Recent Applications of Melanin-like Nanoparticles as Antioxidant Agents

Abstract

Nanosized antioxidants are highly advantageous in terms of versatility and pharmacokinetics, with respect to conventional molecular ones. Melanin-like materials, artificial species inspired by natural melanin, combine recognized antioxidant (AOX) activity with a unique versatility of preparation and modification. Due to this versatility and documented biocompatibility, artificial melanin has been incorporated into a variety of nanoparticles (NP) in order to give new platforms for nanomedicine with enhanced AOX activity. In this review article, we first discuss the chemical mechanisms behind the AOX activity of materials in the context of the inhibition of the radical chain reaction responsible for the peroxidation of biomolecules. We also focus briefly on the AOX properties of melanin-like NP, considering the effect of parameters such as size, preparation methods and surface functionalization on them. Then, we consider the most recent and relevant applications of AOX melanin-like NPs that are able to counteract ferroptosis and be involved in the treatment of important diseases that affect, e.g., the cardiovascular and nervous systems, as well as the kidneys, liver and articulations. A specific section will be dedicated to cancer treatment, since the role of melanin in this context is still very debated. Finally, we propose future strategies in AOX development for a better chemical understanding of melanin-like materials. In particular, the composition and structure of these materials are still debated, and they present a high level of variability. Thus, a better understanding of the mechanism behind the interaction of melanin-like nanostructures with different radicals and highly reactive species would be highly advantageous for the design of more effective and specific AOX nano-agents.

Effect of Size, Shape and Surface Functionalization on the Antibacterial Activity of Silver Nanoparticles

“…[21,22] Indeed, due to their size, nanoparticles can be internalized in cells via mechanisms that are different with respect to small molecules [23], and that can change based on the physiochemical parameters of the nanoparticles [24][25][26][27]. Additional beneficial characteristics of nanoparticles' application in the biomedical field include biocompatibility [28,29], specific target recognition [24] and the ability to functionalize the surface and use them as carriers for drug delivery [30,31]. Most of the research attention in antibacterial activity has been focused on the development of silver nanomaterials.…”

Therapeutic strategy of biological macromolecules based natural bioactive compounds of diabetes mellitus and future perspectives: A systematic review

“…Nonetheless, there has been a resurgence of interest in and popularity of herbal drugs for several causes, containing privileges concerning the efficacy of herbal drugs, shifting user favorites towards natural drugs, the extreme prices and adverse side effects of current drugs, and advancements in herbal drugs brought about by the progress of modern technology [ 41 ]. Examining medicinal plants' chemical components and their traditional applications might lead to ground-breaking new drugs with fewer side effects [ 42 ]. More than 400 plant species have been found with hypoglycaemic action; a few of these plants are mentioned in Table 1 , including ivy gourd (Coccinia grandis), ginseng, and bitter melon (Momordica charantia).…”

“…Drug delivery systems based on nanotechnology have been investigated to see whether they can circumvent these drawbacks [ [45] , [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] ]. Nanostructured drug delivery devices have superior physicochemical and biological features to their microscale counterparts [ [38] , [39] , [40] , [41] , [42] ]. Optically, the former systems are superior; their surface areas, conductivities, and interactions with biological molecules are enhanced ( Fig.…”

Melanin-like nanoparticles alleviate ischemia-reperfusion injury in the kidney by scavenging reactive oxygen species and inhibiting ferroptosis

“… 10 , 11 , 12 , 13 In the meantime, the PDA’s catechol structure enables it to purge ROS. 14 , 15 This suggests that the combination of rutin and melanin-like nanoparticles (NPs) 16 could be a promising strategy for protection against ROS 17 and ferroptosis in IRI, despite the fact that this combination has not yet been established.…”