Stimuli-Responsive Multilayers Based on Thiolated Polysaccharides That Affect Fibroblast Cell Adhesion

Abstract

Control of the biomaterial properties through stimuli-responsive polymeric platforms has become an essential technique in recent biomedical applications. A multilayer system of thiolated chitosan (t-Chi) and thiolated chondroitin sulfate (t-CS), consisting of five double layers ([t-Chi/t-CS]), was fabricated here by applying a layer-by-layer coating strategy. To represent a novel class of chemically tunable nanostructures, the ability to cross-link pendant thiol groups was tested by a rise from pH 4 during layer formation to pH 9.3 and a more powerful chemical stimulus by using chloramine-T (ChT). Following both treatments, the resulting multilayers showed stimuli-dependent behavior, as demonstrated by their content of free thiols, wettability, surface charge, elastic modulus, roughness, topography, thickness, and binding of fibronectin. Studies with human dermal fibroblasts further demonstrated the favorable potential of the ChT-responsive multilayers as a cell-adhesive surface compared to pH-induced cross-linking. Because the [t-Chi/t-CS] multilayer system is responsive to stimuli such as the pH and redox environment, multilayer systems with disulfide bond formation may help to tailor their interaction with cells, film degradation, and controlled release of bioactive substances like growth factors in a stimuli-responsive manner useful in future wound healing and tissue engineering applications.

Thiolated Chitosans: A Multi-talented Class of Polymers for Various Applications

“…For the analysis of the amount of immobilized −SH groups of these thiolated chitosans, Ellman’s reagent optionally with previous reduction of disulfide bonds with borohydride or iodometric titration can be used . Phadungcharoen et al, for instance, have conducted the Ellman’s assay via smartphone, providing an easy, fast, and reliable analysis of thiolated polymers without access to sophisticated equipment. …”

Enhanced Skull Bone Regeneration by Sustained Release of BMP-2 in Interpenetrating Composite Hydrogels

“…The thiol group content of Gel-SH was 1.858 mM, which was measured by Ellman's reagent and calculated by using a cysteine standard curve (Figures S1 and S2). 44,45 2.3. Fabrication of Coacervates and Gelatin Microparticles.…”

Engineering Thiolated Surfaces with Polyelectrolyte Multilayers

“…Also useful are methods that deposit ultrathin coatings presenting free thiols for further reactions. Such thiolated surfaces include monolayers of dithiols on Au, ,,− 3-mercaptopropyltrimethoxysilane for silica, − X-ray or electron-induced conversion, multilayering thiolated biomolecules, and modification of surfaces with Grignard reagents and alkanethiols …”

“…9 Also useful are methods that deposit ultrathin coatings presenting free thiols for further reactions. Such thiolated surfaces include monolayers of dithiols on Au, 6,7,10−13 3mercaptopropyltrimethoxysilane for silica, 14−17 X-ray or electron-induced conversion, 18 multilayering thiolated biomolecules, 19 and modification of surfaces with Grignard reagents and alkanethiols. 20 Once a thiol is presented at a surface, various methods have been used for further modification, such as Michael-type thiolene, 21,22 radical-mediated thiol-ene, 23−25 and thiol-yne addition.…”