Control of the pore architecture in three-dimensional hydroxyapatite-reinforced hydrogel scaffolds

Abstract

Hydrogels (gellan or agarose) reinforced with nanocrystalline carbonated hydroxyapatite (nCHA) were prepared by the GELPOR3D technique. This simple method is characterized by compositional flexibility; it does not require expensive equipment, thermal treatment, or aggressive or toxic solvents, and yields a three-dimensional (3D) network of interconnected pores 300-900 µm in size. In addition, an interconnected porosity is generated, yielding a hierarchical porous architecture from the macro to the molecular scale. This porosity depends on both the drying/preservation technology (freeze drying or oven drying at 37• C) and on the content and microstructure of the reinforcing ceramic. For freeze-dried samples, the porosities were approximately 30, 66 and below 3% for pore sizes of 600-900 µm, 100-200 µm and 50-100 nm, respectively. The pore structure depends much on the ceramic content, so that higher contents lead to the disappearance of the characteristic honeycomb structure observed in low-ceramic scaffolds and to a lower fraction of the 100-200-µm-sized pores. The nature of the hydrogel did not affect the pore size distribution but was crucial for the behavior of the scaffolds in a hydrated medium: gellan-containing scaffolds showed a higher swelling degree owing to the presence of more hydrophilic groups.

Tuning dual-drug release from composite scaffolds for bone regeneration

“…3). Scaffolds 235 fabricated with similar composition and drying method to those 236 used in this work (Román et al, 2011) showed a porosity around 237 95%, with 30% for the pores with the highest diameter, around 65% (Vorndran et al, 2010). The release profiles of Figs.…”

“…In previous work we have described an easy and inexpensive 64 method to obtain agarose/hydroxyapatite scaffolds with hierar-65 chical porosity at room temperature for bone repair application 66 Román et al, 2011). Biocompatibility studies 67 demonstrate that these scaffolds allow the culture of osteoblasts 68 inside and outside the material (Alcaide et al, 2010;Cabañas et al, 69 2014 (Cattalini et al, 2012;83 Coleman et al, 2011;Giger et al, 2013;Nancollas et al, 2006; 84 Rosenqvist et al, 2014).…”

“…The composition employed to prepare the DDDS (50% ceramic 134 and 50% hydrogel) was chosen according to previous results Román et al, 2011;.…”

Hybrid Organic-Inorganic Scaffolding Biomaterials for Regenerative Therapies

“…The aim is that the global properties of the scaffold are supported by both constituents [115,116]. A typical example of a composite is a scaffold prepared by incorporating hydroxyapatite (HA) granules or fibers in a polymeric matrix [117][118][119][120][121][122]. Such studies reveal, how-ever, that the contents of the inorganic and organic phases directly influence the bioactivity and mechanical properties of the scaffolds.…”

Development of Porous Polysaccharides-Hydroxyapatite Composite Scaffolds via Freeze Drying Method and in vitro Osteoconductivity on MG 63 Cells

“…Further, it is simple, cost effective and environmental friendly since water is used as solvent. Moreover, water has the advantage of being functioning as a porogen upon freezing [23,24]. Several two component porous scaffold composed of polysaccharide and HAP have been prepared by freeze drying method which include gellan-HAP [25], chitosan-alginate [26], chitosan-HAP [27] and alginate-HAP [28] for bone tissue engineering.…”