A compound found in sunless tanning spray may help to heal wounds following surgery

Results published today in the Proceedings of the National Academy of Sciences show that a sticky gel composed of polyethylene glycol and a polycarbonate of dihydroxyacetone (MPEG-pDHA) may help to seal wounds created by surgery.

Procedures to remove cancerous breast tissue, for example, often leave a hollow space that fills with seroma fluid that must typically be drained by a temporary implanted drain. "This is an unpleasant side effect of surgery that is oftenunavoidable," explains Dr. Jason Spector, co-author of the study and plastic surgeon at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.

The gel could potentially be used in all different reconstructive surgeries to prevent seroma formation. "The new substance would act to glue together the hole left behind to prevent seroma buildup," says Dr. Spector.

DHA is a compound that sticks to compounds in biological tissues, called amines. The sticky properties of DHA are what allows sunless tanner to adhere to the skin without being wiped off. However, it is biodegradable and water soluble as well, which means that the compound does not stay tacked onto the body's tissues forever. Currently used "bio-glues" are made from animal products and take a long time to degrade in the body -- both factors that raise the risk of infection.

"DHA is a compound that is naturally produced in the body," explains Dr. David Putnam, the study's senior author and a biomedical engineer from Cornell University's Department of Biomedical Engineering and School of Chemical and Biomolecular Engineering. "The glue is broken down, or metabolized, and then safely removed by the body."

Dr. Putnam's lab and his collaborators work to create safe, synthetic compounds from chemicals found in nature. DHA is an intermediary compound produced during the metabolism of glucose, a sugar used by the body for fuel.

To create the new compound, MPEG-pDHA, Dr. Putnam and his lab first bound the single molecule monomer of DHA, which is highly reactive, to a protecting group molecule, making it stable enough to manipulate. This allowed the engineers to bind the monomers together to form a polymer, or chain of molecules, along with MPEG. Doing so allows the polymer gel to be injected through a syringe.

"Making a polymer from DHA has eluded chemical engineers for about 20 years," says Dr. Putnam.

Now in gel form, the compound has the ability to stick tissues together, preventing the pocket from filling with seroma fluid, like an internal Band-Aid, explains Dr. Putnam. The researchers found that the gel prevented or significantly lowered seroma formation or fluid buildup in rats that had breast tissue removed.

"The next step would be to test the gel on larger animals and then in clinical trials in human surgical cases," says Dr. Spector.

Previous results, published by Drs. Putnam and Spector, in the August 2009 issue of the Journal of Biomedical Materials Research, showed that the gel also prevented bleeding in a rat liver.

"This is another aspect of the compound that would be greatly beneficial if proven to be applicable in humans," says Dr. Spector. "The gel could speed the healing and decrease bleeding within the body."

Talecris Biotherapeutics to Present at the 2010 Citi Investment Research Global Health Care Conference

RESEARCH TRIANGLE PARK, N.C., May 20 /PRNewswire-FirstCall/ -- Talecris Biotherapeutics Holdings Corp. (Nasdaq:TLCR) today announced that Lawrence D. Stern, chairman and chief executive officer of Talecris, will present at the 2010 Citi Investment Research Global Health Care Conference at 11:30 a.m., Thursday, May 27, 2010, at the Hilton New York Hotel inNew York, N.Y.

A live webcast of Talecris' presentation will be accessible through the investor relations section of the Talecris Web site,www.talecris.com/investor-relations.htm. A replay of the webcast will be available until June 10, 2010, and can be accessed at the same Web address.

Coils for Nosebleeds

(Reuters Health) - A small study suggests that a surgical treatment generally used on patients with tumors and certain brain disorders may put a stop to nosebleeds that won't stop any other way.

The surgery - which involves injecting coils into the arteries of the nose through arteries in the leg - isn't for everyone. For most people, home remedies such as pressure and tissues work just fine. If they're not enough, doctors may pack the nasal passages with gauze, or sear the bleeding shut using cauterization.

But the author of the study told Reuters Health that about one percent of the population - generally older adults taking blood thinners - suffers from uncontrollable nosebleeds severe enough that surgery may be considered.

