Using the Power of Nanotechnology for Cancer Detection and Treatment

8 min readNov 26, 2020

According to the CDC, cancer is the 2nd leading cause of death in the United States, just after heart disease. And it’s no secret that, although we do currently have some options for cancer treatment, there is plenty of room for improvement. This complex disease has stumped doctors and scientists for over 3500 years, since the first documented case of cancer in ancient Egypt in 1500 BC.

What’s bad about current cancer treatments?

Current treatment mostly involves surgery, radiotherapy, and/or chemotherapy. In all three cases, there are plenty of negative side effects, as well as the potential for the cancer to return.

Surgery is used to remove larger tumors, but it does not necessarily remove all cancer cells. These remaining cancer cells can go on to develop into new tumors post-surgery.

Radiotherapy is the use of ionizing energy applied over the tumor area. The radiation damages the DNA in tumor cells, thereby preventing its multiplication and destroying it. However, since this only works on a targeted area, any cancer cell outside of the target zone is not affected and can continue to grow.

Chemotherapy involves the use of chemicals to target any cell throughout the body that goes through high rates of division. Although this treatment can eliminate cancer cells that are outside of the primary tumor site, it can also destroy many healthy fast-growing cells as well (i.e. hair follicles, GI tract, bone marrow), causing extreme side effects.

All of these treatments are nonspecific, meaning that they do not distinguish between tumor cells and healthy cells. Nanotechnology seeks to change that.

The basics of nanotechnology

Nanotechnology is the interdisciplinary field of science, technology, and engineering, that uses matter on the molecular level to develop systems and devices.

The nanoparticles used in nanotechnology are between 1 and 100 nanometers (nm). For reference, the average cancer cell is about 20 to 30 micrometers (μm) in diameter. So the average cancer cell is on the scale of 100 to 10,000 times larger than a nanoparticle.

For a visual reference — a sheet of newspaper is about 100,000 nanometers thick. They’re tiny!

Nanoparticles are effective because, with their size, they can easily penetrate the cell membrane within the human body. This makes nanoparticles the ideal agent for treating cancer from within the cancer cell itself, as opposed to surface-level treatment.

How is nanotechnology being used in cancer treatment?

Gold-Coated Nanoshells for Photothermal Therapy
I’ll start with my personal favorite: using gold to treat cancer.

An important quality of gold is that it is a good thermal conductor, and can respond to a specific wavelength of light. Researchers have found a way to take advantage of this property, using heat to eliminate tumors.

This technology involves the use of 100 nm silica particles with a gold outer coating. These gold nanoshells are coated with antibodies that recognize certain proteins on the surface of cancer cells (such as EGFR). When nanoshells are inserted into the patient, they can specifically locate and target cancer cells through the antibody coating. Once these nanoshells are bound to cancer cells, a near-infrared laser is shone over the tumor location, inducing electron oscillation at the gold metal surface. These electrons vibrate rapidly enough to convert light to thermal energy, heating up the tumor and destroying it.

This form of treatment is promising because it is tumor-specific, and it does not involve the use of damaging chemicals or radiation. Instead, the near-infrared light passes through healthy tissue harmlessly.

Dendrimers for Detection and Drug Delivery
A dendrimer is a special type of nanoparticle that can perform a variety of functions. It consists of a spherical core and multiple branches, with each branch tip capable of carrying a different molecule to serve a different function. Dendrimers are thus able to recognize cancer cells, bind them, and deliver treatment all at the same time.

Dendrimers can use folic acid to recognize and attract cancer cells, as cancer cells have a greater need for folic acid than healthy cells. It’s like going fishing! The cancer cell is the fish, and the folic acid is the bait. Once the cancer cells attach themselves to the folic acid on the dendrimer branch, the dendrimer can then deliver an anticancer drug (such as methotrexate or doxorubicin) located on another branch to destroy the cancer cell.

Thus, dendrimers are a specific yet versatile agent in cancer therapy.

Biodegradable Remote-controlled Nanobots
A tiny remote-controlled nanobot created from the organism spirulina algae is being researched by a team of scientists, led by Professor Li Zhang of the Chinese University of Hong Kong, to detect and fight cancer.

The algae nanobots have an iron magnetic coating to help with biodegradation, and they are guided magnetically to their target sites. The algae has natural fluorescence that can be imaged, allowing them to be visually tracked when close to the skin’s surface. For deeper tissue, these algae nanobots can be tracked by MRI due to the magnetic iron-oxide coating.

