Raman comparison of skin dermis of different ages: focus on spectral markers of collagen hydration

Abstract

Skin aging is the most visible sign of aging of the body. This complex process involves molecular and structural alterations of the main skin constituents. The major cutaneous constituent is type I collagen that gives strength and resilience to the skin. This macromolecule possesses a particular triple helix structure and is arranged in the form of a fibrous network. Water plays a crucial role for maintaining this molecular assembly which is altered during intrinsic chronological aging. To investigate some of these structural alterations, Raman microspectroscopy was employed since this biophotonic approach permits to probe the biomolecular composition of the skin in a non‐destructive manner. In addition, type I collagen gives specific Raman vibrations; some of which being sensitive to the molecule conformation and to the water environment. In this purpose, Raman spectra of four skin samples of different ages (two samples of 40 year old and two samples of 70 year old) were collected by varying the relative environmental humidity. Our experiments highlighted spectral differences between the four samples. The analysis of the Raman data permitted to suggest a model for the interactions between collagen and water molecules and a decrease in collagen fibers compactness with chronological aging. Our study demonstrates that Raman spectroscopy can be a useful tool to investigate skin aging, with innovative applications in dermatology as well as in cosmetics. Copyright © 2013 John Wiley & Sons, Ltd.

RM1 semi empirical and DFT: B3LYP/3-21G theoretical insights on the confocal Raman experimental observations in qualitative water content of the skin dermis of healthy young, healthy elderly and diabetic elderly women’s

“…(2) Water is able to form H-bonds with the carbonyl (-C@O) groups of the amino acids of the collagen fibers. (3) H-bonds with the C@O groups lower the wave number position of the Amide I band due to electron transfer of the -C@O groups to the semi empty s orbital of hydrogen with partial positive charge; in this way, the C@O force constant becomes weaker.…”

“…Therefore, in vivo confocal Raman spectra of human skin dermis, which is rich in type I collagen, could be used to study volunteers of different ages to analyze the effects of skin aging due to the glycation process of this protein. It is also well known that the water quantity in the skin dermis increases with age [2,3,30]. Furthermore, elderly people with diabetes usually have higher glucose content [26] (with water solubility of 133 mg/mL).…”

“…The reticular dermis, which corresponds to 90% of the total thickness of the dermis, consists of collagen fibers around 60-100 nm in diameter and is the primary region responsible for skin biomechanics, providing structure and elasticity to the tissue [1,2]. The extracellular matrix content is around 60-65% water [3].…”

Automated Quantification of Tumor Viability in a Rabbit Liver Tumor Model after Chemoembolization Using Infrared Imaging

“…The Matlab randfeatures function (available in the MatLab Statistics Toolbox and MatLab Bioinformatics Toolbox) was used to identify the most discriminant infrared wave numbers among our five populations of spectra (tumor necrosis, viable tumor, fibrosis, liver parenchyma, and liver parenchyma necrosis). 37,38 The randfeatures function randomly selects a subset of 15 wave numbers and reduces all the spectra from 451 wave numbers to the 15 selected. The mean spectrum of each category was subtracted from the corresponding spectra.…”

Confocal Raman study of aging process in diabetes mellitus human voluntaries

“…The band centered at 855cm -1 was assigned to C-C stretching vibration of HP ring residue and P and 876 cm -1 corresponding to C-C stretching vibration of HP ring residue. The band at 891 cm -1 assigned to the protein at 921 cm -1 to C-C stretching vibration of the ring residue P at 938 cm -1 to C-C stretching vibration of HP and P, 972 cm -1 ascribed collagen [23][24][25] .…”