The study, published today in the Journal of NeuroInterventional Surgery, tracked 20 such patients who had received the coil treatment. Dr. Walter Lesley, lead author of the study and director of neuroradiology at the Scott & White Clinic in Temple, Texas, and colleagues monitored patients for 30 days, after which 18 of the 20 needed no further surgery.

One patient had another procedure to control bleeding, while another died of unrelated causes.

The study, say the authors, is an important step in figuring out which kind of surgery is safest and most effective.

"There really isn't a lot of good numerical data on using coils at all for nosebleeds," Lesley told Reuters Health. "Our results were encouraging and certainly warrant a larger study comparing (the procedure) head to head with other methods."

Doctors use a few other surgeries to treat severe uncontrollable nosebleeds, including a catheter to plug an artery with sponge-like particles, rather than coils, and tying off an artery in the back of the nose with a staple-like clip.

The current study did not directly compare different treatment methods, but the coil method had a lower failure rate and fewer serious complications than other methods have in other studies. Those complications - which can include stroke and blindness - affected none of the study's participants.

The risks may be different, said Dr. Peter Willems, a neurosurgeon at Leiden University Medical Center in the Netherlands, because the coils don't penetrate as far into the nasal artery as smaller particles. While this could reduce the possibility of some complications, it may make it more difficult to repeat the surgery on those who need it.

Dr. Richard Orlandi, an ear, nose and throat specialist at the University of Utah, believes that each of the procedures is relatively safe, and that the question comes down to cost and availability. Orlandi and his colleagues published a study in 2005 which found that the cost of a procedure similar, but not identical, to the one tested here was $14,088 per patient, compared to $7,561 for a procedure that clipped the nasal artery.

"Performing this procedure really does require a fair amount of skill by a radiologist," which could be a problem in rural settings, he told Reuters Health.

Lesley said the platinum-coil based procedure takes about an hour to complete, and patients either go home that day or the next morning - similar to the recovery time for other treatments.

The researcher said the need for such procedures could grow "because of the benefits of new drugs that thin the blood and can cause more bleeding problems."

SOURCE: here Journal of NeuroInterventional Surgery, May 27, 2010.

CryoLife to present at the Jefferies 2010 Global Life Sciences Conference

CryoLife, Inc. , an implantable biological medical device and cardiovascular tissue processing company, announced today that it will participate in the Jefferies 2010 Global Life Sciences Conference at The Grand Hyatt Hotel in New York City.

Steven G. Anderson, president and chief executive officer of CryoLife, Inc., will present a corporate overview on Tuesday, June 8, 2010 at 9:30 a.m., Eastern Time.

CryoLife's live presentation may be accessed through its Web site, www.cryolife.com, on the Investor Relations page. An archived copy of the presentation will be available for 90 days on the same Web site.

Interesting article on bovine harvesting

CORDIS Launches ExoSeal(TM) Vascular Closure Device

New Trial Results on ExoSeal(TM) Vascular Closure Device Support its Clinical Safety* and Efficacy

PARIS, May 27, 2010 /PRNewswire/ -- Cordis Corporation, a worldwide leader in the development and manufacture of interventional vascular technology, announced the launch of the ExoSeal(TM) Vascular Closure Device. ExoSeal(TM) incorporates a number of new advances in technology and simplicity of design to provide precise and secure extravascular arterial closure. Cordis Corporation received CE-Marking approval for ExoSeal(TM) Vascular Closure Device in May 2010. This new product was launched during EuroPCR, the leading medical conference in Europe for physicians specializing in interventional cardiovascular medicine.

ExoSeal(TM) was shown in a recent clinical trial to have an excellent clinical safety* profile during vascular procedures. The 'ECLIPSE Trial' recorded no adverse clinical events and achieved a level of safety comparable to manual compression while significantly reducing time to ambulation. The device has achieved this level of clinical safety by combining easy-to-use functionality with trusted bioabsorbable technology and precise extravascular closure.

