Behavior of Calcium Phosphate–Chitosan–Collagen Composite Coating on AISI 304 for Orthopedic Applications

Abstract

Calcium phosphate/chitosan/collagen composite coating on AISI 304 stainless steel was investigated. Coatings were realized by galvanic coupling that occurs without an external power supply because it begins with the coupling between two metals with different standard electrochemical potentials. The process consists of the co-deposition of the three components with the calcium phosphate crystals incorporated into the polymeric composite of chitosan and collagen. Physical-chemical characterizations of the samples were executed to evaluate morphology and chemical composition. Morphological analyses have shown that the surface of the stainless steel is covered by the deposit, which has a very rough surface. XRD, Raman, and FTIR characterizations highlighted the presence of both calcium phosphate compounds and polymers. The coatings undergo a profound variation after aging in simulated body fluid, both in terms of composition and structure. The tests, carried out in simulated body fluid to scrutinize the corrosion resistance, have shown the protective behavior of the coating. In particular, the corrosion potential moved toward higher values with respect to uncoated steel, while the corrosion current density decreased. This good behavior was further confirmed by the very low quantification of the metal ions (practically absent) released in simulated body fluid during aging. Cytotoxicity tests using a pre-osteoblasts MC3T3-E1 cell line were also performed that attest the biocompatibility of the coating.

Galvanic Deposition of Calcium Phosphate/Bioglass Composite Coating on AISI 316L

“…The performance of the coating is linked to its morphology, composition, and adhesion to the substrate, which strongly depend on the substrate itself, the deposition method, and the deposition conditions (i.e., temperature, agitation, and pH). However, we can compare these results with those concerning other coatings we obtained using the galvanic deposition method [82,84,[86][87][88]. According to these results, it can be concluded that the composite with Bioglass has excellent performance, which is only surpassed by the composite with biopolymers such as chitosan and collagen.…”

“…In addition, another positive point to highlight is the controllability of the galvanic process since the deposition rate depends on the ratio between anodic and cathodic areas. Using this method, we have obtained different types of coatings on stainless steel [81][82][83][84][85][86][87][88]. The galvanic deposition of brushite on Ti alloy, which was converted into hydroxyapatite through a subsequent hydrothermal treatment, was also reported by Chen et al [89].…”

Novel incorporation of charged hydroxyapatite nanoparticles into resin adhesive

“…This method relies on the correlation between the vibrational movement of atoms and molecules (10,11). The FTIR spectra of Nano-hydroxyapatite, as shown in Figure 3, exhibit two strong absorption bands at 1022 cm -1 and 555 cm -1 , which are attributed to PO4 -3 and the weak absorption band at 3695 cm -1 corresponding to the hydroxyl group (12). The FTIR spectra of APTS shows the peak at 3400 cm -1 which is attributed to -NH2 stretching, while -NH2 bending vibration bands at 1697 cm -1 , the strong band at 1199 cm -1 is corresponding to the Si-O group (13).…”

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.…”

“…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.…”