The topical application of Sphistin_12-38 in combination with sponge spicules for the acne treatment

We demonstrated for the first time that a marine-derived antimicrobial peptide (AMP), Sph_12-38, exhibit high antimicrobial activity against P. acnes with a minimum bactericidal concentration (MBC) value of 7 μM. Meanwhile, Sph_12-38 has no significant cytotoxicity to human keratinocytes (HKs) at its high concentration (33.5 μM). The topical application of sponge Haliclona sp. spicules (SHS) dramatically enhanced the skin penetration of Sph_12-38 up to 40.9 ± 5.9% (p < 0.01), which was 6.1 ± 0.9-fold higher than that of Sph_12-38 alone. Further, SHS resulted in the accumulation of most Sph_12-38 in viable epidermis and dermis. Further, the combined use of Sph_12-38 and SHS resulted in a cure rate of 100% for rabbit ear acne treatment in vivo for two weeks, while the one induced by other groups was 40%, 0% and 0% for SHS alone, Sph_12-38 alone and control group, respectively. The strategy of combined using AMP and SHS can also be applied in a rational designed topical delivery system for the management of other deep infection of the skin. The effectiveness of SHS by itself on the treatment of acne was also demonstrated by clinical trials. After 14 days of treatment by 1% SHS gel. The number of skin lesions decreased by 51.4%.