What is nanotechnology?

"Nano" comes from the Greek word for dwarf. In science, a nanometre is one billionth (10^-9) of a metre, and is approximately 40,000 times smaller than the thickness of human hair.⁴ In the 1966 science-fiction film Fantastic Voyage, a team of surgeons are shrunk down and journey into a Russian scientist's body in a miniature submarine to remove a blood clot in his brain. Although technology has not yet discovered how to downsize physicians, it has created instruments for treating cancer and other illnesses.⁵

The mechanisms inside our bodies that cause cancer occur at the nanoscale. A broad range of scientific disciplines, including chemistry, biology, physics, materials science, and engineering, may benefit from the study and use of nanoscale phenomena.

Nanotechnology applications in medicine include imaging, diagnostics, and medication delivery, which help medical practitioners in the treatment of various ailments.⁶ Nanoscale devices have the same size as major biological molecules ("biomolecules") like enzymes and receptors. The ability to manage structures and characteristics of the cell at the nanoscale in medicine is analogous to having a sub-microscopic lab bench on which to handle cell components, viruses, DNA fragments using various tools, robots, and tubes.⁴

Nanotechnology in cancer diagnosis

Some cancer patients may only need a single round of therapy, however most patients get a combination of therapies, like surgery, chemotherapy, and/or radiation therapy. Immunotherapy, targeted therapy, and hormone therapy are also all options for treatment. Patients with cancer may also consider participating in clinical trials. When there is a visible alteration in the tissue, doctors often request imaging tests, such as X-rays, computed tomography (CT) scans, endoscopy, ultrasound and magnetic resonance imaging (MRI) to aid in the diagnosis of cancer.^1,5,7

These tests can only detect the illness after it has grown to a visible size. By that point, hundreds of cancer cells may have multiplied and potentially spread throughout the body, making it more difficult to treat. Furthermore, these scans are unable to determine if a tumour is cancerous or not. In most cases, a biopsy is required to determine the outcome.⁸ A tiny number of cells can be monitored using nanotechnology because of the small size of the particles involved.⁵ It can distinguish between normal and cancerous cells, and reach cancer in its early stages, when the cells have recently begun to divide, and the disease is easier to treat. 

Interestingly, when using conventional scanning devices such as positron emission tomography, and CT, nano-based imaging contrast agents like superparamagnetic iron oxide nanoparticles, and Gadolinium-based contrast agents improve tumour detection and imaging in vivo.² 

Tumours may be easier to detect on imaging tests due to nanotechnology. Imaging methods, as well as morphological tissue investigation (histopathology) or cells (cytology), might help in early cancer identification.¹ It is possible to coat nanoparticles with antibodies or other chemicals to help them locate and adhere to cancer cells. Particles may also be coated with chemicals that, when they contact cancer, relay a signal. For example, iron oxide nanoparticles emit a powerful signal detectable by an MRI when in contact with cancer cells. Specialists may also use nanotechnology to help detect cancer in blood or tissue samples. It has the potential to detect cancer cells or DNA that are too tiny to be detected by present methods.^5,9

Treatment using nanotechnology

Cancer therapies may be safer and more precise with the use of nanotechnology. As nanoparticles are specially engineered, they can deliver chemotherapy directly to tumours.^5,10 They do not discharge the medication until they have reached their destination, thereby preventing the medications from causing damage to healthy tissues in the tumour vicinity. Due to their tiny size, they can deliver medications to parts of the body that would otherwise be difficult to reach. 

Consider the blood-brain barrier, which stops hazardous chemicals from entering the brain and causing damage, with the additional effect of blocking several medications. Research has proven that nanotechnology can be used to effectively develop different systems, enhancing a drug’s pharmacokinetics while reducing associated toxicity.

These technologies reduce drug-related side effects and improve a patient's chances of survival. They also enable more selective chemotherapies by assisting in the delivery of medicines to particular tumour areas. Such procedures include the creation of nano-sized carriers that encase and carry the medicine to its intended target.