"We are very pleased to announce the launch of our first Vascular Closure Device" said Campbell Rogers, M.D., Chief Scientific Officer and Global Head, Research and Development, Cordis Corporation. "The ExoSeal(TM) Vascular Closure Device incorporates key advancements including the use of the Polyglycolic Acid Plug, two visual indicators to moderate control of the device and lockout features to reduce the risk of complications. The device is designed for ease of use, reducing the number of components and deployment steps."

"From our experience in the ECLIPSE trial, we were impressed with the safety and the effectiveness of this new closure device. It is very easy to use and nothing is left inside the vessel to threaten arterial blood flow. An advantage compared to other devices is the procedural sheath does not need to be changed which helps promote patient comfort. The two visual indicators are important for positioning the bioabsorbable plug ," explains Marcus Wiemer, M.D., Primary Investigator, Department of Cardiology, Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, in Bad Oeynhausen, Germany**.

ExoSeal(TM) in detail

The ExoSeal(TM) Vascular Closure Device makes use of key technological developments to support the clinical safety of the closure procedure. In the ECLIPSE Trial, the extravascular plug placement was associated with no embolization, infection or other major adverse events, comparable to manual compression [despite the significantly shorter time to ambulation for ExoSeal(TM)]. The bioabsorbable PGA-plug, which is designed to close the femoral artery puncture site with minimal or no inflammation, is fully reabsorbed in 60-90 days. PGA (Polyglycolic Acid) is a trusted non-collagen plug material that is metabolized to carbon dioxide and water. A system of deployment through the existing procedural sheath makes ExoSeal(TM) quicker and easier to use and increases physician convenience by minimizing or eliminating the need for sheath exchange during the procedure. The device uses visual indicators to help the clinician deploy the device correctly. This "visual feedback" also promotes patient comfort during deployment and the 'lock-out' system of ExoSeal(TM) helps ensure that only extra-vascular plug placement can take place.

Flush with VC, Cohera Medical Raises $12.2M of $20M

PITTSBURGH, Pa. -- According to an SEC filing, Cohera Medical has raised $12.2 millionagainst a targeted $20 million from Bradford Capital Partners and Kern Whelan Capital.

The company has now amassed more than $60 million in venture backing. As reported by citybizlist, in May 2008 Cohera collected more than $7.6 million from Kern Whelan and in October of the same year secured $16.1 Million in Series B Financing from Whelan and Bradford. In January of 2010 the company received Series C funding totaling $25 million.

Cohera is a Pittsburgh based company that develops a line of surgical adhesives that are synthetic, biocompatible and resorbable. It is planning to enter clinical trials with its product starting with a target application in plastic surgery.

Named in the filing are Patrick Daly, co-founder president and chief executive officer, Richard Wonsettler, vice president of finance and chief financial officer, Dottie Clower, vice president of research and development and operations, and Eric Beckmanco, co-founder and chief scientific officer; and directors Albert Dombrowski, James Liken, John Kern (Kern Whelan Capital),Doros Platika and Martin Calihan (Bradford Capital Partners).

Bradford Capital Partners is a Pittsburgh-based private investment company that participates in venture capital investments and engages in the acquisition and development of entrepreneurial businesses.

Based in San Francisco, Calif., Kern Whelan Capital manages investment portfolio stretching from new ventures to established and profitable businesses across many industry sectors. The company invests only in few companies and has long term approach towards it liquidity horizon.

CryoLife Requests Medafor Shareholders WITHHOLD Support for Medafor Directors

Dear Fellow Medafor Shareholder:

You should have recently received a proxy statement from Medafor asking you to re-elect the five incumbent members of their board of directors.

As Medafor's largest shareholder, we are deeply concerned by both Medafor's rush to hold their annual shareholders' meeting and by the troubling information disclosed in their proxy statement and recently issued financial statements and letters to shareholders. We are writing to urge you to WITHHOLD your support for directors Michael Pasquale, Paul Gray, Robert Halverson, Gary Shope andGerald Van Eeckhout given their poor oversight of Medafor.

• Do NOT return your proxy to management.
• If you have already given management your proxy, revoke it by writing Medafor.
• If you can, attend the meeting in person.

