Traditional memory materials remember one shape at one temperature and a second shape at a different temperature. Until now, they have been limited to change shape at only one temperature. The Waterloo technology stretches their memory banks allowing them to remember multiple memories, each with a different shape.

“We have developed a technology that embeds several memories in a monolithic smart material,” explains Ibraheem Khan, a research engineer and graduate student working with Norman Zhou, a professor of mechanical and mechatronics engineering. “In essence, a single material can be programmed to remember more shapes, making it smarter than previous technologies.”

The patent pending technology, which is available for licensing, allows virtually any memory material to be quickly and easily embedded with additional local memories.

The transition zone area can be as small as a few microns in width with multiple zones, each having a discrete transition temperature. As the processed shape memory material is subject to changing temperature, each treated zone will change shape at its respective transition temperature. As well, transition zones created side-by-side allow for a unique and smooth shape change in response to changing temperature.

Several prototypes have been developed to demonstrate this pioneering technology. One such prototype mimics a transformer robot. A video demonstrating the miniature robot can be seen below.

The engineering technology was developed in the Centre for Advanced Materials Joining, based in Waterloo’s department of mechanical and mechatronics engineering.

People suffering from age-related macular degeneration and retinitis pigmentosa gradually go blind. Developers of intraocular implants, notes the article, are looking for ways to stimulate the remaining functional nerve endings within the retina to recreate vision. One type of device currently under development places a miniature video camera in a special pair of glasses to capture the scene in front of the patient. The resultant electrical signals are sent to a signal processor on the patient’s hip where they are converted into digital video data. The eyeglass assembly also contains an inductive coil for data and power transmission into the eye. A companion coil and electronics package within the eye convert the video data stream from thehip processor into signals that are scanned onto an electrode matrix attached to the retina. The electrode matrix stimulates the retinal nerves, producing an image in a manner similar to the way a video monitor creates a picture. The retina nerve endings send the image to the brain and the patient can again see. Parylene is an ideal coating for this type of device, according to the company, because it protects the device from the eye’s fluids and chemistry as it protects the eye from the device.

Suncica Canic, a professor at the University of Houston, uses computer models to design stents. Here, a 3-D computer model of a stent. Credit: Suncica Canic, Mate Kosor and Josip Tambaca; University of Houston and University of Zagreb

Even though stents are designed to be compatible with the human body, they sometimes cause unwanted reactions such as blood clots and scar tissue formation, explains Stephanie Dutchen from the NIGMS/NIH. So, scientists have tried to coat stents with cells that make the tiny tubes even more compatible. But these, too, aren’t yet perfect, says Suncica Canic, a professor of mathematics at the University of Houston. Blood flowing over a coated stent can still clot or tear cells away. This is, as Canic put it, “not good.” Supported by a joint grant from the National Science Foundation (NSF) and the National Institutes of Health’s National Institute of General Medical Science (NIH/NIGMS), Cancic makes computer models to guide the search for a better stent coating.

She also uses computer models to study the strengths and weaknesses of different stent structures. Her work could help manufacturers optimise stent design and help doctors choose the right stents for their patients, ultimately improving patient outcomes.

Computer scientists usually model stents in three dimensions. Keeping track of about 200,000 points, or nodes, along the stent mesh, the models are massive.

Together with her collaborator, Josip Tambaca of the University of Zagreb in Croatia, and her doctoral student, Mate Kosor, Canic wrote a much simpler program that approximates stents as meshes of one-dimensional rods. This program let the researchers achieve the same result using just 400 nodes.

Using their simplified model, the researchers have examined the designs of several stents on the market to see which structures seem to be best for specific blood vessels or procedures. For instance, they found that stents with an “open design”—where every other horizontal rod is taken out—bend easily, which makes them good to put in curvy coronary arteries.

Canic and Tambaca have also used the model to design a stent with mechanical properties specifically tailored to an experimental heart-valve replacement procedure. She found that this specialised stent works best for the procedure when it’s stiff in the middle and less stiff at the ends. In addition, she has found that combining “bendiness” with radial stiffness—where you can bend the stent into a U shape, but you can’t squeeze the tube shut—produces a stent with less chance of buckling than those that are currently in use.

