A NANOWIRE MICROSCOPE
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NEWS OF THE WEEK FDA FINALIZES RULES FOR DIETARY SUPPLEMENTS QUALITY CONTROL: Agency will require testing of ingredients D OMESTIC AND FOREIGN manufacturers of vitamins, herbs, and other dietary supplements must follow new standards to show that their products are labeled properly and are not contami- nated. On June 22, FDA officials announced new standards for testing the purity, strength, and composition of all supplements. "This rule helps to ensure the quality of di- etary supplements so that consumers can be confident that the new products they purchase contain what is on the label," says FDA Commis- sioner Andrew G. von Eschenbach. Supplements have always been regulated as a category of food, not as drugs. The standards lay out practices to ensure quality during manufacturing, labeling, and storage of dietary supplements. They list requirements for quality-con- trol procedures, the design of manufacturing plants, and the testing of ingredients and final products. They take effect for large plants in June 2008 and for small companies in June 2010. Furthermore, because of recent amendments to the federal Food, Drug & Cosmetic Act, manufacturers in this $21 billion dietary supplement industry will be required to report adverse events caused by their products. The power to establish the new manufacturing stan- dards was granted in a 1994 federal law, but some critics say the new rules do not do enough to ensure safety. "Today's final rule on Good Manufacturing Practices is an example of better late than never. But the require- ments do not appear to go as far as they could have," notes Sen. Richard J. Durbin (D-I1L). Under the rules, FDA will be able to inspect manu- facturing plants for compliance. Companies must keep records showing that supplement ingredients have been tested, but they do not have to submit these re- cords to FDA. Supplement makers are responsible for devising scientifically defensible tests for the purity of ingredients, the agency says. FDA plans to inspect some of the plants, but it does not have additional money for enforcement. Resources will be shifted according to the risk posed by the manu- facturers, says Robert E. Brackett, head of the agency's Center for Food Safety & Applied Nutrition. If a com- pany violates the rules, FDA could fine the firm or ask it to voluntarily withdraw a product. "Even with these new manufacturing practices, there will be no assurance that dietary supplements work or are safe," says Sidney Wolfe, director of the Health Research Group at Public Citizen, a nonprofit public in- terest organization. He urges Congress to address "this enormous deficiency in the law."—BETTE HI LEMAN Artists rendition shows laser tweezers (red, right) positioning a KNb0 3 nanowire as it probes a nanoparticle. A NANOWIRE MICROSCOPE NANOPHOTONICS: Optical probe combines fluorescence and force techniques U SING A POTASSIUM NIOBATE (KNb0 3 ) nanowire as their key component, researchers have created an optical probe that potentially combines fluorescence microscopy and force micros- copy (Nature 2007,447,1098). The probe—developed by scientists at the University of California, Berkeley, and Lawrence Berkeley National Laboratory—is at- tractive as a bioimaging tool and could also be used in advanced information technology, cryptography, and signal-processing circuits. The probe makes use of infrared optical tweezers that perform two functions at the same time: They physically grab onto and manipulate the nanowire so that it can be gently pressed against an object to be imaged. The tweezers also make the nanowire emit light like a tiny fiber-optic filament so that it can excite fluorophores. The probe allows the researchers to image objects at the subwavelength level; that is, it resolves features that are smaller than the wavelength of visible light. "Before this probe, you could, for example, mechani- cally manipulate a cell using atomic force microscopy, and you could image the cell using confocal or fluo- rescence microscopy," explains Jan T. Liphardt, who spearheaded the research with colleague Peidong Yang. "But it was difficult to do them both at the same time." The new nanowire probe, Liphardt says, can be used to characterize material by fluorescence microscopy. The system is particularly interesting for biological imaging because it requires no electrodes or electrical wiring and the niobate is compatible with physiological environments. Many problems still need to be resolved, though. For example, the researchers found that as they gently pressed the nanowire against a living cell, the cell began to engulf the nanowire. "This is truly beautiful work—a tour de force—that represents a major advance in nanowire nanophoton- ics," comments Harvard University professor Charles M. Lieber. "The creation of tunable subwavelength sources opens up many opportunities and will substan- tially impact imaging in chemistry and biology, as well as other fields."—BETHANY HALFORD WWW.CEN-0NLINE.ORG (} JULY 2, 2007
Transcript of A NANOWIRE MICROSCOPE
NEWS OF THE WEEK
FDA FINALIZES RULES FOR DIETARY
SUPPLEMENTS QUALITY CONTROL: Agency will require testing of ingredients
DOMESTIC AND FOREIGN manufacturers of vitamins, herbs, and other dietary supplements must follow new standards to show that their
products are labeled properly and are not contaminated. On June 22, FDA officials announced new
standards for testing the purity, strength, and composition of all supplements.
