Transmittance Fourier Transform Infrared Spectra of Liquid Water in the Whole Mid-Infrared Region: Temperature Dependence and Structural Analysis

Freda, M.; Piluso, A.; Santucci, A.; Sassi, Paola

doi:10.1366/0003702055012591

Cited by 67 publications

(97 citation statements)

References 29 publications

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“…8 has been decomposed into the four contributions labelled as I i (i = 1, 4) corresponding to the different populations of OH oscillators present in the system. [50][51][52] As shown in previous studies, [36][37][38]40 the sums of the percentage intensities of the two sub-bands found, respectively, at the lowest and highest wavenumbers, i.e. (I 1 + I 2 ) and (I 3 + I 4 ) in Fig.…”

Section: Restructuring Of the Hb Network Of Confined Watersupporting

confidence: 79%

Toward an understanding of the thermosensitive behaviour of pH-responsive hydrogels based on cyclodextrins

et al. 2015

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The molecular mechanism responsible for the thermosensitive behaviour exhibited by pH-responsive cyclodextrin-based hydrogels is explored here with the twofold aim of clarifying some basic aspects of H-bond interactions in hydrogel phases and contributing to a future engineering of cyclodextrin hydrogels for targeted delivery and release of bioactive agents. The degree of H-bond association of water molecules entrapped in the gel network and the extent of intermolecular interactions involving the hydrophobic/ hydrophilic moieties of the polymer matrix are probed by UV Raman and IR experiments, in order to address the question of how these different and complementary aspects combine to determine the pH-dependent thermal activation exhibited by these hydrogels. Complementary vibrational spectroscopies are conveniently employed in this study with the aim of safely disentangling the spectral response arising from the two main components of the hydrogel systems, i.e. the polymer matrix and water solvent. The experimental evidence suggests that the dominant effects in the mechanism of solvation of cyclodextrin-based hydrogels are due to the changes occurring, upon increasing of temperature, in the hydrophobicity character of specific chemical moieties of the polymer, as triggered by pH variations. The achievements of this work corroborate the potentiality of the UV Raman scattering technique, in combination with more conventional IR experiments, to provide a ''molecular view'' of complex macroscopic phenomena exhibited in hydrogel phases.

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Section: Restructuring Of the Hb Network Of Confined Watersupporting

confidence: 79%

Toward an understanding of the thermosensitive behaviour of pH-responsive hydrogels based on cyclodextrins

et al. 2015

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“…Infrared (IR) absorption spectra were recorded between 800 and 4000 cm −1 with an IFS28 Bruker spectrometer (resolution of 2 cm −1 ), using a cell with CaF 2 windows and without a spacer 25…”

Section: Methodsmentioning

confidence: 99%

Reversible and irreversible denaturation processes in globular proteins: from collective to molecular spectroscopic analysis

Sassi

Perticaroli

Comez

et al. 2011

J Raman Spectroscopy

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Different spectroscopic techniques were applied for studying the structural properties of lysozyme in salt-free aqueous solutions. The results of vibrational and Brillouin scattering measurements were compared to obtain both single-molecule and collective properties of the solutions. The characterization of the protein system, from the conformation of the polypeptide chain to the exposure of side chains to the solvent and the arrangement of the solution network, was then achieved in the range 25-85 • C. Through the analysis of the indole breathing mode, a different environment for the six tryptophan residues of an unfolded lysozyme could be evidenced. Short and long exposures to high temperatures were used to modulate the competition between the thermally induced reversible and irreversible denaturation processes. These different thermal treatments were applied to distinguish between the effects of global unfolding of the single molecule from those of self-aggregation and gel formation. It has been observed that clusterization occurs at melting temperatures with slow kinetics; also, aggregates evolve from the completely unfolded state of the protein and lead to a sensitive increase in viscosity. This effect probably hinders any further conformational rearrangement of the molecules in the aggregate; thus as a consequence, the disordered structure of clusters does not change to give the β-sheet organization, characteristic of filaments or fibrils.

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“…Transmission spectra were collected at various temperatures, in the 295-365 K range, using a specially designed cell with CaF 2 windows [26]. Temperature of the experiment was controlled through a circulating water bath (Haake F6 ultra-thermostat), with a precision of 0.1K.…”

Section: Ftir Spectramentioning

confidence: 99%

Unfolding and aggregation of lysozyme: A thermodynamic and kinetic study by FTIR spectroscopy

Sassi

Giugliarelli

Paolantoni

et al. 2011

Biophysical Chemistry

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The unfolding of hen egg-white lysozyme dissolved both in D 2 O and CH 3 CH 2 OD/D 2 O was studied by Fourier Transform Infrared (FTIR) absorption spectroscopy at different protein concentrations.A detailed description of the local and global rearrangement of the secondary structure upon a temperature increase, in the range 295 to 365 K, was obtained through the analysis of the amide I band. Thermodynamic parameters for the melting, and the effect of the co-solvent in determining a change in thermal stability of the protein were evaluated. The protein-protein interactions were also followed as a function of temperature: a strong dependence of the cluster stability and aggregation yield on the solvent composition was observed. Finally, FTIR spectra taken at successive time steps of the aggregation enabled intermolecular contacts to be monitored as a function of time, and kinetic information to be obtained showing that both unfolded and folded states of lysozyme act as reactants for the clustering event.

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Transmittance Fourier Transform Infrared Spectra of Liquid Water in the Whole Mid-Infrared Region: Temperature Dependence and Structural Analysis

Cited by 67 publications

References 29 publications

Toward an understanding of the thermosensitive behaviour of pH-responsive hydrogels based on cyclodextrins

Toward an understanding of the thermosensitive behaviour of pH-responsive hydrogels based on cyclodextrins

Reversible and irreversible denaturation processes in globular proteins: from collective to molecular spectroscopic analysis

Unfolding and aggregation of lysozyme: A thermodynamic and kinetic study by FTIR spectroscopy

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