Nanomedicine: nanoparticles in medicine

Nanomedicine: nanoparticles in medicine

What is nanomedicine? Nanos means dwarf in Greek. So dwarf medicine? What is meant is a technique that treats the smallest structures in the body and uses the smallest materials to treat diseases.

Definition

It's about structures that are 10,000 times smaller than the average of a human hair, a nanometer is a millionth of a millimeter. Various artificially produced nanoproducts already exist today - there are, for example, nanoparticles made of titanium dioxide in sunscreen, silver nanoparticles in clothing, and in food packaging.

The EU Commission defines: "Nanomaterial is a natural, process-generated or manufactured material that contains particles in an unbound state, as an aggregate or as an agglomerate and in which at least 50 percent of the particles have one or more external dimensions in the number size distribution in the range of 1 Have nanometers to 100 nanometers. (…) Deviating (…), fullerenes, graphene flakes and single-walled carbon nanotubes with one or more external dimensions below 1 nanometer are to be considered as nanomaterials. ”

First, nanotechnology should produce things smaller and smaller and therefore more precisely. Second, it provides access to atoms and molecules and can thus create new materials and entire material systems.

There are natural nanoparticles such as soot particles, proteins in the blood or fat particles in milk. Researchers either create synthetic nanoparticles on purpose or as a side effect, for example when diesel burns.

What is special about nano?

Nano-structures develop special functions at the level of atoms and molecules, both in animate and inanimate matter. The past decades have been shaped by research on it: the first thing was to capture nanosystems.

Today, scientists apply this knowledge in living systems - this is the basis of Naon medicine. Like any new technique that interferes with the body, it also involves risks: for example, nanocapsules are supposed to use medication in the body exactly where the illnesses are located, and this promises huge advances in cancer medicine, for example. However, these nanoparticles could penetrate cell walls, collect in the body or ignite the respiratory tract.

Common nanomaterials

Nanosilver: Silver kills germs, and science uses this in nanoparticles, for example as a surface layer on door handles, in wound dressings or in textiles - nanosilver helps against the smell of sweat.

Soot particles can be produced artificially to serve as a black pigment in colors, but also as an antistatic additive in plastics.

Carbon nanotubes are constructed from carbon, are very stable and thus secure plastics. Today you can find them in top class bicycles.

Titanium dioxide refines surfaces to repel dirt. It promotes the decomposition of organic materials by sunlight and keeps the color of building facades clean, for example.

Nanoparticles in zinc oxide absorb the UV radiation from the sun and are therefore found in sunscreen. The industry also uses it in liquid crystal displays or LEDs. Zinc oxide coatings also promote the effect of solar cells.

Nanomedicine

The American visionary Robert Freitas sees nanomedicine as a golden age: nanorobots in the near future are supposed to repair gene damage, artificially produced red blood cells prevent heart attacks - nanomachines then kill viruses, repair cells or charge the blood with oxygen.

Medicine promises a lot from nanotechnology. More than 100 drugs already contain nanoparticles, as well as diagnostic methods and devices that work with nanoparticles. Drugs are less about new active ingredients than new efficacy: nanocapsules, which only release the substances in the environment of certain molecules, are supposed to transport the active ingredients directly to their destination.

Many doctors expect a milestone in medicine for the therapy of neurological diseases that are related to blood and brain. Because nanoparticles can break through this “blood-brain barrier”. This opens up new perspectives, for example for Alzheimer's and Parkinson's, and possibly also for multiple sclerosis.

Devices, floors, walls and furniture in clinics with nanos could promote sterility. Resistant bacteria can probably be better controlled this way. Wound dressings already contain nano-silver, for example in the event of fire injuries.

Nanotechnology should also improve diagnostics: The nanoparticles are prepared so that they adhere to organs or cells. For example, tumor tissue can be identified with nano-iron oxide particles.

This leads to probable nanotherapies in the near future: in cancer medicine, nanotechnology will soon be used to identify and fight tumors. Today, doctors are already experimenting with cancer treatment in which magnetic nano-iron oxide particles electromagnetically heat the tumor and thereby destroy the cancer cells.

For example, nanocapsules could contain pancreatic cells, release insulin in the blood, and thus treat diabetes.

There is already a toothpaste, Theramed S.O.S. Sensitive based on nanoparticles. She builds up a layer of artificial tooth material with nanoparticles; so the teeth should feel less pain.

Hydroxyapatite is similar to the minerals in the bones and dental implants grow in half better, the nanomaterial shortens the process to up to two weeks, in contrast to conventional 2-4 months.

Nanoporous silicon or titanium dioxide is characterized by hole structures. These stimulate bone growth on the implants, stop inflammation by releasing active substances like a sponge.

Nanotechnology will undoubtedly become particularly important for other implantations, because surfaces made of nanoparticles can be better linked to biological organs and artificial devices than with conventional methods. Whether pacemakers or endoprostheses such as artificial knee, hip or shoulder joints: nano-layers are likely to reduce the body's defense against foreign bodies.

