Collagen-silica nanocomposites as dermal dressings preventing infection in vivo

Highlights: • Improved collagen hydrogels performance • Co-deliver two types of antibiotic molecules • In vivo antimicrobial activity • Confirmed nanocomposites biocompatibility - Abstract: The controlled delivery of multiple drugs from biomaterials is a timely challenge. In particular the nanocomposite approach offers a unique opportunity to combine the scaffold-forming ability and biocompatibility of hydrogels with the versatile and tunable drug release properties of micro- or nano-carriers. Here, we show that collagen-silica nanocomposites allowing for the prolonged release of two topical antibiotics are promising medicated dressings to prevent infection in wounds. For this purpose, core–shell silica particles loaded with gentamicin sulfate and sodium rifamycin were combined with concentrated collagen type I hydrogels. A dense fibrillar network of collagen exhibiting its typical periodic banding pattern and a homogenous particle distribution were observed by scanning electron microscopy. Antibiotics release from nanocomposites allowed a sustained antibacterial effect against Staphylococcus aureus over 10 days in vitro. The acute dermal irritation test performed on albino rabbit skin showed no sign of severe inflammation. The antibacterial efficiency of nanocomposites was evaluated in vivo in a model of cutaneous infection, showing a 2 log steps decrease in bacterial population when loaded systems were used. In parallel, the histological examination indicated the absence of M1 inflammatory macrophages in the wound bed after treatment. Taken together, these results illustrate the potentialities of the nanocomposite approach to develop collagen-based biomaterials with controlled dual drug delivery to prevent infection and promote cutaneous wound repair.