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Emerald Group Publishing Limited
Copyright © 2009, Emerald Group Publishing Limited
UK company develops novel biosensor technology
Article Type: News From: Sensor Review, Volume 29, Issue 1
UK company e2v Technologies plc, formerly Marconi Applied Technology and originally part of the GEC group, is a manufacturer of electronic tubes, imaging systems, radar, semiconductors and gas sensors, with a turnover of £205 million. It is a market leading supplier of catalytic sensors for detecting combustible gases and has more recently added infra-red and metal oxide sensor to its range, the latter through the acquisition of the Swiss company MiCS Microchemical Systems SA, in 2007. Most recently, it has taken the bold step of diversifying into the biosensor field and has set up a subsidiary company, e2v Biosensors Ltd, to commercialise the technology which arose from research within the Department of Pure and Applied Chemistry at the University of Strathclyde. This research first attracted the interest of e2v in 2002 and the company subsequently awarded a PhD scholarship to a post-graduate student at the university. Since then, further ties were developed, including the recruitment of a Strathclyde researcher to e2v, followed by a licensing agreement between the company and the University’s Research and Innovation Department. In mid-2008, e2v Biosensors appointed Dr Paul Rodgers, an entrepreneur with almost 30 years experience in the life sciences industry, as the CEO of e2v Biosensors.
The biosensor is aimed at a range of applications in the healthcare and life sciences sector, such as point of care medical diagnostics and drug development, with the rapid analysis of protein biomarkers in samples of whole blood, serum or plasma being the initial, target use. The technology is based on the surface enhanced resonance Raman spectroscopy (SERRS) effect. Raman spectroscopy is a light scattering technique and can be thought of in its simplest form as a process whereby a photon interacts with a sample to produce scattered radiation of different wavelengths. Surface enhanced Raman spectroscopy (SERS) provides greatly enhanced Raman signals from Raman-active molecules that have been adsorbed onto certain specially prepared metal surfaces, typically silver or gold. Increases in the intensity of Raman signal have been regularly observed in the order of 104-106, and can be as high as 108 or even 1014 for some systems. The importance of SERS is that it is both surface-selective and highly sensitive, whereas conventional RS is neither. A further enhancement can be achieved if the molecule adsorbed onto the metal surface contains a chromophore with an electronic transition coincident with the excitation wavelength; this is SERRS. The biosensor employs this phenomenon in conjunction with an immunoassay, a “displacement assay”, which uses a single antibody rather than the more conventional and complex dual antibody approach which involves fluorescence-based detection. The assay incorporates proprietary peptide SERRS dyes which only generate a signal when they are within the plasmon field in close proximity to the SERRS-active surface and activated by laser illumination. When the target compound is introduced into the system it is recognised by the antibody, displacing the incumbent reporter peptide dye. The released peptide is free to migrate to the silver surface where the SERRS dye becomes active and the signal intensity of the reporter peptide dye provides quantification of the concentration of the biomarker in the sample. A normalising dye, which is unaffected by the biomarker concentration, acts as a reference to provide a reliable measurement.
The sensor is packaged in a disposable, plastic microfluidic chip (Figure 1) which includes all of the reagents necessary to conduct the assay, thus simplifying the analysis by eliminating the need for any sample pre-conditioning. The sample is introduced into the chip which is then placed into a bench-top reader which includes the interrogating laser. Data are typically available in less than 10 min. The system offers several advantages over other techniques used for biomarker point of care analysis by combining a multiplexing capability offering the simultaneous analysis of three different proteins, with high sensitivity and specificity and a simple user protocol. The target sensitivity is 1 pg/ml for biomarkers with a mass of 240 kDA and the system operates with sample volumes of less than 20 μl. The biosenor is constructed on what the company claims to be a generic platform which could be used in a range of other applications. e2v Biosensors has secured substantial intellectual property through two patent families, with a further 11 pending.
For further information, please contact: Dr Brian Allen, General Manager, e2v Biosensors Ltd, 106 Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK. Tel.: +44 (0)1235 493493, Fax: +44 (0)1235 492492, E-mail: firstname.lastname@example.org, web site: www.e2v.com