Molecule-Resolved Visualization of Particulate Matter on Human Skin Using Multimodal Nonlinear Optical Imaging

Area of Science:

• Dermatology
• Biophysics
• Materials Science

Background:

• Particulate matter (PM) exposure is linked to various skin conditions.
• Accurate methods for measuring PM on skin are crucial for understanding and preventing PM-related skin diseases.

Purpose of the Study:

• To visualize and quantify the deposition and penetration of particulate matter (PM) into human skin.
• To assess the impact of skin barrier integrity on PM deposition and penetration.

Main Methods:

• Utilized a multimodal nonlinear optical (MNLO) imaging system to visualize PM.
• Merged C-C vibrational frequency and autofluorescence signals for PM detection.
• Simultaneously imaged skin anatomical features (keratin, collagen, elastin).
• Investigated PM deposition and penetration in ex vivo human skin, including after tape-stripping to disrupt the skin barrier.

Main Results:

• Morphologically dependent PM deposition was observed.
• Disruption of the skin barrier via tape-stripping led to increased PM deposition.
• Increased tape-stripping resulted in deeper and more extensive PM penetration.
• PM penetration significantly increased the secretion of pro-inflammatory cytokines.

Conclusions:

• MNLO imaging is a powerful technique for visualizing and quantifying PM in ex vivo human skin.
• Skin barrier integrity plays a critical role in modulating PM deposition and penetration.
• PM penetration into the skin can trigger inflammatory responses.