Electrostatically Self-Assembled Microalgae Facial Masks for Dual-Functional Therapy: Anti-Infection and Healing...

Facial skin infections present clinical challenges due to limited anti-infective efficacy of commercial masks and rising antibiotic resistance. An innovative electrostatically self-assembled microalgae facial mask (MCSM) via a scalable chitosan (CS)-microalgae flocculation strategy is proposed. The rod-shaped morphology of Synechococcus elongatus provides extensive surface area for stable substrate immobilization and efficient loading of bioactive molecules, while its well-established photosynthetic capability enables sustained oxygen generation to counteract local hypoxia. Through electrostatic attraction between cationic CS and anionic S. elongatus, robust photosynthetic microalgae coatings are constructed on diverse mask substrates while preserving algal bioactivity. Modulating surface electronegativity enables efficient loading of berberine (Bbr), achieving sustained drug release (12 h antibacterial rates: 99.98%-99.84% against MRSA, E. coli, and C. albicans) and rapid photodynamic sterilization under white light (20 min: 99.98% against S. aureus, 97.69% against P. acnes). The microalgae neutralize excess ROS, mitigating phototoxicity and supplying oxygen to accelerate healing. In vivo, MCSM-Bbr promotes near-complete wound closure in MRSA- (100%) and C. albicans-infected (95.15%) wounds by day 14 via pathogen eradication, anti-inflammation, and enhanced collagen deposition. This strategy's universality is further demonstrated by extending it to diverse microalgae and substrates. The work pioneers a non-antibiotic skincare strategy integrating microbial activity with materials science.