Weakly and strongly associated nonfreezable water bound in bones.
ABSTRACT Water bound in bone of rat tail vertebrae was investigated by 1H NMR spectroscopy at 210-300 K and by the thermally stimulated depolarization current (TSDC) method at 190-265 K. The 1H NMR spectra of water clusters were calculated by the GIAO method with the B3LYP/6-31G(d,p) basis set, and the solvent effects were analyzed by the HF/SM5.45/6-31G(d) method. The 1H NMR spectra of water in bone tissue include two signals that can be assigned to typical water (chemical shift of proton resonance deltaH=4-5 ppm) and unusual water (deltaH=1.2-1.7 ppm). According to the quantum chemical calculations, the latter can be attributed to water molecules without the hydrogen bonds through the hydrogen atoms, e.g., interacting with hydrophobic environment. An increase in the amount of water in bone leads to an increase in the amount of typical water, which is characterized by higher associativity (i.e., a larger average number of hydrogen bonds per molecule) and fills larger pores, cavities and pockets in bone tissue.
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ABSTRACT: Structural characterisation of such bio-objects as fibrinogen solution, yeast cells, wheat seeds and bone tissues has been done using two versions of cryoporometry based on the integral Gibbs–Thomson (IGT) equation for freezing point depression of pore liquids and the measurements by 1H NMR spectroscopy (180–200Applied Surface Science 04/2007; 253(13):5640-5644. · 2.54 Impact Factor
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ABSTRACT: The effect of hydration on the mechanical properties of osteonal bone, in directions parallel and perpendicular to the bone axis, was studied on three length scales: (i) the mineralized fibril level (∼100 nm), (ii) the lamellar level (∼6 µm); (iii) the osteon level (up to ∼30 µm).We used a number of techniques, namely atomic force microscopy (AFM), nanoindentation and microindentation. The mechanical properties (stiffness, modulus and/or hardness) have been studied under dry and wet conditions. On all three length scales the mechanical properties under dry conditions were found to be higher by 30–50% compared to wet conditions. Also the mechanical anisotropy, represented by the ratio between the properties in directions parallel and perpendicular to the osteon axis (Anisotropy Ratio, designated here by AnR), surprisingly decreased somewhat upon hydration. AFM imaging of osteonal lamellae revealed a disappearance of the distinctive lamellar structure under wet conditions. Altogether, these results suggest that a change in mineralized fibril orientation takes place upon hydration.Journal of biomechanics 01/2013; · 2.66 Impact Factor
Conference Paper: Molecular Spectroscopic Identification of Water Compartments in Bone[Show abstract] [Hide abstract]
ABSTRACT: Bone has a significant amount of water, up to 20% bone’s wet weight. Water molecules exist in unbound state in the microscopic pores or they are bound to collagen and mineral with affinities ranging from tightly to loosely. While Raman spectroscopy is one of few nondestructive modalities to assess the hydration status in bone, it has not been used to study the OH-band in bone. Methods: A sequential sample treatment protocol was developed so as replace unbound (heat drying below 100 ºC) and bound (ethanol or deuterium replacement of hear dried samples) water. Raman spectra were collected in the range of 2700-4000 cm-1 after each treatment step to track the OH-band during dehydration. Band assignments were further supported by computational simulation of molecular vibrations of Gly-Pro-Hyp tripeptide. The library of experimentally and theoretically obtained spectra was interpreted cumulatively for band-assignments. Water loss was measured gravimetrically and correlated to Raman intensities. Results: The results indicated that there are four peaks which were sensitive to dehydration. The first peak is at 3220 cm-1 and belongs to only water, the second peak at 3325 cm-1 belongs to NH and water, the third one at 3453 cm-1 belongs to OH of Hyp and water, and the last one at 3584 cm-1 belongs to OH of mineral and water. These peaks had differential sensitivity to deuterium treatment such that some were replaced faster than the rest, indicating that peaks at 3325 and 3584 cm-1 are more tightly bound to the matrix. In addition, the results indicate that the OH-range of bone is mostly dominated by collagen and the water bound to collagen.7th World Congress of Biomechanics, Boston, MA; 07/2014