Hydroxyapatite can already be injected as a paste to build up bones. Such nanomaterial is well tolerated because it resembles the mineral components in the bone. The next step is to be hydrooxyapatites, which are combined with carbon nanotubes in a composite matrix and serve as bone cement.

Victims of accidents may soon benefit from replacement tissue in the form of glass-collagen composites in nano-format that support artificial skin and artificial bones. In addition, implants with nanotechnology are said to be more stable than conventional ones.

Already in 1998, the company Abraxis BioScience LLC in the USA performed clinical tests with nanomedicine against cancer. The Abaxane agent was finally approved. It consists of insoluble paclitaxel and albumin, this albumin binds to the protein SPARC, which is affected by pancreatic cancer - unlike other drugs.

Tekmira Pharmaceuticals from Canada developed nanos for liopsomes, which are thought to act against hypercholesterolemia in the liver. However, one of the test patients showed symptoms similar to that of the flu, and the experiment was then stopped.

The French Bioalliance Pharma used nanoparticles against liver cancer with the drug dexorubicin. However, three subjects died of lung problems.

Nanotherapy of brain tumors - hyperthermia - is approved in the EU. Iron oxide particles are injected into the brain and excited there with magnetic waves. They heat the tumor and thus kill it. Magnetic particle imaging (MPI) can also be used to film the heart and blood vessels.

Michael Bamberg of the German Cancer Society said: “Hyperthermia will become the fourth pillar of cancer therapy - alongside surgery, radiation therapy and chemotherapy. His idea is based on proven healing successes for breast cancer, skin cancer, tumors, intestinal and uterine cancer.

Rapid tests with nanosensors to detect cancer, nanohormone tests, nanobots to repair cells and nanoparticles to heal spinal cord injuries from paralyzed people are planned. Some researchers believe that they can give paraplegics a normal life. But it is still basic research.

Magnetic particle imaging

A new imaging technique, Magnetic Particle Imaging, was launched in 2005 by Philips Healthcare researchers. They presented three-dimensional films of hearts, vessels, and tumors, and no other method could do that.

This technique would make it possible to detect heart problems much faster than before. The doctor would only have to film the heart and its surroundings from the outside and could immediately identify damage to the heart wall or cardiac muscle weakness. All he has to do is inject magnetic nanoparticles into the patient. A conventional heart diagnosis, on the other hand, sometimes takes months.

Artificial organs

Nanotechnology makes you think about what was science fiction until recently, namely to artificially create organs and even organisms. Interdisciplinary researchers want to combine nanotechnology with biotech, information and cognitive science and thus create artificial intelligence or increase human capabilities beyond natural boundaries.

This is not a fixed idea, but already a reality. This is how skin and cartilage can now be produced artificially. With larger organs, nanoscience has so far failed to supply oxygen and nutrient cells. It doesn't work yet, so the cells die.

However, the Massachusetts Institute of Technology in Cambridge, USA is developing a method to solve precisely this problem. A computer designs a cell network pattern and etches it onto a silicon surface. This pattern is then transferred to biological material, two layers are placed on top of one another and sealed. The cells can adhere to this structure. The cells themselves are grown in petri dishes. The liver and kidney cells remained intact for two weeks.

The researchers planted a "nano-liver" with a layer of cells in rats. A liver needs around 30-50 such layers to function. The nano fabric survived for a week.

Nanotech and science fiction

Greg Bear established nanotechnology in science fiction as a central theme in 1985 with "Blood Music". A researcher grows molecules and teaches them some form of intelligence. He injects one of these cultures himself.

The nanobots are now multiplying and acting independently in the body: his visual acuity increases, he no longer suffers from colds. The nanos are constantly evolving and creating an ideal environment: from servants to rulers over their host bodies. They reprogram and control the researcher.

This has advantages for its inventor: The survival of the nanos depends on the health of the host body, and so they constantly improve its abilities.

But they do not change the host as it would be best for him, but rather how the nanoorganisms themselves have ideal living conditions. Now scientific progress is becoming a horror.

In “Lord of all things”, Andreas Eschbach invented self-sufficient nanorobots that kill cancer cells. “Virus-sized nano-cells that recognize cancer cells by their signatures. For control purposes, they are connected to the doctor via radio so that they cannot carry out incorrect actions; the wireless connection goes directly to the doctor's brain, which is traversed by nano-thick cables to guide the healing cells. They work as follows: The machines do not simply dissolve the cancer cells; that would be too dangerous because it would flood your body with more waste than it can drain. Instead, they penetrate the cell and trigger apoptosis, the cell's own mechanism of controlled self-destruction. Most of the remains are eaten up by your leukocytes. Everything that is left is transported by the submarines themselves, deposited in your bladder or intestine. "

Nanotechnology plays a role in many novels: as a central plot, as a side event or as a backdrop.

Bruce Sterling, an inventor of cyperpunk literature, has been focusing on nanotechnology in his vision of the future since the late 1990s. He sees himself as a futurist and said that with the breakthrough of the internet a lot had happened that he had written about in fiction - that's why he was now dealing with a technology that was just beginning.

