Nanotechnology: One of the Keys for the 21st Century
by Wiebke Heiss / MEDICA.de
Other laws rule the world where everything is smaller than one hundred nanometres. Scientists start to discover and to employ them. Why? A huge market - also for medical products - is predicted for the next decades.01/09/2008
Nanotechnology has already been used in ancient times - the people back then just did not know about it. It must have been by accident that the Romans discovered how to colour glas in a special way: Just mix small amounts of gold into molten glass and heat it up again for a few hours. Today scientists know that - through this process - gold particles aggregate in nanometre size which break light in a way that the glass appears to glow in ruby.
Particles and tubes in nanometre size are also relevant in everyday life of modern man, for example, in varnish, wheels and sunscreen. However, experts are convinced that they will become a lot more important in future times than already and they talk about nanotechnology being one of the key technologies of the 21st century. The National Science Foundation in the USA, for example, assumes that the market volume will reach one billion US-dollars in 2015. The most important areas being affected: environment and energy, information and communication technology and medicine.
Millions are being invested in research and development
„Nanotechnology promises great progress in medicine for diagnostics and therapy“, Dr. Viola Klamroth says, press officer of the German Federal Ministry of Education and Research (BMBF). „That is especially true for widespread maladies such as cardiovascular diseases and age-related degenerative illnesses of the neurological system.“ These are some reasons why research concerned with nanomaterial and -technologies is being state-aided: Germany pays for an initiative called NanoforLife 27 million Euros from 2005 until 2009 and for the technology initiative Molecular Imaging 150 million Euros for the next ten years – the industry is going to participate with an additional 750 million.
One nanometre versus one metre equals cent next to Earth
© Pixelio.de
The research aims at a better understanding of the incomprehensible nanosized world: If one compares a nanometre to a metre than the same relation applies to a one cent piece next to the Earth. These are dimensions so small that instead of the classical principles of physics the rules of quantum mechanics apply. Objects in nanosize consist almost only of surface: A spherical particle's surface with a diametre of 3 nanometres combines 50 per cent of the atoms. Magnetic, electronic, optical, thermal or thermodynamic properties change completely. Materials in nano size behave different to materials on the macro scale – seldom predictable.
Biochemist Andreas Jordan experienced this at the beginning of the 90s when he worked as a Doktor at the Charité in Berlin trying to develop a new approach to combat cancer. His idea: „Deliver things into the tumour and heat them up on location to kill cancer cells without harming surrounding healthy tissue“, Christofer Radic explains, press officer of MagForce Nanotechnologies, a business founded by Jordan that is dedicated to producing everything involved in his idea.
Magnetic particles against cancer
„At that time nobody was really concerned with nanoparticles“, says Radic. Jordan randomly did experiments with particles of different sizes until a sample arrived from Japan – a test tube filled with a liquid. The biochemist applied a magnetic field to it and the test tube heated up until it burst. „It turned out that this effect was due to nanoparticles“, Radic explains. This was the beginning of thermotherapy using magnetic nanoparticles. The method works by injecting iron oxide particles into a brain tumour which are then taken up by cancer cells. By applying a magnetic alternating field near the patient's head the magnetic particles start to swing back and forth, they heat up, the temperature in the tumour rises to over 70 degrees Celsius and the cancer cells die.
Currently patients with brain tumours are being treated in clinical studies. „The results are promising so far“, Radic reveals. „We expect approval for the treatment of glioblastoma at the beginning of 2010.“ However, the companies plans more: It would like to complement cancer therapy in the whole, because thermotherapy using magnetic nanoparticles could "in principal be applicable to any body region". Radic: „In the long run we regard our therapy as being the fourth column in the treatment of cancer next to chemotherapy, radiation and surgery.“
2nd Part: Medical products more compatible for body
However, nanoparticles are able to achieve even more: Nano sized carriers are supposed to transport drugs to a sick organ without harming healthy ones or to cross biological barriers like the blood-brain barrier - important for treating Alzheimer's, Parkinson's or epilepsy. New contrast agents could one day revolutionize clinical diagnostics. The theory: Nanoparticles bind to specific diseased cells and help to identify cardiovascular diseases or they could support physicians by estimating the risk that emanates from a tumour. And some day, researchers would like to practice early stage diagnosis that would not be possible any earlier: they are aiming at observing molecules in the cell. If something went wrong there, it could be evaluated as a warning against serious future diseases.
