Wound‐Healing with Mechanically Robust and Biodegradable Hydrogel Fibers Loaded with Silver Nanoparticles

Abstract

The objective of this study is to provide a novel synthetic approach for the manufacture of wound-healing materials using covalently cross-linked alginate fi bers loaded with silver nanoparticles. Alginate fi bers are prepared by wet-spinning in a CaCl 2 precipitation bath. Using this same approach, calcium cross-links in alginate fi bers are replaced by chemical cross-links that involve hydroxyl groups for subsequent cross-linking by glutaraldehyde. The cross-linked fi bers become highly swollen in aqueous solution due to the presence of carboxyl functional groups, and retain their mechanical stability in physiological fl uids owing to the stabilized network of covalent bonds. Alginate fi bers can then be loaded with silver ions via the ion-exchange reaction. Silver ions are reduced to yield 11 nm silver nanoparticles incorporated in the polymer gel. This method provides a convenient platform to incorporate silver nanoparticles into alginate fi bers in controlled concentrations while retaining the mechanical and swelling properties of the alginate fi bers. Our study suggests that the silver nanoparticles loaded fi bers may be easily applied in a wound healing paradigm and promote the repair process though the promotion of fi broblast migration to the wound area, reduction of the infl ammatory phase, and the increased epidermal thickness in the repaired wound area, thereby improving the overall quality and speed of healing.

Tannic acid-modified silver nanoparticles for wound healing: the importance of size

“…Other authors showed that not only uncoated AgNPs sized 5-15 nm but also those with a diameter of ~20 nm accelerated re-epithelialization, enhanced migration of fibroblasts and reduced neutrophil and macrophage infiltration at the wound site in rodent models. 36,38,39 Histological evaluations revealed that TA-modified AgNPs sized 13 nm, and to a lesser degree, 10-65 nm unmodified AgNPs, maintained neutrophil infiltration at the wound site up to 14 days. In contrast, TA-modified 33 nm AgNPs significantly accelerated neutrophil disappearance during the remodeling phase.…”

Nano-Engineered Biomaterials for Tissue Regeneration: What Has Been Achieved So Far?

“…Recent in vitro and in vivo work has pointed toward the unprecedented ability of AgNP to reduce inflammatory macrophage and neutrophil infiltration, to inhibit the production of inflammatory cytokines, and to regulate the expression of metalloproteinases (Wright et al, 2002;Bhol and Schechter, 2007;Tian et al, 2007;Wong et al, 2009;Liu et al, 2010;Zhang et al, 2014). Thus, it stands that the incorporation of AgNP in biomaterial dressings is expected not only to add an antimicrobial element to the scaffold but also to further improve wound healing (Lu et al, 2012a;Neibert et al, 2012;Fan et al, 2014;Herron et al, 2014). For example, a chitosan-AgNP dressing by Lu et al significantly increased the healing rate of dermal wounds 10% of the body surface area in a rat model as compared to silver sulfadiazine or chitosan film alone while the percentage of silver dissemination away from the area of injury was lower for AgNP (Lu et al, 2012a).…”

A self-regulating antimicrobial model based on the ion-exchange stimuli

“…, leading to an ordered conformational structure called ''egg-box'' array. The property of Alg hydrogels being sensitive to pH and calcium ions showed potential applications in the field of intelligent DDSs [20][21][22][23][24][25][26][27][28]. However, few studies about the controlling release of nano-silver regulated by the intelligent response of Alg have been reported in the field of antimicrobial wound dressing.…”