Authors: Tabinda Riaz
Source: SPIRE - Sciences Po Institutional REpository (preprint, 2020-11-10)
Field: Materials Science — Biomaterials

Fabrication and characterization of a modern bilayer electrospun wound dressing for biomedical applications The aim of this research was to develop a bilayer wound dressing using electrospinning technique toproduces fine fibers. For this purpose, first layer was fabricated using a biocompatible biodegradable polymer poly(Ɛ-caprolactone) (PCL) whereas, second layer was composed of a hydrogel film of gelatin (GE) and sodium hyaluronate (HA) that are well known for tissue regeneration properties. Novelty of this study lies in the blend electrospinning of PCL with PEG having a very low molar mass 400g/mol in order to enhance the wettability of PCL nanofibers. No research study has been yet reported using this low molar mass of PEG for PCL blending. Anti-inflammatory drug Ibuprofen (IBU) was used as pain relieving agent and HA was incorporated for its moisture retaining and tissue repairing abilities. Two different techniques, single-needle electrospinning and NanoSpider electrospinning were employed to produce PCL nanofibers. Physico-chemical properties of all kinds of nanofibers were investigated by using SEM, DSC, TGA, water contact angle measurements and in-vitro drug release analysis of IBU. ImageJ software was used to measure the mean diameters ofall nanofibers by taking 50 bar measurements per sample. Mechanical strength of PCL/PEG and IBU loaded nanofibers and of GE/HA film were determined by using tensile strength testing equipment. Furthermore, the antibacterial analysis of bilayer wound dressing material was also tested against two kinds of bacteria. Results from these characterization techniques revealed that all the PCL nanofibers had heterogeneous morphology consisting of micro and nano fibers which were predominantly round in shape. Mean diameters of nanofibers electrospun by NanoSpider technique were ranging between 400-800nm whereas, mean diameters of nanofibers produced by single-needle technique were in a range of 400nm to 3 µm. Results of DSC analysis showed that crystallinity ratios of electrospun PCL nanofibers was higher than that of pure PCL pellets as well as nanofibers with PEG showed highest crystallinity ratios. TGA studies not only explained the thermal degradation behavior of these nanofibers but also helped in quantifying the amount of IBU into these nanofibers. In-vitro drug release profiles of EBU loaded PCL nanofibers presented a two-step release behavior with an initial rapid release during first 5h followed by a prolonged release until 48h. However, percentage release efficiencies of IBU in some cases was less than 50% that indicated incompleterelease of drug. This steady release of IBU from nanofibers emphasize the fact that they could perform efficiently as a controlled drug delivery system in the first layer of wound dressing. Good wettability and mechanical strength of GE/HA film predicted an effective performance of this hydrogel layer for absorbing wound exudate and maintaining a moist environment around wound for rapid healing. Finally, the in-vitro antibacterial analysis of this IBU/HA loaded bilayer wound dressing was performed against two bacterial strains E. coli (gram negative) and S. epidermidis (gram positive). Mild inhibition zones were seen against E. coli bacteria whereas, no inhibition zones were observed against S. epidermidis bacteria. Characterization (materials science) ; Fabrication ; Nanotechnology ; Wound dressing ; Bilayer ; Materials science ; Electrospinning ; Biomedical engineering ; Engineering ; Medicine ; Composite material ; Chemistry ; Polymer ; Membrane ; Pathology Electrospun Nanofibers in Biomedical Applications ; Silk-based biomaterials and applications ; Polymer Surface Interaction Studies