High-tech Gel

The yellow rubbery gel between the thigh and shin bone of this model knee (shown at different angles) may not be an aesthetically dazzling material, but it is a beautiful example of what can be achieved by combining two novel yet disparate technologies – hydrogel synthesis and 3D printing. Together the techniques have been used to create a synthetic meniscus – the cartilage that cushions the knee. The hydrogel (a mixture of polymers and water) has been specially engineered to be biocompatible, to mimic the strength and elasticity of human cartilage, and to be 3D printable – it can flow through a print nozzle like liquid, but then hardens allowing desired shapes to be built up in layers. The hope is that such synthetic cartilage could be printed on demand to the exact shape of a patient’s knee in which the cartilage is damaged – a common problem – thus providing a tailored, comfortable fit.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image by Feichen Yang
• Department of Chemistry, Duke University, Durham, NC, USA
• Image copyright held by the American Chemical Society 2017
• Image reprinted from ACS Biomaterials Science & Engineering Journal, April 2017, with permission