Developing natural hard tissue as scaffolds for tissue repairs

A natural bone structure of a species of starfish (Pisaster giganteus) was investigated as potential matrix for bone tissue engineering. The scaffold possessed a very porous structure and highly interconnected network of the pores with size ranging from 10-20 μm. Porosity is one of the important issues that must be primarily considered as the matrix of bone tissue engineering. These pores will regulate the nutrients and gas transportation into the cells. If gas and nutrients can diffuse through the interconnected pores, it is likely the cells will be able to go inside the pores and live there. Bone substitutes must also have several properties that allow them to be used as tissue substitutes. They should be biocompatible, meaning they do not trigger immunological responses from the organism (in this case, human). They should have comparable mechanical properties from the true bone, so that they can withstand biomechanical loading from the body. Another important property is that the matrix should support cell attachment, proliferation and differentiation. Preferably, the matrix can serve as a guide for cell growth and new bone formation. The inorganic matrix of the starfish is of calcium carbonate based material. Osteoblasts and human bone marrow-derived stem cells (hBMSC) attachment, cell viability and cell proliferation with starfish bone structure as the matrix were investigated. These are to see whether the scaffolds have the potential to support cell growth, proliferation and differentiation. The scaffolds network porous structure and its materials are the reasons why we expect the starfish bone structure as a potential matrix for bone tissue engineering. Several studies were done to assess the cell attachment, cell proliferation, and cell growth. To investigate the cellular morphology and the attachment of the cells to the scaffolds, Phase Contrast Light Microscopy was used. Further assessments on the cell attachment were carried out using Scanning Electron Microscopy (SEM) and Confocal Laser Microscopy (CLM). Cell distribution was investigated as well using SEM and CLM. CLM was used also to assess the cell viability, while cell proliferation was assessed by Alamar Blue™ assay.