Two papers from the University of Glasgow make the top 30 accessed papers collection from Lab-on-a-Chip in 2014

Issued: Mon, 14 Sep 2015 16:19:00 BST

The journal Lab-on-a-Chip (published by the Royal Society for Chemistry) recently published a themed collection of its top 30 accessed papers for 2014 which included two papers from the University of Glasgow. These two papers “Microfluidic resonant cavities enable acoustophoresis on a disposable superstrate” by Christian Witte et al. and “Cell patterning with a heptagon acoustic tweezer – application in neurite guidance” by Frank Gesellchen et al. both detail work using acoustic forces to create the desired pattern of microscopic particles.

The first paper details work from the Advanced Diagnostics Group on how acoustic waves (vibrations) that travel across the top of a material can be refracted up into a superstrate placed in contact with it and that if the superstrate has a fluid filled channel embed within it particles in the fluid can be moved by the waves. The waves are generated as Surface Acoustic Waves (SAW) but become bulk waves as they travel into the superstrate and are a potentially very useful means of manipulating microparticles such as cells as they are relatively harmless to biological particles and are compatible with physiological buffers. This method of getting acoustic waves into a channel is exciting because it reduced the alignment accuracy needed between the acoustic actuator and the channel making the assembly of the device much less complicated and so could allow this technique to be used for a broad range of applications.

a channel superstrate for SAW actuation (C. Witte's paper LOC)

The second paper featured in this collection of Lab-on-a-Chip demonstrates the patterning of cells using a device that consists of eight acoustic transducers arranged into a heptagonal pattern, with the Division of Electronics and Nanoscale Engineering. By turning on specific individual actuators different patterns of acoustic waves can be generated as the waves from each actuator interfere with each other. As cells can be attracted to these patterns of pressure created within a fluid this allows the dynamic patterning of cells, into complex structures, as demonstrated in the figure below with a cellular 'tartan'. The paper goes on to demonstrate an application for cell patterning by arranging Schwann cells (cells from the nervous system) from neonatal rats into a linear patterns that resemble “Bands of Büngner-like structures” which occur naturally in the process of healing parts of the nervous system. This application shows the benefits of the system in that the cells can be arranged into structures using benevolent acoustic forces which are unlikely to perturb the cells from their natural states, compared to other methods that use electrical fields, and can then allow these structures to be tested with no electrical interference.

   ‌cell patterning