Nanoparticle Delivery for Macular Degeneration

Nanoparticle Delivery for Macular Degeneration

Researchers have been working with nanoparticle technology for decades and recent studies show how this application may be assisting in the fight against macular degeneration. 

Microscopic medicine allows scientists and doctors to work on such a small scale they are able to  override many antiquated procedures that have drawbacks due to various factors such as size and adverse systemic reaction. Nanoparticles offer a wide range of implementations once considered impossible to achieve but currently may be another groundbreaking area of science that increases rapid healing possibilities never seen before. 

Nanoparticle delivery for macular degeneration gives more hope for advancing the ability to bring continually improving remedies to the eye and eradicating this disease once and for all. 

What is a Nanoparticle?

The word nanoparticle may sound like something out of a sci-fi movie, yet nanotechnology is a branch of science that is rapidly becoming a real, applicable treatment. Science Daily describes what a nanoparticle is:

“A nanoparticle (or nanopowder or nanocluster or nanocrystal) is a microscopic particle with at least one dimension less than 100 nm. Nanoparticle research is currently an area of intense scientific research, due to a wide variety of potential applications in biomedical, optical, and electronic fields.”

A nanoparticle, made up only of a few hundred atoms, is measured in nanometers (nm) and is undetectable to the human eye. However, these particles can significantly exhibit a range of different physical and chemical properties compared to larger materials. Nanoparticles are smaller than visible light wavelengths and must require the use of an electron microscope to be seen. 

Recently, the nanotechnology industry has been called upon by another field of medicine, ophthalmology. A new study shows a unique way to use nanoparticles to deliver various proteins capable of combatting macular degeneration including anti-VEGF (vascular endothelial growth factor) and DNA (deoxyribonucleic acid). 

Therapeutic Gene Delivery

It has been studied that large genes associated with macular degeneration can be manipulated and  applied to the retina resulting in slowing, and recently in some rodent models, completely stopping the disease. However, getting the genes to be delivered to the sub-retinal area has proven to be challenging. This is mainly due to the current delivery system consisting of using viral-vectors for transport. Viral-vectors are harmless virus molecules capable of holding the gene material and traveling to the retina. The challenge, however, is that even though these are harmless virus spores, the body still recognizes them as intruders setting off a series of immune responses to stop the infiltration. This has tied the hands of researchers and scientists for years as they could not load the retina with the proper treatment due to this immune response. The treatment can only be implemented in small doses before it sets off a systemic attack. In addition, even some viral-vector deliveries could not handle the size of large genes needed for treatment. 

Peter Campochiaro, M.D., Eccles Professor of Ophthalmology at the Johns Hopkins University School of Medicine, and a member of the Johns Hopkins Medicine Wilmer Eye Institute commented, 

“Some of the most prevalent inherited retinal degenerations are due to mutations in large genes that simply cannot fit into the most commonly used viral vector,” 

Enter nanoparticles. These tiny molecules have now shown the ability to carry large genes directly into the retina making for a more streamlined, less compromised delivery option. If testing continues the way it’s going, nanoparticles may be a common, non-invasive, painless application that gets AMD drugs where they need to go fast. 

Nano-Highway

Known as ‘nanoparticle-delivered gene therapy,’ laboratory models are showing great promise in using this system to transport healing proteins to stop the excessive growth of blood vessels on the retina. This blood vessel malfunction leads to wet macular degeneration which is more dangerous than dry AMD (age-related macular degeneration) and can lead to blindness much more rapidly. 

Technology Networks (TN) reported on the process out of the Johns Hopkins laboratory, 

“[Dr.] Campochiaro and Jordan Green, Ph.D., developed a new approach involving a biodegradable polymer that surrounds and compacts long stretches of DNA, creating nanoparticles that can enter the cells. This technology allows the researchers to convert the cells of the eye into mini-factories for a therapeutic protein.”

To test this new approach, the research team first loaded the nanoparticles with a specialized glowing molecule that, if released, can be detected by electron microscope to mark its location. 

TN reported, 

“They found that even eight months after treatment, the majority of the light-sensitive cells in the rats’ eyes glowed, showing that the nanoparticles effectively deposited the florescent gene into the [retinal] cells.”

Dr. Green summed up these findings,

“These results are extremely promising. We have the ability to reach the cells most significantly affected by degenerative eye disease with non-viral treatments that can allow the eye to create its own sustained therapies.”

Nanonparticles were then used to deliver VEGF (vascular endothelial growth factor) proteins into the eyes of laboratory rodents to mimic abnormal blood vessel growth, one of the main developments of macular degeneration. Next, they used nanoparticles again, this time to deliver anti-VEGF proteins capable of deactivating the blood cell growth. This anti-VEGF therapy is currently being used to slow AMD through scheduled office visits which require an injection into the eyeball to deliver the protein. This laboratory VEGF testing was successful showing the anti-VEGF protein capable of being delivered and activated without injections into the eye. 

In 2018, the study ‘Applications of Nanoparticle Systems in Drug Delivery Technology’ published in the Saudi Pharmaceutical Journal concluded that, 

“It is evident through this review that application of nontechnology in drug delivery and medicine has paved new pathways and opened many doors for providing customizable and safer treatment option. The treatment of cancer and HIV/AIDS, non-invasive imaging as well as nutraceutical delivery have all progressed with the application of nanotechnology. Ultimately, through the manipulation of molecular size and surface properties, researchers are able to deliver drugs for longer period of time with less frequent dosing (sustained release) and with greater precision and penetration in difficult to access tissues.”

Nanoparticle delivery for macular degeneration is a promising development that looks as if it is finally going to make its way into mainstream ophthalmology treatment.