The Future of Medicine is at the Nanoscale
Meghan Brown posted on February 15, 2019 |
Nanotechnology shows a great deal of promise for medicine, from drug delivery to health monitoring.

Personalized healthcare is the Holy Grail of medicine—the idea that every illness or disease can be treated on an individual basis for each patient, with medicines, drugs and treatments designed for each person’s biology to be optimally successful.

Right now, while diagnosis and treatment have improved leaps and bounds over the course of the 20th and 21st centuries, medicine still often relies on trial and error—such as trying multiple drugs or treatments until finding one that works—which is not only costly in the monetary sense, but also means that it takes much longer to see results in improved condition or being cured.

We’ve seen how advanced technologies such as artificial intelligence (AI) can help improve disease diagnoses, analyze medical images and crunch the numbers to discover trends or perform research.  But there are other technological paths that researchers are following in their quest for individualized medicine—such as nanotechnology.

Nanotechnology and Nanomedicine

This image shows the bamboo-like structure of nitrogen-doped carbon nanotubes for the treatment of cancer. (Courtesy of Wake Forest and the National Cancer Institute)

This image shows the bamboo-like structure of nitrogen-doped carbon nanotubes for the treatment of cancer. (Courtesy of Wake Forest and the National Cancer Institute)

The general definition of what makes something qualify as “nanotechnology” is described by the National Nanotechnology Initiative as “the understanding and control of matter at the nanoscale, at dimensions between approximately 1 and 100 nanometers.” Nanotechnology exists in a cross-section between engineering, science and technology, and generally encompasses applications from imaging, materials, measuring, and manipulation of matter at this size and scale.

What makes nanotech so appealing for medical applications is this small scale, since many biological molecules and structures like those of the body’s systems—cells, DNA, etc.—exist and operate on the micro and nano scales, as well. In particular, nanotech is often much smaller than the body’s natural systems, which is what enables nanotech to help with specialized tasks such as drug delivery, sensing and imaging, repairing damaged cells, and more.

“What gets a lot of people in the medical field excited about nanotechnology is that size scale can penetrate your skin,” said Thomas Webster, a chemical engineering professor at Northeastern University whose research focuses on using nanotechnology to improve the health of Americans. “That whole size range is just incredible,” he added, because nanoscale objects can not only enter the skin, but also pass through the intestinal wall, the blood-brain barrier and the more porous parts of bone.

The application of nanotech in the medical field is often termed “nanomedicine” and includes the use of nanomaterials, nano-scale biological devices, and nanoelectric biosensors to assist with diagnostics, analytical tools and  treatment therapies, among others.

Nanotech for Drug Delivery

One of the primary desirable applications for nanotechnology in medicine is drug delivery, due to the advantages for diagnosis and treatment of disease.  Without nanotechnology, drug treatments are limited to topical, oral or injected, which requires the drug to travel through the body before reaching the treatment site.  Not only does this mean it takes longer for the drug to start working effectively, but it also increases the chances of the drug compounds damaging other tissues, and increasing the intensity and frequency of side effects.

Targeted drug delivery is already in the early stages of use, but further nanotechnology advances will continue to improve the effectiveness of these kinds of treatments.

Conventional drug treatments suffer from problems including poor bioavailability and low solubility, in addition to greater incidences of side effects resulting from each successive treatment.  Ideally, nanotech developed for targeted drug delivery needs to fulfill multiple objectives designed to improve the effectiveness of treatment:

  • Improve delivery of poorly-water-soluble drug components
  • Enable site-specific targeting to avoid the accumulation of drug compounds in healthy cells or tissues
  • Improve drug retention to increase treatment effectiveness
  • Enable drug compounds to be transported across epithelial and endothelial barriers
  • Extend the period of drug bioactivity by protecting drug compounds from the surrounding biological environment
  • Combine diagnostic and therapeutic capabilities into a single agent

Nanoparticles and nanoengineered devices are nanotech methods being explored for targeted drug delivery.  Nanoengineered devices, or nanodevices, are much less invasive than existing medical devices, and could even be implanted directly within the body, enabling shorter biochemical reaction times and greater sensitivity.  Nanoparticles offer a large surface area relative to their small size, which allows the manipulation of the particles to enable them to carry high concentration levels of drug compounds.  The stability of these particles means they can deliver the drug effectively and over a longer period of time.

Artist’s conception of nanoscale drug delivery using nanoparticles encapsulated in materials designed to protect the drug compounds from degradation while travelling to the site of treatment.
Artist’s conception of nanoscale drug delivery using nanoparticles encapsulated in materials designed to protect the drug compounds from degradation while travelling to the site of treatment.

By efficiently encapsulating the drug, successfully delivering it to the site of treatment, and releasing the drug precisely where and when required, nanotech can greatly improve treatment outcomes.

It’s this ability to precisely control the behaviors of the drug delivery that helps nanotech-based treatments to avoid causing additional adverse side effects to the patient.

This has shown great promise so far in the treatment of certain cancers, specifically with chemotherapy treatments, in which powerful chemo drugs can be precisely directed to treat cancer cells while avoiding healthy tissue.

Other nanotech treatments being pursued include improving the effectiveness of biologics, or drug products derived from living organisms, with poor bioavailability. For example, insulin used for the treatment of diabetes.  Insulin cannot be administered orally because it degrades in the human gastrointestinal tract, but by packaging the drug in hollow nanoparticles, the compounds are protected from this degradation, enabling the appropriate systemic delivery within the body.

