Novel method for stratum corneum pore size determination using positron annihilation lifetime spectroscopy

Area of Science:

• Materials Science
• Biophysics
• Analytical Chemistry

Background:

• Positron annihilation lifetime spectroscopy (PALS) is a potent technique for microstructure analysis.
• While widely applied to metals, semiconductors, and polymers, its use in biological sciences remains limited.
• PALS offers molecular-level insights into pore properties and free volume.

Purpose of the Study:

• To investigate the microstructure of Yucatan miniature pig stratum corneum using PALS.
• To compare the pore properties and free volume of stratum corneum with cyclodextrins.
• To explore the potential of PALS in biological science applications.

Main Methods:

• Positron annihilation lifetime spectroscopy (PALS) was employed.
• Yucatan miniature pig stratum corneum samples were prepared using heat and trypsin digestion.
• Comparison was made with cyclodextrin samples.

Main Results:

• Stratum corneum samples exhibited a longer positron annihilation lifetime than cyclodextrins.
• This indicates larger pores and/or greater free volume in the stratum corneum.
• Cyclodextrin pores were characterized with diameters of 0.5-0.8 nm and a torus height of 0.79 nm.

Conclusions:

• PALS can effectively probe nano-pore properties and free volume in biological materials.
• The stratum corneum possesses distinct microstructural characteristics compared to cyclodextrins.
• PALS holds promise as a novel analytical technique for biological sciences.