Synthesis of a highly fluorescence nitrogen-doped carbon quantum dots bioimaging probe and its in vivo clearance and printing applications

Abstract

Highly fluorescent, broad range pH and ionic-stable N-doped carbon quantum dots (N-CQDs) were successfully synthesized and their chemical structure and fluorescence mechanism were characterized.

Facile synthesis of N-rich carbon quantum dots from porphyrins as efficient probes for bioimaging and biosensing in living cells

“…Similar to other CQDs reported in literature, [41][42][43] the asprepared CQDs and M-CQDs in aqueous solution exhibited strong luminescence. Figures 6A, S2, and S3 show the UVvis absorption, PL spectra, and excitation spectrum of the CQDs and M-CQDs in aqueous solution, respectively.…”

Synthesis and characterization of Mono-disperse Carbon Quantum Dots from Fennel Seeds: Photoluminescence analysis using Machine Learning

“…The lattice fringes within the particles indicate that the as-synthesized C-QDs were crystalline; noticing that the lattice spacing in the C-QDs was found to be 0.21 nm (see the SI Fig. S2 for high-resolution lattice spacing) can be assigned to (100) plane of carbon particle 24 . In general, C-QDs synthesized from natural and synthetic molecular carbon sources have the amorphous carbon structure; either the whole C-QD structure was amorphous, or C-QDs have a crystalline core with an amorphous outer shell 14,29 .…”

“…Unlike to the thermal decomposition process, the narrow size distribution of C-QDs can be easily achieved via hydrothermal method because molecular carbon precursors provide much needed homogenous nucleation to govern the size of as-synthesized C-QDs 24 . However, the narrow size distribution of C-QDs synthesized by thermal decomposition, in the present report, is comparable with hydrothermal method 24 and it is quite remarkable because by using the natural carbon source such kind of narrow size distribution was never reported beforehand 14,17 . There are multiple reports where the authors have used the pyrolysis method and natural carbon source as starting materials; however, the synthesized C-QDs had a considerable size variation 16 .…”

“…The fluorescence emission of the C-QDs is quite complex and not yet fully understood. Traditionally, pH-dependent photoluminescence (PL) spectra of C-QDs are analyzed at a fixed excitation and completely ignore many other possible excitations, however, using such approach only partial information is extracted 6,8,9,13,16,17,19–21,24,25 . Analyzing the C-QDs at different pH for a wide range of excitation can, additionally, provide much valuable information than the conventional techniques.…”

“…(ii) Can ML assist in finding out the source of PL mechanism given that the multiple-set PL measurements at various pH and excitation wavelength can activate the different type of surface state? C-QDs of narrow size distribution are highly desirable and have a range of potential applications in bio-sensing, cellular imaging, LED, solar cell 13,27,28 , supercapacitor 29 , printing 24,30 , and sensors 31 .…”