Growing new bones with nanotechnology

Bioengineers at the National University of Singapore, together with colleagues in London, UK, and Chennai, India, have developed a new composite that brings us a step closer to mimicking the architecture of the extracellular matrix which gives animal bodies form and shape.

Bone tissue engineering is a medical treatment in which the principles of biology and engineering are applied to restore and maintain the function of damaged or missing bone tissue. It involves the construction of three-dimensional scaffolds of biomaterials to provide mechanical support, and induce and direct the growth of new bone.

Collagen nanofibres

Biomaterials used in tissue engineering can be either permanent or biodegradable, naturally occurring or synthetic. But whatever they are made from, they must be compatible and integrate fully with the biological tissues with which they are combined. With nanotechnology, engineered biomaterials can be manipulated at atomic, molecular, and macromolecular levels.

Using a simple electro-spinning technique, the researchers fabricated polycaprolactone/nanohydroxyapatite/collagen (PCL/nHA/Col) nano-fibrous scaffolds which provide mechanical support, and, in time, break down leaving newly-formed bone tissue to take over. The research is described in detail in a recent issue of the journal Nanotechnology. Animal and clinical trials are planned.

Human foetal osteoblast cells on a collagen nanofibre scaffold

The nano-fibrous scaffolds provide an open-pore structure for cell growth, whilst allowing the free transport of nutrients and metabolic waste products, and facilitating angiogenesis, or the growth of new blood vessels. The principles involved could lead to the fabrication of fibrous scaffolds for skin wound healing, bone filling, skin, bone, cartilage, nerve, and vascular tissue engineering.

When asked why nanotechnology and not other materials, research team leader Jayarama Venugopal replied: ‘With electro-spun nanofibres, it is easy to control the morphology, diameter, mechanical properties and patterning of fibre deposition. Nanofibre scaffolds with seeded cells from tissues can be implanted in a patient’s body to repair the damaged tissues.’

Figure: Scanning electron microscope images of (top) collagen nanofibres; and (bottom) human foetal osteoblast cells on a collagen nanofibre scaffold. Taken from: Venugopal et al., Nanotechnology 18, 055101 (2007) (subscription required). © 2007 Institute of Physics.

Article first published in Nanomaterials News.