Effective wound management plays a vital role in enhancing patient outcomes, especially through the early detection of infections an‎d continuous monitoring of wound conditions. In response to this clinical imperative, the present study synthesizes two novel hydrogel formulations an‎d fabricates nanofibrous hydrogel matrices functionalized with indicator dyes. To achieve this, three transparent, pH-responsive phosphate-based hydrogels were initially synthesized. Their physicochemical properties including morphological characteristics, swelling behavior, mechanical properties, an‎d in vitro cytocompatibility, were eva‎luated. Swelling tests showed that all hydrogels exhibited cationic pH sensitivity, swelling in acidic conditions an‎d contracting in alkaline environments. Gel-B demonstrated lower sensitivity than Gel-A; its swelling in acidic pH was about 40% less than Gel-A, whereas in alkaline pH, it swelled approximately 200% more, likely due to the presence of hydroxyl groups. Both Gel-A an‎d Gel-B maintained good stability in acidic an‎d alkaline media, unlike Gel-C, which completely dissolved after 6 hours at pH 10. Scanning electron microscopy (SEM) revealed Gel-A possessed a porous structure with large pores, while Gel-B had a layered morphology with thick walls. Cytotoxicity an‎d cell stress assays confirmed the hydrogelsʹ biocompatibility an‎d non-irritating nature. Mechanical testing indicated Gel-A was brittle with compressive stress around 14 kPa, while Gel-B showed significantly enhanced mechanical strength, tolerating at least 16 times higher stress. To improve usability as wound dressings, hydrogel nanofiber matrices with Full-IPN structures were fabricated via electrospinning using biocompatible polyvinyl alcohol (PVA) an‎d the monomers from Gel-A an‎d Gel-B. Citric acid served as a green, non-toxic crosslinker for PVA, activated by thermal treatment. FTIR spectroscopy confirmed incorporation of Gel-A an‎d Gel-B within the nanofibers, an‎d DSC analysis showed successful formation of a dual polymer network. Increasing the Gel-A to PVA ratio led to a progressive increase in nanofiber diameter, nearly two times at the 1:1 ratio, indicating effective Gel-A integration. In contrast, PVA/Gel-B samples showed no significant diameter change, due to surface migration of monomers an‎d hydrogel formation on fiber surfaces. BET analysis confirmed decreased pore volume an‎d specific surface area in Full-IPN nanofibrous hydrogels compared to pure PVA, consistent with SEM images. Zeta potential measurements indicated that dual-network nanofibers exhibited cationic-anionic behavior, whereas PVA nanofibers were purely anionic. These results matched swelling behavior an‎d confirmed the nanofibers’ distinct chemical structures. For stable, rapid visual infection detection, pH-sensitive dyes responsive within the physiological pH range of skin an‎d infected wounds were applied using two methods. First, dyes containing 2-hydroxyethylsulfonyl groups (GJM-492 an‎d 1H3S) were covalently immobilized onto nanofiber substrates through conversion of the sulfonyl group to reactive vinyl sulfone, which then bonded with hydroxyl an‎d amine groups on the fibers. Second, bromothymol blue (BTB) was incorporated into the hydrogel matrix an‎d immobilized through ionic interaction with the cationic complexing agent poly(diallyldimethylammonium chloride) (PDADMAC), effectively minimizing dye leaching. The halochromic behavior of these substrates was tested across a range of pH values, demonstrating their ability to visually detect pH changes. These systems operate through visible color changes an‎d securely retain the dyes within the nanofiber matrix. They offer clear, real-time insights into wound conditions, making them as promising tools for smart diagnostic wound dressings.

فرزانه علي حسيني

حسين ايزدان

محمد ديناري , هاله خليلي , محسن محسني