By fernando herranz* (CSIC) and Mar Gulis
A friend of mine [Albert R. Hibbs] commented, although it is a crazy idea, how interesting it would be in surgery if the patient could swallow the surgeon. You put the mechanical surgeon in the blood vessels and it goes to the heart “looking” around […]. That machine finds which valve is faulty, pulls out the knife, and cuts it. Other machines could be permanently incorporated into the body to assist in the functioning of a faulty organ..
This is an excerpt from the famous talk that the theoretical physicist Richard Feynman He gave in 1959 at the annual meeting of the American Physics Society. In this intervention, considered the origin of nanotechnology, the scientist and his colleague Hibbs anticipated many of the concepts and developments that are a reality today, such as the use of nanomaterials to improve the diagnosis and treatment of pathologies.
Thirty years after Feynman’s talk, in the 1990s, research in nanomedicine began to grow systematically and, starting in the year 2000, it experienced a veritable explosion. After little more than two decades, the scientific community has generated a catalog of nanomaterials with applications for biomedical problems as wide as it is surprising. The tests to detect diseases such as COVID-19 at home, or the efficient messengers that, within our body, deliver a drug in time and form where it is needed, or even treatments for certain pathologies are just some of the many achievements of nanotechnology applied to medicine.
The most commonly used nanomaterial in kits for COVID-19 are gold nanoparticles. / Jernej Furman
The most important thing about a nanomaterial is the size because, as it increases or decreases, its optical, magnetic or electrical properties, among others, can be completely different. For example, it is possible to obtain a whole range of fluorescent colors using the same material, with identical chemical composition, varying only its size. Sometimes a tiny difference of one nanometer causes the light emitted by the nanomaterial to change. The applications of a property like this are enormous in areas such as the diagnosis of a disease.
Nanomedicine to know what happens to us
One of the most important applications of nanoparticles is diagnostic test. In the case of diagnosis in vitrowhen the sample leaves the patient and is applied to an analysis system, the most widely used nanomaterials are gold nanoparticlespresent both in pregnancy tests and in the popular kits for COVID-19.
In fact, thanks to nanomaterials, several versions of kits were obtained in record time during the pandemic sensitive enough and with low production costs. And today you can already buy tests that use gold nanoparticles and that, in a single measurement, can detect the presence of SARS-CoV2 and influenza A and influenza B viruses.
When you want to study the inside of the patient to take a test live molecular imaging is used. Different techniques are used to perform these tests, such as magnetic resonance imaging (MRI) or positron emission tomography (PET). The list of potential advantages of nanoparticles in this area is very long, because for each imaging modality there is at least one type of nanoparticle that can be designed with an ‘à la carte’ size and thus improve the diagnosis, or reduce the toxicity of the substances injected into the patient. There are materials that directly function as a barcode made from nanoparticles, since each disease corresponds to a unique fluorescence profile.
Gold nanoparticles of different colors due to their different sizes. / Fernando Herranz
Drug carriers and therapeutic nanoparticles
Since the origin of nanomedicine, nanoparticles have been used as efficient drug delivery systems. The same thing happens here as in other fields: the variability of nanomaterials is enormous. Its mission is to improve the performance live, safety or stability of an active pharmaceutical ingredient. To fulfill this function, nanomedicine already has a notable presence in oncology and hematology. And after the success of the COVID-19 vaccines, mRNA (messenger RNA) vaccines are also growing rapidly.
Until now, nanomedicine has helped to detect a pathology faster and more accurately and has served as fundamental support for the release of drugs within us. But, What if nanoparticles could also cure us? What if they had a therapeutic effect? This is not science fiction. Some nanoparticles are already in clinical trials for new anticancer treatments. In this line, there is a technique called magnetic hyperthermia which tries to kill cancer cells by applying heat. In order to ensure that this reaches mainly cancer cells and not healthy ones, magnetic nanoparticles are used, mainly iron oxide. If we place magnetic nanoparticles inside a magnetic field, they will align themselves in the direction of said field. If we now change the direction, the nanoparticles will rotate with it. If that turn is done continuously and quickly, using an alternating magnetic field, the spin will generate heat in the area where the nanoparticles are accumulated. This type of treatment seems promising for pancreatic cancer (trials are already underway in Spain) and could also be effective in prostate cancer.
The flow of scientific articles and medical applications does not stop growing, so the future in this area has a good prognosis. The straight for the scientific community expert in nanomaterials reside in go hand in hand with clinical professionals. It is also necessary promote the simplicity of nanomaterials, because many times those of us who work in chemistry, tempted to demonstrate the complexity that these materials can reach, build systems with many more components than are necessary, and this can be a stumbling block for agencies evaluating new drugs.
* fernando herranz He is a CSIC researcher at the Institute of Medicinal Chemistry (IQM-CSIC) and author of the book Nanomedicine (CSIC-Waterfall).