Calcium Phosphates–Chitosan Composite Layers Obtained by Combining Radio-Frequency Magnetron Sputtering and Matrix-Assisted Pulsed Laser Evaporation Techniques

Abstract

In this work, we report the synthesis of calcium phosphate–chitosan composite layers. Calcium phosphate layers were deposited on titanium substrates by radio-frequency magnetron sputtering technique by varying the substrate temperature from room temperature (25 °C) up to 100 and 300 °C. Further, chitosan was deposited by matrix-assisted pulsed laser evaporation technique on the calcium phosphate layers. The temperature at the substrate during the deposition process of calcium phosphate layers plays an important role in the embedding of chitosan, as scanning electron microscopy analysis showed. The degree of chitosan incorporation into the calcium phosphate layers significantly influence the physico-chemical properties and the adherence strength of the resulted layers to the substrates. For example, the decreases of Ca/P ratio at the addition of chitosan suggests that a calcium deficient hydroxyapatite structure is formed when the CaP layers are generated on Ti substrates kept at room temperature during the deposition process. The Fourier transform infrared spectroscopy analysis of the samples suggest that the PO43−/CO32− substitution is possible. The X-ray diffraction spectra indicated that the crystalline structure of the calcium phosphate layers obtained at the 300 °C substrate temperature is disturbed by the addition of chitosan. The adherence strength of the composite layers to the titanium substrates is diminished after the chitosan deposition. However, no complete exfoliation of the layers was observed.

Biomaterial composed of chitosan, riboflavin, and hydroxyapatite for bone tissue regeneration

“…Earlier studies on composites produced on the basis of CS and HAP showed similar spectral characteristics that were mainly attributed to the formation of hydrogen bonds between CS and HAP through the functional groups mentioned above 56 , 62 , 63 , 65 , 66 . The examined spectra also resembled, to some extent, phosphorylated chitosan spectra 67 , 68 , which may also suggest the formation of covalent bonds with the participation of phosphate groups.…”

Calcium Phosphate Loaded Biopolymer Composites—A Comprehensive Review on the Most Recent Progress and Promising Trends

“…The highly porous composite scaffolds (with pore size between 100 and 200 µm) allowed the 3D arrangement of cells that were able to diffuse into the composite [77]. It is worth mentioning that chitosan-CaP composites can be applied not only as scaffolds but also as coatings [92,93]. Zanca et al [92] deposited chitosan-collagen-CaP composite layers onto AISI 304 type stainless steel using a galvanostatic method and characterized their morphological, structural, degradative, and ion-releasing properties and their biological performances.…”

“…They found that the coating provided good corrosion protection and the viability tests on MC3T3-E1 cells confirmed their excellent biocompatibility. In another recent work, Zarif et al [93] combined two types of coating preparation methods, namely radio-frequency magnetron sputtering (RFMS) and matrix-assisted pulsed laser evaporation (MAPLE). In their research, the CaP layer was deposited by RFMS by changing the temperature of the substrate, following the chitosan deposition by MAPLE onto the previously deposited CaP coating.…”

Spectral Analysis of Strontium-Doped Calcium Phosphate/Chitosan Composite Films

“…Radio frequency magnetron sputtering (RF-MS) discharge is a plasma technique used to deposit various materials on different substrates [22]. The plasma processes involve the bombardment of a sputtering target by energetic ions created in the discharge plasma.…”

“…The advantages of this technique are the good adhesion between the substrate and film, the control of the film chemical composition, the control of temperature during the deposition process, and the control of the uniformity and density of the coatings [24]. The coating composition depends on the discharge power, the deposition time, and the thickness of the film [22].…”