Analysis of saliva by Fourier transform infrared spectroscopy for diagnosis of physiological stress in athletes

Abstract

Introduction: Saliva is the most promising biofluid to monitor the physiological state of athletes, because this method is not invasive and has low contamination risks. The characterization of saliva by Fourier transform infrared spectroscopy (FT-IR) has been studied as an alternative technique to the standard clinical analysis. However, methodological procedures for saliva analysis are not completely clear, especially in terms of influence of storage conditions and sample preparations for infrared analysis. Thawed saliva includes a precipitate, which may influence the infrared spectral analysis. Thus, the purpose of this study was to show the spectral differences of the precipitate, supernatant, and a combo, as well as the best way to classify the physiological state of the athletes by FT-IR. Methods: The saliva collection was performed before, immediately after, and two hours after a handball match. After the storage of samples at -20 ○ C, it was possible to identify two phases (precipitate and supernatant) and to determine the biochemical differences between the spectra of each phase, which were distinctly analyzed by the second derivative and deconvolution bands. Results: The precipitate and supernatant results showed characteristic bands, especially in the protein regions. All FT-IR spectra were also statistically classified by linear discriminant analysis (LDA), using principal component analysis (PCA). The LDA precipitate and supernatant had lower value when compared to combo spectra (Combination of precipitate and supernatant) with 82%, showing that this combination is the best way to discriminate spectra of saliva samples collected before, immediately after, and 2 h after physical effort. Discussion: The results showed that it is possible to differentiate biochemically the two salivary phases, as well as the importance of the homogenization process of saliva samples to classify the physiological status of athletes using FT-IR.

Does dentifrice provide the necessary saturation of ions in oral fluids to favour remineralisation?

“…The analysis of the obtained IR spectra was performed based on a number of data taken from a set of reference sources, where human mixed saliva and hard dental tissues, as well as phosphates related to the formation of dentin and enamel were investigated by means of IR spectroscopy [5,38,[41][42][43][44][45]. A list of the active vibrations in the spectra of the first and second stages of the study, the ranges, and the frequencies with the peaks of vibration bands are presented in Table 1 along with their assignments to the groups of vibrations.…”

“…Mixed saliva samples were analysed by infrared (IR) spectroscopy, a highly selective and sensitive method allowing extensive information on the structure of substances, the effect of atomic groups comprising compounds, as well as the detection of neogenic organic and mineral phases [5,9,[36][37][38]. It can also be used to analyse multi-component compounds.…”

“…Hence, the application of IRspectroscopy for the analysis of the changes in the molecular composition of the oral fluid is a logical and tested approach demonstrating high-precision results [4,5,41,36]. All the vibration mods of the samples were signed in accordance of the reference sources of IR spectroscopy [5,38,[41][42][43][44][45] and tabulated in Table 2.…”

“…The significance of the changes in the molecular composition of mixed saliva has been previously shown in diabetes, oncology and pathologies of the oral cavity [4][5][6][7][8][9]. Considerable deviation of the molecular composition in the oral fluid can have an influence on the content of mineral complexes in plaque fluid and thus, impact on the process of enamel remineralisation [1,[10][11][12][13].…”

Application of FT-IR spectroscopy to assess physiological stress in rugby players during fatigue test

“…In our previous work, the homogenization of saliva samples by vigorous mixing were the most Volume 32, Number 2, p. 123-128, 2016 appropriated way for FT-IR measurements, which was used mainly to classify the physiological status of athletes in exercise training by FT-IR (Caetano et al, 2015). In this context, the purpose of this study was to discriminate FT-IR spectra of mixed saliva collected before and after fatigue test continued, using cluster analysis.…”