Naturally-Derived Biphasic Calcium Phosphates through Increased Phosphorus-Based Reagent Amounts for Biomedical Applications

Abstract

Calcium carbonate from marble and seashells is an eco-friendly, sustainable, and largely available bioresource for producing natural bone-like calcium phosphates (CaPs). Based on three main objectives, this research targeted the: (i) adaptation of an indirect synthesis route by modulating the amount of phosphorus used in the chemical reaction, (ii) comprehensive structural, morphological, and surface characterization, and (iii) biocompatibility assessment of the synthesized powdered samples. The morphological characterization was performed on digitally processed scanning electron microscopy (SEM) images. The complementary 3D image augmentation of SEM results also allowed the quantification of roughness parameters. The results revealed that both morphology and roughness were modulated through the induced variation of the synthesis parameters. Structural investigation of the samples was performed by Fourier transform infrared spectroscopy and X-ray diffraction. Depending on the phosphorus amount from the chemical reaction, the structural studies revealed the formation of biphasic CaPs based on hydroxyapatite/brushite or brushite/monetite. The in vitro assessment of the powdered samples demonstrated their capacity to support MC3T3-E1 pre-osteoblast viability and proliferation at comparable levels to the negative cytotoxicity control and the reference material (commercial hydroxyapatite). Therefore, these samples hold great promise for biomedical applications.

Novel Synthesis of Core-Shell Biomaterials from Polymeric Filaments with a Bioceramic Coating for Biomedical Applications

“…The maximum temperature used in this study (215 °C) has a defining influence on the of both polymer types revealed specific peaks of the HA main elements, especially Ca and P [44]. The 192 presence of the carbon peak in the spectra denotes the existence of the polymeric substrate.…”

“…The present research involved preliminary studies on PLA and TPU filaments with modified core (polymer)-shell (ceramic) structure. These studies were based on morpho-compositional analysis, given that coating morphology is a must-criteria and the most important factor for the targeted materials along with chemical composition [44].…”

“…In addition, as mentioned above, a clear difference can be observed between the PLA 196 and TPU filament regarding carbon peak intensity. In the case of the first polymer, several particles 197 adhered to its surface; therefore, a higher degree of surface coverage determined a low carbon peak Regarding the compositional analysis, the EDS (Energy-Dispersive X-ray Spectroscopy) spectra of both polymer types revealed specific peaks of the HA main elements, especially Ca and P [44]. The presence of the carbon peak in the spectra denotes the existence of the polymeric substrate.…”

Animal Origin Bioactive Hydroxyapatite Thin Films Synthesized by RF-Magnetron Sputtering on 3D Printed Cranial Implants

“…The sharp and well-split IR absorption bands of orthophosphate groups recorded in the case of the Bio-HA film (Figure 6a) testified for it its high crystallinity [69], in full agreement with the XRD data. All the characteristic IR bands of HA were evidenced for the Bio-HA sputtered structure: ν 4 bending (~565 and~600 cm -1 ), ν 1 symmetrical stretching (~962 cm −1 ), and ν 3 asymmetric stretching (~1032 and~1088 cm -1 ) vibration modes of orthophosphate groups, and ν L libration (~632 cm -1 ) and ν S stretching (~3753 cm -1 ) of structural hydroxyl units [26,36,69]. Only slight shifts and intensity modification of the Bio-HA film bands (Figure 6a) with respect to the pure HA reference and Bio-HA source powder (Figure 6b) were noticed.…”

“…This is why the extraction of Bio-HA from animal bones could represent a viable solution, not only due to the intrinsic natural doping with ions which can promote specific biofunctional traits, but also due to their high availability and reduced costs [17,20]. For biomedical research purposes, bovine [21,22], ovine [23], or swine bones [24] are the most commonly used resources, but also fish [25] and sea-shells [26], as well as more exotic sources such as camel [27] or shark [28] have been explored. For depositing calcium phosphate-based coatings onto metallic implants, the industrial technique of choice is plasma spray (PS), due to the deposition speed, large area coverage, and inexpensive working atmosphere (i.e., ambient or argon) [29,30].…”