Adhesive nanostructured multilayer films using a bacterial exopolysaccharide for biomedical applications

Abstract

Medical adhesives and sealants often require that long-term adhesiveness is achieved. In this work, nanostructured coatings consisting of chitosan and the adhesive bacterial exopolysaccharide levan are fabricated using layer-by-layer (LbL) assembly. Taking advantage of the electrostatic self-assembly mechanism of LbL, the charges of both chitosan and a phosphonate-derivatized levan (Ph-levan) are measured and the feasibility of constructing hybrid films is monitored and confirmed using a quartz crystal microbalance with dissipation monitoring (QCM-D). The adhesive properties between two identical bonded films with a total of 100 layers are compared to control films in which Ph-levan is replaced by alginate, revealing that the detachment force of the former is about 3 times higher than the control. Scanning electron microscopy of the films surface shows that the surface of Ph-levan films is smooth and homogeneous. Cell adhesion tests were conducted using a L929 cell line. Early cell adhesion is significantly higher in chitosan/Ph-levan films when compared to chitosan/alginate controls.These findings establish levan derivatives as bioinspired ingredients for conceiving medical adhesive devices that allow achieving enhanced mechanical and biological performance.

High performance free-standing films by layer-by-layer assembly of graphene flakes and ribbons with natural polymers

“…32 The roughness of the side in contact with the substrate increases in the FS films that contain o-GFs and o-GNRs, which was attributed to the particles embedded in the polymeric matrix, as also found by Ionita et al 17 Nevertheless, these FS films still exhibit a flat morphology that could be an important characteristic to achieve adhesive properties and thus, to strengthen the adhesion to medical devices or even to anatomic structures such as bone. 17,48 The addition of o-GFs resulted in less porous films compared to the controls Fig. 3(b 1 )) and concerning the cross-section ( Fig.…”

Effective stimulating factors for microbial levan production by Halomonas smyrnensis AAD6T

“…With this microbial system, productivity levels were improved by use of cheap sucrose substitutes like molasses (10) as well as other cheap biomass resources (11) as fermentation substrate. Moreover, levan and aldehyde-activated levan were successfully deposited by matrix-assisted pulsed laser evaporation (MAPLE) resulting in uniform, homogeneous, nanostructured, biocompatible, thin films (6,7) and furthermore the feasibility of phosphonate-modified levan as adhesive multilayer films were demonstrated (12). In addition, the antioxidant potential of this levan polysaccharide in high glucose condition in the pancreatic INS-1E cells by demonstrating a correlation between reduction in oxidative stress and apoptosis with its treatment was reported for the first time by our research group (13).…”

Characterization of Microbial Communities Associated with Ceramic Raw Materials as Potential Contributors for the Improvement of Ceramic Rheological Properties

“…It also serves as an extracellular nutrient reservoir that can be used as an energy source by bacteria under starvation conditions [51]. Many applications for levan have been reported in the literature, which are particularly related to its capacity to form thin films for medical uses or for bio-based food packaging films [52]. Levan-based films are clear, flexible and good oxygen barriers when mixed with the clay montmorillonite [53].…”