| Abstract [eng] |
In recent years, there has been a great demand for the development of bio-artificial organs/tissues in the field of organ transplantation and in-vitro toxicological drug screening (L. G. Griffith & Swartz, 2006). Engineering of functional tissue/organs by controlling the cells microenvironment to resemble in vivo situation is of central importance. This has led to the evolution of various techniques for controlling the cellular microenvironment to facilitate cell proliferation, organization and differentiation. When engineering tissues in vitro, there is a requirement for structures or scaffolds that are able to support cell growth, and that closely mimic the physiological environment including the geometrical, topographical and physical features of the targeted tissue. Specifically for the generation of thick 3D tissues, the development of highly dense vascular networks that are able to meet the nutrient and oxygen requirements of large masses of living cells remains a tissue engineering challenge often limiting the size of engineered tissues to a few hundred microns (Khademhosseini, Vacanti, & Langer, 2009). The ideal tissue engineering scaffold supports the spatial distribution of cells in a three dimensional structure, provides mechanical stability to the cells and enables optimum nutrient transport and metabolic waste removal (Hoganson, Pryor, & Vacanti, 2008; Lu, Li, & Chen, 2013). There have been many approaches to create three-dimensional (3D) highly vascularized engineered tissue scaffolds to accommodate a high density of cells in high surface to volume ratio structures (Almeida & Bártolo, 2014; Lu et al., 2013). One strategy that has been employed is the use of highly porous structures with interconnected pores/micro channels that provide space for penetration and growth of cells and enable favourable mass transport characteristics (Langer, 2009)(Guillemette et al., 2010). The structural, mechanical and mass transport properties of such scaffolds are determined by parameters such as pore size, pore shape, porosity, pore interconnectivity, permeability, scaffold surface area, scaffold effective stiffness and scaffold material (Jeong & Hollister, 2010). This work presents a novel approach for manufacturing structured pores/channels in a scalable 3D elastomeric scaffold. The method involves 3D printing (using a commercially available 3D printer) a sacrificial PVA mould whose geometrical features are designed according to the required vascular channel network. In addition to its biocompatibility, PVA is an idea material for use as a sacrificial mould because it’s water solubility in combination with its high melting temperature (190°C) which makes it robust for subsequent polymer casting and curing steps. The required polymer is cast around the PVA mould and following cross linking, the mould is dissolved leaving behind a structured porous elastomeric scaffold. In brief, work carried out through these steps are, scaffold design is done through Solid Works and Make Ware software. 3D printing of mould by using PVA filament is done by Maker Bot printer. The two types of polymers are used, PDMS (synthetic polymer), Silk Protein (natural polymer) to fabricate tissue scaffolds. Fabrications steps are described below. Obtained scaffold was examined by using SEM and mechanical testing’s. |
