Lab-on-a-chip. Close up light micrograph of a silicon lab-on-a-chip designed for live cell culture. The device is etched with 'microfluidic' channels and wells that lead towards a central 3D matrix, or scaffold, where the living cells can be cultured in a gel medium. Chemicals can be introduced into the channels to affect cell growth. This device allows cells to grow in a 3D environment compared to standard methods which rely on flat 2D surfaces. Lab-on-a-chip devices such as this offer a cost-effective method for scientific analysis, tissue engineering or disease diagnosis. Photographed in 2009 at the Kamm Laboratory, Massachusetts Institute of Technology, USA.