Fabrication of polysaccharide-based pH responsive anti- inflammatory nanofibers and their characterization for wound dressing applications Beste Elveren and Manja Kurečič University of Maribor, Slovenia Responsive materials are sensitive to specific signals that allow them to change their physical or chemical properties. Commonly, these changes are reversible when the stimulus is removed. In the last decade, responsive materials became intriguing because of the dynamic and mostly reversible changes they introduce[1]. Incorporation of halochromic dyes into electrospun fibers has been intriguing for wound healing applications. Furthermore, it is known, that the pH value within the wound milieu influences all biochemical reactions taking place in the process of wound healing[2].It has been proven that the surface pH of a wound plays an important role in wound healing as it helps control infection and increases antimicrobial activity, oxygen release, angiogenesis, protease activity, and bacterial toxicity[3]. Many researchers focused on the development of versatile responsive materials but achieving the sensitivity of these materials, which will bring the desired therapy to the right place and at the right time in a physiologically important dose, remains a challenge[4]. In this study, we developed a polysaccharide-based responsive smart material with controlled drug release by using electrospinning technique, which allowed us to produce responsive nanofibers with rapid visual detection of pH change in the wound bed along with anti-inflammatory activity. Produced nanofibers were characterized according to their morphological and chemical properties.Responsiveness of the nanofibers was achieved by different halochromic dyes [bromocresol green (BCG), bromothymol blue (BTB) and thymol blue (TB)]. To tackle the problem of leaching of the dyes, we used complexing agent; poly-diallyldimethylammonium chloride (PDADMAC) and the complexation was analyzed using pH-potentiometric titration and Quartz Crystal Microbalance with Dissipation (QCM-D) techniques.Additionally, release tests showed that the leaching of the halochromic dyes is reduced significantly up to 99%.Furthermore, the responsiveness of the nanofibers was investigated by exposing the nanofibers to different buffers with pH values 4, 7 and 10. The color change of the nanofibers was analyzed using the CIELab system while a visual color shift was observed according to their characteristics displayed in Figure 1.Lastly, diclofenac(DFC), an anti-inflammatory drug molecule was integrated into the system and drug release studies were performed by using Franz diffusion cells. A controlled release of the drug molecule (DFC) to the wound bed is achieved and quantitative evaluations were done.
Figure 1. pH ranges of the halochromic dyes References 1. Li; Q. Intelligent Stimuli‐Responsive Materials: From Well‐Defined Nanostructures to Applications ; Li; Q.; Ed. John Wiley & Sons; Inc.: 2013;https://doi.org/10.1002/9781118680469. 2. Pakolpakçıl; A.; Karaca; E.; Becerir; B. Investigation of a Natural pH-Indicator Dye for Nanofibrous Wound Dressings. IOP Conference Series: MaterialsScience andEngineering 2018 ; 460 ; 012020;doi:https://doi.org/10.1088/1757- 899X/460/1/012020. 3. Bazbouz; M.B.; Tronci; G. Two-layer Electrospun System Enabling Wound ExudateManagement and VisualInfection Response. Sensors (Basel; Switzerland) 2019 ; 19 ;doi:https://doi.org/10.3390/s19050991. 4. Strecker-McGraw; M.K.; Jones; T.R.; Baer; D.G. Soft tissue wounds and principles of healing. EmergMedClinNorthAm 2007 ; 25 ; 1-22; doi:https://doi.org/10.1016/j.emc.2006.12.002.
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