Carbon Nano-onions: A Valuable Class of Carbon Nanomaterials in Biomedicine

Abstract

: The development of nanoscale materials is an important area of research as it provides access to materials with unique properties that can be applied to improve quality of life. Multi-layer fullerenes, also known as carbon nano-onions (CNOs) are an exciting class of nanostructures which show great versatility and applicability. They find applications in several fields of technology and biomedicine. This review highlights the potential advantages of CNOs for biomedical applications, which include but are not limited to bioimaging and sensing. Their good biocompatibility renders them promising platforms for the development of novel healthcare devices.

Carbon Nano‐Onions Made Directly from CO2 by Molten Electrolysis for Greenhouse Gas Mitigation

“…In 2015 we introduced a chemistry to synthesize CNTs at high yield by electrolysis of CO 2 , [1,[29][30][31][32][33][35][36][37][38][39] rather than their conventional CVD synthesis from organometallics. We have demonstrated [31] and quantified [39] the affinity for molten lithium carbonates to absorb both atmospheric and flue gas levels of CO 2 , and have previously utilized 13 C isotope CO 2 to track and demonstrate in molten lithium carbonate that CO 2 originating from the gas phase serves as the renewable carbon building blocks in the observed CNT product and the net reaction is in accord with [31] ( ) (…”

“…CO 2 is bubbled into a molten carbonate and split by electrolysis, and the moltenate carbon has a high affinity for CO 2 absorption. [12] Biomedical applications have also been investigated, [13] and functionalized [14] and larger CNOs have been demonstrated to support high pressure before fracture, and demonstrated for aqueous-based lubrication as "ball bearings." Due to synthetic complexities, CNOs are only available in small quantities, but this value is 20 000 fold higher than the price of power plant coal.…”

“…[26] According to a recent review, thermal detonation anneal of nanodiamond powders has emerged as the most practical method for producing carbon nano-onions with a pricing that needs to include the ≈$2.4 million per ton price of the nanodiamonds precursor. We have demonstrated [31] and quantified [39] the affinity for molten lithium carbonates to absorb both atmospheric and flue gas levels of CO 2 , and have previously utilized 13 C isotope CO 2 to track and demonstrate in molten lithium carbonate that CO 2 originating from the gas phase serves as the renewable carbon building blocks in the observed CNT product and the net reaction is in accord with [31] ( ) ( A producer sells 40±20 nm quasi spherical carbon nano-onions in gram quantities at a ton extrapolated price of $195 million per ton (including the academic discount), [27] another sells 37±7 nm carbon onions with 50-55 concentric layers with an extrapolated price (from 0.1 g units sold) of $3350 million per ton.…”

“…[10] Balancing symmetry and defects with high conductivity facilitates CNOs use as effective electromagnetic shielding provides efficient attenuation of the EMF spectrum from 12 to 203 THz, [11] and strong optical limiting action with negligible nonlinear refraction. [12] Biomedical applications have also been investigated, [13] and functionalized [14] and larger CNOs have been demonstrated to support high pressure before fracture, and demonstrated for aqueous-based lubrication as "ball bearings." [15] Carbon nano-onions can be produced in gram-scale quantities by treatment of commercially available nanodiamonds or by the combustion of naphthalene [14,16] or by CVD (catalytic and noncatalytic).…”

Surfactant-mediated dispersions of carbon nano-onions in aqueous solution

“…The development in recent years of efficient chemical approaches based on covalent and non-covalent functionalization of the CNO surface has helped to address this drawback, opening the way for their use in a vast range of applications [5,6].…”