Medical Device Daily Contributing Writer

STUTTGART, Germany — “Ideas about nanotechnologies are far more numerous than nano-products,” noted Professor J rge Vienken during his presentation at MEDTEC Stuttgart last week

Before an audience that included some who have won international reputation for their mastery in machining devices measured in microns, or one-millionth of a meter, Vienken offered a tour de force of recently developed materials used for medical devices that are measured a full magnitude lower at one-billionth of a meter, or in nanos.

Vienken, who is VP of biosciences at Fresenius Medical Care (Bad Homburg, Germany), was part of a day-long session at MEDTEC devoted to “Materials and Nanotechnology” that ran parallel with sessions on advanced manufacturing.

The question posed by this professor from the laboratory to the nuts-and-bolts manufacturers fresh off the shop floor was wonderfully blunt: “How can we work with these materials when microscopes do not have the resolutions to see these elements?

“We need tools,” he said, pointing to an image representing an impossibly tiny nano fiber emerging from an extrusion nozzle with a pair of scissors super-imposed.

The issue is no longer academic. As applications for nanotechnologies in diagnostics and therapies move from the possible to the proven in laboratory projects, the medical device industry faces an emerging, and disruptive, challenge to a core competency.

Another presenter at the MEDTEC conference, Ottilia Saxl, CEO of the University of Stirling’s (Stirling, Scotland) Institute of Nanotechnology, said the ability to create and use nanocomposites for specific medical applications is leading to a transformation of the device industry.

“Of course nano tools exist, or you could not build a nano part,” was the response of an engineer, though a discussion followed as to whether micron-level tooling was being used to modify materials at a nano-level.

“We do not do nano,” said an engineer from Rofin/Baasel Lasertech (Starnberg, Germany), quickly adding, “but we can do nanostructures, surface modifications to nano measures for roughness, for example.”

Another engineer in the audience asked, “Why would you need scissors? Even nano-scissors would damage nano fibers. Just cut it with a laser.”

“You are going to need a robot and a hexapod,” said another.

Vienken presented surface manipulations as the first practical applications in the case of implants that while large, have “areas of concern for nano manipulations are quite small to encourage attachment of cells, for the coating of surfaces, for creating structures to attach pockets for drug agents”

But he added, “These are not so easy to do.”

Gregory Flynn, of SPI Lasers (Southhampton, UK), said flatly that a nano laser tool is impossible. “You would need sub-wave lengths for that. Using ordinary optics you cannot achieve the sub-wavelength focal spots. The laser we are displaying is 1,000 nanometers and the best lasers might reach to 500 nanometers, though a realistic beam focus is a few microns.”

At Teledyne Medical Microsystems (Los Angeles), Ilya Grigorov, PhD, manager for business development and engineering, said, “We work from the semiconductor level up, not down to the level of semiconductor processing. Though I recently chaired a session on nanotechnologies and can tell you while nano is there for pharmaceuticals, that is not machinery. This is self-organized chemistry.”

In other news from MEDTEC:

• “Tyvek is big in the U.S., but here in Europe our customers are trying to reduce expenses,” said Michel Terwolbeck, business manager with Wipak Medical (Nastola, Finland), which presented a new see-through line of bags.

For single-use items used in the surgical theater, such as drapes, gowns and large disposable instrument trays, Wipak presented the multi-layer polyethelene Steriking Window Bags sealed with a single strip of Tyvek rather than the full top web. The Tyvek provides a breathable surface at the narrow edge of the bag, to allow a sterilizing medium such as ethylene oxide to penetrate, and provides the familiar peelable opening.

Reducing the Tyvek to a single strip considerably reduces cost, the company says. The layered film also is stronger, greatly enhancing puncture resistance. Another plus for the design is the full transparency of OR bag contents.

• Kobusch-Sengewald (Warburg, Germany) was presenting the SterileVent line from its sister company, MultiVac (Kansas City, Missouri), that claims to reduces costs 80% over traditional Tyvek construction. But the company also promoted its own deep draw pack where the bottom web film carries the adhesive rather than the top web, which it says further reduces the cost of Tyvek for customers and requires less curing time.

• Nanon (Br ndby, Denmark), a specialist in nanoscale manipulation of polymers, brought to MEDTEC Stuttgart a new surface material direct from the nearby Mercedes-Benz factories. The switches mounted on the steering wheel of new Mercedes models feature Nanon’s Softplasma, a silicon rubber molecularly modified so it can be tinted, coated, painted or glued. It also can be designed to accommodate backlighting.

The soft and durable surface is created through a low-energy modification of the surface properties of silicone rubber. The surface is polymerize with a 12-nanometer to 20-nanometer layer to increase surface tension and provide sufficient adhesion of a polyurethane coating. A Nanon executive said the company is currently running tests for prospective customers to apply the surface material to medical devices.

Nano also presented an environmentally friendlier method for post-production curing of silicon rubber components for medical devices. ColdCuring is a low-energy and lower-cost “washing machine” that recycles its waste. Liquid carbon dioxide is the extraction agent, as effective as hydrocarbons such as acetone, but without the toxicity. It cleans up a traditionally “messy process,” said a company spokesman, because it is non-corrosive, non-flammable and safer to work with.

• Morgan Advanced Ceramics (Stourport, UK) displayed a new range of 36 mm-diameter femoral heads and acetabular cups to meet what it called an increasing demand for bigger, better joint stability in hip replacement surgery. The upsizing of the company’s HIP Vitox line aims to reduce recurrent dislocations and the risk of product fracture for patients needing a larger femoral heads. A biocompatible alumina-ceramic construction exhibits exceptionally low wear rates, according to the company.

• The Baasel Lasertech division of Rofin (Hamburg, Germany) presented a new-generation StarCut Tube, a laser system for cutting medical implants, especially stents. The technology contained in the all-in-one housing can cut a coronary stent of 8 mm length in less than 1 minute, 10 times faster than the original launched a decade ago.

Lasers can be specified to achieve cutting widths below 15 microns. Laser, controls, drives with supply modules and automated tube loading are built into the unit that has a pressure capacity up to 25 bar. The unit features a high-quality stereo microscope. A camera to view processes is available with an upgrade option.

• Further minimizing the minimally invasive treatment of the body’s smallest vasculatures such as the neurovascular system, Creganna Medical Devices (Galway, Ireland), presented Microflex. The micro tube, shown being threaded through the eye of a sewing needle, is available in OD ranges of 0.013” or less and features stainless steel design and single-piece construction with variable transition of lateral stiffness along its length.