Figure 29: Graphical representation of the potential mechanisms of biothiol sensing based on (**a**) the effect of biothiols on the growth and aggregation of gold nanoparticles and (**b**) gold-coated CTAB micellar assemblies. 16.21. Breath Alkanes Study of the Effectiveness of Spirulina Supplement in Recovering from Exercise-Induced Muscle Damage in Humans K. Mikedi 1,*, P. Zeimpekis 1, S. Karma 1, P. Athanasakis 1, I. Katsoulakis 1, A. Pappa 1, A. Krokidas 2, T. Nomikos 2 and M. Krokida 1  
Laboratory of Inorganic and Analytical Chemistry, School of Chemical Engineering, National Technical University of Athens, 10431 Athens, Greece Department of Nutrition and Dietetics, School of Health Science and Education, Harokopio University, 17671 Kallithea, Greece Correspondence: mikedi@chemeng.ntua.gr  
Human expired air contains hundreds of Volatile Organic Compounds (VOCs) that could provide important insights into environmental exposure, dietary habits, lifestyle, diseases, and medication. Determining VOCs in breath for studying various health issues has significantly increased since 1990. Breath analysis has certain advantages over analysis of other body liquids (blood, urine, or sweat); it is non-invasive and pain-free, sample is always available, and long sampling and preconcentration makes the analysis sensitive to low levels of VOCs. In the current study, breath analysis is used for studying the effectiveness of spirulina supplement in recovering from exercise induced-muscle damage (EIMD). EIMD is a pathophysiological phenomenon occurring after intense or accustomed exercise and it is characterized by the acute activation of oxidative stress and inflammation. Intake of supplements, such as spirulina, can potentially attenuate EIMD and accelerate recovery of athletes. Spirulina was selected as it is considered a well-known microalgae genus with significant content of proteins, vitamins, pigments, fatty acids, sterols, and having proven health benefits; hence, athletes prefer to consume it. For this work, a group of eight healthy volunteers of mild physical activity participated in a randomized, cross-over, double-blind intervention study. The intervention started with a supplementation period of 15 days where the volunteers consumed daily 42 mg/Kg body weight Spirulina Nigeria or maltodextrin as placebo. By the end of the supplementation period, the volunteers followed an eccentric exercise protocol that is able to induce muscle damage. The volunteers consumed the supplement three more days post-exercise. Samples of exhaled breath have been collected in Tedlar bags prior to supplementation (baseline), prior to exercise, and 1 h, 24 h, 48 h, and 72 h post-exercise. Breath samples were analysed by Thermal Desorption-Gas Chromatography /Mass Spectrometry (TDU-GC/MS). Ergo-physiological methods and blood analysis were also used as reference methods. Analysis of the chromatographic data targeted to straight-chain alkanes and monomethylalkanes (C5-C9), which are among the oxidative stress biomarkers originated from lipid peroxidation of polyunsaturated fatty acids [1]. Preliminary results have shown a significant interindividual variability with no obvious correlation with classical markers of exercise-induced muscle damage while the kinetic are similar after the placebo and spirulina intervention. A different set of molecules are currently being investigated for the ability to assess post-exercise inflammation and oxidative stress. The research leading to these results has received funding from Hellenic Foundation for Research and Innovation under NutrID project, \"Novel technologies of isolation and micro-nano encapsulation for personalized 3-D food printed nutritional products. Detection of metabolic products through breath analysis\", No. HFRI-FM17-1482. ## References  
* Ratcliffe et al. 2020 Ratcliffe, N.; Wieczorek, T.; Drabinska, N.; Gould, O.; Osborne, A.; Costello, B.D.L.