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Articles from 2009 In November


"Bo-Tax" on Cosmetic Surgery

Surgery that would fall under the tax umbrella include procedures that are "not necessary to address deformities arising from congenital abnormalities, personal injuries resulting from an accident or trauma, or disfiguring diseases," according to The New York Times. Critics of the tax proposal argue that it will further contribute to the decline in nip and tuck procedures, and will drive patients to foreign countries where they can pay a fraction of the price for cosmetic surgery (as well as pay a potential price for sacrificing safety). Other groups, such as the National Organization for Women, say the tax will hit middle-age women the hardest.

Platinum-Grade Rubber Offers Enhanced Processability

Primasil Silicones (Weobley, UK) will soon introduce a new platinum-grade material. Currently being tested to USP Class VI and ISO 10993, the high-consistency rubber (HCR) known as PR 410 reportedly features greater processability than existing silicone materials. "The formulation can shave minutes off typical processing times of current platinum HCRs that are available from other silicone suppliers," says Andrew Thomas, Primasil's new projects manager. The material is primarily intended for molding applications, he adds. Primasil manufactures liquid silicone injection-molded parts and extruded platinum-cured silicone. The company performs assembly and packaging work in three separate cleanroom areas, and quality systems are certified to EN ISO13485:2003. The company also offers SureTrace laser etching, which permanently marks tubes with the part number, batch number, and expiration date.

Silk-Based Adhesive Gel Provides Potential for In Situ and In Vivo Devices

Aspects of the silk electrogelation process: (a) basic process using 8% w/v silk solution with pencil lead electrodes (+ on the right); (b) syringe-based experiment with 8% silk solution and a spiral positive electrode; (c) demonstration of impressive adhesive qualities; and (d) prototype device to perform silk electrogelation and delivery for biomedical applications, such as burn treatment.

Aspects of the silk electrogelation process: (a) basic process using 8% w/v silk solution with pencil lead electrodes (+ on the right); (b) syringe-based experiment with 8% silk solution and a spiral positive electrode; (c) demonstration of impressive adhesive qualities; and (d) prototype device to perform silk electrogelation and delivery for biomedical applications, such as burn treatment.

It's been a big year for silk. Researchers have been spinning new ways to employ silk for a variety of medical device applications in 2009, including using it as a base for nanoparticle composites, mimicking muscle, and employing it as a substrate for degradable electronics. Scientists at Tufts University (Medford, MA) are responsible for one of the latest developments: They've produced a novel, electrically mediated adhesive from silkworm silk that shows promise for future medical applications. The Tufts researchers have yielded a highly viscous and tacky adhesive gel through a process called electrogelation, which means that the adhesive properties are controlled by electrical inputs. Beginning with electrodes immersed in an aqueous solution of silkworm silk protein, the researchers then applied 25 V dc to a pair of mechanical pencil leads for a 3-minute period. In response to these electric fields, gel formed on the electrode. Upon switching off the electric field, however, the electrogel (e-gel) remains stable. Thus, it is not dependent on an electrical field once formed. This particular project is unique for several reasons, according to the researchers. Although electrospinning of polymers has been performed at high voltages, the use of low dc voltages to generate a controlled volume of silk is a new development. Furthermore, the process is reversible, depending on voltage, time, and conditions. Atypical for silk-based systems, the reversal can be achieved using a reverse electrical process. The gel thus can be transformed from a solid state to the solution; this state change can be performed over multiple cycles. Able to function on both hydrated and dry surfaces, the e-gel can also be applied to a variety of substrates. "E-gel displayed unique adhesion characteristics when compared to other bioadhesive systems," according to an article written by the researchers for the journal Advanced Materials. "After the initial linear regime, the stress progressively increased, while the stress-strain curve showed sporadic fluctuations presumably due to an interplay between the decreasing e-gel/plate interface area, due to partial de-adhesion, and apparent stiffening of the e-gel, due to dehydration and elongational forces. Strains up to 2500% were recorded until failure upon complete de-adhesion." Because all biocompatible components were used in the development of the gel, it is potentially suited for a number of in vivo and in situ devices, the researchers note. They cite such possible applications as a handheld gel-forming and delivery device for burn treatment and a medical instrument that could navigate through the body and then temporarily adhere to a location in vivo.

