The effect of pH on amino acids binding to silver nanoparticles

The study of interaction between biologically molecules and nanoparticles has attracted many interest because of potential application in adverse area. In order to improve their biospecificity, biologically active molecules such as amino acids, peptides and protein are usually attached to nanoparticles. This report here describes the interaction between silver nanoparticles and amino acids. The control of binding degree of amino acids to silver nanoparticles is achieved by the pH change the reaction environment. The pH values have been adjusted by adding hydrochloric acid (HCl) or sodium hydroxide (NaOH) to the stock solution prepared. The characterization of the amino acids binding to silver nanoparticles at different pH condition are done by using UV-Vis Spectrophotometer and IR spectroscopy. The pH dependent binding studies of different charge amino acids, namely L-glutamic acid, L-phenylalanine, Alanine and Lysine with silver nanoparticles have been reported. From UV-Vis obtained data, association constant (K) were calculated. The association constant indicates the binding properties of amino acids to silver nanoparticles. Our result showed that, acidic condition shows higher K value for almost all the amino acids except for glutamic acid which has higher K value at neutral condition. For FTIR, the presence of N-H vibration at 3100cm-1 confirm the formation of complex molecules.