"This rule helps to ensure the quality of dietary supplements so that consumers can be confident that the new products they purchase contain what is on the label," says FDA Commissioner Andrew G. von Eschenbach. Supplements
have always been regulated as a category of food, not as drugs. The standards lay out practices to ensure quality
during manufacturing, labeling, and storage of dietary supplements. They list requirements for quality-control procedures, the design of manufacturing plants, and the testing of ingredients and final products. They take effect for large plants in June 2008 and for small companies in June 2010. Furthermore, because
of recent amendments to the federal Food, Drug & Cosmetic Act, manufacturers in this $21 billion dietary supplement industry will be required to report adverse events caused by their products.
The power to establish the new manufacturing standards was granted in a 1994 federal law, but some critics say the new rules do not do enough to ensure safety. "Today's final rule on Good Manufacturing Practices is an example of better late than never. But the requirements do not appear to go as far as they could have," notes Sen. Richard J. Durbin (D-I1L).
Under the rules, FDA will be able to inspect manufacturing plants for compliance. Companies must keep records showing that supplement ingredients have been tested, but they do not have to submit these records to FDA. Supplement makers are responsible for devising scientifically defensible tests for the purity of ingredients, the agency says.
FDA plans to inspect some of the plants, but it does not have additional money for enforcement. Resources will be shifted according to the risk posed by the manufacturers, says Robert E. Brackett, head of the agency's Center for Food Safety & Applied Nutrition. If a company violates the rules, FDA could fine the firm or ask it to voluntarily withdraw a product.
"Even with these new manufacturing practices, there will be no assurance that dietary supplements work or are safe," says Sidney Wolfe, director of the Health Research Group at Public Citizen, a nonprofit public interest organization. He urges Congress to address "this enormous deficiency in the law."—BETTE HI LEMAN
Artists rendition shows laser tweezers (red, right) positioning a KNb03 nanowire as it probes a nanoparticle.
A NANOWIRE MICROSCOPE NANOPHOTONICS: Optical
probe combines fluorescence and force techniques
U SING A POTASSIUM NIOBATE (KNb03) nanowire as their key component, researchers have created an optical probe that potentially
combines fluorescence microscopy and force microscopy (Nature 2007,447,1098). The probe—developed by scientists at the University of California, Berkeley, and Lawrence Berkeley National Laboratory—is attractive as a bioimaging tool and could also be used in advanced information technology, cryptography, and signal-processing circuits.
The probe makes use of infrared optical tweezers that perform two functions at the same time: They physically grab onto and manipulate the nanowire so that it can be gently pressed against an object to be imaged. The tweezers also make the nanowire emit light like a tiny fiber-optic filament so that it can excite fluorophores.
The probe allows the researchers to image objects at the subwavelength level; that is, it resolves features that are smaller than the wavelength of visible light.
"Before this probe, you could, for example, mechanically manipulate a cell using atomic force microscopy, and you could image the cell using confocal or fluorescence microscopy," explains Jan T. Liphardt, who spearheaded the research with colleague Peidong Yang. "But it was difficult to do them both at the same time."
The new nanowire probe, Liphardt says, can be used to characterize material by fluorescence microscopy. The system is particularly interesting for biological imaging because it requires no electrodes or electrical wiring and the niobate is compatible with physiological environments.
Many problems still need to be resolved, though. For example, the researchers found that as they gently pressed the nanowire against a living cell, the cell began to engulf the nanowire.
"This is truly beautiful work—a tour de force—that represents a major advance in nanowire nanophoton-ics," comments Harvard University professor Charles M. Lieber. "The creation of tunable subwavelength sources opens up many opportunities and will substantially impact imaging in chemistry and biology, as well as other fields."—BETHANY HALFORD
WWW.CEN-0NLINE.ORG ( } JULY 2, 2007
