Natural zwitterionic organosulfurs as surface ligands for antifouling and responsive properties

Abstract

Natural sulfur-containing zwitterionic compounds, l-cysteine (Cys), l-methionine, and glutathionine (GSH), have been employed as surface ligands to prevent protein nonspecific adsorption on planar substrates. These organosulfur compounds form self-assembled monolayers (SAMs) on gold substrates by gold–sulfur interaction. The chemical elements of SAMs were confirmed using x-ray photoelectron spectroscopy. The surface wetting tests for SAMs show that films prepared from Cys and GSH exhibited super-hydrophilicity (contact angles of θ = ∼5°) due to their high coverage and strong hydration via ionic solvation and formation of hydrogen bonding. Quartz crystal microbalance with dissipation sensor was used to quantitatively and qualitatively monitor the adsorption of bovine serum albumin (BSA) from buffer onto these SAMs. It was found that the GSH film enables the resistance of BSA adsorption to the best extent at a physiological pH. Moreover, the surface charges of modified substrates were modulated by varying the pH value to control BSA adsorption. The effect of electrostatic repulsion on the antifouling behavior becomes prominent at a pH where the protein and the surface carry same charges. Consolidating the BSA adsorption measurements at different pH values, the antifouling properties of GSH-modified Au should be attributed to prevention of entropy gain and enthalpy loss, making BSA adsorption energetically unfavorable. It is believed that the surface modification with natural organosulfur ligands holds great potential in improving the biocompatibility of medical devices and in offering intelligent biointerfaces in response to environmental stimuli.

Bio-inspired multifunctional catecholic assembly for photo-programmable biointerface

“…Therefore, the surface mass densities on SB-DA and SB-nDA were = 8.85 and 24.78 ng/cm 2 , whereas on bare TiO 2 the fouling level reached 300.90 ng/cm 2 . The low fouling levels of SB-conjugated dopamine derivatives in this study were quite close to those obtained using other zwitterionic SAM systems based on thiol and silane anchoring groups [13][14][15][16]. From the bacterial and protein adsorption studies, we confirmed that the nitro substitution on the catecholic group does not affect the formation of compact and stable thin films, and the function of SB in the fouling resistance.…”

“…The TiO 2 covered QCM crystal chips (AT-cut quartz crystals, f 0 = 5 MHz) (Q-Sense AB, Gothenburg, Sweden) were cleaned according to previous publication [13]. After SB-DA or SB-nDA modification, the chip was mounted in a flow cell with a quartz window.…”

“…Polyzwitterions are particularly attractive because of their high thermal and hydrolytic stability and relatively low susceptibility to http pH value and temperature changes [11,12]. Zwitterionic moieties of sulfobetaine (SB), carboxybetaine, and phosphorylcholine appear not only as pendant groups in polymers but also as head groups of self-assembled monolayers (SAMs) for the quick preparation of antifouling interfaces in multidimensional materials [13][14][15][16]. Numerous dopamine derivatives have recently been developed for the surface modification and functionalization to make the devices biocompatible, to introduce bactericidal properties, or to promote integration with living systems [17][18][19][20][21][22][23][24].…”

Thrombosis‐Responsive Thrombolytic Coating Based on Thrombin‐Degradable Tissue Plasminogen Activator (t‐PA) Nanocapsules

“…Fibrinogen adsorption decreased further to 0.067 µg cm −2 upon blocking with GSH. As well as blocking the remaining uncovered PDA the GSH presumably provided additional protein resistance through its intrinsic zwitterionic character . In addition, GSH, as a small molecule, hindered thrombin interactions with the surface‐immobilized NCs to a lesser extent than the larger repellent PEG molecule (Figure S3, Supporting Information).…”

Nanostructure-Enabled and Macromolecule-Grafted Surfaces for Biomedical Applications

“…The coating showed antifouling behaviors in resistance of protein absorption, platelets, and bacteria adhesion. Others used natural sulfur-containing compounds, such as l -cysteine (Cys), l -methionine, and glutathione (GSH), for the fabrication of surface zwitterionic ligands to prevent protein nonspecific adsorption on gold substrates [ 88 ]. Results suggested that coatings that were made from Cys and GSH displayed a high hydrophilicity, whereas coating made from GSH showed the best performance in resistance to BSA adsorption.…”