HHS Outlines Healthcare Reform Effects

Sebelius told reporters "I think what is important, in addition to looking at the expansion of various programs and how much money is coming back to the states ... is that the cost of doing nothing is a huge burden on states. It's not only a burden that they pick up in terms of insured costs, and a sicker workforce and less preventative care, but it is a burden they pay for directly in state employee premiums."

The Department asserts that if nothing is done, by 2019 the number of uninsured people will grow by more than 30% in 29 states and by at least 10% in every state. In addition, the amount of uncompensated care will more than double in 45 states, and businesses in 27 states will see their premiums more than double. Finally, fewer people will have coverage through employers.

Biodegradable Fibers Advance Drug-Eluting Stents

Drug-eluting fibers from Tel Aviv University can be used to coat both metal and biodegradable stents. Image: AFTAU

Drug-eluting fibers from Tel Aviv University can be used to coat both metal and biodegradable stents. Image: AFTAU

The topic of much research and anticipation, biodegradable stents are a major goal for many medical device manufacturers, as is controlled release of drugs via drug-eluting stents. Contributing to the advancement of drug-eluting biodegradable stents is the development of a composite fiber-based coating technology by researchers at Tel Aviv University (Israel). Coating manufacturers have struggled with controlled release of therapeutic agents because the drugs are not soluble in water and thus do not release well, according to lead researcher Meitel Zilberman, a professor in the university's department of biomedical engineering. Her team's fiber platform, however, features a strong core coated with an eluting solution and an extremely porous construction. The porous construction is key, Zilberman notes; engineering the fiber platform to have such a large surface area for diffusion facilitates controlled release and provides what she dubs a "desired release profile." Measuring only five times the thickness of a human hair, the drug-eluting fibers dissolve after completing their preprogrammed drug-delivery task. Although this functionality is ideal for biodegradable stents, it can also be applied to metal stents, according to Zilberman. In addition to stents, the researchers believe that there may be alternate uses for the composite drug-eluting fibers in various cancer treatments.

STD Cases Rise, Point-of-Care Testing Critical

According to the Centers for Disease Control, about 19 million new cases of STD infections occur each year and about half of them occur in people between 15 and 24 years of age. Standard syphilis tests can require up to two weeks for results, while a rapid test could reduce the chances of a patient potentially spreading a disease. "Individuals in high-risk groups should be diagnosed at the point of care so as to provide the best chance for behavior modification, other prevention strategies and, where appropriate, treatment," says Larry Siebert, CEO of Chembio. New technology for diagnosing syphilis allows doctors to start treatment right away. Chembio presented information about one of its new rapid testing products at the 18th Society for Sexually Transmitted Disease Research Congress in London, England.

Injection Molder Expands Operations

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A view of the production floor at Venture Plastics' 45,000-sq-ft facility in Newton Falls (OH).

