Thanks to science fiction films, series and books, we have long imagined a world where tiny machines travel through our bodies, giving us special abilities.
This concept, which sounds impossible and futuristic, leads us to think of a distant future where nano-machines will be able to cure us, improve us and prolong our lives in ways that we do not yet fully understand. But the surprising thing is that this future is already here.
Far from being just a fantasy, nano-machines have long existed in the field of medicine and are being used, for example, to combat devastating diseases such as cancer. These tiny structures not only detect cancer cells, but attack them with surgical precision that is revolutionizing medical treatments.
Science fiction? More like science fact, and it's happening right now.
Nab-paclitaxel
During my training in biomedical engineering, I discovered this drug within the subject of nanomedicine, and having to do a project on it, made me even more fascinated by this area and delve more eagerly into the nano-worlds of health.
Nab-paclitaxel, known worldwide as ABRAXANE®, is a form of chemotherapy used primarily in the treatment of cancer. Paclitaxel, the active ingredient, is a drug that inhibits the proliferation of cancer cells by interfering with cell division.
“Nab” refers to nanoparticle technology containing albumin, a protein that transports the drug more efficiently to cancer cells, improving their absorption and reducing some side effects. This was discovered by observing that cancer cells tend to accumulate albumin by attracting a large amount of this transport protein.
By binding to albumin, paclitaxel is encapsulated in nanoparticles, creating nab-paclitaxel (Nanoparticle Albumin-Bound Paclitaxel). These nanoparticles have a size of about 130 nanometers, allowing them to circulate efficiently in the body.
Nab-paclitaxel, therefore, instead of being injected into the body and spreading throughout our tissues like common drugs, is injected into the blood and, as if it were a remote-controlled toy, is transported by albumin nanoparticles directly to the cancer cells, thus attacking them directly without damaging healthy tissues.
The problem with paclitaxel
Paclitaxel was first used as a chemotherapy treatment in 1992 after its approval by the U.S. Food and Drug Administration (FDA) for the treatment of ovarian cancer. It was later expanded to other cancers, including breast and lung cancer.
Although nab-paclitaxel was approved in 2005 to treat metastatic breast cancer, traditional paclitaxel has not been completely replaced. Both are still used today, and the choice between paclitaxel and nab-paclitaxel depends on the type of cancer, the patient's condition, and other clinical factors. The main difference is that nab-paclitaxel tends to be used in patients who cannot tolerate the side effects of conventional paclitaxel or who require better distribution of the drug in the body.
Nab-paclitaxel was developed to address several problems associated with the use of traditional paclitaxel:
- Traditional paclitaxel requires solvents such as Cremophor EL to dissolve, as it is insoluble in water. This solvent is toxic and can cause severe allergic reactions, requiring patients to be premedicated with steroids and antihistamines prior to administration. Nab-paclitaxel does not require these solvents, as it uses albumin nanoparticles for administration, eliminating the need for premedication.
- The use of solvents such as Cremophor EL in traditional paclitaxel is associated with severe side effects, such as peripheral neuropathy and hypersensitivity reactions. Nab-paclitaxel has been shown to have less toxicity and reduce the severity of these side effects.
- Traditional paclitaxel has difficulty reaching tumor cells efficiently due to its method of administration and the need for solvents. Nab-paclitaxel, being bound to albumin, improves the distribution of the drug to the tumor, taking advantage of the body's natural mechanisms, such as the affinity of albumin for tumor tissues. This results in better penetration and effectiveness of the treatment.
- Due to the better tolerance of nab-paclitaxel, patients can receive higher doses of the drug compared to traditional paclitaxel, which improves the efficacy of treatment without significantly increasing toxicity.
Process of nab-paclitaxel in the body
Phase 1. Administration
Nab-paclitaxel is administered intravenously without premedication with steroids or antihistamines.
Phase 2. Transport through the body
Once in the bloodstream, albumin nanoparticles transport paclitaxel throughout the body, preventing it from being rapidly degraded or accumulating in other tissues.
Albumin is a protein that circulates naturally in the body and has a high affinity for tumor sites. Tumor cells, due to their rapid growth, demand greater amounts of nutrients, including those transported by albumin, which facilitates the accumulation of nab-paclitaxel at the tumor site.
Phase 3. Passage through the blood vessels
Tumors are often surrounded by abnormal blood vessels, with walls that are more porous than normal vessels. This porosity makes it easier for albumin nanoparticles containing paclitaxel to pass from the bloodstream into tumor tissue, in a process known as the enhanced permeability and retention (EPR) effect .
Albumin takes advantage of this permeability to penetrate the blood vessels that feed the tumor, depositing the nanoparticles directly into the tumor microenvironment, as if they were a Trojan horse that, instead of carrying nutrients, carries paclitaxel to kill it.
Phase 4. Paclitaxel release into the tumor
Once the albumin nanoparticles have reached the tumor, the albumin is actively taken up by tumor cells through a process called caveolin-mediated transport . Caveolins are proteins that form “cavities” in cell membranes, facilitating the uptake of large molecules such as albumin.
