thiolated

Thiolated describes a molecule or material that has been chemically modified to introduce thiol, or sulfhydryl (-SH), groups. The thiol group is highly reactive and can form covalent bonds with metals, especially gold, via gold–thiol (Au–S) bonds, and can engage in disulfide exchange with other thiols or disulfides. Thiolation thereby enables surface attachment, bioconjugation, crosslinking, and assembly of complex materials.

Methods for thiolation vary by starting material. In bioconjugation, amine groups on proteins or peptides can be converted to thiols using reagents such as Traut’s reagent (2-iminothiolane) or N-succinimidyl S-acetylthioacetate (SATA), followed by deprotection. For polymers and surfaces, thiol groups can be introduced by grafting thiol-terminated silanes, by post-synthetic modification with thiolating reagents, or by reducing disulfide bonds to reveal free cysteine-like thiols. Thiolated ligands and polymers are often designed with protection strategies to control reactivity.

Applications of thiolated materials are broad. They include immobilizing biomolecules on metal or oxide surfaces, forming self-assembled monolayers, creating thiol-based linkers for nanoparticle functionalization, designing mucoadhesive polymers for drug delivery, and constructing biosensors that rely on thiol–metal chemistry for signal transduction. In tissue engineering, thiolated polymers can form disulfide crosslinks under reducing conditions, enabling degradable networks.

Safety and handling considerations include odor from thiols and potential reactivity of thiol groups, which require appropriate protective equipment and fume hoods during synthesis and handling.