In 2002, Michael Crichton, the author of Jurassic Park, published "Prey". Researchers in Nevada are developing nanocameras for the military. But they become self-employed and kill everything they come across. They multiply and manipulate the thoughts and motor skills of their inventors. The nanos develop into a super organism that copies the shape of people.

The nanos then behave like humans, they destroy the planet to get raw materials for their multiplication. Science fiction, which thinks further about what would be technically possible and designs a fictionally realistic scenario, was not “Prey”, but an old-fashioned story about “the ghosts that I called” by the Faustian man who no longer has his technical monsters under control.

By contrast, Angelika Fehrenbach wrote “The Lotus Effect”, a thriller that remains close to reality. A scientist at the University Hospital Marburg notices that a newly researched nanotechnology is risky when the laboratory rats die in rows. She realizes that those responsible are hiding something, does some research and soon fights for her life.

Jeff Carlsson published “Plague Year” in 2007, the work appeared in German a year later as “Nano”. Nanoparticles provide the background for a classic end time post. The plot is traditional: artificial intelligence becomes self-employed and kills its inventors.

These Frankenstein creatures are nano robots here. They multiply and kill all warm-blooded animals. People flee to the high mountains because the nanos don't work there. The survivors in the alpine winter meanwhile are fighting cold and hunger. They are trying to join a group on another summit that has more food and accommodation.

Carlson is well-versed in nanotechnology; however, this only provides the framework for the question: How do people behave in extreme situations?

Self-acting nanobots are a favorite idea of ​​science fiction. These roam the body and eliminate every poison, every tapeworm, they fix malformations of cells, heal internal injuries, they regenerate the cells and thus stop aging - and that every day for 24 hours.

If there were such nanomachines, we could even live unhealthily because they would immediately eliminate any damage.

Nanomedicine risks

American studies from 2002 showed potential savings in ovarian cancer from nanomaterials, mainly because those treated had fewer side effects from the nanoparticles. However, undesirable side effects were a massive problem, with 100,000 people dying from it in one year in the United States.

Little has been researched into the risks of nanotechnology, and it is unknown which companies use which nanosubstances. One problem is likely to involve nanoparticles that are released into the environment; they are smaller than fine dust and stay in the air for a long time.

Experts are therefore calling for a central registration register, in which nanosubstances are reported, and investigations into each individual substance.

Nanoparticles in filter systems probably do not pose any health risk in operation because they are sealed tightly in plastics. However, disposal will become problematic in the future, as there is a risk of a similar effort to that of asbestos.

All products with which nanoparticles are released into the environment should be avoided. For example, the nano-silver particles in certain socks dissolve the first time they are washed, get into the wastewater there and presumably damage bacteria in sewage treatment plants.

So far, nobody really knows how the risks of nano-material should be classified: is it about the size or are the properties of the substances important? Is it about the amount of substances in the environment as with other threshold values, or are the number and structure of the particles also decisive for the danger?

Most Europeans are hardly aware of nanotechnology, and every third person in Germany does not know what it is. Those to whom nanotechnology says something are usually positive about it.

It becomes clear that people who are familiar with the term nanotechnology have usually acquired their own knowledge about it and that is why they rarely devalue or support it without criticism.

Consumer protection associations are calling for nanoparticles to be removed from cosmetics and food until they can be classified as harmless. At Naturland, for example, nanoparticles are prohibited.

In Germany, nanomaterials can be regarded as both active and auxiliary substances, depending on how they are used. The German Medicines Act specifies what the safety checks look like, i.e. both the advisory procedures and the clinical tests before approval, the approval procedures themselves and monitoring and reporting after approval.

Ethics committees must approve clinical tests. The German Federal Institute for Drugs and Medical Devices monitors the approval.

The crossing of the blood-brain barrier is particularly controversial. Although it makes it possible to improve the brain performance of Alzheimer's patients, it can also be used to improve performance in people who are not therapeutically induced - with unforeseeable side effects.

The EU bans research on methods to develop materials to improve healthy people. The ethics committees pay particular attention to military use: Nanotech medication should increase the concentration among soldiers or enable them to work continuously without sleep. Last but not least, nanotechnology opens up countless opportunities to develop synthetic-biological warfare agents.

However, ethics committees achieve little because projects that use nanotechnology in this sense take place in secret.

While real medical research is now massively promoting the functional replacement of damaged parts of the body with nanomedicine, ethicists are discussing the problem of organs and prostheses that are said to surpass the human original.

This discussion is not straightforward: The improvements in the body that are medically necessary, acceptable or unacceptable are defined very differently in societies.

The debate about what is medically and technically possible with nanomedicine and what is ethically justifiable are currently taking place separately in Germany. (Dr. Utz Anhalt)

Swell:

http://www.ingenieur.de/Fachgebiete/Mikro-Nanotechnik

http://www.nano.fraunhofer.de/de/nanotech.html

http://library.fes.de/pdf-files/stabsabteilung/05709.pdf

http://www.umweltbundesamt.de/themen/chemischen/nanotechnik

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