These nanobots have enormous potential, with the ability to:
1. Deliver drugs to parts of the body that are difficult to reach
2. Sense chemical changes, allowing for remote diagnosis of disease onset
3. Selectively attack cancer cells through the release of toxic compounds during algae biodegradation

As put by Professor Kostarelos, “Creating robotic systems which can be propelled and guided in the body has been and still is a holy grail in the field of delivery system engineering.”

DNA Origami Nanorobots to Destroy Tumors
A different type of nanorobot is being researched by scientists from Arizona State University and the Chinese Academy of Sciences, programmed to destroy tumors by blocking their blood supply.

DNA origami is the orchestrated folding of DNA to create building blocks for nanoparticle synthesis. In this case, the nanorobot is a DNA origami sheet (90 x 60 nm), with a blood-clotting enzyme called thrombin attached to its surface. Thrombin acts by clotting the blood within vessels, thereby blocking blood flow and causing cancer cell death.

In order to make these nanobots tumor-specific, they employ a selective DNA aptamer sensor on their surface. The DNA aptamer can recognize a protein that is present only on tumor endothelial cells and not on healthy cells, called nucleolin. Upon binding to nucleolin, the nanobot then delivers its thrombin into the tumor, resulting in blood clotting and tumor destruction.

Photodynamic Therapy to Generate Reactive Oxygen Species
Photodynamic therapy takes advantage of electromagnetic radiation to generate cytotoxic reactive oxygen species.

Reactive oxygen species are very unstable and can cause damage to DNA, RNA, and proteins, causing mutation or cell death. In this case, the destructive nature of reactive oxygen species is taken advantage of to destroy cancer cells.

Nanoparticles are injected and, once they are localized at the tumor site, they are irradiated by X-rays to cause emission of light photons from the metal core. The light photons stimulate a photosensitizer to generate reactive oxygen species for tumor destruction.

Nanoscale Cantilever Biosensors
Nanoscale cantilevers, or nanocantilevers, can be used to detect pre-tumor cancer cells. They are shaped like a comb, with teeth acting as extremely sensitive biosensors . Changes that occur on the surface of the teeth cause bending and oscillation of the teeth, allowing for the detection of particles on the nanoscale.

In the case of cancer detection, the teeth are coated with specific antibodies that bind to cancer cell proteins. Upon binding to a cancer protein, the teeth of the cantilever will bend, and the deformation causes a change in conductivity in the cantilever, thereby indicating cancer cell presence.

This allows for the early detection and therefore early treatment of cancer.

Challenges with nanotech in cancer therapy

The common theme across all of these developments is that the treatment is cancer-specific, as it will selectively target cancer cells while leaving healthy cells intact. Thus, the treatments are much less toxic than traditional chemotherapy and radiotherapy. However, there are still many limitations to these techniques.

Nano-sized particles are extremely small and can easily pass through cell membranes and blood vessels, giving them nearly unlimited access to every crevice of the body. The use of nanoparticles must be carefully regulated, and they must be highly cancer-specific to prevent damage to healthy tissues.

Another barrier is the unpredictable behavior of nanoparticles that behave differently from their larger-sized counterparts. For example, there has been some concern over the toxicity of nano-sized gold, despite gold generally being considered as a nontoxic metal. Additionally, some nanoparticles have a tendency to clump together, which may unintentionally block respiratory or circulatory pathways.

Finally, as with other foreign organisms and potential threats, nanoparticles that enter the body can cause a complicated and potentially undesirable immune response. Nanoparticles can be engineered to avoid negative interactions with the innate immune system, but this must be carefully designed.

And that doesn’t even include the challenges pertaining to each individual technology. For example, with the gold-coated nanoshell photothermal treatment, barriers include the limited depth of the near-infrared laser, and the large number of nanoshells (~5000) required to generate sufficient heat. With the algae nanobots, additional challenges are found in “motion tracking, biodegradation, and diagnostic and therapeutic effects.”

Some closing thoughts

The potential to treat cancer with nanotechnology is endless — cancer detection, mapping and visualization, drug delivery, therapy, and continued monitoring of cancer progression, to name a few.

Nanotechnology is an ever-growing field, combining elements of biology, physics, chemistry, engineering, materials science, and others. In medical and therapeutic applications, it’s the blend between the organic and the inorganic. And it’s bursting with innovation and creativity, full of possibilities waiting to be explored.