A comparative study of wound dressings loaded with silver sulfadiazine and silver nanoparticles: In vitro and in vivo evaluation

In the current study, two series of antimicrobial dressings conjugated with silver sulfadiazine (SSD) and silver nanoparticles (AgNPs) were developed and evaluated for chronic wound healing. Highly porous polycaprolactone (PCL)/polyvinyl alcohol (PVA) nanofibers were loaded with different concentrations of SSD or AgNPs and compared comprehensively in vitro and in vivo. SSD and AgNPs indicated a strong and equal antimicrobial activity against S. aureus. However, SSD had more toxicity against fibroblast cells over one week in vitro culture. An in vivo model of wound healing on male Wistar rats was developed with a full thickness wound. All the wound dressings indicated enough flexibility and hydrophilicity, which resulted an adequate adhesion into the wound closure. After 30 days, the control group without any treatment indicated 31% wound closure while the group treated with PCL/PVA (without antimicrobial components) indicated 44% wound closure. Presence of antimicrobial components in the PCL/PVA nanofibers resulted into a lower inflammation response leading to a faster proliferation and maturation phases. In agreement with the higher biocompatibility of AgNPs than SSD, a faster angiogenesis, epithelialization and subsequently, remodeling were observed for the wound dressings loaded with AgNPs. The group treated with the highest concentration of AgNPs showed the fastest healing process leading to a final epithelialization with 96% wound closure after 30 days. This study indicated that AgNPs have higher biocompatibility and regulate wound healing process more efficiently compared to SSD. PCL/PVA nanofibers conjugated with AgNPs are promising wound dressings for full-thickness wounds.