Reverse Iontophoretic Extraction of Skin Cancer-Related Biomarkers

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Dermatology

Background:

• Non-invasive early skin cancer detection is crucial.
• Monitoring biomarkers like tryptophan (Trp) and kynurenine (Kyn) on skin surface is a potential diagnostic approach.

Purpose of the Study:

• To investigate if reverse iontophoresis (RI) enhances Trp and Kyn extraction from skin.
• To determine if the surface Trp/Kyn ratio mirrors epidermal tissue ratio.
• To assess the impact of receiver medium pH and explore liquid crystals for extraction.

Main Methods:

• In vitro study using reverse iontophoresis (RI) for biomarker extraction.
• Analysis of tryptophan (Trp) and kynurenine (Kyn) concentrations.
• Varied receiver solution pH and tested bicontinuous cubic liquid crystals.

Main Results:

• RI significantly increased Trp and Kyn extraction, particularly towards the cathode.
• The Trp/Kyn ratio obtained via RI on the skin surface accurately reflected the ratio within the viable epidermis.
• Extraction efficiency improved with increased receiver pH (4-9), but the Trp/Kyn ratio remained stable.
• Liquid crystals showed comparable extraction performance to buffer solutions.

Conclusions:

• Reverse iontophoresis (RI) shows promise for non-invasive sampling of low-molecular-weight biomarkers.
• The Trp/Kyn ratio from skin surface extraction is a reliable indicator of epidermal levels.
• Further in vivo investigations are recommended to validate RI for diagnostic applications.