Time filter

Source Type

Fernandez-Saiz P.,Novel Materials and Nanotechnology Laboratory | Ocio M.J.,Novel Materials and Nanotechnology Laboratory | Ocio M.J.,University of Valencia | Lagaron J.M.,Novel Materials and Nanotechnology Laboratory
Carbohydrate Polymers | Year: 2010

This study reports for the first time about the formulation, morphology, water barrier and the antimicrobial activity of high and low molecular weight chitosonium-acetate based solvent-cast blends with ethylene-vinyl alcohol (EVOH) copolymers. The blends based on the low molecular weight chitosan grade showed enhanced phase morphology, transparency, enhanced water barrier properties, up to 86% water permeability reduction compared to pure chitosonium-acetate films, as well as excellent antimicrobial activity. When the fraction of low molecular weight chitosan exceeded the phase inversion in the blend, phase segregation became noticeable but good interfacial adhesion was still observed. On the other hand, the blends with the high molecular weight chitosan grade were translucent, even when this component was in the dispersed phase, and exhibited clearly separated phase morphology but also presented antimicrobial performance. In both cases, and in accordance with previous works in our laboratory, the release from the blends of protonated glucosamine groups (so-called active species) correlated well with the antimicrobial phenomenology of the developed materials. The study also showed that EVOH copolymers can also be made antimicrobial by a water sorption-induced release mechanism, if acetic acid is incorporated into the polymer formulation before casting from solution. On the overall, antimicrobial chitosan-based blends with EVOH copolymers, when low molecular weight chitosan was used as the dispersed phase in the blend, exhibited optimum performance in terms of optical properties, water resistance, enhanced water barrier and, therefore, excellent application outlook in antimicrobial applications. © 2010.

Sanchez-Garcia M.D.,Novel Materials and Nanotechnology Laboratory | Lagaron J.M.,Novel Materials and Nanotechnology Laboratory
Journal of Applied Polymer Science | Year: 2010

This article presents novel solvent cast biocomposites of poly(lactic acid) (PLA), polyhydroxybutyrateco-valerate (PHBV), and polycaprolactone (PCL) with enhanced barrier properties to UV light, oxygen, water, and limonene by means of incorporating an organomodified mica-based clay grade. The TEM results suggested a good clay dispersion but with no exfoliation in the three biopolyesters. In agreement with the crystallinity data, which was found to generally increase with increasing filler content, oxygen but specially water and D-limonene permeability coefficients were seen to decrease to a significant extent in the biocomposites and an optimum property balance was found for 5 wt % of clay loading in the three biopolymers. With increasing clay content, the light transmission of these biodegradable biocomposites decreased by up to 90% in the UV wavelength region due to the specific UV blocking nature of the clay used. As a result, these new biocomposites can have significant potential to develop packaging films, coatings and membranes with enhanced gas and vapor barrier properties and UV blocking performance. © 2010 Wiley Periodicals, Inc.

PubMed | Novel Materials and Nanotechnology Laboratory
Type: Comparative Study | Journal: ACS applied materials & interfaces | Year: 2010

Collagen, as the major structural protein of the extracellular matrix in animals, is a versatile biomaterial of great interest in various engineering applications. Electrospun nanofibers of collagen are regarded as very promising materials for tissue engineering applications because they can reproduce the morphology of the natural bone but have as a drawback a poor structural consistency in wet conditions. In this paper, a comparative study between the performance of different cross-linking methods such as a milder enzymatic treatment procedure using transglutaminase, the use of N-[3-(dimethylamino)propyl]-N-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide, and genipin, and the use of a physical method based on exposure to ultraviolet light was carried out. The chemical and enzymatic treatments provided, in this order, excellent consistency, morphology, cross-linking degree, and osteoblast viability for the collagen nanofibers. Interestingly, the enzymatically cross-linked collagen mats, which are considered to be a more biological treatment, promoted adequate cell adhesion, making the biomaterial biocompatible and with an adequate degree of porosity for cell seeding and in-growth.

Loading Novel Materials and Nanotechnology Laboratory collaborators
Loading Novel Materials and Nanotechnology Laboratory collaborators