TY - JOUR
T1 - Reverse Iontophoretic Extraction of Skin Cancer-Related Biomarkers
AU - Morin, Maxim
AU - Björklund, Sebastian
AU - Jankovskaja, Skaidre
AU - Moore, Kieran
AU - Delgado-Charro, Begona
AU - Ruzgas, Tautgirdas
AU - Guy, Richard
AU - Engblom, Johan
N1 - Funding Information:
Acknowledgments: We would like to acknowledge the Knowledge Foundation for financial support of the project. M.M. would like to acknowledge the Reidar Peters Internationalization Fund for financial support to visit R. H. Guy’s lab at University of Bath, UK. J.E., and T.R. also thank the Gustaf Th Olsson foundation for financial support.
Funding Information:
Funding: This research was funded by Knowledge Foundation via the project “Non-invasive monitoring of skin-disorders progression and healing—a low molecular weight biomarker approach” (Grant number—20170058).
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2022/1/31
Y1 - 2022/1/31
N2 - Non-invasive methods for early diagnosis of skin cancer are highly valued. One possibleapproach is to monitor relevant biomarkers such as tryptophan (Trp) and kynurenine (Kyn), onthe skin surface. The primary aim of this in vitro investigation was, therefore, to examine whetherreverse iontophoresis (RI) can enhance the extraction of Trp and Kyn, and to demonstrate how theTrp/Kyn ratio acquired from the skin surface reflects that in the epidermal tissue. The study alsoexplored whether the pH of the receiver medium impacted on extraction efficiency, and assessedthe suitability of a bicontinuous cubic liquid crystal as an alternative to a simple buffer solution forthis purpose. RI substantially enhanced the extraction of Trp and Kyn, in particular towards thecathode. The Trp/Kyn ratio obtained on the surface matched that in the viable skin. Increasingthe receiver solution pH from 4 to 9 improved extraction of both analytes, but did not significantlychange the Trp/Kyn ratio. RI extraction of Trp and Kyn into the cubic liquid crystal was comparableto that achieved with simple aqueous receiver solutions. We conclude that RI offers a potential fornon-invasive sampling of low-molecular weight biomarkers and further investigations in vivo aretherefore warranted.
AB - Non-invasive methods for early diagnosis of skin cancer are highly valued. One possibleapproach is to monitor relevant biomarkers such as tryptophan (Trp) and kynurenine (Kyn), onthe skin surface. The primary aim of this in vitro investigation was, therefore, to examine whetherreverse iontophoresis (RI) can enhance the extraction of Trp and Kyn, and to demonstrate how theTrp/Kyn ratio acquired from the skin surface reflects that in the epidermal tissue. The study alsoexplored whether the pH of the receiver medium impacted on extraction efficiency, and assessedthe suitability of a bicontinuous cubic liquid crystal as an alternative to a simple buffer solution forthis purpose. RI substantially enhanced the extraction of Trp and Kyn, in particular towards thecathode. The Trp/Kyn ratio obtained on the surface matched that in the viable skin. Increasingthe receiver solution pH from 4 to 9 improved extraction of both analytes, but did not significantlychange the Trp/Kyn ratio. RI extraction of Trp and Kyn into the cubic liquid crystal was comparableto that achieved with simple aqueous receiver solutions. We conclude that RI offers a potential fornon-invasive sampling of low-molecular weight biomarkers and further investigations in vivo aretherefore warranted.
KW - Bicontinuous cubic liquid crystals
KW - Cancer-related biomarkers
KW - Kynurenine
KW - Non-invasive extraction
KW - Tryptophan
KW - Tryptophan-to-kynurenine ratio
UR - http://www.scopus.com/inward/record.url?scp=85122161916&partnerID=8YFLogxK
U2 - 10.3390/pharmaceutics14010079
DO - 10.3390/pharmaceutics14010079
M3 - Article
SN - 1999-4923
VL - 14
JO - Pharmaceutics
JF - Pharmaceutics
IS - 1
M1 - 79
ER -
