Macroporous Calcium Phosphate/Chitosan Composites Prepared via Unidirectional Ice Segregation and Subsequent Freeze-Drying

Abstract

Calcium phosphate chitosan-based composites have gained much interest in recent years for biomedical purposes. In this paper, three-dimensional calcium phosphate chitosan-based composites with different mineral contents were produced using a green method called ice segregation induced self-assembly (ISISA). In this methodology, ice crystals were used as a template to produce porous structures from an aqueous solution of chitosan (CS) and hydroxyapatite (Hap) also containing acetic acid (pH = 4.5). For better characterization of the nature of the inorganic matter entrapped within the resulting composite, we performed either oxygen plasma or calcination processes to remove the organic matter. The nature of the phosphate salts was studied by XRD and NMR studies. Amorphous calcium phosphate (ACP) was identified as the mineral phase in the composites submitted to oxygen plasma, whereas crystalline Hap was obtained after calcination. SEM microscopy revealed the formation of porous structures (porosity around 80–85%) in the original composites, as well as in the inorganic matrices obtained after calcination, with porous channels of up to 50 µm in diameter in the former case and of up to 20 µm in the latter. The biocompatibility of the composites was assessed using two different cell lines: C2C12GFP premyoblastic cells and MC3T3 preosteoblastic cells.

A Comparative Analysis of the Reinforcing Efficiency of Silsesquioxane Nanoparticles versus Apatite Nanoparticles in Chitosan Biocomposite Fibres

“…There are two key findings according to this study [69]. (A) Calcined samples showed a pattern similar to enamel (highly crystalline apatite mineral, ca.…”

“…An interesting study has been carried out by Aranaz et al [69] to investigate the type of calcium phosphate formed in the CSCaP monoliths. There are two key findings according to this study [69].…”

Mineral‐induced bubbling effect and biomineralization as strategies to create highly porous and bioactive scaffolds for dentin tissue engineering

“…Phase separation is a simple method to form chitosan scaffolds by segregating the polymeric phase during freezing, followed by ice elimination via freeze drying. However, this technique provides no control over the degree of porosity 9,42,43 . Therefore, in this study, we applied a manufacturing method previously developed by our group, 15 in which a Ca(OH) 2 suspension is added to the CH solution under stirring, at a 1:2 ratio, creating highly porous scaffolds with increased and organized pores in comparison with pure chitosan scaffolds.…”

“…However, this technique provides no control over the degree of porosity. 9,42,43 Therefore, in this study, we applied a manufacturing method previously developed by our group, 15 as the CO 2 source upon carbonation and reactions with acetic acid, increasing the pore diameter and total porosity compared with those of plain chitosan scaffolds. 15 Therefore, based on our results, we believe that βTCP and nHA also promoted a bubbling effect upon incorporation into chitosan solution, leading to pore enlargement as network, with pore size varying from 100 to 400 μm, and porosity higher than 80%, was achieved, whereas the plain chitosan solution resulted in a lamellar pore network.…”

Biomaterial-Assisted Regenerative Medicine

“…Due to the low cost and versatility, chitosan is effective biomaterial as food packaging films [113,117], preservation of food [118] and drink [119], pharmaceutical science [120], cosmetics [121], or antibacterial agents [115]. In regenerative medicine, chitosan is often selected for blood vessels [42][43][44], cartilage [45][46][47][48][122][123][124], bone [49,50,125,126], the intervertebral disc [51][52][53]127,128], or skin [54,55,129] regeneration. For example, glycosaminoglycan (GAG) is essential to stimulate the formation of cartilage.…”