MEDAFOR'S DIRECTORS: ENRICHING THEMSELVES AT THE EXPENSE OF SHAREHOLDERS

Medafor's management and board have continually diluted shareholders, issuing new shares to finance the company without receiving adequate value in return. Their proxy statement and financial statements provide further evidence of this fact.

Specifically, the proxy discloses several instances during 2009 where stock, warrants and options were issued to employees, contractors, distributors and others at prices inconsistent with Medafor's statements about the value of Medafor shares.

In 2009, Medafor's board granted shares to themselves that they valued at only $1.50 per share. In the fourth quarter of 2009, Medafor issued options to management with an exercise price of $2.00 per share. This means that at the end of 2009, the Medafor board concluded that $2.00 per share was "fair market value," as is required under the stock incentive plan that Medafor shareholders approved. Despite this, just two months later, Medafor urged its shareholders not to sell their shares to CryoLife because, in Gary Shope's words, $2.00 per share was not "even close to a fair price" and was "grossly inadequate." Apparently, $2.00 per share is unconscionably low when Medafor shareholders want to sell their shares, but it's fair enough when Medafor's insiders are compensating themselves. One thing is certain, either the Medafor board and management have been enriching themselves at the shareholders' expense by undervaluing their equity and option awards, or their statements regarding the adequacy of CryoLife's$2.00 per share offer were not made in good faith.

Also raising a concern is the fact that, in its proxy statement, Medafor implied that the shares issued to Magle in conjunction with the technology transfer transaction were issued at an average price of $5.28 per Medafor share. This valuation raises questions as to why Medafor routinely granted stock, options and warrants that were priced considerably below $5.28 per share in the months leading up to the consummation of the Magle transaction. Have Medafor's board and management unjustly, and potentially illegally, enriched themselves and key partners at the expense of other shareholders by granting stock and options at prices considerably below market value or have they not been candid in their statements to Medafor shareholders regarding the Magle transaction and its impact on Medafor and its shareholders?

The proxy also indicates that Medafor has entered into severance and change in control agreements with its CEO and CFO, providing the current management with golden parachutes that could deter potential buyers. These agreements are in addition to the excessive compensation earned by key executives. For instance, in addition to stock awards and stock option grants, Medafor's CEO and CFO earned a combined $700,000 in cash in 2009 while delivering questionable financial performance and significant shareholder dilution. The amount of cash taken out of the business by the CEO and CFO for their compensation represents over 70 percent of Medafor's available cash at the end of 2009. These are compensation levels that public company executives would be pleased to receive. They are not appropriate for a private company at Medafor's stage of development with limited cash.

MEDAFOR'S LIMITED FINANCIAL DISCLOSURES RAISE NEW CONCERNS

We do not believe that Medafor has sufficient capital to invest adequately in its business in order to protect its technology from competition or to maximize its commercial potential. Medafor has disclosed in its financial statements that it must repay $3.2 millionin convertible notes in 2011 and that it is currently in default of the covenants of its $1.0 million credit facility that expires in November 2010, but it has not provided shareholders with any clarity as to how it plans to fund the $3.2 million in convertible note payments.

Furthermore, the Medafor board continues to withhold information that is required in order to accurately assess the company's current financial condition and performance. In fact, Medafor has failed to provide any financial statements for the first quarter of 2010. In addition, Medafor's directors entered into a highly unusual and material contract with Magle, involving substantial dilution to shareholders and a significant cash outlay, while concealing the information that would be necessary to allow an accurate assessment of Medafor's current financial condition following the transaction. Despite our repeated requests, Medafor has refused to allow us to see the contract with Magle, or their accounting records related to this transaction, including what value Medafor ascribed to the technology. They have also failed to provide key balance sheet data, shareholders' equity information, or detail on the company's cash position, as they have in the past, which would allow shareholders to gauge the impact of the transaction. Additionally, Medafor has trumpeted some improvement in earnings for the first quarter of 2010, without noting the impact on earnings per share of the Magle transaction. This lack of disclosure suggests that Medafor's board has significantly impaired the value of Medafor shares and is hiding it from shareholders.

