Fluorescent Carbon Nano-onion as Bioimaging Probe

Abstract

Concentrically arranged multilayered fullerenes exhibiting onion-like morphology are popularly known as carbon nano-onion (CNO) and are useful in bioimaging application. On the basis of the origin of the fluorescence, the CNO-based nanoprobes are classified into type I and type II. The type I CNO-based nanoprobe needs a secondary moiety such as organic dyes or an amine functionalization at its surface to induce the fluorescence. On the other hand, the emission in type II does not originate from such an external surface passivating agent. The CNO-based system not only shows structural similarity to the well-known multiwalled carbon nanotube but is also a bit more advantageous because of its low cytotoxicity. These features enable their prolonged use in the biological system for imaging purposes. In particular, we have covered the aspects of synthesis, surface functionalization, the origin of fluorescence, and biocompatibility. In addition, recent developments directed toward in vitro and in vivo imaging studies by utilizing CNO-based nanoprobes are summarized here.

Prospects of nano-carbons as emerging catalysts for enzyme-mimetic applications

“…Further, surface defects like dangling bonds, missing graphitic planes, steps, kinks, edge effects are responsible for the generation of surface-active sites. 46,87,88 Decrease in particle size also lowers the absorption energy and hence increases catalytic efficiency. The edge-rich nano-carbons provide a diverse set of flexible tuning options for the engineering and design of nanozymes.…”

Carbon Graphitization: Towards Greener Alternatives to Develop Nanomaterials for Targeted Drug Delivery

“…However, CNOs can have different structures, for example, a more spherical or polyhedral shape or different numbers of layers. CNOs show very low toxicity and, differing from fullerenes, good light emission properties, so they have been studied as bioimaging probes [ 193 ].…”

Carbon Nanomaterials Derived from Black Carbon Soot: A Review of Materials and Applications

“…This can be achieved via simple oxidation , and functionalization , methods. Moreover, in many cases, nanocarbons showed inherent photoluminescent properties that did not require any surface passivation/functionalization. , Additionally, good aqueous solubility and lesser toxicity make these nanocarbons very applicable in the field of imaging, bioimaging, sensing, etc. − Figure A shows the multiemissive emission profiles of CS-derived nanocarbons covering the full visible spectrum . Subsequently, the CS collected on the copper surface shows good fluorescence in aqueous and organic solvents without any further functionalization …”