Non-invasivein vivodetermination of the carotenoids beta-carotene and lycopene concentrations in the human skin using the Raman spectroscopic method

Abstract

Resonance Raman spectroscopy was used as a fast and non-invasive optical method of measuring the absolute concentrations of beta-carotene and lycopene in living human skin.Beta-carotene and lycopene have different absorption values at 488 and 514.5 nm and, consequently, the Raman lines for beta-carotene and lycopene have different scattering efficiencies at 488 and 514.5 nm excitations. These differences were used for the determination of the concentrations of beta-carotene and lycopene. Using multiline Ar+ laser excitation, clearly distinguishable carotenoid Raman spectra can be obtained which are superimposed on a large fluorescence background. The Raman signals are characterized by two prominent Stokes lines at 1160 and 1525 cm−1, which have nearly identical relative intensities. Both substances were detected simultaneously.The Raman spectra are obtained rapidly, i.e. within about 10 s, and the required laser light exposure level is well within safety standards. The disturbance of the measurements by non-homogeneous skin pigmentation was avoided by using a relatively large measuring area of 35 mm2.It was shown that beta-carotene and lycopene distribution in human skin strongly depends upon the skin region studied and drastically changed inter-individually. Skin beta-carotene and lycopene concentrations are lower in smokers than in non-smokers and higher in the vegetarian group.

Influence on the Carotenoid Levels of Skin Arising from Age, Gender, Body Mass Index in Smoking/Non-Smoking Individuals

“…Therefore, blue light at 488 nm excites all the carotenoid substances with approximately the same Raman scattering efficiency. [24] Lycopene can be determined using an excitation wavelength of 514 nm. [24] In principle, the arbitrary units of the Raman signal can be transferred into absolute concentrations of β-carotene and lycopene, if the lutein concentration is negligible.…”

Comment on ‘Dengue viral infection monitoring from diagnostic to recovery using Raman spectroscopy’

“…We state that the three developed bands peaked at ~1023, 1170 and 1527 cm −1 in Raman spectra of blood plasma from healthy volunteers are assigned to C-CH 3 rocking mode and C-C and C = C stretch vibrations of the conjugated backbone of carotenoids, respectively [5,6]. The presence of carotenoids in the blood serum is confirmed using various techniques, for example, high-pressure liquid chromatography [7].…”

Changes of the skin barrier and bacterial colonization after hair removal by clipper and by razor

“…As a result, the resonance amplification of the Raman signal of cutaneous carotenoids occurs and is easily detected on the high fluorescence background. The twowavelength excitation scheme is used to determine most prevalent cutaneous carotenoids beta-carotene and lycopene separately [27]. The technical description of the utilized device, its advantages and limitations in comparison to other measuring techniques, were previously described in detail by our group [27,28].…”