thiolfunctionalized

Thiol.functionalized describes materials, surfaces, or molecules that bear thiol groups (-SH) as functional handles. The thiol moiety enables strong, often chemisorptive, attachment to metal surfaces (notably gold and silver) and provides a reactive site for further conjugation with biomolecules, polymers, or inorganic fragments.

Common approaches to introduce thiol functionality include: grafting thiol-terminated ligands or small molecules onto surfaces; silanization of oxide substrates with thiol-containing silanes such as (3-mercaptopropyl)trimethoxysilane; ligand exchange on nanoparticle surfaces with thiol-containing ligands; and reduction of preformed disulfides to reveal free thiols. Thiols can also be installed via thiol-ene or related click reactions.

Thiol groups are easily oxidized to disulfides, which can alter binding properties. On metal surfaces, gold–thiol bonds are robust but can be dynamic and replaceable by competing thiols or oxidative processes. Stability and reactivity depend on the surrounding environment, pH, and the specific thiol or protecting group used.

Applications span biosensing, surface functionalization for assays and cell attachment, immobilization of enzymes and antibodies, construction of functionalized nanoparticles for imaging or therapy, and catalysts in organometallic chemistry. Classic examples include gold surfaces modified with 11-mercaptoundecanoic acid to enable bioconjugation and silica surfaces silanized with (3-mercaptopropyl)trimethoxysilane; thiolated DNA probes are used in gene detection.

Characterization typically employs X-ray photoelectron spectroscopy to detect sulfur, infrared spectroscopy to monitor S–H vibrations, and electrochemical methods or contact-angle measurements to assess surface coverage and hydrophobicity. Because of their chemistry, thiol-functionalized materials require careful handling to preserve active thiol groups.