More information on the research is available from the National Science Foundation.

So far, the detection analyses of these cells have been performed in medical laboratories requiring labor-intensive, expensive and time-consuming sample processing and cell isolation steps. A full tumor cell detection analysis can take more than a day. According to a press release issued by imec yesterday, lab-on-chip, integrating the many processing steps, would enable a faster, easy-to-use, cost-effective detection of tumor cells in blood.

Within the framework of the MIRACLE project, imec as project coordinator, collaborates with the Universitat Rovira I Virgili (Spain), the Institut für Mikrotechnik Mainz, AdnaGen, ThinXXs and Consultech (Germany), MRC Holland (The Netherlands), the Oslo University Hospital (Norway), the KTH Royal Institute of Technology, Multi-D and Fujirebio Diagnostics (Sweden), ECCO – the European CanCer Organisation and ICsense (Belgium) and Labman (UK). The project aims at developing a fully automated and integrated microsystem providing the genotype (gene expression profile) of CTCs and DTCs starting from clinical samples. MIRACLE is partly funded by the European Commission (FP7-ICT-2009.3.9).

The EC report confirms that even with all the evidence and scientific opinion available, “it is not possible to quantify the risk associated with the use of reprocessed single-use medical devices.” The Commission also took a calibrated approach to the ethics involved: the balance between informed consent of patients and cost saving to the healthcare system could not be determined. It should be noted that the document was never intended to draft policy measures, which will be addressed within the context of the recast of the medical device directives. In other words, stay tuned.

For more on this issue, you may be interested in reading an editorial I wrote, An Inconvenient Truth about Reprocessing Single-Use Devices, along with a sternly worded retort from the Association of Medical Device Reprocessors.

Further details are can be accessed in a white paper on the reuse of single-use devices from Eucomed and scientific opinion from the Scientific Committee on Emerging and Newly Identified Health Risks.

The Ambient Assisted Living Forum is an annual international conference under the Ambient Assisted Living Joint Programme (AAL JP). The conference serves as an information and discussion platform for stakeholders, scientists and users in Europe. AAL JP is a European programme with the main objective to improve the quality of life for elderly citizens through the development of age-sensitive ICT (Information and Communication Technologies).

You can register for the event on the AAL Forum 2010 website.

Babak Ziaie, a professor at Purdue University shows a new type of pump for drug-delivery patches that might use arrays of microneedles to deliver a wider range of medications than now possible with conventional patches. Image source: Mark Simons/Purdue University

Researchers at Purdue University have developed a new type of pump for drug-delivery patches that might use arrays of “microneedles” to deliver a wider range of medications than now possible with conventional patches. The current “transdermal” patches are limited to delivering drugs that, like nicotine, are made of small hydrophobic molecules that can be absorbed through the skin, says Babak Ziaie, a professor of electrical and computer engineering and biomedical engineering.

“There are only a handful of drugs that currently can be administered with patches,” he says. “Most new drugs are large molecules that won’t go through the skin. And a lot of drugs, such as those for treating cancer and autoimmune disorders, you can’t take orally because they aren’t absorbed into the blood system through the digestive tract.”

Patches that used arrays of tiny microneedles could deliver a multitude of drugs, and the needles do not cause pain because they barely penetrate the skin, he says. ”It’s like a bandage – you would use it and discard,” Ziaie says.

Purdue doctoral student Charilaos Mousoulis demonstrates a prototype pump for drug-delivery patches Image source: Birck Nanotechnology Center / Purdue University

The patches require a pump to push the drugs through the narrow needles, which have a diameter of about 20 microns, or roughly one-fourth as wide as a human hair. However, pumps on the market are too complex for patches, he says.

