Sialic acids are an important sub-group of nine carbon acidic sugars. Sialic acid plays a significant role in mediating and modulating a variety of physiological activities due to its widespread distribution in human body. Several pathogens and toxins also bind to sialic acid, change its level and signal pathological conditions. The identification and quantification of sialic acid levels are also significant for early detection of many diseases such as breast and colon cancer. In this study, sialic acid determination in the form of N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) was aimed. Serotonin has specific affinity for sialic acid. Hence a novel detection strategy, which is based on the sialic acid-induced aggregation of serotonin functionalized gold nanoparticles, was proposed. Serotonin was bonded on gold nanoparticles utilizing two crosslinkers with different lengths: 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide / N-Hydroxysuccinimide (EDC/NHS) and Dithiobis(succinimidylpropionate) (DSP). Progressive additions of various sialic acid concentrations resulted in distinct color changes on serotonin modified gold nanoparticle probes (DSP-AuNPs@SER and EDC/NHS-AuNPs@SER) from red to purple and blue which indicates the affinity- aggregation. At optimal conditions while using EDC/NHS-AuNPs@SER probe, the absorbance ratio (A625/A521) was linear with respect to N-acetylneuraminic acid concentrations ranging from 300 to 750 µM. The limit of quantification 257.5 μM was achieved for Neu5Ac. Furthermore, at optimal conditions while using DSP-AuNPs@SER probe, the absorbance ratio (A625/A521) was linear with respect to N-acetylneuraminic acid concentrations ranging from 16.7 to 58.3 µM . The limit of quantification 10.0 μM was achieved for Neu5Ac. Moreover, at optimal conditions while using DSP-AuNPs@SER probe, the absorbance ratio (A625/A521) was linear with respect to N-glycolylneuraminic acid concentrations ranging from 8.3 to 58.3 µM . The limit of quantification 17.3 μM was calculated for Neu5Gc. Both probes were successful only for sialic acid among glucose, fructose, mannose, lactose, sucrose, and maltose. Applications of serotonin assembled gold nanoparticles in human serum to determine total serum sialic acid are in progress.


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Yener, Meryem Esra (2001-01-01)
The correlations for vapor pressures of fatty acids, fatty acid methyl and ethyl esters, and simple triglycerides were given based on the available data in the literature. The developed equations enable easy estimation of the critical properties. The group contribution methods were used to develop the estimation method. The estimated properties of the most common lipids were tabulated and the differences between the estimation methods were critically discussed.
Determination of germanium by AAS in chloride-containing matrices
Anwari, MA; Abbasi, HU; Volkan, Mürvet; Ataman, Osman Yavuz (1996-06-01)
Interference effects of NaCl on the ET-AAS determination of Ge have been studied. The use of several matrix modifiers to alleviate this problem such as Ni and Zn perchlorates and nitrates, nitric acid, ammonium nitrate are reported. The stabilizing effect of Zn and Ni perchlorates allows the use of high pretreatment temperatures. NaCl is thus thermally volatilized from the atomizer by employing pretreatment temperatures higher than 1500 degrees C resulting in an improved sensitivity. Germanium levels in zin...
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Alagöz, Eda; Hamamcı, Haluk; Yücel, Ayşe Meral; Department of Biotechnology (2013)
Rhizopus oryzae is a filamentous fungus which can ferment sugar to ethanol, and lactic acid. Increasing demand of the world for use of renewable carbon sources has put this and similar organisms into a position where the biotechnology industries are more and more interested with these organisms. R. oryzae can grow on some renewable carbon sources which makes it a good candidate for production of ethanol as well as lactic acid. The major use of lactic acid is in food industry and food- related application, w...
Characterization of Pectin-Based Gels: A 1H Nuclear Magnetic Resonance Relaxometry Study
Beira, Maria J.; Öztop, Halil Mecit; Sebastião, Pedro J. (2021-10-01)
Rare sugars are monosaccharides and their derivatives that are not commonly found in nature. d-Allulose is a rare sugar that is C-3 epimer of fructose and presents an alternative to sucrose with potential health benefits. In this study, different amounts of sucrose, d-allulose, and soy protein isolate (SPI) were used to prepare a set of pectin gels. The effect of these ingredients on the gels was studied at both a molecular level, by 1H nuclear magnetic resonance (NMR) relaxometry, and a macroscopic level, ...
MELLATI, AA; YUCEL, M; ALTINORS, N; Gündüz, Ufuk (1993-10-01)
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Citation Formats
E. AKIN, “DETERMINATION OF SIALIC ACID BY USING PLASMONIC NANOPARTICLES,” M.S. - Master of Science, Middle East Technical University, 2022.