A NONSTOP BIOSENSOR PERSONALIZED MEDICINE: Device continuously measures drugs in blood
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BIOSENSOR that could continuously measure
drugs and biomolecules in the blood of living patients promises to aid early diagnosis of disease and help physicians customize drug doses to individuals, a key goal of personalized medicine. The technology has been used to monitor drugs in live rats and human blood but not yet in people. However, “in the wide, deep sea of silly biosensors that don’t stand a chance of ever working in practice, this one VIDEO ONLINE is the real deal,” comments biosensor expert Richard M. Crooks of the University of Texas, Austin, who wasn’t involved in the study. Biosensors for specific drugs and biomolecules in body fluids have long been available, but most do single measurements. Continuous monitoring is currently available for only a few analytes, such as glucose, lactose, and oxygen. Devices for continuous measurement of a wider range of target molecules in blood could help detect the onset of diseases and optimize drug dosing. But creating them is a tall order. They would have to operate without sample preparation, be sensitive and selective enough to analyze targets reliably at low levels in complex matrices, and resist fouling from body fluids. MEDIC (microfluidic electrochemical detector for in vivo continuous monitoring), devised by Brian Scott Ferguson and professor Hyongsok (Tom) Soh of the University of California, Santa Barbara, and cowork-
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ers, meets those requirements (Sci. Transl. Med. 2013, DOI: 10.1126/scitranslmed.3007095). It is based on an electrochemical approach demonstrated earlier by Soh’s UCSB collaborator Kevin W. Plaxco and coworkers. The device relies on aptamers, single-stranded nucleic acids that bind target molecules selectively. The aptamers are modified at one end with a redox molecule and then tethered at the other end to an electrode. When a target molecule binds, the aptamer changes shape. The change increases the current that flows from the redox agent to the electrode, generating an electrochemical signal proportional to concentration. A layer of flowing buffer lets analyte molecules reach the sensor but prevents other blood components from fouling it. The device is reconfigured for different targets by swapping aptamers. Soh and coworkers demonstrated the system by using it to measure ther- FLOW MEDIC chip (top) would be apeutic levels of the cancer drug doxo- connected to patient’s bloodstream to continuously measure a target rubicin and the antibiotic kanamycin drug. Inside the device (illustrated in live rats and in human whole blood at bottom), binding of target (green for hours, at intervals shorter than sphere) to aptamer (gray) causes 60 seconds. It could conceivably be used to monitor hospital patients with shape change that boosts electrontransfer rate (curvy arrows) from an intravenous lines, but the researchers electrochemical reporter (blue) to hope a portable version can also be gold electrode (rectangular base), developed. generating detection signal. Aptamers have been difficult to develop, but Soh notes recent improvements in this area. “The truth is that I am jealous as hell of this achievement,” Crooks says. “I would dearly love to have thought of this idea myself. It is clever with a capital C.”—STU BORMAN
TRADE SECRETS Europe proposes new legal protections for confidential business information The European chemical industry is hailing a move by the European Union to increase legal protections for companies’ trade secrets against theft and use by competitors. The EU late last month proposed legislation that would provide greater legal redress to companies that have trade secrets stolen from them. This would empower chemical manufacturers to invest more confidently in the EU, says Hubert Mandery, director general of the European Chemical Industry Council (CEFIC). Trade secrets aren’t protected by patent or copyright, so competitors may work independently to discover, develop,
and use the same information. But it’s illegal to obtain this knowledge through theft, bribery, or other illicit means. Trade secrets, which companies guard as confidential because they give them a competitive edge, run the gamut from steps in a manufacturing process to product formulas to the results of marketing studies. A patchwork of national rules now provide uneven legal protections for trade secrets across the EU. Citing industrial espionage and cyber crime, EU Commissioner for Internal Market & Services Michel Barnier says, “We have to make sure our laws move with the times and that the strategic assets of our companies are ad-
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equately protected against theft.” The proposal would establish an EUwide definition of what constitutes a trade secret. It also would make it easier for companies to sue for financial damages from anyone stealing, unlawfully using, or disclosing their confidential business information. And it would create a procedure for courts to order removal of products from the EU market that were made with purloined trade secrets. “This is a critical step to protect European companies’ confidential business information in the case of misappropriation,” CEFIC’s Mandery says of the proposal.—CHERYL HOGUE
