Red fluorescent carbon nanoparticles derived from Spinacia oleracea L.: a versatile tool for bioimaging and biomedical applications

Carbon-based fluorescent nanoparticles are an emerging class of nanoparticles for targeted bioimaging and biomedical applications. We present a facile microwave-assisted approach for synthesizing carbon nanoparticles with bright red fluorescence using ethanolic extracts of Spinacia oleracea leaves, with a quantum yield of 94.67%. These nanoparticles, called CNPs, of size 98 ± 20 nm, demonstrated fluorescence emission in the near-infrared (NIR) region between 650 and 700 nm, independent of the excitation wavelength. Upon excitation at a wavelength of 410 nm, they exhibit an emission maximum peak at 672 nm. The significant uptake of CNPs by mammalian cells and zebrafish larvae highlights their potential as a bioimaging agent in diverse biomedical applications in vivo. Furthermore, these quantum dots enhance cellular proliferation and migration as observed by wound healing assay in mammalian cells, indicating their possible application in tissue engineering and regenerative medicine. These findings suggest that the biosynthesized carbon nanoparticles possess significant potential for biomedical applications, which can serve as a robust benchmark for researchers towards promoting sustainability.