Biomass-derived phosphorous-doped carbon quantum dots (P-CQD): An excellent biocompatible material for in-vitro cell imaging.

[Display omitted] • Fluorescent phosphorous doped carbon quantum dots from banana stem were synthesized by a facile hydrothermal method. • P-CQDs exhibited excellent water solubility, fluorescent stability and superb biocompatibility. • The P-CQD have been employed for fluorescence-based imaging of biological samples. In this work, a simple hydrothermal process was employed to create phosphorous-doped fluorescent carbon quantum dots (P-CQD) from biomass banana stems. The formation of the P-CQDs and the surface functional group was confirmed through a variety of characterization methods, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), (transmission electron microscopy) TEM, (field emission scanning electron microscopy) FESEM, Fourier transform infrared spectroscopy (FTIR), and (ultraviolet–visible) UV–vis spectroscopy. The quantum yield of the synthesized P-CQDs was found to be 15 %. The P-CQDs showed excitation-dependent photoluminescence (PL) emission behaviour possessing a blue fluorescence under UV light. The P-CQDs was utilized for in vitro cytotoxicity effect on Muscle (L6) and Kidney cells (HEK293). The minimum cell viability for the P-CQD was 96.24 %, while the maximum cell viability was approximately 100 % at a concentration of 400 μg/mL. This study suggests that P-CQDs were non-toxic and could be employed for fluorescence-based cell imaging. [ABSTRACT FROM AUTHOR]