A team of researchers from the Polytechnic University of Valencia in Spain has developed a device that uses Blu-ray technology and a laser to provide a simple, cost-effective way of detecting pathogenic bacteria and toxic substances in biological samples. The research, published in the journal Biosensors and Bioelectronics in February, could be used for clinical diagnosis and environmental monitoring in the future.
In the new technique, the scientists first deposited biological samples in small quantities on the Blu-ray discs in the form of microarrays or two-dimensional arrays. ‘The hydrophobic nature of the surface of the Blu-ray disc allows the proteins to be locked in place by passive adsorption in a high-density format (64 points in each 1mm2 drop),’ explained Ángel Maquieira, one of the authors of the paper.
‘On the 90cm2 surface of these discs, it’s possible to imprint 138,000 points, each one 125µm in diameter,' he added. ‘Furthermore, the low sample volume used (5-10µl) and the low cost of the developed hardware make this technology a very practical and economically competitive tool.’ The laser reader of the Blu-ray player is then used to identify the bacteria and determine the concentration in the biological samples.
According to the researchers, the accuracy and sensitivity of these electronic devices is similar to that obtained with conventional laboratory techniques, such as the quantitative polymerase chain reaction (PCR). The study warned that the lack of simple sensor systems that combine a high detection resolution with low costs is the reason why some analytical technologies are not found in installations with a low budget.
Though it’s not an official methodology, the new process offers a simple yet practical strategy to eliminate samples before applying more exhaustive analytical techniques. ‘Samples that are shown to be positive by this methodology will also be positive using the other techniques,’ said Sergi Morais, another author of the paper.
The researchers anticipate that their method of using Blu-ray technology could be used in other applications such as clinical diagnosis, in the agrofood industry or in environmental monitoring. ‘This type of test can also be used to detect tumoural biomarkers, food and drug allergens, and pesticides in water, for example,’ Morais stated. ‘The level of pollutants in water and air are regulated by directives that set a maximum residue limit, and the sensitivity of our technique allows analytes below that required by government to be detected.’