Cancer nanomedicine has been clinically translated for many decades, and the number of nano-based medicines and components for imaging, diagnostics, and radiation therapy in clinical usage has continuously risen.^2,11 The CellSearch® system is the first FDA-approved diagnostic blood test that uses magnetic nanoparticles that target EpCAM and cell labelling to detect circulating tumour cells.² Abraxane and Doxil, two FDA-approved therapies, help improve the effectiveness of chemotherapy medications. 

Abraxane is a nanoparticle created from the protein albumin and the chemotherapy chemical docetaxel, preventing cancer cells from reproducing.^5,12,13 Abraxane is used to treat malignancies of the breast and pancreas that have spread, as well as non-small-cell lung cancer. Doxil is the chemo medication doxorubicin that has been encapsulated in a liposome, which is a fatty sack. It interferes with cancer genes, preventing cancer cells from reproducing. Doxil is used to treat ovarian cancer, multiple myeloma, and Kaposi's sarcoma, among other conditions.¹⁴ 

Researchers are currently investigating other nanotechnology-based therapies in clinical trials.⁵ Some of these therapies encapsulate harmful medications in nanoparticles to make them safer or to aid the drug's survival throughout the journey through the circulatory system. Nanoparticles may have the potential to administer radiation to cancer patients in the future.

How is nanotechnology different from other treatment methods?

Nanotechnology already brings significant advances in health-care delivery, targeting malignancies, medication delivery systems, and enhancing medical imaging.¹⁵ By directing medications specifically to target cancer cells, nanotechnology improves chemotherapy and decreases side effects. It also improves the precision of surgical tumour excision and increases the effectiveness of radiotherapies and other existing therapeutic options. As a result, the patient is in less danger and has a better chance of surviving. 

Research is currently advancing rapidly, with several major lines of inquiry emerging. Including the development of nanoparticle packages, active pharmaceutical ingredients to facilitate the exploration of a broader range of active ingredients, and establishing immunogenic cargo and surface coatings in combination with nanoparticle-mediated therapy, radiotherapy, chemotherapy, and stand-alone therapies.¹⁵

Nanoparticles' enormous surface area allows them to be decorated with ligands, DNA and RNA strands, peptides, or antibodies. These 'add-ons' provide extra functionality, such as enhancing the therapeutic impact of nanoparticles directed to a particular spot. Some nanoparticle-based therapies are multi-functional, used to detect cancers and transport medications. As a result, nanoparticles make combination medication delivery, multi-modality therapy, and "theranostic" (combined therapeutic and diagnostic) activity possible. Nanoparticles' energy absorption and re-radiation capabilities enable them to enhance laser ablation and hyperthermia applications, damaging sick tissue.¹⁵

Benefits 

Nanotechnology has the potential to improve the selectivity and efficacy of chemical, physical, and biological methods to cancer cell killing, while reducing collateral harm to nonmalignant cells. It allows identification of molecular alterations occurring in tiny cell fractions, while creating innovative and extremely effective medicinal medicines.³ This is used in cancer detection to collect cancer biomarkers such as cancer-associated proteins, circulating tumour DNA, circulating tumour cells, and exosomes.¹

Nanoparticles have a modest size range compared to cells and cellular organelles, enabling them to interact with certain cell properties of localised tumour cells through active targeting.³ The size is also suitable for passive targeting tumour tissue via enhanced permeability and retention.³ Thus, nano-sized materials provide different benefits for cancer therapy compared to low molecular weight medications. These features are extensively utilised for better chemotherapeutic drug delivery, resulting in greater anticancer efficacy and decreased systemic toxicity.³

Side effects

Cancer cells are more precisely targeted by nanotechnology, allowing healthy tissues to remain unaffected. Compared to conventional therapies such as chemotherapy and radiation, it should have less side effects, in principle at least. 

