The role of deep eutectic solvents and carrageenan in synthesizing biocompatible anisotropic metal nanoparticles

Abstract

Plasmonic metal nanoparticles are widely used for many applications due to their unique optical and chemical properties. Over the past decade, anisotropic metal nanoparticles have been explored for imaging, sensing, and diagnostic applications. The variations and flexibility of tuning the size and shape of the metal nanoparticles at the nanoscale made them promising candidates for biomedical applications such as therapeutics, diagnostics, and drug delivery. However, safety and risk assessment of the nanomaterials for clinical purposes are yet to be made owing to their cytotoxicity. The toxicity concern is primarily due to the conventional synthesis route that involves surfactants as a structure-directing agent and as a capping agent for nanoparticles. Wet chemical methods employ toxic auxiliary chemicals. However, the approach yields monodispersed nanoparticles, an essential criterion for their intended application and a limitation of the green synthesis of nanoparticles using plant extracts. Several biocompatible counterparts such as polymers, lipids, and chitosan-based nanoparticles have been successfully used in the synthesis of safe nanomaterials, but there were issues regarding reproducibility and yield. Enzymatic degradation was one of the factors responsible for limiting the efficacy. Hence, it is necessary to develop a safer and nontoxic route towards synthesizing biocompatible nanomaterials while retaining morphology, high yield, and monodispersity. In this regard, deep eutectic solvents (DESs) and carrageenan as capping agent for nanoparticles can ensure the safety. Carrageenan has the potential to act as antibacterial and antiviral agent, and adds enhanced stability to the nanoparticles. This leads to a multidimensional approach for utilizing safe nanomaterials for advanced biomedical and clinical applications.

Natural Deep Eutectic Solvents in the Synthesis of Inorganic Nanoparticles

“…The mechanisms of nucleation and growth of nanoparticles are strongly dependent on the composition of the DES. The choice of components influences the production of a material with the desired reducing potential, and the presence of selected groups and compounds in the NDES system enables the preferential growth of crystals [ 11 ].…”

“…In the first step, the iron oxides were dissolved in ChCl/maleic acid with the oxides of the other metal. After 2 h of stirring, calcination processes were carried out (at 400, 500 or 600 °C) to obtain final nanoparticles with sizes of 120–480 nm, depending on the process conditions [ 11 ].…”

“…NDESs, which can be composed of several compounds, allow for the preparation of nanoparticles with well-defined sizes and shapes [ 10 , 11 ]. When using them in the synthesis of nanomaterials, NDES can play the role of redox agent, stabiliser, supramolecular template, reaction environment or pH regulator, all with no need to introduce additional reactants.…”

Recent Advances in the Synthesis of Inorganic Materials Using Environmentally Friendly Media

“…Platinum icosahedral nanocrystals with high-index facets and a higher electrocatalytic activity and stability were electro-synthesized in reline [ 54 ]. Further details on the role of Deep Eutectic Solvents in the synthesis of plasmonic (Au, Ag, Pt) nanoparticles can be found in the recent review of Des et al [ 55 ], who also describe biocompatible capping strategies that make use of polysaccharides (carrageenan), resulting in highly monodisperse nanoparticles. Other non-electrochemical redox reactions were carried out using environmentally friendly routes based on reline as a solvent: CuCl nanocrystal powder, which is a very useful catalyst for organic synthesis, was obtained either through the synproportion of CuCl 2 and Cu [ 56 ] or by the reduction of CuCl 2 by ascorbic acid [ 57 ].…”

Implication of adipocytes from subcutaneous adipose tissue and fatty acids in skin inflammation caused by λ-carrageenin in gilthead seabream (Sparus aurata)

“…Carrageenan has also been used in agriculture and in the pharmaceutical industry due to its antioxidant, antiviral, anticoagulant, antithrombotic, immunomodulatory and antitumor effects derived from the large negative charges it possesses, due to the sulphate groups [18]. In fact, these negative charges also allow carrageenan to form biopolymers that are being exploited in nanotechnology [25]. However, about 80% of all carrageenan produced (mostly from aquaculture algae of the genera Chondrus, Eucheuma, Gigartina, Iridaea, Furcellaria and Hypnea spp.)…”