TG and DSC studies of bone tissue: Effects of osteoporosis

Water adsorbed in human bone tissue both healthy (sample S-1) and destroyed by the osteoporosis disease (sample S-2) was investigated by using differential scanning calorimetry (DSC) and thermal analysis (TG, DTG and DTA). Thermal analysis was used to estimate water and organic matter contents in the healthy human bone and that changed by the osteoporosis disease. The impact of the additional medium (chloroform) on the process of water freezing at the solid/water/chloroform interface in the bone tissue was also examined. The studies of freezing and melting processes in the low temperature range (from +20 to −175 °C) depending on the porosity of the biological matter showed the shift of water freezing and ice melting temperatures in relation to the bulk water. There was observed a decrease in the freezing point of water in narrow pores of the samples of S-1 series in comparison to the samples of S-2 series. The values of this shift are closely related to the pore size and the degree of water saturation. The existence of the solid/water and water/air interfaces in the test systems causes displacement of the freezing/melting point which is also dependent on the degree of saturation of the biological material with water. The data are in good correlation with those obtained using the SEM microscopy.