Impact of Gamma Irradiation on the Properties of Magnesium-Doped Hydroxyapatite in Chitosan Matrix

Abstract

This is the first report regarding the effect of gamma irradiation on chitosan-coated magnesium-doped hydroxyapatite (xMg = 0.1; 10 MgHApCh) layers prepared by the spin-coating process. The stability of the resulting 10 MgHApCh gel suspension used to obtain the layers has been shown by ultrasound measurements. The presence of magnesium and the effect of the irradiation process on the studied samples were shown by X-ray photoelectron spectroscopy (XPS). The XPS results obtained for irradiated 10 MgHApCh layers suggested that the magnesium and calcium contained in the surface layer are from tricalcium phosphate (TCP; Ca3(PO4)2) and hydroxyapatite (HAp). The XPS analysis has also highlighted that the amount of TCP in the surface layer increased with the irradiation dose. The energy-dispersive X-ray spectroscopy (EDX) evaluation showed that the calcium decreases with the increase in the irradiation dose. In addition, a decrease in crystallinity and crystallite size was highlighted after irradiation. By atomic force microscopy (AFM) we have obtained images suggesting a good homogeneity of the surface of the non-irradiated and irradiated layers. The AFM results were also sustained by the scanning electron microscopy (SEM) images obtained for the studied samples. The effect of gamma-ray doses on the Fourier transform infrared spectroscopy (ATR-FTIR) spectra of 10 MgHApCh composite layers was also evaluated. The in vitro antifungal assays proved that 10 MgHApCh composite layers presented a strong antifungal effect, correlated with the irradiation dose and incubation time. The study of the stability of the 10 MgHApCh gel allowed us to achieve uniform and homogeneous layers that could be used in different biomedical applications.

Studies of the Tarragon Essential Oil Effects on the Characteristics of Doped Hydroxyapatite/Chitosan Biocomposites

“…The large maxima noticed (for all the studied samples) at about 3450 cm −1 are specific to the hydroxyl vibration from HA. For the ZnHACh and ZnHAChT samples, the broad maxima specific to the chitosan (N-H vibration) and hydroxyapatite (O-H vibrations) observed between 3300 and 3600 cm −1 are overlapped [41].…”

“…Furthermore, for a more compressive study of the molecular structure of obtained samples, the second derivative spectra were achieved in the conditions described elsewhere [41]. The red lines from Figure 6 represent the second derivative spectra of ZnHA, ZnHACh and ZnHAChT samples.…”

Biological and Physico-Chemical Properties of Composite Layers Based on Magnesium-Doped Hydroxyapatite in Chitosan Matrix

“…In addition, similar results regarding the physico-chemical characteristics of magnesium-doped hydroxyapatite/chitosan coatings obtained by rf magnetron sputtering discharge have been reported by B. Bita and collaborators [ 57 ]. In the study conducted by D. Predoi and coworkers [ 31 ] the strong antifungal activity of chitosan-coated magnesium-doped hydroxyapatite (x Mg = 0.1) layers obtained by spin-coating was proved against C. albicans fungal strain. At the same time, previous studies have demonstrated that the surface morphology and optical properties of chitosan-hydroxyapatite coatings obtained by rf magnetron sputtering discharge are influenced by the Ar gas working pressure [ 33 ].…”

“…The synthesis of magnesium-doped hydroxyapatite in a chitosan matrix (Ca 10 −x Mg x (PO 4 ) 6 (OH) 2 ; x Mg = 0, 0.08 and 0.3) was conducted following our previous studies [ 25 , 31 ]. For this purpose, the value used for the Ca/P molar ratio was 1.67.…”

“…Previous studies conducted on hydroxyapatite/chitosan and doped hydroxyapatite/chitosan composite coatings highlighted the fact that the biological properties of these biomaterials are influenced by the deposition conditions and by their exposure to various doses of gamma radiation [ 31 , 32 , 33 ].…”