Layer-by-layer coating of photoactive polymers for biomedical applications

Abstract

The design of advanced, nanostructured materials at the molecular level is of tremendous interest for the scientific community because of their potential in several fields, including medicine, biology and tissue engineering. Layer-by-layer (LbL) assembly is a versatile technique for the realization of multilayered films with tailored characteristics at the nanometer scale. Photoactive nanostructured films were prepared by LbL assembly of photozymes: an amphiphilic zwitterionic copolymer, poly(sodium styrene sulphonate-stat-vinyl naphtalene-stat-3dimethyl(methacryloylethyl) ammonium propane sodium sulfonate) (PSSS-stat-VN-stat-DMPAS; code: ZI), and a cationic polyelectrolyte, chitosan-g-fluorescein (code: CHFL), on a crosslinked gelatin substrate. Although successful LbL assembly of photozymes was proven by the performed characterization, gelatin was not an optimal substrate for the coating, due to its low charge density and amphoteric nature. A regular growth of the layers was found after at least 6 layers were deposited. The macromolecules of the zwitterionic photozyme adopted a coiled micellar conformation in solution which was kept during the assembly. The obtained nanostructured films are promising candidates for carrying out efficient electron transfer process within them, responsible for the anti-microbial activity and the osteointegration ability of the coating.

Functionalised nanoscale coatings using layer-by-layer assembly for imparting antibacterial properties to polylactide-co-glycolide surfaces

“…Furthermore, PAH top layer had a contact angle value higher than PSS top layer, in fact the contact angle fluctuated between 70° and 80° (Figure 4). The same trend was found in different paper in literature, in which contact angles of LbL films generally vary between the values of the pure components of each layer [24,35].…”

“…LbL assembly is based on the alternating exposure of a charged substrate to solutions of positively and negatively charged polyelectrolytes. A rinsing step is included between the two previously described adsorption processes, to remove excess as well as to prevent cross-contamination of the polyelectrolyte solutions [24]. The LbL technique allows fine control of the coating properties and the obtainment of homogeneous multilayered structures.…”

Novel reforming of pyrolized fuel oil by electron beam radiation for pitch production

“…As shown in the MALDI spectrum, the range of the molecular weight distribution became narrower following E-beam irradiation because low molecular weight components were converted to gas or polymerized with other molecules, while high molecular weight components were simultaneously decreased by E-beam irradiation. Thus, E-beam radiation treatment did not increase the molecular weight sub- ) [14,15]. The adsorption bands of aromatic bonds increased in response to heat and Ebeam treatments.…”

Layer-by-layer coating of stainless steel plates mediated by surface priming treatment to improve antithrombogenic properties

“…10 The contact angle value of SS coated with 2 bilayers increased due to the increase of surface roughness caused by polyelectrolyte islet formation. The contact angle was not significantly different from that of SS-APTES, for substrate coated from 5 to 10 layers.…”

“…7,8 LbL approach is a promising tool to engineer interfaces, moreover its applicability to geometrically complex substrates provides a method for the control of cell adhesion on biomaterial substrates. 9,10 LbL is an alternative and simple approach for the preparation of functional surfaces with antithrombogenic properties and supporting endothelialisation for vascular tissue engineering and stent coating. Tan et al 11 developed a multilayer film consisting of polyethylenimine (PEI) and heparin on biomedical 316L stainless steel surfaces via LbL technique.…”