Nanotech for Medical Treatment
In this article, we continue brief overview of modern nanotechnology in the field of biomedicine. The subject of analysis is the topics of works nominated for the competition in the field of nanotechnology RUSNANOPRIZE 2016 International Award. Let us remind that according to the rules of competition to be contenders for the prize can be only development that has a significant amount of commercialization. It means that the heroes of our review are not related to science fiction; a technology that is available today and can be significantly enhanced in the coming years.
Targeted Drug Delivery
One of the very practical trends in the development of modern biomedical technologies is associated with the targeted delivery of drugs. The point is that many drugs have a lot of side effects. Especially it is true for medications that designed to kill cells, in particular tumor cells. In fact, all these drugs are strong poisons and there is only one hope for traditional therapy is that tumor cells will die before the healthy cells in important organs for life. Therefore, scientists do not stop looking for new ways to improve selectivity - poison attacked only the "bad" cells.
Box with a secret
Simple and intuitive method for targeted delivery has been proposed for the treatment of tumors in the brain. When taking a conventional method not all substances go in the brain, and which go still, they have a low dose compared with other organs. The method consists in the fact that a small piece of the nanostructured material, which contains a high concentration of the active drug substance, is laid in a brain surgically. Due to the properties of the material medicine comes out of it very slowly, gradually. As a result, a sufficiently high concentration of the therapeutic drug is created and maintained in the brain. When it comes to all other tissues and organs, it is diluted to near trace amounts and it is no longer a danger for normal body function and does not affect health.
It is clear that for this purpose, as well as two approaches to the delivery of potent potentially hazardous substances, as described below, the principal is the ability to accurately measure the amount and dynamics of drug release from the related forms. One of the developments participating in the competition is devoted to this. The method is based on the use of stable isotopes of radioactive.
The nanoemulsions - simple and effective
Another original method of targeted delivery is based on the fact that in tumor vessels are not as dense as in the normal tissues. In tumors vascular wall freely transmit nanoscale particles so these particles can accumulate a little in tumor tissue. The drug is not injected into the body in a free form but in the form of nanosized droplets bilayer - nanoemulsions. Medicine tucked away in a drop is not dangerous to normal or cancer cells, but due to the nature of the vascular walls, more droplets are around cancer cells than in other tissues. And then the local ultrasound impact is focused in the area of the tumor (if it is already detected and the doctor knows where it is localized). Ultrasound destroys the emulsion droplets and the drug completely falls into the interstitial fluid. High drug concentration is obtained in the ultrasonic treatment zone, and it is permissible in the surrounding tissues and organs. The tumor disappears, the person recovers.
Polymeric micelles - precision guidance
Another way to precisely fill medicine in affected tissues is based on the properties of polymeric nanoparticles - micelles. Combining polymer materials with different properties it can be set in a wide range of nanoparticles properties, such as hydrophobicity / hydrophilicity, size, ability to bind, and release low-molecular compounds, which include the most common anti poisons. If way to aiming accumulation of these micelles in tumor is developed, the polymer nanoparticle composite design provides constant and prolonged presence of the active ingredient in the immediate vicinity of the target cells.
In addition to the above-described accumulation of nanoparticles associated with a higher vascular permeability in cancerous tumors, tumor-specific antibodies can also be used for targeted delivery and retention of loaded nanoparticles, they will bind micelle container with the surface of the target cell. In this way, the toxic container will be in tumor before death associated cells, and then it will find a new target. This method of "targeting", i.e. “aiming at the target” allows not only to treat the tumor that already decorated, but also to find and eliminate the metastases - stem cells from cancer degeneration, which travel throughout the body and can give rise to new tumors in any organ.
A vaccine against HIV - a game of chess with a deadly particle
Truly puzzling problem must be solved by scientists who design a vaccine against the human immunodeficiency virus (HIV). Why do we need a vaccine? To prepare in advance the body of the people to the meeting with a virus for which the probability of this meeting is high, especially in high-risk groups. Ideally, the immunized person in case of infection is not going to be sick because the virus is quickly neutralized by already configured on it and gain sufficient protection tools, such as specific antibodies against the virus particles and cell-killers that kill infected cells.
However, HIV is much more sophisticated than many other viruses, it is perfectly camouflaged, both due to high volatility and due to the distribution in the body. Variability hamper to develop effective antibodies and the infected cells are hiding from "killers" to secure "tank" - tissues, which is usually rarely dropped by «killer".
In one of the applications submitted for the award RUSNANOPRIZE HIV vaccine development is presented, which is in clinical trials of phase I and II has proven its safety and preliminary efficacy.
Among the many clever tricks that developers had to put in the structure to achieve the desired performance, two large blocks can be called main - efficient solutions for production of antibodies and solutions to stimulate a cellular response.
In order to "catch" the virus despite its variability, the researchers studied the structure of the major surface protein of the virus particle in detail and chose those areas that are least likely to change. Still, the virus cannot change everything in itself - in other protein machines will stop working. So, exactly these conserved regions were selected as future targets for antibody binding. In addition, immunizing particles were strictly optimized in length to increase the specificity in order to the power of soluble immune response was directed at the most sensitive area of the virus.
To improve cellular link, killer cells are specially prepared by using DNA vaccine. This is called the vector design that integrates into the genome of immune cells and makes them scream at the very first contact with the virus, "Here is an enemy, faster, kill, kill!"
This integrated approach significantly increases the overall efficiency of the vaccine administered to the body. Preliminary results give us hope that the resulting effectiveness of vaccination would be enough to stop the spread of the virus in the population groups that often do not ask for professional medical help and cannot afford to buy their own medicines to treat HIV infection. I.e. It will be possible to cut off the main channel, which feeds the epidemic process in general and therefore the risk of ill this dangerous disease will significantly reduce for all of us.