Design and characterization of nitrogen-doped reduced graphene oxide-enhanced silk fibroin/gum tragacanth hydrogels for wound healing
Fatemeh Mohammadzadeh, Mitra Gharivi, Mehdi Hekmati, Farzad Montazeri, Asal Sadat Mirmohammadali, Adrine Malek Khachatourian
Abstract
• N-rGO reinforced SF/GT hydrogels show enhanced strength and reduced porosity. • N-rGO addition improves antibacterial activity against E. coli and S. aureus. • Hydrogels maintain cell viability with sustained N-rGO release over 72 hours. • N-rGO loading slows biodegradation, aiding long-term wound stability. • Freeze-dried SF/GT/N-rGO sponges offer multifunctionality for wound healing. Wound healing remains a major challenge in healthcare, requiring advanced biomaterials that promote tissue regeneration while preventing infections. Hydrogel-based wound dressings offer an ideal platform by providing mechanical support, maintaining a moist healing environment, and exhibiting antibacterial properties. In this study, nitrogen-doped reduced graphene oxide (N-rGO) was incorporated into a silk fibroin (SF)/gum tragacanth (GT) hydrogel matrix to fabricate porous sponge dressings using the freeze-drying method. The structural, mechanical, and biological properties of the N-rGO-reinforced SF/GT hydrogels were evaluated. The bonding between SF, GT, and N-rGO eliminated any need for post-treatment and provided structural stability in the aquatic environment. The optimal formulation, STG150, demonstrated outstanding performance: exhibiting a compressive strength of 194.02 ± 14.97 kPa and a modulus of 1.57 ± 0.17 kPa, representing a multiple-fold increase over the control, a 17.7 % reduction in average pore size, and 27.5 % mass retention after 21 days (27-fold higher than STG0). Furthermore, it exhibited excellent antibacterial activity with inhibition zone widths of 0.14 mm against Escherichia coli ( E. coli ) and 0.30 mm against Staphylococcus aureus ( S. aureus ) and maintained high cell viability (98.11 % after 72 hours). The hemolysis test further confirmed excellent blood compatibility with a hemolysis ratio of 0.18 % for STG150, well below the 2 % threshold defined by ASTM F756-17 standards. The sustained release profile ensured long-term antibacterial efficacy. These findings highlight the potential of the SF/GT/N-rGO sponge as a multifunctional wound dressing, offering an optimal combination of mechanical strength, antimicrobial performance, and biocompatibility for advanced wound healing applications.