Commercially available Blu-ray discs could serve as cheap detectors of toxins,B microorganisms, allergens and cancer biomarkers, Spanish researchers have found.
The technology designed to store movies and other data presents a cheap and convenient, though surprisingly accurate, tool for clinical diagnostics and environmental monitoring.
The researchers from the Polytechnic University of Valencia have described the innovative Blu-ray-based detection method in the latest issue of the Biosensors and Bioelectronics journal.
"We have used the surface of these commercial discs as a platform for analysis to carry out the tests and then, with the laser reader of the recorder/player we can identify the bacteria and determine their concentration," said one of the papers’ authors Sergi Morais.
In their study, the team has focused on detecting two types of pathogenic micro-organisms – the bacteria causing salmonellosis and an intestinal parasite Cronobacter Sakazakii. However, the method could also be used to identify tumour biomarkers, food and drug allergens and pesticides in water.
The results provided by the Blu-ray discs are as accurate as those obtained by costly diagnostic machines used in conventional laboratories. The team believes Blu-rays could be used for pre-screening of samples before employing more exhaustive analytical techniques.
"Samples that are shown to be positive by this methodology will also be positive using the other techniques," Morais explains.
To carry out the screening, the samples have to be deposited in small quantities on the discs in the form of micro-arrays 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 1 mm2 drop)," explained another team member Ángel Maquieira.
"On the 90 cm2 surface of these discs it's possible to imprint 138,000 points, each one 125 µm in diameter. Furthermore, the low sample volume used (5-10 microlitres) and the low cost of the developed hardware make this technology a very practical and economically competitive tool," he said.
The study warns 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 low budget installations.