FTIR and XPS studies of protein adsorption onto functionalized bioactive glass

Babes-Bolyai University, Faculty of Physics & Interdisciplinary Research Institute on Bio-Nano-Sciences, Cluj-Napoca, Romania
Biochimica et Biophysica Acta (Impact Factor: 4.66). 05/2012; 1824(7):873-81. DOI: 10.1016/j.bbapap.2012.04.008
Source: PubMed


Adsorption and structural changes that occur upon interaction between methemoglobin (MetHb) and 5-methyl-aminomethyl-uridine forming enzyme (MnmE) with the surface of a bioactive glass (BG) were investigated by Fourier Transform Infrared (FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The effect of glutaraldehyde (GA) as a coupling agent for protein adsorption on BG was also investigated. The comparative analysis of FTIR spectra recorded from lyophilized proteins and from bioactive glass surface after protein adsorption was considered in order to obtain information about the changes in the secondary structure of the proteins. XPS data were used to determine the surface coverage. The unfolding of adsorbed proteins due to interactions between the internal hydrophobic protein domains and the hydrophobic BG surface was evidenced. After adsorption, the amount of α-helix decreases and less ordered structures (turns, random coils and aggregates) are preponderant. These changes are less pronounced on the BG functionalized with GA, suggesting that the treatment with GA preserves significantly larger amounts of α-helices in the structure of both proteins after adsorption.

Download full-text


Available from: C. Gruian
  • [Show abstract] [Hide abstract]
    ABSTRACT: The interactions between nanostructures and biomolecules are intensely studied. Noble metal nanoparticles can modify the optical response of macromolecules. In this study, we analyzed by spectroscopic methods (UV–Vis Spectroscopy, Steady State Fluorescence, and FTIR) the bio-conjugation of horse hemoglobin with gold nanorods. Upon the formation of the gold nanorods–hemoglobin complex, the fluorescence signal increases, through Metal-enhanced fluorescence phenomenon.
    No preview · Article · Jan 2013 · Journal of Molecular Structure
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The corrosion of CoCrMo, an alloy frequently used in orthopedic implants, was studied with an electrochemical quartz crystal microbalance (QCM) in three physiologically relevant solutions. Mass changes were measured during potentiodynamic tests, showing material deposition in protein solutions at potential levels that caused mass loss when the proteins were not present. X-ray photoelectron spectroscopy (XPS) data indicated that the deposited material was primarily organic and therefore was most likely derived from proteins in the electrolyte. Material deposition consistently occurred at a critical potential and was not dependent on the current density or total charge released into solution. Corrosion studies on pure Co, Cr, and Mo in protein solutions found material deposition only on Mo. We hypothesize that organic deposition results from the interaction of Mo(VI) with proteins in the surrounding solution. The organic layer is reminiscent of tribochemical reaction layers that form on the surface of CoCrMo hip bearings, suggesting that these types of layers can be formed by purely electrochemical means.
    Preview · Article · Apr 2013 · Langmuir
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The structure and conformational dynamics of insulin entrapped into a silica matrix was monitored during the sol to maturated-gel transition by electron paramagnetic resonance (EPR) spectroscopy. Insulin was successfully spin-labeled with iodoacetamide and the bifunctional nitroxide reagent HO-1944. Room temperature continuous wave (cw) EPR spectra of insulin were recorded to assess the mobility of the attached spin labels. Insulin conformation and its distribution within the silica matrix were studied using double electron-electron resonance (DEER) and low-temperature cw-EPR. A porous oxide matrix seems to form around insulin molecules with pore diameters in the order of a few nanometers. Secondary structure of the encapsulated insulin investigated by Fourier transform infrared spectroscopy proved a high structural integrity of insulin even in the dried silica matrix. The results show that silica encapsulation can be used as a powerful tool to effectively isolate and functionally preserve biomolecules during preparation, storage, and release.
    Full-text · Article · Jul 2013 · Biomacromolecules
Show more