Novel preparation of graded porous structures for medical engineering

Abstract

The gradation of porosity in a biomaterial can be very useful for a variety of medical engineering applications such as filtration, bone replacement and implant development. However, the preparation of such structures is not a technologically trivial task and replication methods do not offer an easy solution. In this work, we elucidate the preparation of structures having a graded porosity by electrohydrodynamic spraying, using zirconia (ZrO 2 ), which is widely used in biomedical and other applications. The processes are generic and can be achieved using other bioactive ceramics with similar particle characteristics. The pores on the sprayed surface, the innermost surface and lengthwise cross sections have been analysed in addition to the change in depth of penetration as a function of spraying time. Control of porosity, pore size and depth of penetration has been obtained by varying parameters such as the spraying time, sintering temperature and the sacrificial template. It has been possible to obtain structures with interconnected pore networks of pore size greater than 100 mm as well as scattered pores smaller than 10 mm in size.

Improvement of the microstructure and mechanical properties of bioceramic scaffolds using electrohydrodynamic spraying with template modification

“…The improvement of coating on the template by the ceramic by immersing the template in ethanol prior to electrospraying was demonstrated in the authors' previous work (Muthutantri et al, 2008b). This has made the electrospraying method more efficient by significantly reducing the spraying time to a few minutes rather than the 1-2 h as in the literature (Jayasinghe and Edirisinghe, 2002;Chen et al, 2006).…”

“…A combination of electrospraying with the traditional dipping method (Muthutantri et al, 2008a) has been used to improve the mechanical properties of hydroxyapatite scaffolds for bone TE applications (Muthutantri et al, 2008c). The possibility of manipulating this electrospraying method to produce functionally graded porous structures which could find uses in both industrial and biomedical applications has also been investigated (Muthutantri et al, 2008b).…”

Interfacial and biological properties of the gradient coating on polyamide substrate for bone substitute

“…As discussed earlier, the composite coating shows a gradient variation in both microstructure and chemical composition. Coating with such a gradient structure is usually believed to be excellent in clinical application [28,35].…”

“…Polymer/ nHA composite coating is also fabricated for its antibacterial property or excellent cell response, but the composite coating suffers from poor interfacial bonding and a sharp coatingsubstrate interface, which can reduce the adhesion strength between the substrate and the composite coating [26,27]. Therefore, it is important to develop a structurally stable coating with a composition gradient across the coating thickness [28].…”

Designing, fabrication and characterization of nanostructured functionally graded HAp/BCP ceramics

“…[5,[27][28][29][30][31][32]. Among mentioned, powder processing is a simplest method for producing ceramic components and frequently used since simplicity of the overall process is usually highly demanded.…”