Plasma & Microwaves as Greener Options for Nanodiamond Purification: Insight Into Cytocompatibility

Abstract

The potential biomedical applications of nanodiamond have been considered over the last few decades. However, there is still uncertainty regarding the extent to which the surface characteristics of this material can influence potential applications. The present study investigated the effects of surface characteristics alongside the prospective of improving nanodiamond production using cold plasma and microwave technologies for the surface tailoring of the nanocarbons. Numerous approaches were applied to purify, refine and modify a group of nanosized diamonds at each step of their production cycle: from the detonation soot as the initial raw material to already certified samples. The degree of surface changes were deliberately performed slowly and kept at different non-diamond carbon presence stages, non-carbon elemental content, and amount converted superficial moieties. In total, 21 treatment procedures and 35 types of nanosize diamond products were investigated. In addition cultures of human fibroblast cells showed enhanced viability in the presence of many of the processed nanodiamonds, indicating the potential for dermal applications of these remarkable nanomaterials.

Advances in the Surface Functionalization of Nanodiamonds for Biological Applications: A Review

“…Recently, purification of the DND has been reported based on cold plasma treatment under vacuum followed by microwavebased purification to complete elimination of the remaining adsorbed organic and ionic species. 67 The application of oxidative (O 2 , air) or reductive (H 2 ) conditions has been shown to remove the majority of sp 2 -hybridized carbon from the DND surface, without the need of solution-based chemical interventions. This technique is an efficient and convenient procedure that is also employed to tailor the DND surface directly with functional groups such as -NH 2 , -SH, and -F.…”

“…In that work, the DND was treated with ozone under ambient temperature to form ozonide on the surface of a ND, which could be oxidized with H 2 O 2 to form carbonyl groups or be reduced with sodium borohydride (NaBH 4 ) to generate alcohol groups on the surface of NDs (Scheme ). Recently, purification of the DND has been reported based on cold plasma treatment under vacuum followed by microwave-based purification to complete elimination of the remaining adsorbed organic and ionic species . The application of oxidative (O 2 , air) or reductive (H 2 ) conditions has been shown to remove the majority of sp 2 -hybridized carbon from the DND surface, without the need of solution-based chemical interventions.…”

Designing functionalized nanodiamonds with hyaluronic acid–phospholipid conjugates for enhanced cancer cell targeting and fluorescence imaging capabilities

“…1 As a result, a wide variety of methods for their production has been developed, encompassing both top-down approaches, like detonation of carbon-containing explosives 1,2 and grinding of High-Pressure High-Temperature (HPHT) microdiamond powders, 3 and bottom-up techniques, such as Chemical Vapor Deposition (CVD) 4 and synthesis from adamantane derivatives. 5 Similarly, an extensive array of post-synthetic procedures, including treatments with microwave plasma, 6,7 high-temperature thermal processes in controlled environments [8][9][10] and wet chemistrybased strategies, [11][12][13] have been established. This combined spectrum of synthesis methods and subsequent modifications enables the creation of NDs with diverse sizes, covering the 5-300 nm range, morphologies, and surface characteristics.…”