Nanotechnology and Drug Delivery

Nanotechnology is the use of extremely small particles to carry out an ever-increasing number of functions in a wide variety of fields. Its application in medicine, called nanomedicine, has proved very useful in drug transport, imaging and diagnostics. For example, nanocarriers, only 1-100 nanometers (nm) in size, are often used to transport drugs to specific areas of the body. [One nm equals one-billionth of a meter. As a point of reference, 1 sheet of paper is about 100,000 nm thick)]. Nanoparticles have a more natural interaction with cells due to the similarity in size, ensuring movement across challenging barriers for drugs that are normally too large. In the case of chemotherapy, precise targeting of drugs to tumor cells with nanocarriers allows for increased efficacy with lower doses. This reduces toxicity to neighboring healthy cells and the attendant unpleasant side effects, thereby improving the patient’s quality of life.

The precise targeting potential of nanoparticles enables limitless applications. In addition to chemotherapy, they could be extremely useful in pain-related therapies as an alternative to opioid therapy. Opioids are a class of highly addictive analgesic drugs and, although they provide powerful pain relief, the side effects can be very detrimental to patient health. They are often given after surgery for short-term pain relief. I have had a couple outpatient surgeries in the last year, and I was prescribed four oxycodone pills each time in case I experienced too much postop pain. Fortunately, my negligible pain after surgery never gave me reason to take one. Maybe it’s a bit of irrational paranoia, but I was determined not to.

It can be a nightmare becoming dependent on opioid painkillers, and the longer a patient takes these drugs, the greater the risk of developing an addiction. The danger is increased with prolonged use, since the effectiveness of opioids becomes progressively weaker and higher doses are required to achieve the same analgesic effect. Consequently, they are no longer seen as a desirable option for extended pain relief.

It is known that when pain-inducing molecules bind to certain receptors on the surface of nerve cells, a pain response is initiated. A drug has been developed that can bind to these receptors and prevent such a response, but unfortunately, after pain-inducing molecules bind to the receptors, this complex is taken up by the neuron within membrane enclosed vesicles, called endosomes, that prevent access to the receptors by the drug.

In a landmark study, researchers were able to bind the drug to nanoparticles, and because of their tiny size, they are able to travel into endosomes and release the attached drug that can then inhibit the neuronal pain cascade. Ingeniously, pH-sensitive nanoparticles were used because of the acidic conditions within the endosomes, ensuring the breakdown of the nanoparticles and drug release.

This type of pain treatment is much more specific than broad-spectrum drugs, including opioids. It is cheaper and more sustainable for chronic pain sufferers, plus it would greatly reduce the risk of addictive opioid dependency.