When the first cells appeared on Earth approximately 3.8 billion years ago, viruses were already here to greet them. Ever since, viruses have been devising ways to infect cells, and cells have been responding by evolving ways to stop these infections. This evolutionary dance eventually led to the development of your immune system.
A key aspect of your immune system is to distinguish “self” from “nonself” so it can destroy and remove foreign materials from your body. While this immune reaction protects you from viruses, it also has implications for how well foreign materials such as medications work.
I am a researcher studying ways to make drugs work better, including how to get them to the site of disease within the body before being removed or destroyed. One way to do this is to encapsulate drugs in nanoparticles – materials small enough to be taken up by cells. While these materials still trigger an immune response to get them out of the body, scientists like me have found that this reaction could actually be used to improve the effectiveness of cancer treatment.
The immune system and drug delivery
In addition to detecting pathogens, your immune system also responds to tissue damage. You might observe this reaction as inflammation – such as redness and swelling – when drugs are injected into your body with a needle.
Typically this inflammatory response is minimal. But the potential for a sustained reaction increases when drugs are administered slowly over a prolonged period of time, such as during chemotherapy infusions that can take an hour or more. For this reason, some patients are given anti-inflammatory medications before infusion to reduce the potential for an adverse immune response during treatment.
The most recent breakthroughs in getting drugs into the body is using nanoparticles. These materials – which can be made from lipids, proteins, gold or other components – have the advantage of being very small: The diameter of a typical nanoparticle is about 10-thousandths of a millimeter. Their small size allows diseased cells to easily take them up. So when nanoparticles contain drugs, they can act as a drug delivery system.
Nanomaterials are used across many industries, including medicine.
Despite being so small, nanoparticles can hold a large number of drug molecules, allowing them to deliver a potent cargo of treatment directly into a cell. They can also deliver drugs made of DNA and RNA. The most well-known example of this technology is the COVID-19 vaccine, which uses nanoparticles made of modified fat molecules to deliver mRNA that teaches the immune system to protect itself against COVID-19 infection.
Your innate immune system also identifies nanoparticles as foreign invaders when they are injected into your body. As a result, some patients experience an initial inflammatory reaction when the body tries to attack the…