MEDAFOR: CURTAILING SHAREHOLDER RIGHTS

Medafor's directors have unexpectedly scheduled their annual shareholders' meeting just seven months since the last meeting and have given shareholders barely three weeks' notice of this surprising meeting. This timing appears designed to prevent shareholders from being able to meaningfully evaluate the performance of Medafor and its board, nominate an alternative slate of directors, put forth shareholder proposals or otherwise participate fully in the meeting. In addition to attempting to prevent shareholder action at the meeting, the timing leads us to believe that Medafor's directors are anxious to ensure their re-election before shareholders have any possibility of discovering the impact that the Magle transaction has had on the company's condition and the value of their shares.

Medafor has also been actively attempting to curtail the shareholder rights granted in its bylaws by attempting to keep shareholders from being able to call their own meetings. They are working in court to take away the right guaranteed certain Medafor shareholders to call a special meeting at any time for any purpose.

Additionally, Medafor is attempting to deny shareholders access to records of board proceedings in order to conceal information from shareholders about the board's activities and the current financial condition of the company. Medafor has also stated that it has granted Magle the right to terminate its exclusive supply agreement with Medafor in the event that Medafor is acquired without board approval, regardless of whether a majority of shareholders think the transaction is fair.

MEDAFOR'S DIRECTORS ARE DESTROYING SHAREHOLDER VALUE AND LIMITING SHAREHOLDER RIGHTS

Medafor's board of directors has overseen the destruction of Medafor's business, its technology, and the value of its shares. Please join CryoLife in sending a message to Medafor's board that they must provide shareholders with up-to-date, complete information about the current condition of the company, especially the recent Magle transaction, and that they must respect our fundamental rights as shareholders to participate in director elections.

• Do NOT return your proxy to management ? this communicates you are WITHHOLDING your vote.
• If you have already voted, you can rescind your proxy by writing to Medafor at 2700 Freeway Blvd., #800, Minneapolis, MN55430-1757 and stating "I hereby revoke the proxy that I previously provided to you in connection with the annual shareholders' meeting to be held on June 10, 2010." Your revocation should be dated and signed, using your exact name as it appears on your Medafor shares. EVEN IF YOU HAVE RETURNED YOUR PROXY TO WITHHOLD YOUR VOTES FOR THE MEDAFOR BOARD, IT IS IMPORTANT THAT YOU RESCIND IT, IN ORDER TO AVOID GIVING MEDAFOR MANAGEMENT DISCRETIONARY AUTHORITY TO VOTE WITH RESPECT TO ANY OTHER PROPOSALS THEY MAY BRING AT THE MEETING WITHOUT HAVING GIVEN YOU PROPER NOTICE.
• If you can, we also encourage you to attend the meeting and voice your discontent in person.

By NOT returning your proxy to management, thereby withholding your vote for Medafor board of director nominees, you will be sending a clear message to the Medafor management and board that its actions are unacceptable!

If you have any questions, please do not hesitate to contact Nina Devlin at 212-704-8145.

Sincerely,

Steven G. Anderson

Founder, CEO and President

Shareholders may continue to visit www.cryolife.com/medaforoffer

Hemostasis Blog Valued Resource!

The Medical Hemostat Blog has gained wide geographical and company interest. You are welcome to contact me at hemostatguy@gmail.com. I also have consulted with market research firms such as Frost and Sullivan amongst other research organisations.

While I address a need for comprehensive information regarding hemostasis, I am pleased to announce our top, google analytics identified company visitors:

1. Johnson & Johnson
2. CryoLife
3. Baxter
4. Trauma Cure
5. Tyco
6. Zymogenetics
7. Medafor
8. Hemcon
9. King Pharmaceuticals
10. Entegrion
11. St. Jude
12. Aventis Behring

I would appreciate any contributions readers care to send and am actively seeking projects in this field.

Thank You for following the Blog.

HG

Gore Reports First Patient Case Using GORE® DrySeal Sheath

GORE® DrySeal Sheath. The sheath aids in minimally invasive treatment for patients with abdominal aortic aneurysms (AAA) with the GORE® EXCLUDER® AAA Endoprosthesis and thoracic aortic aneurysms (TAA) with the GORE® TAG® Thoracic Endoprosthesis. The successful procedure was performed by Alan Lumsden, M.D., chairman of the Department of Cardiovascular Surgery, The Methodist Hospital (TMH) in Houston, TX, during a Gore-sponsored Acute Symptomatic AAA Workshop conducted in The Methodist DeBakey Heart and Vascular Center.