Inside the tumor, the albumin nanoparticles are degraded and release paclitaxel directly into the tumor cells.
Phase 5. Action of paclitaxel on cancer cells
Once inside cancer cells, paclitaxel binds to microtubules, cellular structures that are essential for cell division. Paclitaxel stabilizes microtubules and prevents them from disassembling, which interferes with the cell division cycle. As a result, cancer cells cannot divide and end up dying.
This mechanism is particularly effective in rapidly dividing tumors, such as those of breast, lung and pancreatic cancer.
Phase 6. Elimination of cancer cell remains
Once paclitaxel has destroyed the tumor cells, the body removes the remains of the dead cells through the immune system and the lymphatic system.
Phase 7. Repetition
Nab-paclitaxel is given in cycles, allowing cancer cells to be attacked repeatedly until the tumor shrinks or is completely eliminated.
The future of nanomedicine
The future of nanomedicine points to a radical transformation in the way we treat diseases, with key advances such as the use of nanoparticles, nanomachines and carbon nanotubes. These technologies will enable the development of more precise and personalized treatments that directly attack diseased cells without damaging healthy tissue, reducing the side effects of therapies such as chemotherapy.
As research advances, nanomedicine, driven by carbon nanotubes and other innovations, promises to significantly improve the quality and expectancy of life, taking personalized, high-precision medicine to new heights.
Carbon nanotubes
Carbon nanotubes are cylindrical structures made up exclusively of carbon atoms, arranged in a hexagonal arrangement similar to that of a graphene sheet (a single layer of carbon atoms arranged in a two-dimensional honeycomb structure). At a physical level, these tubes can have diameters of only a few nanometers (billionths of a meter), but they can reach much greater lengths, forming structures with a very high aspect ratio (length much greater than its diameter).
You can read more about carbon and its properties in our article on the importance of carbon .
Carbon nanotubes have great potential in medicine due to their unique properties, such as their high resistance, electrical conductivity, adaptable chemical surface, and their ability to interact at the cellular level is very high, and they could be useful in a multitude of situations:
Drug release
Carbon nanotubes are being investigated as vehicles for targeted drug delivery. Their hollow structure allows drugs to be encapsulated and transported directly to target cells, such as tumor cells. Due to their ability to penetrate cell membranes, nanotubes can release the drug directly inside the cell, increasing the efficacy of the treatment and reducing side effects.
Medical imaging and diagnosis
Carbon nanotubes can enhance medical imaging techniques such as magnetic resonance imaging (MRI) , computed tomography (CT) and fluorescence imaging . Because of their conductivity and ability to generate clear signals in different types of scanners, nanotubes can label specific cells or tissues to improve the detection of diseases, including cancer. They are being investigated as contrast agents to improve the quality of images in diagnostic tests, allowing tumors and other abnormalities to be detected more accurately.
Biosensors
Carbon nanotubes are used in the development of highly sensitive biosensors that can detect specific biomolecules, such as proteins, DNA or metabolites, at extremely low levels. These sensors can be used for early diagnosis of diseases or to monitor health status in real time.
Example: Carbon nanotube-based biosensors have been created to detect tumor markers in blood or tissue, which could allow for earlier and more accurate diagnoses of different types of cancer.
Gene therapy
Carbon nanotubes are being investigated as vehicles for gene therapy, which involves the delivery of genetic material (such as DNA or RNA) into cells to correct genetic defects or modify the expression of certain genes. Because of their ability to penetrate cells without being degraded, carbon nanotubes can effectively transport genetic material and enable efficient gene expression.
Tissue regeneration
Carbon nanotubes are also being investigated for use in tissue engineering, as they can be incorporated into scaffolds to promote cell growth and tissue regeneration. Due to their structure and electrical properties, they can influence stem cell differentiation and assist in the repair of damaged tissues, such as bone, nerve or muscle tissue.
Example : They are being used to create bone regeneration implants that promote cell growth and integration with biological tissue, or to repair damage to nerve tissue through electrical stimulation.
Cancer treatments
In addition to their use in drug delivery, carbon nanotubes can be used in photothermal or photodynamic therapies for the treatment of cancer. In these techniques, nanotubes are directed toward tumors, and then lasers or near-infrared radiation are used to heat the nanotubes, resulting in the destruction of tumor cells by heat or release of reactive oxygen species.
In experimental models, carbon nanotubes have been used to successfully destroy tumors through laser irradiation, without affecting the surrounding healthy tissue.
Prosthetics and medical devices
Due to their strength, lightness and conductivity, carbon nanotubes are being incorporated into the design of prosthetics and other medical devices . They are being used to improve the durability and functionality of prosthetics, as well as to create implantable medical devices, such as pacemakers and body-integrated sensors .
They are also being studied for use in coronary stents , which help keep arteries open in patients with heart disease. Carbon nanotubes may improve the biocompatibility of these devices and reduce the risk of inflammation or rejection.
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1 comment
Excelente articulo refleja el progresivo avance de la medicina y la mejor calidad de vida de la humanidad