Additionally, nanotechnology can also help to render prostheses more biocompatible. Hip joints made of steel or dental implants made of titan need to be incorporated properly into the bone. This is also true for artificial cornea implants - though they need to be adhered to living tissue. Joachim Storsberg from the Fraunhofer Institute for Applied Polymer Research in Potsdam, Germany develops ultra thin films in order to tackle a great problem: the base material an artificial cornea is made of repels water and human cells – that is important because the carrier needs to be able to see through the optical part of the implant. „The edges of the artificial cornea on the other hand must adhere well to the natural tissue surrounding it and needs to accept tears on the anterior optical part“, Storsberg explains.
In-vitro cell culture test: The artificial cornes's left side is
colonised by natural cells, the optical part on the right side
remains free; © Fraunhofer IAP
Biocompatible and bio-integrable surfaces are the solution. With the help of nanotechnological procedures the chemist coats the cornea's edges with a special protein that triggers the cells of the remaining natural cornea to settle down. „The optical part is covered by an ultra thin hydrophilic polymer film“, Storsberg explains. That way tears are not repelled on the outside of the cornea.
New competition through businesses normally not connected to medicine
Nanotechnology does not only change the physician's everyday life, it also changes working conditions for manufacturers of medical products. „Nanotechnology creates new competitive situations since businesses enter the medical market that previously did not concern themselves with medicine“, Andreas Greiner observes. The professor for macromolecular chemistry and technology at the University of Marburg works on new methods for regenerative medicine. „Companies primarily concerned with chemistry get in on, for example, tissue engineering.“ Nanotechnology - not being a classical technology with defined boundaries - starts to merge researchers and businesses from different areas - let it be medicine, electronics, optics or material sciences.
Electrospinning, for example, has once been patented for producing artificial silk using electrical charges. Today the procedure is being applied in regenerative medicine - in a modified manner. „We manufacture nanofibres with electrospinning that are being used as a film for surgical dressings amongst other things. But it is also used for creating scaffolds in tissue engineering“, Greiner explains. Previously it had turned out that cells grow better on thin fibres than on others.
Support for cells: Nanofibres made of collagen (l.) and
chitosan (r.); © Angewandte Chemie
The procedure works by applying a strong electrical field to a droplet of a polymer solution at the tip of a conductive die. The charging of the fluid leads to the ejection of a fluid jet from the tip of the cone. The charged jet is accelerated toward the counter electrode and thins rapidly during this period due to elongation and evaporation of the solvent until solid fibers are deposited onto the substrate located on top of the counter electrode. „This is a very complex procedure and it is at present the only technique that makes it possible to produce endless fibres with a diameter of only a few nanometres“, Greiner says. However, the process has not been implemented yet in practice but Greiner and colleagues pursue this goal for the near future.
3rd Part: Check with the Risks first
However, many new medical developments originating from the nanoworld often have to wait for implementation in the market. The reason: „The industry keeps awaiting results that determine possible risks emanating from nanotechnology first. Especially in medicine, the danger for people is of greatest importance“, Professor Harald Krug says, a toxicologist from the University of Bern in Switzerland. He and colleagues investigate the influence of nanoparticles or nanotubes on living tissue and the human body. In this context, the German Federal Ministry of Education and Research funds the research project called NanoCare.