“We have developed a simple pump that’s activated by touch from the heat of your finger and requires no battery,” Ziaie says. The pump contains a liquid that boils at body temperature so that the heat from a finger’s touch causes it to rapidly turn to a vapor, exerting enough pressure to force drugs through the microneedles. ”It takes 20 to 30 seconds,” Ziaie said.

The liquid is contained in a pouch separated from the drug by a thin membrane made of a rubberlike polymer, called polydimethylsiloxane, which is used as diaphragms in pumps.

Research findings are detailed in a paper being presented during the 14th International Conference on Miniaturized Systems for Chemistry and Life Sciences on 3–7 October at University of Groningen in The Netherlands.

More information on the research is available from Purdue University.

The press release issued by Clariant notes that ICSE visitors will be the first to discover how its controlled, compliant and consistent products deliver colour and functionality whilst minimising the risks and costs of noncompliance.

The new brand will be produced at Clariant’s three centres of competence dedicated to the production of specialty formulated master batches and compounds for medical and pharmaceutical applications. The company expects to achieve full ISO 13485:2003 accreditation, having already gained accreditation for two out of the three sites. Located in the United States, Europe and Asia, the plants feature manufacturing-line segregation to reduce risk of cross contamination between products. Consistency and reliability of formulations and procedures is ensured through alignment with the globally harmonised quality management system.

The company will introduce a range of globally harmonised standard colours for PP and PE as well as PEBA materials at the event. The ingredients have been biologically evaluated according to ISO 10993 and USP parts 87 and 88 (Class VI). Clariant’s laser marking and friction-reduction capabilities also will be highlighted at ICSE 2010.

A ring-like polymer molecule was stretched by an ultrasonic process and then sprung back to be smaller than it was initially (right).

A research team from Duke University and Stanford University has found a polymer molecule that’s so springy it snaps back from stretching much smaller than it was before. Duke graduate student Jeremy Lenhardt and associate professor Stephen Craig have been systematically hunting through a library of polymers in search of a molecule that might be useful for “self-healing” materials. They hope to find a polymer that can trigger a chemical reaction when it is stretched and enable a material to build its own repairs.

Imagine a sheet of plastic wrap that could fix a microscopic puncture before the hole ever got big enough to see. This would require that the polymer molecules immediately around the tear could somehow jump into action and perform new chemistry to build bridges across the hole.

To stretch polymers and see what happens to them, Lenhardt uses an apparatus that pumps up and down on a solution filled with polymers, pressurising it and depressurising it 20,000 times a second which causes tiny bubbles to form fleetingly. The void created by the bubbles exerts a tug on the ends of some of the polymers in the solution and stretches them, if only for a billionth of a second.

“Think of two rafts going down a river with a rope between them,” Craig explains. “As the first raft enters a rapids and accelerates forward, that rope – the polymer – gets pulled taught and stretches.”

Over and over Lenhardt ran the experiment, characterizing different polymer species that became more reactive when stretched, potentially able to do “stress-induced chemistry.”

Then, while looking at polymers that contained tiny ring-shaped molecules called gem-difluorocyclopropanes (gDFC), he was surprised to find that some of these molecules emerged from the stretching noticeably shorter than when they went in.

“I ran up to his office,” Lenhardt says. ” ‘Steve, something funny is going on here. Look at this!’ ” A technique called nuclear magnetic resonance had revealed the shapes of the rings after pulling and shown that they were, in fact, shorter.

More information is available from Duke University.

“We are extremely pleased and grateful for the effort Sil-Pro employees put forth,” says Brian Higgins, Sil-Pro Vice President of Sales and Marketing. “Our primary business objective is to make Sil-Pro the leading supplier of custom silicone moulded components for the medical device industry. Our growth and the Boston Scientific award are evidence that we are achieving our goals.”
Sil-Pro has been a supplier of silicone moulded components to Boston Scientific for more than 10 years. The company provides liquid silicone moulding, gum stock moulding, silicone extrusion and thermoplastic injection moulding services. In addition, it uses medical grade adhesives to bond silicone parts to plastics, metal and other silicone parts. Other services offered by the firm include in-house mould design, automation, subassembly and packaging.