Friday, June 10, 2011

The Nanomechanics Revolution in Medicine and Microbial Detection

When I teach my comprehensive training course on Rapid Microbiological Methods, I always include novel and next generation technology platforms in my discussions. One of my favorite topics is the future of microbial detection using nanotechnology, in particular, micro and nano cantilevers. I have recently come across a nice review of microcantilevers from the Medical technology Business Europe website. In this article, the authors discuss the use of microcantilevers for the assessment of drug-target interactions for a broad range of antibiotics and drugs under development. However, the technology can also be used for microbial detection. For example, scientists at Purdue University are developing advanced nanocantilever sensors capable of detecting minute quantities of viruses, bacteria and other contaminants in air and fluids by coating the cantilevers with proteins and antibodies that attract these contaminants.

I am providing a condensed version of the online article below, but if you would like to read the full paper, please visit

Within all areas of medical science, there is a constant need for new techniques, drugs, and ideas. One crucially urgent area is that of anti-bacterial drugs. The current international portfolio of antibiotics is becoming increasingly redundant as healthcare acquired infections (HAI) are on the up, and an increasing proportion of these are with Multi-Drug Resistant (MDR) bacterial strains, which are resistant to normal antibiotics.

However, a novel technique exploiting nanotechnology used in the micro-electronics industry presents the opportunity to speed up the discovery process for antibiotics and other pharmaceutical products, as well as many other diagnostic and therapeutic processes.

The nanotechnology in question uses microcantilevers, and their bending properties to evaluate the binding interactions between small molecules such as drugs or DNA. Microcantilevers are thin (<10┬Ám) strips of silicon (0.5mm long and 0.1mm wide) which can detect the binding of molecules, target analytes, to ligands attached to the cantilever.

Each cantilever is ‘functionalised’ with particular surface coatings: these comprise of a primary layer (a self-assembled monolayer, SAM) and ligands that bind to specific target analytes. The ligand is immobilised on one side of the cantilever and the relevant target analyte is added to the system in solution. Binding interactions of the ligand and target analytes results in bending of the cantilever.

These highly sensitive biosensors detect minute changes in surface stress as the drug binds specifically to the ligands tethered on the cantilever (click on the illustration at the top of this blog post for a closer look). They can also be operated in a dynamic mode, when the added mass of bacteria or other biological substances can be detected.


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