Gore received FDA clearance in April 2010 to market the GORE DrySeal Sheath, which is comprised of the innovative hemostatic GORE DrySeal Valve attached to the introducer sheath. The GORE DrySeal Valve is truly unique in that it is pressurized to create a seal, thereby minimizing blood loss and accommodating multiple wires and catheters simultaneously. The valve consists of a silicone outer tube and an inner film tube that create an effective hemostatic seal that easily adapts to the profiles of the inserted devices. The device is available in profiles from 12 to 26 Fr, in 2 Fr increments, and has a working length of 28 cm.

According to Dr. Lumsden, “The ability of the GORE DrySeal Valve to accommodate multiple devices during difficult procedures with minimal blood loss keeps the operating field free from excess blood, while helping to prevent unnecessary blood loss to the patient. The GORE DrySeal Sheath requires no intra-procedural manipulation of the valve, delivering consistent performance throughout the procedure and allowing the physician to maintain focus on the endovascular procedure – without being concerned about blood loss at the patient access site.”

Gore Aortic Business Leader David Abeyta added, “This latest addition to Gore’s portfolio of world-class endovascular devices and accessory products minimizes patient blood loss during procedures with endovascular devices, such as the GORE EXCLUDER AAA Endoprosthesis.”

FDA Issues St. Jude Warning Letter Over Epicor Surgical Ablation Device

A Warning Letter from the U.S. Food & Drug Administration (FDA) to St. Jude Medical Inc. has been posted on the agency’s web site. The letter alleges that St. Jude promoted the Epicor surgical ablation device to treat atrial fibrillation, a use that has not been approved by the agency.

Surgical ablation devices like the Epicor system are approved for “ablation,” or the burning of tissue, to seal a wound to stop bleeding. While doctors are permitted to use medical devices in any way they see fit, manufacturers are legally barred from marketing or promoting such uses. St. Jude has received the go-ahead from the FDA to investigate the Epicor system’s use in treating atrial fibrillation, but not approval to market it for this use.

In a Warning Letter dated April 23, the FDA cited marketing statements such as one on the St. Jude’s website last year that the Epicor system is “designed to safely, effectively and reproducibly create a classic box lesion in a single step.” According to The Wall Street Journal, the statement referred to a pattern of burns imprinted on the heart during atrial fibrillation surgery. The letter said statements like that violated the Federal Food, Drug and Cosmetic Act.

The letter also said the FDA found similar problems with marketing brochures and materials aimed at physicians.

Recently, St. Jude acknowledged an investigation by the U.S. Department of Justice into similar false marketing claims involving Epicor. In its most recent quarterly report, the firm stated that it had received a letter from the Department in October 2008.

In March, we reported that Medtronic Inc. and Boston Scientific Inc. had confirmed that the Department of Justice was investigating their marketing of the devices. Another firm, AtriCure, agreed to pay $3.8 million to resolve allegations it marketed its surgical ablation devices for the unapproved purpose of treating atrial fibrillation.

It is estimated the about 80 percent of atrial fibrillation patients are effectively treated with drugs. Unfortunately, there are few studies available that compare the safety of ablation to other types of atrial fibrillation treatments. Since 2008, there have been at least five U.S. patient deaths reported to an FDA data base in procedures using AtriCure devices and one involving a Medtronic device.

