There is a pressing need for further advancement in tissue engineering of functional organs with a view to providing a more clinically relevant model for drug development and reduce the dependence on organ donation. Polymer based scaffolds, such as polycaprolactone (PCL), have been highlighted as a potential avenue for tissue engineered kidneys, but there is little investigation down this stream.Focus within kidney tissue engineering has been on 2-dimensional cell culture and decellularised tissue. Electrospun polymer scaffolds can be created with a variety of fibre diameters and have shown a great potential in many areas. The variation in morphology of tissue engineering scaffold has been shown to effect the way cells behave and integrate. In this study we examined the cellular response to scaffold architecture of novel electrospun scaffold for kidney tissue engineering. Fibre diameters of 1.10±0.16 µm and 4.49±0.47 µm were used with 3 distinct scaffold architectures. Traditional random fibres were spun onto a mandrel rotating at 250 rpm, aligned at 1800 rpm with novel cryogenic fibres spun onto a mandrel loaded with dry ice rotating at 250 rpm. Human kidney epithelial cells were grown for 1 and 2 weeks. Fibre morphology had no effect of cell viability in scaffolds with a large fibre diameter but significant differences were seen in smaller fibres. Fibre diameter had a significant effect in aligned and cryogenic scaffold. Imaging detailed the differences in cell attachment due to scaffold differences. These results show that architecture of the scaffold has a profound effect on kidney cells; whether that is effects of fibre diameter on the cell attachment and viability or the effect of fibre arrangement on the distribution of cells and their alignment with fibres. Results demonstrate that PCL scaffolds have the capability to maintain kidney cells life and should be investigated further as a potential scaffold in kidney tissue engineering.

Chronic kidney disease is a major global health problem affecting millions of people; kidney tissue engineering provides an opportunity to better understand this disease, and has the capacity to provide a cure. Two-dimensional cell culture and decellularised tissue have been the main focus of this research thus far, but despite promising results these methods are not without their shortcomings. Polymer fabrication techniques such as electrospinning have the potential to provide a non-woven path for kidney tissue engineering. In this experiment we isolated rat primary kidney cells which were seeded on electrospun poly(lactic acid) scaffolds. Our results showed that the scaffolds were capable of sustaining a multipopulation of kidney cells, determined by the presence of: aquaporin-1 (proximal tubules), aquaporin-2 (collecting ducts), synaptopodin (glomerular epithelia) and von Willebrand factor (glomerular endothelia cells), viability of cells appeared to be unaffected by fibre diameter. The ability of electrospun polymer scaffold to act as a conveyor for kidney cells makes them an ideal candidate within kidney tissue engineering; the non-woven path provides benefits over decellularised tissue by offering a high morphological control as well as providing superior mechanical properties with degradation over a tuneable time frame.

Polymer scaffolds have shown promising results in bone and cartilage repair when the underlying property being designed for is morphological. Despite their ability to mimic the morphology of the native extracellular matrix, current studies have not managed to find a polymer-solvent-method combination that provides sufficient mechanical strength. This study performs a comparison of the strength, stiffness and structure of different biomedical scaffolds created using a thermally-induced phase separation (directional freezing) method with different solvents and polymer concentrations. 1,4-dioxane and glacial acetic acid are used with polycaprolactone, a combination which has not been studied before using the directional freezing method. Strength tests are performed with an Instron compression/tension tester and structural comparisons made using Scanning Electron Microscopy. It is found that higher polymer concentrations create stiffer and stronger scaffolds and that using 1,4dioxane as a solvent creates substantially stiffer scaffolds than using glacial acetic acid. The 15 w/v% 1,4-dioxane scaffold had a maximum tensile strength of 840.7±117.3 kPa compared to 93.5±26.2 kPa for glacial acetic acid. The 1,4-dioxane scaffolds display significant cross-linking compared to glacial acetic acid scaffolds and also showed a porous structure similar to that of a cartilage extracellular matrix. This method produced scaffolds with a distinctive bi-phasic polymer structure, similar in morphology to cartilage which requires load bearing properties and lubricating properties. The study shows that thermally-induced phase separation can create porous scaffolds which mimic the physiological properties of the native extracellular matrix.