Bioactive glass-based fibrous wound dressings

Abstract

Since the discovery of silicate bioactive glass (BG) by Larry Hench in 1969, different classes of BGs have been researched over decades mainly for bone regeneration. More recently, validating the beneficial influence of BGs with tailored compositions on angiogenesis, immunogenicity and bacterial infection, the applicability of BGs has been extended to soft tissue repair and wound healing. Particularly, fibrous wound dressings comprising BG particle reinforced polymer nanofibers and cotton-candy-like BG fibers have been proven to be successful for wound healing applications. Such fibrous dressing materials imitate the physical structure of skin's extracellular matrix and release biologically active ions e.g. regenerative, pro-angiogenic and antibacterial ions, e.g. borate, copper, zinc, etc., that can provoke cellular activities to regenerate the lost skin tissue and to induce new vessels formation, while keeping an anti-infection environment. In the current review, we discuss different BG fibrous materials meant for wound healing applications and cover the relevant literature in the past decade. The production methods for BG-containing fibers are explained and as fibrous wound dressing materials, their wound healing and bactericidal mechanisms, depending on the ions they release, are discussed. The present gaps in this research area are highlighted and new strategies to address them are suggested.

Keywords: Angiogenesis; Bioactive glass; Fibers; Scaffolds; Wound healing.

Figure 1.

Cotton-like microfibers composed of: (a) 45S5, (b) 13-93B3, and (c) Cu-doped 13-93B3 BGs. (d) Image of 13-93B3 BG microfibers at a high magnification (the arrows mark glass beads). (e) Camera image of the Cu-doped 13-93B3 BG microfiber implant. The periodic acid Schiff (PAS)-stained sections of soft tissue exposed (for 4 weeks) to implanted BG microfibers composed of: (f) none (sham control); (g) 45S5, (h) 13-93B3, and (i) Cu-doped 13-93B3 (the arrows mark the microvessels found in the tissues). Reproduced with permission from [36]. Copyright 2014, John Wiley and Sons

Figure 2.

Scanning electron microscopy images showing: (a) 45S5 BG nanofibers produced through the laser spinning process, (b) conversion of a 45S5 BG nanofiber to a hydroxycarbonate apatite tube after immersion in simulated body fluid for 48 h. (c) The laser spinning method that employs a powerful laser to get a small fraction of a precursor material melted. Meanwhile, a high-velocity gas jet draws and cools the molten material, forming a nanofiber. Reproduced with permission [88]. Copyright 2009, John Wiley and Sons

Figure 3.

Schematic illustration of electrospinning of a BG particle/polymer suspension in various set-ups with different nozzle configurations: (a) single nozzle, (b) multichannel nozzle, and (c) coaxial nozzle. Reproduced and re-drawn (section a) with permission [94]. Copyright 2019, Elsevier

Figure 4.

Schematic illustration of the preparation procedure of bioactive glass (BG) (here shown as BAG; Cu- and Co-doped) reinforced fish collagen electrospun fiber mats with improved human dermal fibroblast (HDF) cell response and enhanced in vivo wound healing reflected in neovascularization, re-epithelialization, and extracellular matrix (ECM) deposition. Reproduced with permission from [100]. Copyright 2022, ACS