Strong infiltrative HHC36 antimicrobial peptide/silver nanoparticles-loaded carboxymethyl chitosan/sodium alginate hydrogel for acne vulgaris therapy

Acne is a common chronic skin inflammatory disease closely related to Cutibacterium acnes (C. acnes), which affects the life quality of patients worldwide, especially adolescents and young adults. However, the physical barrier of the skin makes drugs difficult to infiltrate effectively into infected site, causing acne hard to cure and easy to recur. Herein, we developed an antibacterial skin dressing with strong infiltration of antibacterial agents which can co-delivery small-molecular antimicrobial agents through stratum corneum deeply into dermis, achieving high antimicrobial efficacy. The antibacterial dressings were constructed with carboxymethyl chitosan/sodium alginate (CMCS/SA) hydrogel loading with HHC36 (an antimicrobial peptide) and silver nanoparticles (AgNPs) conjugates (Ag-H2/CMCS/SA hydrogel). The released Ag-H2 from Ag-H2/CMCS/SA hydrogel can early infiltrate into dermis, co-delivery HHC36 and AgNPs due to the infiltration and targeting of HHC36, presenting the superior antibacterial effect compared to HHC36 or AgNPs alone and killing 100% C. acnes and 100% Staphylococcus epidermidis (S. epidermidis) at a very low concentration of Ag-H2 (15 μg/mL Ag with 7.1 μg/mL HHC36). Meanwhile, Ag-H2/CMCS/SA hydrogel was biocompatible due to the natural polysaccharides carboxymethyl chitosan and sodium alginate. The HaCaT cells spread well in Ag-H2/CMCS/SA hydrogel extracts. These results indicate that the co-delivery small-molecular antimicrobial agents is a promising strategy and Ag-H2/CMCS/SA hydrogel has a great potential in the therapy of acne.