Venture Plastics Inc. (Newton Falls, OH) has invested approximately $600,000 in new injection molding machines for its two processing facilities in Newton Falls and El Paso, TX. A supplier of molded parts and components to the medical device manufacturing industry, Venture offers a range of services, including injection molding and structural foam molding, overmolding, insert molding, and gas-assist molding. Value-added services include a variety of assembly, painting, decorating, and packaging processes. At its 45,000 sq-ft facility in Newton Falls, the full-service, ISO/TS-16949-certified custom thermoplastic injection molder has added three pieces of equipment: a 2009 Arburg 520A all-drive 165-t electric servo horizontal molding machine with a Mulitlift robot, 8.2- and 2.5-oz injection units, a 20.47 × 20.47 tie bar, and a double-core pull; a 2009 Arburg 570A all-drive 220-t electric servo horizontal molding machine with a 15.3-oz injection unit, a 22.4 × 22.4 tie bar, and a single-core pull; and a 2004 Mitsubishi 390MJ hydraulic-ram horizontal molding machine with a 36-oz injection unit, a 29.6 × 29.6 tie bar, and a double-core pull. All new systems will be complemented with RJG EDarts to enable process control and monitoring. The 48,000-sq-ft El Paso facility has added a 2009 Toyo Electric SI-150IV 150-t machine with an 8.91-oz injection unit and a 20.07 × 18.11 tie bar. In addition to capital expenditures, Venture has upped its investment in personnel, spending more than $50,000 in 2009 to train employees in processing techniques and lean/green plant initiatives. "Our recent capacity and personnel expansions have been driven by a significant amount of new business acquired during the second and third quarters of 2009, but also by additional production activity that will be scheduled in the near future," remarks Venture Plastics president Steve Trapp. "We are currently operating three full shifts five to six days a week and are dedicated to supporting the expertise of our processing professionals with new molding equipment that provides for the growing needs of our customers."

Comparative Effectiveness: More About Cost or Care?

Although the main goal for Congress and policy makers is deliver data that helps doctors and patients make informed decisions, yesterday's panel of speakers proved yet again that there are still a lot of unanswered questions surrounding the matter. "In the financial industry, I think it's added a new layer of uncertainty for the public and private companies," said Amit Bhalla, director at Citigroup Investment Research (New York City). "In concept, comparative effectiveness is great--who doesn't want more data? The question is how it's going to be implemented: Is it going to be truly clinical effectiveness, or is it going to be cost effectiveness?" For physicians, the one-size-fits-all approach doesn't work. Neal Cayne, MD, expressed concern that if only devices that are more cost effective and proven medically effective than others are reimbursed, he could be limited in what devices he can use on patients. "There is clinical judgment when you're making decision about patients," said Cayne, the director of the endovascular surgery program at NYU Langone Medical Center. "I'm really concerned that I might not have the best treatment [option] for the patient." Aside from potentially inhibiting innovation, Cayne's point is amplified by the fact that comparative effectiveness and the direction of the economy could change the kind of healthcare people receive in the United States. "It's hard for me to look at a patient with a problem that I know I can fix and the technology is out there, and my hands are tied. It's very frustrating, and hopefully we can somehow adjust the monetary problem and have the care available for the individual patient that we need. But it's not going to be easy to do."

Microfluidic Connector Relies on Magnetism

he microchip has five inlets and one outlet, all linked to tubing via the magnetic connectors. The inset at upper right shows the setup of the tube-magnet combination. Image: G. Cooksey, NIST

The microchip has five inlets and one outlet, all linked to tubing via the magnetic connectors. The inset at upper right shows the setup of the tube-magnet combination. Image: G. Cooksey, NIST

Designing microfluidic devices presents a variety of challenges, many of which are intrinsically tied to the small size of the products and their parts. Among the most frustrating design aspects of the miniature devices, according to researchers at the National Institute of Standards and Technology (NIST; Gaithersburg, MD), are the connectors that form the fluid pathways from external liquid pumps and regulators to the chip. Taking matters into their own hands, the NIST scientists have developed a new magnetic connector that they believe will improve microfluidic device design. Typically, connectors for microfluidic applications require gluing the tubing directly to the chip or employing a male-female connection that joins the tubing to the male component. But these methods are associated with many potential flaws and defects, such as broken bonds or leaks, cracked chips from heat-curing the glue, or devices rendered unusable from rogue glue that runs into the channels. Using magnets as the basis for the connection, the NIST connectors avoid these potential risk factors, however. The scientists' connector for microfluidic applications consists of a ring magnet engineered with an O-ring gasket on its underside and a tube in the center. The tube is positioned directly on top of the inlet or outlet port of a channel in the chip. To secure the magnet and tubing in place, a disc magnet goes on the bottom of the chip. In addition to being cost-effective, the connector is flexible, reliable, and enables quick assembly of the connection. Furthermore, it is reusable, unlike existing microfluidic connectors, the researchers claim. The magnetic connector appears to be suitable for use with most microfluidic devices, with the exception of iron-containing fluids, superparamagnetic particles, cells with magnetic particles, and temperatures greater than 80°C. Click here to view a video demonstrating assembly and use of the connectors with a microfluidic chip.

