Thiolated Nanoparticles for Biomedical Applications: Mimicking the Workhorses of Our Body

Abstract

Advances in nanotechnology have generated a broad range of nanoparticles (NPs) for numerous biomedical applications. Among the various properties of NPs are functionalities being related to thiol substructures. Numerous biological processes that are mediated by cysteine or cystine subunits of proteins representing the workhorses of the bodies can be transferred to NPs. This review focuses on the interface between thiol chemistry and NPs. Pros and cons of different techniques for thiolation of NPs are discussed. Furthermore, the various functionalities gained by thiolation are highlighted. These include overall bio-and mucoadhesive, cellular uptake enhancing, and permeation enhancing properties. Drugs being either covalently attached to thiolated NPs via disulfide bonds or being entrapped in thiolated polymeric NPs that are stabilized via inter-and intrachain crosslinking can be released at the diseased tissue or in target cells under reducing conditions. Moreover, drugs, targeting ligands, biological analytes, and enzymes bearing thiol substructures can be immobilized on noble metal NPs and quantum dots for therapeutic, theranostic, diagnostic, biosensing, and analytical reasons. Within this review a concise summary and analysis of the current knowledge, future directions, and potential clinical use of thiolated NPs are provided.

Hybrid porous Ni(OH)2‐MnO2 nanosheets/plasma‐grafted MWCNTs for boosted supercapacitor performance

“…We proposed that parts of the -SH are attacked by free radicals and oxidized to SO 2 H (sulfinic acid) or -SO 3 H (sulfonic acid) [25]. This phenomenon changed the lipophilic behavior of CNT to hydrophilic by introducing the thiol group [26].…”

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“…The more robust net positive charge after thiolation makes NANO3-SH particularly interesting for cellular therapeutic applications, namely CRC therapy, as positively charged particles have been recurrently reported to have preferential binding activity to cell membranes and increased uptake [ 58 ]. Moreover, enhanced cellular uptake has been reported for several thiol-containing nanoparticles, which covalently bind/interact with cell surface thiol groups, increasing 100-fold the membrane transfection efficiency and endocytosis [ 59 ].…”

Thiol-Functionalized, Antioxidant, and Osteogenic Mesoporous Silica Nanoparticles for Osteoporosis

“…It is believed that thiols modulate inflammation via the NF-κB pathway. Thiol-based antioxidants have been found to mitigate the effects of oxidative stress in earlier studies. , It has been reported that there are decreased thiol/glutathione levels and thiol/disulfide imbalance in osteoporotic females. − Owing to their mucoadhesive nature and cell permeation ability, thiolated polymers and nanoparticles have been employed in ophthalmic, nasal, and vaginal drug delivery systems (DDS). , Earlier studies have reported tissue regeneration and wound healing by thiolated systems. Li et al studied thiolated gelatin for wound repair and scaffold for tissue engineering; likewise, Lin et al investigated the histatin-modified chitosan hydrogel for wound healing applications .…”

“…20−22 Owing to their mucoadhesive nature and cell permeation ability, thiolated polymers and nanoparticles have been employed in ophthalmic, nasal, and vaginal drug delivery systems (DDS). 23,24 Earlier studies have reported tissue regeneration and wound healing by thiolated systems. Li et al studied thiolated gelatin for wound repair and scaffold for tissue engineering; 25 likewise, Lin et al investigated the histatin-modified chitosan hydrogel for wound healing applications.…”