Thiol/thiolate poly polymer

Thiolated mucoadhesive polymers are synthesized by a covalent attachment between a cysteine (Cys) residue and a polymer of choice, such as polycarbo-phil [46], poly(acrylic acid) [47], and chitosan [48]. These polymers are known as a new generation of mucoadhesive polymers. These moderen class of polymers contain a carbodiimide-mediated thiol bond which exhibit mnch improved bioadhesive properties. 

For example, Wuelfing et al. reported on the synthesis of Au NPs using the thiolated polymer, a-methoxy-co-mercapto-poly(ethylene glycol) (PEG-SH), as stabilizer in a modification of the Brust-Schiffrin method using a 1/12 polymer thiol/ AuC14 ratio. Transmission electron microscopy showed that the product had modestly polydisperse Au cores of average diameter 2.8 1 nm. This nanomaterial led to characteristics uniquely different from alkanethiolate MPCs, notably aqueous solubility, thermal and chemical stability, ligand footprint size, and ionic conductivity [66]. 

In a recent study, some authors proposed the employment of thiolated polymers obtained by the immobilization of thiol groups on well-established multifunctional polymers such as poly(acrylates) and chitosans as functional agents having mucoadhesive, penetration enhancement, and enzyme-inhibiting properties [94,95]. 

---