In situ ATR-FTIR was used to study the interaction of bovine serum albumin（BSA） and hydroxyapatite（HA） in this work.Both on the electrochemically deposited HA and self assemblied titanate nanotubes（TNT） substrates,the adsorption of BSA increases with the increase of time,and its adsorption on HA surface is much larger than that on TNT surface,implying that HA has a good biocompatibility as a biomaterial.It is indicated that Ca2+ plays an essential role in the protein absorption on the HA surface,due to that BSA is negatively charged,and it is able to combine with cation locations in HA particles by electrostatic forces.It is found that,when reacting with BSA,the phosphate band of HA in solution shifts to higher wavenumbers,indicating that PO3-4 can also be an adsorption site for BSA.The spectroscopic study on the interaction between HA and BSA will be helpful for further understanding the nano hydroxyapatite bioproperties on molecular level.
The biosorptive interaction of Ag++ with resting cell of %Lactobacillus sp.% strain A09 has been further studied on a molecular level by means of XPS, EDX, UV-Vis and FTIR techniques. The X-ray photoelectron spectroscopy(XPS) shows that the reductive ratio of the Ag++ to Ag+0 by the A09 biomass reaches to about 54^5% for 3 d. The contain of amino acid residues in dry powder of the biomass such as cysteine, methionine, arginine and lysine, being capable of reducing the Ag++ to Ag+0, are very small in quantity both cysteine and methionine are far less than 0^18%, and both arginine and lysine far less than 0^336%, %via% the analysis with quantitative energy-dispersive X-ray(EDX). The amount of the reducing sugars in the biomass is far larger than 2^71% analyzed by ultraviolet-visible spectrophotometry(UV-Vis). The chemical functional group on cell wass of the biomass such as the carboxylate anion of amino-acid residues seems to be the site for the Ag++ binding and the free aldehyde group of the hemiacetalic hydroxyl from reducing sugars, %i.e.% the hydrolysates of the polysaccharides from the cell wass, plays a protagonist in serving as the electron donor for reducing the Ag++ to Ag+0, characterized by fourier transform infrared(FTIR) spectrophotometry.