New Surgical Device Makes Cleaner Incisions

The scalpel could soon be a thing of the past...A high-tech way to cut through skin and tissue creates less heat damage than standard methods.Wendy Rigby has the story.Deborah Hackworth is about to go under the knife at nix hospital in San Antonio.Her surgeon will be using a new tool to cut out a suspicious lump in her left breast.Hackworth says, "I think patients will recover quicker. I think there will be less pain involved for us."The tool, called the plasma blade, is a new kind of cutting device.Plasma is the same energy used in neon signs and some flat screen TV's.Here in the o-r, the energy is used to cut through skin and tissue, generating less heat than conventional techniques.Breast surgeon Dr. Kathryn Wagner has embraced this new technology.Dr. Kathryn Wagner says, "This is a revolutionary new tool and a way to perform surgery. It replaces both the scalpel and electrocautery, traditional electrosurgery. When you use this device to cut the skin, you get a clean cut with no burn just like a scalpel. Except there's no bleeding."Wagner has been using the plasma blade for about a year now.She says she's impressed with the lack of heat damage it leaves behind.And she's noticed less pain for her patients, a decrease in scarring and faster healing after surgery.Dr. Wagner says, "I think this is the best thing since electrocautery was invented. Aesthetics and pain, a lack of pain from surgery. The difference is pretty impressive."Now, Wagner uses the plasma blade on almost every case.

Excessive use of toxic materials in medical nanotechnology could be avoided

(Nanowerk Spotlight) Metal nanomaterials are often synthesized using the toxic reagent formaldehydeat concentrations thousands of times higher than necessary. Many of these same nanomaterials are being investigated for use in cancer treatment – however, there is a risk that they could do more harm than good. The large excess of formaldehyde that is used originates from methods developed 100 years ago. Because these methods work well, they have stood the test of time. By better understanding the role that formaldehyde plays in nanomaterial synthesis it will become possible to reduce or eliminate this toxic reagent. By eliminating formaldehyde it will become safer to prepare these nanomaterials and safer to use them in cancer treatment.

"The observation that previous synthetic routes for nanoshell and core-shell nanoparticles utilize a large excess of formaldehyde suggested an opportunity for minimizing the quantity of formaldehyde used,"Scott Reed, an assistant professor of chemistry at the University of Colorado at Denver, tells Nanowerk. "However, the synthesis of gold-core, silver-shell nanoparticles that are active in the near-infrared requires the polymer that forms by reaction of formaldehyde and ammonium hydroxide. Until a replacement polymer is found, formaldehyde is required to obtain the desired optical properties."

In a recent paper in the May 19, 2010 online edition of Chemistry of Materials ("Minimizing Formaldehyde Use in the Synthesis of Gold-Silver Core-Shell Nanoparticles"), Reed's team and colleagues from Portland State University describe an effort to minimize the amount of formaldehyde used for coating silver onto gold nanoparticles. They describe a strategy where formaldehyde use can be reduced 100-fold from prior routes and this minimization strategy can be applied to other nanoparticle syntheses.

"We discovered that most of the formaldehyde used in preparing silver nanomaterials is consumed by formation of a polymer" Reed explains. "Formaldehyde reacts with ammonium hydroxide to form a previously unnoticed polymer. When we decreased the ammonium hydroxide concentration it became possible to decrease the formaldehyde concentration, too."

At the same time, these materials maintain optical activity in the near-infrared, the property that makes them attractive for treating cancer with light.

The excessive use of toxic formaldehyde in fabrication processes for nanomaterials is particularly worrisome in the area of nanomedicine where these materials are deliberately injected into the body for diagnostic or therapeutic purposes. Many of the synthetic routes to nanoshells and core-shell metal nanoparticles use a large excess of the toxic reagent formaldehyde as a reducing agent.

Reed notes that one of the early methods reported for coating silver on silica spheres made use of 1 mmol of formaldehyde for reduction of a 0.15 mM solution of silver ("Silver Nanoshells: Variations in Morphologies and Optical Properties").

He estimates that a 3000-fold more formaldehyde is used to prepare silver nanoshells than necessary.

"This large excess is based on Zsigmondy's original silver nanoparticle synthesis reported in 1927 and is typical of coating procedures" he continues. "Other reports have used a 1000-fold excess for coating silver on polystyrene beads or gold nanoparticles, up to 320-fold excess for coating silver on silica nanowires, a 346-fold excess to coat silver onto latex spheres, and a 24000-fold excess for layering silver onto tin-coated silica nanoparticles."

