The 1966 Oscar award-winning film Fantastic Voyage took us on a microscopic journey through the bloodstream. In the film, physicians and scientists were miniaturized to save a patient’s life. Setting aside science-fiction (and shrinking people), scientists and physicians have always been fascinated with the idea of utilizing atomic and sub-atomic particles for healthcare and technology. Now, they are using nanotechnology to do just that.
Nanotechnology, the study of controlling extremely small matter, deals with structures sized between 1 and 1000 nanometers (one billionth of a meter). By comparison, a nanometer is to a meter what a marble is to the earth. At The OSU Havener Eye Institute, we are using some of the world’s smallest particles to deliver much-needed medication to patients with AMD and to discover the mechanisms behind glaucoma, one of the world’s most common blinding diseases.
NANOFIBERS COMBAT GLAUCOMA
In a David and Goliath tale, the nanoparticle is poised to take on a disease that the National Eye Institute calls the second leading cause of blindness in the world. Using tiny nanofibers, OSU researchers Yi Zhao, PhD, Deborah Gryzbowski, PhD, Paul Weber, MD, and Cynthia Roberts, PhD are creating artificial tissue that will be used to study glaucoma.
The eye, unlike most of the body, relies on fluid rather than bone to help maintain its shape. Much like a water balloon, it requires the correct amount of fluid to function properly. Because the eye is constantly producing fluid, it needs to drain fluid to maintain the right amount of intraocular pressure, or pressure within the eye. Glaucoma, which affects 65 million people worldwide, is generally associated with high intraocular pressure (IOP). The trabecular meshwork is located in between the cornea (clear surface of the eye) and the iris (the colored portion of the eye). It is responsible for draining the intraocular fluid and maintaining proper IOP.
There are many theories about why high IOP can lead to glaucoma, but testing these theories can be difficult, as very few trabecular meshwork tissue samples are donated for research. Artificial tissue had to be created for enough to be available for study. trabecular meshwork tissue is very complex, and past methods of construction were limited to less realistic two-dimensional models. This complicates the data analysis and interpretation. Clearly, a model that can more closely resemble natural trabecular meshwork tissues was imperative.
“Nanotechnology gives us a new perspective for research," said Dr. Zhao. "As we shrink things down, we can see many rules that are different from the larger scale world. It’s like opening the door to a new frontier in medicine.”
By weaving tiny fibers that had been nanoengineered, the trabecular meshwork complex natural shape can now be replicated, making closer study possible. The end of this terrible disease could be just around the corner.
NANOBUBBLE DELIVERING DRUG
From potions to pills to injections, the medical community has always tried to find better and faster ways of getting medication to where it will do the most good. In 2010, Genentech, the world’s leading biotech company, granted OSU researchers $80,000 worth of Lucentis®. Lucentis® is an anti-VEGF medication that slows the growth of abnormal blood vessels in the back of the eye (retina) for patients with age-related macular degeneration (AMD). Ronald Xu, PhD, Cynthia Roberts, PhD, Virginia Sanders, PhD, and Alan Letson, MD are now developing a more efficient drug delivery method for anti-VEGF medication using microscopic particles known as nanobubbles.
Intraocular injections of anti-VEGF medication have been used to combat AMD for many years, but despite their success, still have many problems. The anti-VEGF medication quickly leaves the eye after injection, and since a high concentration is needed for proper treatment, more injections are necessary. Each additional injection multiplies the risks of local and systemic adverse reactions.
The new, drug-loaded nanobubbles will allow medication to accumulate in the retina for a longer period of time, until activated selectively using ultrasound. The nanobubbles are dyed a fluorescent yellow, which makes them visible to imaging and to be guided and released when they are in place. The biodegradable nanobubbles keep the medication from disbursing before reaching the target area, reducing the number of injections needed.
“What we are creating is a clinical platform," said Dr. Xu, "right now we are using it for AMD, but really it could be used for delivering medication for all ophthalmic diseases. We are very excited by the possibilities.”
In short, nanotechnology allows for more research, more answers, fewer injections, fewer adverse reactions, and better care for our patients and that is no small thing.