Innovation barrier through unknown health risks
„We need to take a very close look if nanomaterials are able to enter the human body“, says Krug. That is why strict guidelines and intensive research are import - in advance. „From the viewpoint of a toxicologist it is theoretically possible that most nanomaterials can enter the body due to their very small size.“ Results from previous studies investigating the risk of nanotechnology are not satisfactory. „In future, we need standardised studies and - most of all - studies that are comparable. We are preparing for that at the moment.“ Krug thinks that clear arrangements and guidelines for research are going to be determined during the next two years. „The number of utilisable studies will rise intensively from next year.“
„Hopes are high to use nanotechnology in technical, biological and medical areas“, Krug adds. And those hopes are not going to be dashed. Even though some visions will not be realised in the end, many application will enrich human's lives in future. Krug's attitude towards nanotechnology is very positive. „We should avoid mistakes but I do not recognize any severe problems from my perspective.“
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Replacement: New Knee for Obese Beneficial
New research has shown that there is no justification for denying obese patients knee replacement surgery. The research shows that obese people can benefit almost as much as anyone else from the procedure. 21/08/2008
Obese or not is no criterion for or
against a knee replacement;
© Giovanni Borea/Pixelio.de
Around 55,000 knee replacements are performed each year in England to relieve the pain and disability of knee osteoarthritis, according to the researchers. However, they state, in some parts of the country, surgery is offered only to patients who are not clinically obese on the grounds that obesity is itself a risk factor for knee osteoarthritis.
The research team reached its conclusions following a six-year study of two groups of people, all over the age of 45. The first group (325 people) had all had knee replacement surgery and the second group (363 people) had not. At the start and end of the study, all participants completed a validated questionnaire designed to assess their mobility, mental health and wellbeing.
The findings showed that, overall, the mobility of those who had had knee replacement surgery improved over the six years of the study, while it fell in the comparison group. When researchers restricted their analysis to those participants who were clinically obese (those who have a body mass index (BMI) of above 30 kg/m2), improvements in mobility appeared to persist and BMI was not a significant predictor of this improvement.
Professor Cyrus Cooper, Director of the ERC and Professor of Rheumatology at the University of Southampton, said: "The long-term improvement in physical function that we observed in patients who have undergone knee replacement surgery is striking when set against the decline that occurred in the comparison group.
"These benefits extended to those patients who were clinically obese. Our results show that as long as appropriate selection criteria are applied with regard to fitness for surgery, there seems little justification for withholding the operation from patients who are obese."
MEDICA.de; Source: University of Southampton
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Atherosclerosis: Brushing Teeth Means a Healthier Heart
Researchers have discovered a new link between gum disease and heart disease. A molecular mimicry might cause atherosclerosis. 09/09/2008
Well-brushed teeth protect the
heart; © SXC
Already around 50 studies link gum disease with heart disease and stroke. "A number of theories have been put forward to explain the link between oral infection and heart disease," said Professor Greg Seymour from the University of Otago Dunedin, New Zealand.
In recent years chronic infections have been associated with a disease that causes "furring" of the arteries, called atherosclerosis. Seymour: "One of the theories is that certain proteins from bacteria initiate atherosclerosis and help it progress. We wanted to see if this is the case, so we looked at the role of heat shock proteins."
Heat shock proteins are produced by bacteria as well as animals and plants. They are produced after cells are exposed to different kinds of stress conditions, such as inflammation, toxins, starvation and oxygen and water deprivation. Because of this, heat shock proteins are also referred to as stress proteins. They can work as chaperone molecules, stabilising other proteins, helping to fold them and transport them across cell membranes. Some also bind to foreign antigens and present them to immune cells.
Because heat shock proteins are produced by humans as well as bacteria, the immune system may not be able to differentiate between those from the body and those from invading pathogens. This can lead the immune system to launch an attack on its own proteins. "When this happens, white blood cells can build up in the tissues of the arteries, causing atherosclerosis," said Professor Seymour.
"We found white blood cells called T cells in the lesions of arteries in patients affected by atherosclerosis. These T cells were able to bind to host heat shock proteins as well as those from bacteria that cause gum disease. This suggests that the similarity between the proteins could be the link between oral infection and atherosclerosis," said Professor Seymour. This molecular mimicry means that when the immune system reacts to oral infection, it also attacks host proteins, causing arterial disease.
MEDICA.de; Source: Society for General Microbiology
