Banerjee, Indranil

Reduced graphene oxide (rGO) is a potential biomaterial for tissue engineering, photothermal therapy, and drug delivery. However, the hydrophobic nature of rGO results in poor dispersibility in a physiologically relevant aqueous environment, limiting its biomedical applications. To surmount this problem, here, we have developed a silanized derivative of reduced graphene oxide (rSiGO) using 3-Aminopropyl) triethoxysilane and evaluated its impact on [I] stability of rGO in different aqueous solvents, [ii] drug loading capacities, and [iii] biocompatibility. The physico-chemical characterization suggested that silanization alters the 2D carbon skeleton of rGO to a certain extent and improves its aqueous dispersibility and drug-loading capacity. The in vitro cytocompatibility study showed that rSiGO was compatible with the human dermal fibroblasts and murine fibroblast cell lines. It was also found that rSiGO possesses a higher loading capacity for hydrophilic drugs than rGO. The drug-loaded rSiGO showed higher cytotoxicity against hepatocarcinoma cells by inducing intracellular reactive oxygen species production, apoptosis, and nuclear fragmentation. In vivo systemic toxicity studies in mice showed that the rSiGO is nontoxic at the tested concentration. These results clearly showed that silanization improves the aqueous dispersibility, drug loading capacity, and biocompatibility of rGO making it a better candidate for various biomedical applications.

Oleogelation is an efficient oil-structuring technique commonly utilized to form oleogels using vegetable oil. This chapter aims to summarize current developments in the production of oleogels by structuring liquid oil with the help of lipids. The structuration occurs through oleogelators that are classified as high-molecular- and low-molecular-weight oleogelators (LMOGs). LMOGs, importantly waxes, can form a three-dimensional network within the oil at a low concentration (1%–3% w/w). Wax-based oleogels form through the direct dispersion method, giving rise to crystallite formation. The process of oleogel crystallization is similar to fat crystallization, which occurs in three stages, including nucleation, crystal growth, and polymorphic transition. Emulsifiers are amphiphilic molecules that often affect the stages of crystallization in oleogels. The effect of emulsifiers comes from the organization of crystals during the crystallization stages. Majorly the formulated oleogels are characterized through different microscopic studies, molecular characterization, and thermal studies. The field of oleogels has evolved quite progressively since 1960, which has been highlighted in this review through the bibliometric study. The study also confirmed the potential applications of the oleogels highlighting the field of novel delivery systems for drug and nutrient delivery along with their use in replacing saturated solid fat without compromising the organoleptic properties.