New research that enables individual bacteria to be positioned at pre-defined locations within a gel matrix may provide insights into the way cells develop and behave.

Using the force exerted by focussed light beams  -  a technique known as 'holographic optical tweezers'  -  Jonathan Cooper from the University of Glasgow, and colleagues in the UK and Sweden, arranged individual E. coli cells into microscopic patterns and then set them into a fixed position within a gelatin matrix. 

This flexible approach allows cells to be arranged into a variety of complex patterns. The resulting 2D and 3D cell structures stayed intact for many days and could be sealed, moved to different locations and re-imaged using confocal and multi-photon microscopy. In addition, when supplied with appropriate nutrients, the entrapped E. coli cells stayed alive for several days.

Motivated by a desire to use recent discoveries in bioengineering and optics to develop new tools for biologists, the researchers 'hope to explore how arranging just a few cells on a micro-scale may influence their subsequent behaviour'. One of the challenges they face in the application of this technology beyond the research bench involves the creation of larger arrays that have a more general commercial interest. Ultimately, the ability to manipulate cells spatially into well-defined arrays may have a number of potential applications, including tissue replacement therapy and stem cell research. 

Kathryn S Lees