Noninvasive in Vivo Measurement of Natural Moisturizing Factor Content in Stratum Corneum of Human Skin by Attenuated Total Reflection Infrared Spectroscopy

2012 ◽  
Vol 66 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Shingo Takada ◽  
Satoru Naito ◽  
Junko Sonoda ◽  
Yuuki Miyauchi
Keyword(s):  
Infrared Spectroscopy ◽  
Stratum Corneum ◽  
Human Skin ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Factor Content ◽  
In Vivo Measurement

scholarly journals Infrared Spectroscopy with a Fiber-Coupled Quantum Cascade Laser for Attenuated Total Reflection Measurements Towards Biomedical Applications

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5130 ◽  
Author(s):  
Ine L. Jernelv ◽  
Karina Strøm ◽  
Dag Roar Hjelme ◽  
Astrid Aksnes
Keyword(s):  
Infrared Spectroscopy ◽  
Quantum Cascade Lasers ◽  
Spectral Power ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Mid Infrared ◽  
Quantum Cascade ◽  
In Vitro Investigation

The development of rapid and accurate biomedical laser spectroscopy systems in the mid-infrared has been enabled by the commercial availability of external-cavity quantum cascade lasers (EC-QCLs). EC-QCLs are a preferable alternative to benchtop instruments such as Fourier transform infrared spectrometers for sensor development as they are small and have high spectral power density. They also allow for the investigation of multiple analytes due to their broad tuneability and through the use of multivariate analysis. This article presents an in vitro investigation with two fiber-coupled measurement setups based on attenuated total reflection spectroscopy and direct transmission spectroscopy for sensing. A pulsed EC-QCL (1200–900 cm − 1 ) was used for measurements of glucose and albumin in aqueous solutions, with lactate and urea as interferents. This analyte composition was chosen as an example of a complex aqueous solution with relevance for biomedical sensors. Glucose concentrations were determined in both setup types with root-mean-square error of cross-validation (RMSECV) of less than 20 mg/dL using partial least-squares (PLS) regression. These results demonstrate accurate analyte measurements, and are promising for further development of fiber-coupled, miniaturised in vivo sensors based on mid-infrared spectroscopy.

scholarly journals Critical Factors for In Vivo Measurements of Human Skin by Terahertz Attenuated Total Reflection Spectroscopy

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4256
Author(s):  
Lixia Wang ◽  
Sayon Guilavogui ◽  
Henghui Yin ◽  
Yiping Wu ◽  
Xiaofei Zang ◽  
...  
Keyword(s):  
Human Skin ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Deep Penetration ◽  
Reference Spectrum ◽  
Critical Factors ◽  
Contact Duration ◽  
In Vivo Measurements ◽  
Different Types

Attenuated total reflection (ATR) geometry is a suitable choice for in vivo measurements of human skin due to the deep penetration of the field into the sample and since it makes it easy to measure the reference spectrum. On the other hand, there are several critical factors that may affect the terahertz (THz) response in these kinds of experiments. Here, we analyse in detail the influence of the following factors: the contact positions between the thumb and the prism, the contact pressure, the contact duration, and the materials of the prism. Furthermore, we use the THz-ATR technology to evaluate different types of handcream and also establish the theoretical model to investigate the reflectivity after interacting with the skin. The results agree well with experimental ones. Our analysis makes it clear the importance of controlling the above factors during measurements to enable reliable THz response and results which, in turn, may be used to monitor water motion in human skin and to predict possible diseases.

Spectral Differences between Stratum Corneum and Sebaceous Molecular Components in the Mid-IR

2000 ◽  
Vol 54 (8) ◽  
pp. 1175-1182 ◽  
Author(s):  
Lorenzo Brancaleon ◽  
Michael Paul Bamberg ◽  
Nikiforos Kollias
Keyword(s):  
Infrared Spectroscopy ◽  
Stratum Corneum ◽  
Attenuated Total Reflection ◽  
Molecular Composition ◽  
Early Recovery ◽  
Molecular Arrangement ◽  
Conformational Order ◽  
Ft Ir ◽  
Molecular Components

Despite a number of studies on the composition of the lipids of stratum corneum (SC) and sebum, questions remain about the detailed molecular arrangement of the two superficial components of human skin. The investigation of the molecular components of SC in vivo is important to understand the function of what was once thought to be a “dead” epithelium. We have investigated the molecular composition of SC and sebum in vivo, in the mid-infrared, with fiber-based attenuated total reflection Fourier transform infrared spectroscopy (ATR/FT-IR). This technique combines the sensitivity of infrared spectroscopy in detecting molecular composition and conformational order with the capability of probing surfaces to a depth of less than 1 μm. ATR/FT-IR is therefore particularly useful for the investigation of interfaces such as SC and the sebaceous layers. We found that with the use of ATR/FT-IR one can distinguish between the contribution of the molecular components of sebum and SC. The presence of spectral “signatures” of the lipids of sebum allowed us to improve the interpretation of some infrared bands of sebaceous origin as well as of SC in vivo. We also found that ATR/FT-IR can be used to separate the spectral contributions of sebum and SC, and as a method to study the early recovery of superficial lipids after the removal of sebum. Following calibration, a method can be developed to quantify the relative amount of fatty acid in sebum with the use of ATR/FT-IR. We observed that the sebaceous fatty acids that reach the surface of the skin recover at a slower rate than other sebaceous lipids. Our investigation shows that fiber-based ATR/FT-IR is a promising spectroscopic approach to the study of epithelial surfaces and surface contaminants in vivo.

Correction of Baseline Drifts due to the Pressure Changes between Attenuated Total Reflection Prism and Human Skin for Noninvasive Blood Glucose Sensing with Fourier Transform Infrared Spectroscopy

2011 ◽  
Vol 345 ◽  
pp. 119-123
Author(s):  
Dong Min Wang ◽  
Qi Peng Lu ◽  
Li Jun Yao
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Human Skin ◽  
Linear Regression Analysis ◽  
Fourier Transform Infrared ◽  
Glucose Sensing ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Pressure Changes

.For noninvasive blood sensing with attenuated total reflection (ATR)-Fourier Transform infrared spectroscopy(FTIR), the baseline of spectra human skin will drift because of the exitence of pressure changes between ATR prism and human skin . To correct the baseline drifts ,In the paper, the fingertips spectra in mid-infrared were recorded under the special conditions. A line equation was calculated using the last 14 spectra coupled with the linear regression analysis between the absorbance spectra at the 1035cm-1and the 950cm-1. And the corrected absorption intensities, after the removal of the baseline drifts, can be applied for the quantification of glucose concentrations in blood easily with the given method in the paper.

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