Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

MEDTEC Europe 2012: Implant to replace defective venous valve

01.03.2012
If heart valves don’t close properly, they are replaced. Conventional treatment of venous valve failure, however, has up to now always and exclusively been via medication. In future, an implant will assume the function of damaged valves – and a new dispensing tool means these prostheses can be made using an automated process.

It’s one of the most commonly occurring medical conditions – chronic venous in-sufficiency (CVI). Almost ten million German citizens suffer from weak veins that require treatment, with twice as many women being affected as men. The cause of this widespread condition is restricted functioning of the venous valves in the legs.


The finished venous valve is highly durable. © Helmholtz-Institute of Biomedical Engineering of RWTH Aachen

If the venous valve is no longer able to close properly, blood will observe the laws of gravity in between heartbeats and flow down to collect in the legs. This leads to edemas, and can cause open ulcers in particularly severe cases. CVI is usually treated with anti-inflammatory drugs and diuretics; as yet there is no globally available venous valve implant that can be used to treat the illness.

This is something that researchers from the Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart are setting out to change: In close collaboration with four industrial partners and Helmholtz-Institute for Biomedical Engineering of RWTH Aachen University, they have developed an automated production facility that can make venous valve prostheses from polycarbonate-urethane (PCU), a plastic. The project was sponsored by the German Federal Ministry of Economics and Technology BMWI.

The centerpiece of the facility is a 3D droplet dispensing tool which enables the researchers to precisely apply a particular polymer onto freeform surfaces and at the same time combine various grades of polymer hardness, called Shore hardnesses. “3D droplet dispensing technology is an additive procedure that allows three-dimensional geometries to be created layer by layer using a polymer”, explains Dr. Oliver Schwarz, group manager at the IPA. The scientists use PCU because it is particularly strong and flexible, while another useful property of the material is that it is easy to sew into surrounding tissue. PCU structures can be made in very thin layers, which is ideal when replacing wafer-thin atrioventricular valves. “By using PCU in combination with our 3D dispensing kinematics, we can achieve seamless transitions within the material between six different grades of elasticity and hardness – without any breaking points whatsoever. This technique mirrors the design of highly stressed structures in nature. It can’t be done using injection molding”, says Schwarz.

But how does the PCU become a venous valve prosthesis? Initially, the polymers are dissolved in a solvent and deposited onto a venous valve prosthetic mold one droplet at a time, using the dispensing tool. The system is accurate to within 25 micrometers, and can deliver up to 100 droplets per second, each with a volume of 2 to 60 nanoliters. A six-axis kinematic system positions the piezo feeder precisely above the mold. Once it is fully coated with droplets, the mold is bathed in a warm stream of nitrogen. This causes the solvent to evaporate, leaving the polymer behind. Further layers are applied by repeating the dispensing process, and in the end the polymer prosthesis can simply be peeled from the mold. Doctors can take the finished replacement valves and implant them into the veins of the leg via a catheter passed through the skin.

The production facility comprises numerous other components besides the dispenser. The IPA experts are responsible for, amongst other things, the filling and monitoring system, the drying facilities, the entire clean-room box and the control mechanism for the six-axis kinematic system. “We have successfully managed to re-program the Beckhoff control system normally used with milling machines in such a way that it can now be used with additive processes,” Schwarz is happy to report. The solution they have come up with will soon see the researcher and his team in a position to produce thin-walled, highly durable implants such as heart valves or intervertebral disks. The IPA scientists will be presenting a prototype of their 3D droplet dispenser at the MEDTEC Europe 2012 trade fair from March 13 – 15 in Stuttgart (Hall 6, Booth 6211).

Dr. rer. nat. Oliver Schwarz | Fraunhofer Research News
Further information:
http://www.fraunhofer.de/en/press/research-news/2012/march/implant-to-replace-defective-venous-valve.html

More articles from Medical Engineering:

nachricht Visualizing gene expression with MRI
23.12.2016 | California Institute of Technology

nachricht Illuminating cancer: Researchers invent a pH threshold sensor to improve cancer surgery
21.12.2016 | UT Southwestern Medical Center

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Tracking movement of immune cells identifies key first steps in inflammatory arthritis

23.01.2017 | Health and Medicine

Electrocatalysis can advance green transition

23.01.2017 | Physics and Astronomy

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>