When these nanotech-based treatments, and others like them, are refined and proven to be reliably effective, it will improve the quality of life for cancer patients, diabetics, and many others who suffer from both acute and chronic diseases.

Medical Imaging and Nanotechnology

Enhanced imaging capabilities are another way nanotech is improving the medical industry.  Achieving clear and accurate medical images is crucial to the accurate and effective diagnosis of many diseases and illnesses.

Nanoparticles’ small size gives them properties that are ideal for imaging applications because they can enter tissues and collect in concentrations high enough to act as contrast agents.  This improves the distribution and contrast of images generated by MRI or ultrasound, for example, making it easier to identify abnormalities such as tumors or damaged tissues. These improved images give medical practitioners a better view of what’s going on in a patient’s body, which means better monitoring and assessment of treatment progress, and improved success with surgical procedures such as the removal of tumors. 

MRI and ultrasound images can be improved by using nanoparticles that can travel to the site of illness, react to light or other stimuli and enable crisp, precise imaging.
MRI and ultrasound images can be improved by using nanoparticles that can travel to the site of illness, react to light or other stimuli and enable crisp, precise imaging.

Static imaging isn’t the only thing to see improvements from nanotech, however; promising research is using nanoparticles to highlight how a compound moves through the body, making it possible to track how well a drug is being distributed and metabolized.  Historically, the cells that needed to be tracked would be dyed with dyes that react to certain wavelengths of light.  Nanotech offers a more precise method using quantum dots that act as luminescent tags.  These tags are attached to proteins capable of penetrating cell membranes, and can be designed to be a certain size that will glow a certain colour, enabling doctors to get clear images of the growth or shrinkage of tumors, organ trouble, and whether drugs are travelling to the correct treatment locations within the body.

It isn’t just human eyes that benefit from nanotech-enabled imaging.  Having clearer, more detailed medical images will also enable AI and machine learning systems to more accurately learn to identify specific diseases, improving the future application of automated diagnostics.

Nanosensors for Medical Monitoring

Nano-sized sensors can travel or be embedded within the body, and provide monitoring and relay patient health information such as drug absorption, metabolism, blood glucose, toxicity or any number of physical factors that might have an impact on an individual’s health and treatment.

Like the nanoparticles used for drug delivery or imaging, nanomaterials used for nanosensors can operate at a scale similar to biological processes, which gives them benefits in sensitivity and specificity compared to sensors made out of more traditional materials.  Most nanosensors operate in a similar manner, by measuring the signal generated by interaction of the nanosensor and the surrounding biological environment, then processing those signals into some form of useable data.  This is a smaller iteration of the lab-on-a-chip idea, but able to operate at the nanoscale and identify biomarkers such as specific proteins that indicate specific diseases.

Nanosensors incorporate thousands of nanowires—often made from carbon nanotubes—and could one day be capable of measuring biomarkers from inside the body, or externally using nothing more than a breath of air or a drop of blood.  With further advances, these sensors would be sensitive enough to test for and identify many different cancers and diseases simultaneously with a single sensor.

The speed at which nanosensors would be able to identify the signs of illness and diagnose the patient can also mean that treatment can begin earlier, before the disease reaches a critical stage, rather than treatment beginning in a reactionary capacity after the illness has had enough of an impact on the patient to be detectable by the traditional diagnostic tests.

A specific application that is showing a great deal of promise involves the detection of infection at the site of medical implants, such as knee and hip replacements.  A common problem with these implants is the possibility of infection or inflammation post-surgery. In many cases by the time the infection causes symptoms a medical practitioner can identify, the treatment will be less effective, or the implant will need to be replaced all together.  With nanoscale sensors embedded directly into the implant or the tissues surrounding the implant site, infection could be detected much sooner, and treatment administered earlier.  Factor in the targeted drug delivery capabilities of other nanotechnologies, and the sensors could cue nanoparticles to deliver drug treatments directly to the site as soon as the first signs of bacteria or infection are identified.

The hope is that nanosensor technology will be refined to the point where these sensors are used to monitor anything the patient or their doctor may be concerned about.  Diabetic patients who need to track blood sugar could have nanosensor and drug delivery combinations that actively monitor blood glucose levels and release insulin as needed, or cancer patients could have nanosensors constantly monitoring tumor growth and directing other nanoparticles to release drug treatments.

Nanotechnology Still Has Risks, and More Research is Needed

Overall, nanotechnology looks extremely promising for the future of medicine, but a rosy outlook doesn’t guarantee there won’t be any problems.  There’s still a lot of research needed not only to develop and refine medical nanotechnologies, but to ensure that the use of these won’t adversely affect the patient.

For example, the quantum dots that have properties that would help improve medical imaging for cancer diagnosis can often contain materials toxic to humans, such as cadmium, arsenic or lead.  Silver nanoparticles used for infection treatments can also be problematic, with ionized silver being found persistent in the organs of animals exposed to these particles, and the possible long-term effects of this is not yet well understood. 

This means it is essential that nanotechnology receive a great deal of research and testing as we develop these applications in order to determine the best way to use nanoparticles or nanodevices in ways that do not cause additional harm to the safety, health and wellbeing of the patient.

Personalized Medicine Through Nanotechnology

Of course, all these nanotech applications circle back to the idea of personalized medicine.  With the ability to precisely image an organ or tumor, carry a drug to the precise treatment location, and be able to monitor and track both the drug’s progress through the body as well as the treatment results and patient’s overall health status, nanotech will bring significant improvements to both treatment success and quality of life during illness.

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