Nanoparticles Enable Scientists to Connect the Dots inside Cells

Human red blood cells, in which membrane proteins are targeted and labeled with quantum dots, reveal the clustering behavior of the proteins. The number of purple features, which indicate the nuclei of malaria parasites, increases as malaria development progresses. The NIST logo at bottom was made by a photo lithography technique on a thin film of quantum dots, taking advantage of the property that clustered dots exhibit increased photoluminescence. (White bars: 1 ¼m; red: 10 ¼m.)

Human red blood cells, in which membrane proteins are targeted and labeled with quantum dots, reveal the clustering behavior of the proteins. The number of purple features, which indicate the nuclei of malaria parasites, increases as malaria development progresses. The NIST logo at bottom was made using a photo lithography technique on a thin film of quantum dots, taking advantage of the property that clustered dots exhibit increased photoluminescence. (Credit: H. Kang/NIST and F. Tokumasu/NIAID.)

New research from the National Institute of Standards and Technology (NIST; Gaithersburg, MD) and the National Institute of Allergy and Infectious Diseases (NIAID; Bethesda, MD) enables scientists to observe and analyze activities that occur over hours or even days inside cells, opening the door to solving many mysteries associated with molecular-scale events.

The joint NIST/NIAID research team has discovered a method of using quantum dots to illuminate the cellular interior to reveal these slow processes. A type of nanoparticle, quantum dots are semiconductor particles that can be coated with organic materials tailored to be attracted to specific proteins within the part of a cell a scientist wishes to examine. When exposed to light, the dots glow.

"Quantum dots last longer than many organic dyes and fluorescent proteins that we previously used to illuminate the interiors of cells," explains biophysicist Jeeseong Hwang, the NIST team leader. "They also have the advantage of monitoring changes in cellular processes while most high-resolution techniques like electron microscopy only provide images of cellular processes frozen at one moment. Using quantum dots, we can now elucidate cellular processes involving the dynamic motions of proteins."

The NIST/NIAID study focused primarily on characterizing quantum dot properties, contrasting them with other imaging techniques. In one experiment, the team employed quantum dots designed to target a specific type of human red blood cell protein that forms part of a network structure in the cell's inner membrane. When these proteins cluster together in a healthy cell, the network provides mechanical flexibility to the cell so that it can squeeze through narrow capillaries and other tight spaces. But when the cell gets infected with the malaria parasite, the structure of the network protein changes.

"Because the clustering mechanism is not well understood, we decided to examine it with the dots," says NIAID biophysist Fuyuki Tokumasu. "We thought if we could develop a technique to visualize the clustering, we could learn something about the progress of a malaria infection, which has several distinct developmental stages."

The team's efforts revealed that as the membrane proteins bunch up, the quantum dots attached to them are induced to cluster and glow more brightly, permitting scientists to watch as the clustering progresses. More broadly, the team found that when quantum dots attach themselves to other nanomaterials, the dots' optical properties change in unique ways in each case. They also found evidence that quantum dot optical properties are altered as the nanoscale environment changes, offering a greater possibility of using quantum dots to sense the local biochemical environment inside cells.

"Some concerns remain over toxicity and other properties," Hwang says, "but altogether, our findings indicate that quantum dots could be a valuable tool to investigate dynamic cellular processes."

For detailed information on this research, see Probing Dynamic Fluorescence Properties of Single and Clustered Quantum Dots Toward Quantitative Biomedical Imaging of Cells.