Representative TEM image of core-shell nanoparticles prepared using a mixture of formaldehyde and ascorbic acid. One-half a microliter of formaldehyde was incubated with 4.5 mL water for 15 min prior to addition of 0.5 mL of gold nanoparticles and 0.2 mL of 1.1 mM silver nitrate followed by 21.2 µL ammonium hydroxide after a 5 min incubation and 0.1 mL of 0.534Mascorbic acid after an additional 5 min incubation. Scale bar=20 nm. (Reprinted with permission from American Chemical Society)

Demonstrating an approach to developing greener synthesis methods, Reed and his team fabricated silver-coated gold nanoparticles suitable for phototherapy. Although formaldehyde still is an essential component of this process, they were able to reduce its amount 100-fold compared to previous processes. Part of this minimization resulted from the discovery that ascorbic acid (vitamin C) can be used as a reducing agent in combination with formaldehyde.

"Understanding this previously overlooked polymer formation is a good starting point for minimizing formaldehyde use in the synthesis of nanoshells and other core-shell nanomaterials" says Reed. "We expect that this will result in greener syntheses and more biocompatible nanomaterials suitable for medical applications."

In previous Nanowerk Spotlights we have raised the issue that today's nanomanufacturing processes actually are quite dirty and polluting activities ("Not so 'green' nanotechnology manufacturing"). As Reed and his collaborators show, by designing greener synthetic routes it will become possible to more safely prepare metal nanoparticles without creating hazardous waste. An issue that is particularly important for applications in nonomedicine.

As this particular example shows, this new understanding of formaldehyde will allow for changes in how many types of nanomaterials are synthesized. Nanoparticles prepared using green methods are more likely make it through the regulatory hurdles associated with medical applications.

Hemostat Companies Persist With Animal Derived Production Despite Risks

Despite the World Health Organisation (WHO) recommending....."The pharmaceutical industry should ideally avoid the use of bovine materials and materials from other animal species in which TSEs naturally occur. If their use is absolutely necessary, bovine materials should be obtained from countries which have a surveillance system for BSE in place and which report either zero or only sporadic cases of BSE. These precautions apply to the manufacture of cosmetics as well."
Some Medical Device companies are seeming to blithely plunge onward commercialising animal derived hemostatic products. There does seem adequate reason for concern for this along with other technologies from safer sources.

Interested in Human-Horse Diseases? ClickHERE and HERE

Researchers have found new evidence for the existence of a subclinical form of bovine spongiform encephalopathy (BSE). Cattle, sheep, and other animals that are outwardly healthy may be harbouring the infection, with the risk that BSE could still be getting into the food chain.
In a new study based on a mouse model, researchers at the Medical Research Council Prion Unit took a closer look at the species barrier, which limits the ability of prions to jump from one species to another (Proceedings of the National Academy of Sciences 2000;97:10248-53).
In the study, scientists tried to infect laboratory mice with hamster prions and saw no apparent signs of disease. But when they looked more closely they found that the mice had high levels of prion in their brains.
"Previously scientists have injected mice with the hamster disease, found no clinical signs of infection, and concluded it cannot jump the species barrier," said Dr Andrew Hill of the University of Melbourne, one of the authors of the study.
The team, led by Professor John Collinge, director of the MRC Prion Unit, also found that the new subinfection could be easily passed on when injected into healthy mice and hamsters.
"These results have a number of important implications. They suggest that we should rethink how we measure species barriers in the laboratory and that we should not assume that just because one species appears resistant to a strain of prions they have been exposed to, that they do not silently carry the infection," said Professor Collinge.
He continued: "These new findings have important implications for those researching prion disease, those responsible for preventing infected material getting into the food chain, and those considering how best to safeguard health and reduce the risk that, theoretically, prion disease could be contracted through medical and surgical procedures."

Countries or regions with a controlled BSE risk

EU Member States — Belgium, Bulgaria, the Czech Republic, Denmark, Germany, Estonia, Ireland, Greece, Spain, France, Italy, Cyprus, Latvia, Lithuania, Luxembourg, Hungary, Malta, the Netherlands, Austria, Poland, Portugal, Romania, Slovenia, Slovakia, the United Kingdom

EFTA countries — Switzerland, Liechtenstein

Third countries— Brazil, Canada, Chile, Taiwan, Mexico, United States