Abstract
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•Biocompatible agents for early-stage cancer imaging is challenging.•CDs have broad excitation spectra, tunable emission spectra, and high photo-stability.•Surface modification of CDs improves their in vivo toxicity.•CQDs are promising candidates for target-specific bioimaging.
Carbon dots (CDs) are a significant component of fluorescence nanoparticles with exceptional chemical properties including excellent biocompatibility, low toxicity, and chemical inertness. CDs also have good optical properties such as broad excitation spectra, tunable emission spectra, and high photo-stability, drawing a lot of attention. Carbon quantum dots (CQDs) and graphene quantum dots (GQDs) are the two main subgroups of CDs. This review article presents recent developments in CD-based bioimaging and highlights critical surface modification techniques including doping, surface functionalization, polymer capping, nano-composite, and core–shell structures to improve their cutting-edge applications. We also outline recent developments in the field of CD-based bioimaging and summarize accomplishments in two broad categories: in vivo applications focusing on CD distribution and uptake for imaging-guided drug delivery and tumor therapeutics.