Papers by Keyword: Tyrosine

Abstract: Synthesis and stability of silver nanoparticles (AgNPs) using tyrosine as a reducing and capping agent have been done. Synthesis of AgNPs was performed by mixing silver nitrate (AgNO₃) solution as a precursor with tyrosine amino acid and heating it in a boiling water bath until characterized by the appearance of color change from colorless to yellow. Variations in pH, concentration, and reaction time affecting the formation of AgNPs were studied using UV-Vis spectrophotometry in the wavelength range of 300-700 nm as the main device. The synthesis was successfully conducted at pH 11 for 45 min with the optimum tyrosine concentration was 3 mM for 0.5 mM AgNO₃. The optimum mole ratio AgNO₃ 0.5 mM to tyrosine 3 mM was 1:6. TEM and PSA characterizations showed that the particle was a round shape and 29.5 nm is average size, respectively.

Abstract: A novel, simple and environmental friendly approach to fabricate silver nanoparticles (AgNPs) on mesoporous silica nanoparticles (MSNs) using tyrosine (Tyr) as biological reducing agent was developed. The functionalization of Tyr with MSNs (Tyr-MSNs) (150 nm in length) by the sol-gel process was confirmed by the characteristic peaks of amino, carboxyl and silanol groups appeared in FTIR spectrum and the change of the zeta potential from 0 mV at pH 2 to-60 mV at pH 12. Then, AgNPs were formed on the surface of Tyr-MSNs (Tyr-MSN@AgNPs) via only reducibility from phenolic group of Tyr and catalytic activity from base at room temperature. TEM images and UV-Visible absorption band at 420 nm supported the obtained AgNPs (18 nm at pH 11) were tightly bound to Tyr-MSNs even after centrifugation at high speed. These Tyr-MSN@AgNPs would be potentially used as drug carrier in biomedical applications.

Abstract: The thermodynamics and kinetics properties and mechanism of sorption process were studied for adsorpting tyrosine in aqueous solution with multi-wall carbon nanotubes (MWCNTs), and the adsorption isotherms at different temperatures were determined. The results showed that the adsorption of the tyrosine in aqueous solution obeys well with the Freundlich isotherm, The thermodynamic parameters indicated that the adsorption reaction was a spontaneous, exothermal and decreasing entropy process,and the adsorption process had an obvious physisorption characteristic.The pseudo-second-order equation provided the best correlation for the adsorption process, being in agreement with adsorption as the rate controlling step.