Project Lead(s): Leyla Soleymani
Tuberculosis (TB) causes millions of deaths yearly worldwide.
Current gold standard diagnosis by cell culture is slow and may result in further progression of the disease, or further spread.
Molecular techniques are promising but are not widely used.
This implies the need for portable and miniaturized, easy-to-use, low-power and inexpensive point-of-care (POC) platforms, which are highly suitable for use in resource-poor and low-income settings.
Chip-based platforms are ideal for implementing POC systems as several hundreds or thousands of miniaturized devices, with dimensions in the nano- to micro-scale, can be integrated into a single platform using scalable manufacturing methods.
However, their lack of integration with suitable sample preparation systems has restricted their use in resource-poor and POC settings.
Cell lysis is a critical sample preparation step for nucleic acid detection, hence lab-on-a-chip systems rely on bacterial lysis for the release of cellular material. Although electrical lysis devices can be miniaturized for on-chip integration and reagent-free lysis, they often suffer from high-voltage requirements.
The project aim was to create a high-efficiency lysis device with a voltage requirement of less than 12 V (for battery operation), which could be manufactured in a rapid, inexpensive and scalable fashion.
The team sought to engineer lysis electrodes by reducing the inter-electrode separation, incorporating nanoscale materials onto the electrode surfaces and creating solution-penetrating, three-dimensional and high-aspect ratio electrodes.
The project team was able to fabricate a new rapid prototyping method for creating multi-scale electrodes with features to overcome the high energy requirements for cell lysis, as a first step towards developing a portable TB diagnostic device.
This fabrication method enabled them to create disposable chips with high-aspect ratio 3D microelectrodes decorated with nanoscale features and microscale inter-electrode separations at a low cost.
Using structurally-optimized electrodes, they achieved a lysis efficiency higher than 95% at an applied potential of 4 V for E. coli cells, making them a potential candidate for integration in portable lab-on-a-chip systems.
Additional studies are being performed to better understand the effect of applied potential and electrode structure on the lysis of different bacterial cell types, and to determine the applicability of these electrode systems to a wide range of infectious disease applications.
Results have been disseminated through several publications, including Analyst, the Royal Society of Chemistry journal.