. Therefore, carbon dots derived from S. palustris showed potential for a non-toxic antioxidant that can also be used as a fluorescent probe for the detection of Cd 2+ in water. • Carbon dots are notable for their wide range of application especially in biological systems. • Stenochlaena palustris is a climbing fern known for it’s use in traditional medicine. • Carbon dots synthesized from S. palustris showed strong antioxidant activity with minimum cytotoxicity. • It can also be used as a fluorescent probe for heavy metal sensing and bioimaging.