Currently available nanotechnology-based therapies, such as Abraxane and Doxil, have been associated with adverse effects such as weight loss, nausea, and diarrhoea. However, it is possible that the chemotherapeutic medications cause these issues inside them. During clinical trials, researchers should learn more about the negative effects of these therapies, which will help them develop more effective remedies.¹⁷

The nanoparticles toxicity, which needs additional exploration, is one problem that may restrict the application of certain nanoparticles for cancer therapy.³ Furthermore, existing imaging technologies are unable to discriminate between benign and malignant tumours¹. As previously stated, cytology and histopathology cannot be used to identify cancer at an early stage efficiently and independently.¹ 

Advancements 

Radiotherapy is administered to around half of cancer patients during treatment, because it reduces tumour size by exposure to high-energy radiation.¹⁵ However, radiation can also damage healthy cells, so scientists have been working on enhancing the radiotherapy effect, and developing novel externally applied electromagnetic radiation. As a result, it is possible that the combination of nanotechnology and radiotherapy may produce more effective results than radiotherapy alone.¹⁸

Nano-sized carriers are effective in delivering alternative, herbal-based treatments.¹⁵ Researchers developed a unique targeted treatment for triple-negative breast cancer (TNBC), using nanocarriers to carry gambogic acid (GA) to particular locations. This proved effective in boosting GA's anti-cancer activity while reducing harm to healthy tissue. As a result, GA adoption as a therapeutic option for treating TNBC may become more successful. 

Because of their chemical variety, nanoparticles may interact with magnetic fields and other external fields to offer a conduit for highly precise interactions between external fields and tumour tissue, and individual malignant cells in vivo³. The variable material composition also allows external field disruption, providing better contrast for imaging applications³. 

The unprecedented coupling specificity between external fields and malignant cells in the normal tissue setting is predicted to lead to better treatment results, early and more accurate diagnosis. Hence, improved cancer medicines based on nanotechnology will continue to be developed, leading to better treatment results.

Recent research in nanotechnology

Recent studies have shown that nanoparticles and biomaterials enable scientists to manipulate the distribution, pharmacokinetics, and placement of immunomodulatory drugs, resulting in reactions which cannot be elicited by delivering the identical compounds in solution. Understanding the possible implications of nanomaterials on the environment is essential to responsible nanotechnology development. Thus, animal cells, tissues, and plants (soybeans), are studied to determine the nanomaterial impact on them, along with the developing rules to ensure nanotechnology benefits are being derived safely. 

Many attempts have been undertaken to create nanotechnology-based tests for cancer detection.¹⁶ Compared to presently existing cancer diagnostics in the clinic, many nanoparticle-based assays improved selectivity and sensitivity or provided new capabilities which cannot be achieved with conventional methodologies.¹ These advancements will increase patients' survival chances by allowing earlier diagnosis and tracking cancer progression in therapy response, which could help create improved cancer treatment techniques. 

Significant progress has been achieved in nanotechnology-based cancer diagnostics, although only a few nanoparticle-based tests have gone to clinical trials. Nanotechnology-based cancer diagnostics will enter the clinic with tight cooperation between academics, engineers, and doctors. Its high sensitivity, specificity, and multiplexed measuring capabilities offer several prospects to enhance cancer detection, resulting in a higher cancer patient survival rate.¹

One recent technique was used to improve chemotherapy drug effectiveness for treating colon cancer. Clinical study findings showed that the nanoparticle delivery method could significantly boost survival rates by allowing chemotherapy medications to be delivered directly to sick tissues. This technique has been shown in animal experiments to be successful in delivering Capecitabine to sick cells, whilst bypassing healthy ones, minimising hazardous side effects and increasing tumour-reduction activity effectiveness. 

Another promising nanotechnology use in cancer is improving immunotherapy. While immunotherapy has been established as a potentially highly effective treatment option for different cancers, the patient proportion who respond positively to immunotherapy remains low. Only about 15% of patients demonstrate objective response rate across indications.¹⁵

Conclusion

Getting a diagnosis as soon as possible is critical for improving prognosis and patient life quality. Diagnostic technologies are on the verge of experiencing a technological revolution. A steady expansion of nanotechnology has been seen in the fields of cancer chemotherapy and radiation, diagnostics and imaging, indicating the ability to enhance each and progress patient care. Nanomaterials provide a wide range of adaptability, functionality, and uses, enabling the development of cancer therapies that are particularly targeted, accurate early-detection devices, robust imaging modalities, and better radiation adjuvants.