Reconstructed human skin as model for liposome-skin interaction

Area of Science:

• Dermatology
• Materials Science
• Biotechnology

Background:

• Reconstructed human epidermis models are crucial for skin research.
• Liposomes are utilized for topical delivery, but their interaction with skin lipids is complex.
• Understanding liposome behavior on stratum corneum is key for effective drug delivery.

Purpose of the Study:

• To investigate the penetration and interaction of different liposomes with reconstructed human epidermis.
• To evaluate the influence of liposome lipid composition (phosphatidylcholine, phosphatidylserine, stratum corneum lipids) on skin penetration.
• To correlate liposome aggregation and dispersion with penetration rates.

Main Methods:

• Cultivation of human keratinocytes to create a stratified reconstructed epidermis.
• Preparation and application of 50 nm liposomes composed of phosphatidylcholine (PC), phosphatidylserine (PS), and human stratum corneum lipids (hSCL).
• Quantification of lipid penetration using ng lipid/h/cm².
• Microscopic analysis (electron and confocal laser scanning) to observe liposome-skin interactions.
• Fluorescence measurements to assess vesicle mixing.

Main Results:

• Liposome penetration rates varied significantly: PC (1.38 ng/h/cm²), hSCL (0.55 ng/h/cm²), and PS (0.013 ng/h/cm²).
• PS and hSCL liposomes aggregated on the skin surface, while PC liposomes dispersed evenly.
• Native stratum corneum lipids mixed readily with PS liposomes, weakly with hSCL, and not at all with PC liposomes.

Conclusions:

• Phosphatidylcholine liposomes demonstrate superior penetration through reconstructed human epidermis compared to PS and hSCL liposomes.
• Liposome aggregation and dispersion behavior are directly linked to their lipid composition and influence skin penetration.
• The interaction dynamics between liposomes and stratum corneum lipids are critical for optimizing topical delivery systems.