Article

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

ABSTRACT 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.

0 Bookmarks
 · 
497 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Fibrinogen is a major plasma protein. Previous investigations of structural changes of fibrinogen due to adsorption are mostly based on indirect evidence after its desorption, whereas our measurements were performed on fibrinogen in its adsorbed state. Specific enzyme-linked immunosorption experiments showed that the amount of adsorbed fibrinogen increased as the surface became more hydrophobic. Atomic force microscopy (AFM) investigations revealed the trinodular shape of fibrinogen molecules adsorbed on hydrophilic surfaces, whereas all of the molecules appeared globular on hydrophobic surfaces. The distribution of secondary structures in adsorbed fibrinogen was quantified by in situ Fourier-transform infrared (FTIR) analysis. Substrates of identical chemical bulk composition but different surface hydrophobicity permit direct comparison among them. Adsorption properties of fibrinogen are different for each degree of hydrophobicity. Although there is some increase of turn structure and decrease of beta-sheet structure, the secondary structure of adsorbed fibrinogen on hydrophilic surface turned out to be rather similar to that of the protein in solution phase with a major alpha-helix content. Hydrophilic surfaces exhibit superior blood compatibility as required for medical applications.
    Colloids and surfaces B: Biointerfaces 06/2005; 42(3-4):219-25. · 4.28 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Infrared (IR) spectra of normal, hyperplasia, fibroadenoma and carcinoma tissues of human breast obtained from 96 patients have been determined and analyzed statistically. Several spectral differences were detected in the frequency regions of NH stretching, amide I, II and III bands: (1) the bands in the region 3000–3600cm−1 shifted to lower frequencies for the carcinomatous tissue; (2) the A3300/A3075 absorbance ratio was significantly higher for the fibroadenoma than for the other types of tissues; (3) the frequency of the α-helix amide I band decreased for the malignant tissue, while the corresponding β-sheet amide I band frequency increased; (4) the A1657/A1635 and A1553/A1540 absorbance ratios were the highest for fibroadenoma and carcinoma tissues; (5) the A1680/A1657 absorbance ratio decreased significantly in the order of normal>hyperplasia>fibroadenoma>carcinoma; (6) the A1651/A1545 absorbance ratio increased slightly for the fibroadenoma and the carcinoma tissues; (7) the bands at 1204 and 1278cm−1, assigned to the vibrational modes of the collagen, did not appear in the original spectra as resolved peaks and were distinctly stronger in the deconvoluted spectra of the carcinoma tissue and (8) the A1657/A1204 and A1657/A1278 absorbance ratios, both yielding information on the relative content of collagen, increased in the order of normal
    Vibrational Spectroscopy 01/2001; 27(2):165-173. · 1.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Protein adsorption at solid surfaces plays a key role in many natural processes and has therefore promoted a widespread interest in many research areas. Despite considerable progress in this field there are still widely differing and even contradictive opinions on how to explain the frequently observed phenomena such as structural rearrangements, cooperative adsorption, overshooting adsorption kinetics, or protein aggregation. In this review recent achievements and new perspectives on protein adsorption processes are comprehensively discussed. The main focus is put on commonly postulated mechanistic aspects and their translation into mathematical concepts and model descriptions. Relevant experimental and computational strategies to practically approach the field of protein adsorption mechanisms and their impact on current successes are outlined.
    Advances in colloid and interface science 02/2011; 162(1-2):87-106. · 5.68 Impact Factor

Full-text

View
102 Downloads
Available from
May 26, 2014