ABSTRACT
Biodegradable polymers have been extensively used as scaffolds to regenerate lost tissues. The geometry of the three-dimensional (3D) scaffolds has an influence on the cellular behaviour. In this study, we have developed 3D-scaffolds of axially aligned nanofibres of poly(lactic acid) (PLA), poly(caprolactone) (PCL) and PLA:CL (50:50) with diameters in the range 100-400 nm, internal diameter 4 mm, length 4 cm and wall thickness 0.2 mm, by using a dynamic collector. PCL and PLA:CL nanofibres were significantly less hydrophobic than PLA nanofibres. The porosity of PCL (16.23 ± 9.88%) and PLA:CL nanofibres (14.77 ± 3.41%) were comparable, while PLA (6.57 ± 1.54%) nanofibres had lower porosity. The tensile strength and Young's modulus of PLA was significantly lower than PCL and PLA:CL nanofibres and the suture retention strengths of all three scaffolds were comparable. After 4 weeks, the molecular weight of PLA nanofibres was reduced by 53% compared to 44% and 41% for PCL and the PLA:CL nanofibres, respectively. However, the PLA:CL nanofibres maintained their structural integrity even after 28 days. Platelet adhesion studies showed that PCL nanofibres had least tendency to be thrombogenic, while PLA:CL blend nanofibres were highly thrombogenic. Further, in vitro responses such as cell adhesion, proliferation and gene expression of human umbilical vascular endothelial cells (HUVECs) were evaluated. After 6 days of culture, the surfaces of all the three scaffolds were completely covered with cells. Our results demonstrate that expression levels of elastin, angiopoietin, laminin-4α and -5α were upregulated in PCL and PLA:CL nanofibres without the addition of any exogenous factors.
Subject(s)
Blood Vessels/physiology , Nanofibers/chemistry , Tissue Engineering/methods , Animals , Biomechanical Phenomena/drug effects , Blood Vessels/drug effects , Calorimetry, Differential Scanning , Cell Adhesion/drug effects , Cytoskeleton/drug effects , Cytoskeleton/metabolism , Human Umbilical Vein Endothelial Cells/cytology , Human Umbilical Vein Endothelial Cells/drug effects , Humans , L-Lactate Dehydrogenase/metabolism , Lactic Acid/pharmacology , Materials Testing , Molecular Weight , Nanofibers/ultrastructure , Platelet Adhesiveness/drug effects , Polyesters/pharmacology , Polymers/pharmacology , Porosity , Real-Time Polymerase Chain Reaction , Sheep , Surface PropertiesABSTRACT
Electrospinning is a versatile technique to make biomimetic and nanostructured scaffolds for skin tissue engineering. In this study we have electrospun and characterized chitosan (C)-poly(vinyl alcohol) (PVA) blend nanofibers as dermal substitutes and compared with 2D C-PVA films. The in vitro characterization of the C-PVA nanofibers and 2D films were evaluated using mouse 3T3 fibroblast cells and our results demonstrated that the cells adhered and proliferated on the surface of C-PVA nanofibers. In our animal studies, the implantation of C-PVA nanofibers along with topical administration of growth factor R-Spondin 1 on full thickness wounds created on rats showed 98.6% wound closure after two weeks post-surgery. The catalase and superoxide dismutase activity of the healing tissue was significantly higher in the groups treated with topical administration of growth factor and C-PVA nanofibers (p < 0.05). Thus these C-PVA nanofibers along with novel growth factor are promising new biomaterials that could be used as dermal substitutes for accelerated wound healing.
Subject(s)
Chitosan/chemistry , Polyvinyl Alcohol/chemistry , Skin, Artificial , Tissue Engineering/methods , 3T3 Cells , Animals , Biocompatible Materials/chemistry , Biomimetics , Cell Adhesion , Cell Proliferation , Extracellular Matrix/metabolism , Mice , Microscopy, Electron, Scanning/methods , Porosity , Rats , Spectroscopy, Fourier Transform Infrared/methods , Stress, Mechanical , Tensile Strength , Wound HealingABSTRACT
Current liver transplantation strategies face severe shortcomings owing to scarcity of donors, immunogenicity, prohibitive costs and poor survival rates. Due to the lengthy list of patients requiring transplant, high mortality rates are observed during the endless waiting period. Tissue engineering could be an alternative strategy to regenerate the damaged liver and improve the survival and quality of life of the patient. The development of an ideal scaffold for liver tissue engineering depends on the nature of the scaffold, its architecture and the presence of growth factors and recognition motifs. Biomimetic scaffolds can simulate the native extracellular matrix for the culture of hepatocytes to enable them to exhibit their functionality both in vitro and in vivo. This review highlights the physiology and pathophysiology of liver, the current treatment strategies, use of various scaffolds, incorporation of adhesion motifs, growth factors and stem cells that can stabilize and maintain hepatocyte cultures for a long period.
