Photo credit: Georgia Tech
Researchers at the Georgia Institute of Technology believe the use of skin cream infused with microscopic STAR particles could be an effective treatment for diseases such as psoriasis, warts and certain types of skin cancer.
Findings from the study led by Dr. Mark Prausnitz were published online ahead of print in the journal Nature Medicine (Mar. 9, 2020).
The STAR particles look like a powder to the naked eye; however, closer inspection reveals tiny microneedle projections sticking out from the particles similar to a small star.
Following prior studies using microneedle patches for vaccination, Dr. Prausnitz and Dr. Andrew Tadros, a postdoctoral scholar, attempted to advance the technology with the objective of treating skin conditions by rubbing STAR particles on the skin.
Using a mouse model, the researchers treated skin cancer tumours with 5-fluorouracil. The study’s authors found the tumour growth was inhibited when the treatment was rubbed on the skin above the tumour in combination with STAR particles. Without the STAR particles the drug was less effective, the researchers noted.
“[Dr. Tadros] and I teamed up to adapt the microneedle technology and make it useful, especially in dermatology,” said Dr. Prausnitz in a press release. Dr. Prausnitz is a Regents Professor and J. Erskine Love Jr. Chair in the Georgia Tech School of Chemical and Biomolecular Engineering.
“Microneedle patches are good at administering drugs or vaccines to a small area of skin, but many dermatological conditions are spread over larger areas. Rather than trying to make really big patches, which would be difficult to use, we ultimately arrived at STAR particles that can be rubbed on the skin—just like any skin lotion—and poke tiny holes in the skin to better deliver drugs.”
The STAR particles are mixed into a therapeutic cream or gel and applied to the skin, creating micropores in the skin’s surface that temporarily increase the skin’s permeability to treatments.
Researchers noted that most topical treatments do not absorb well into the skin. As a result, a drug often needs to be administered in the form of a pill or injection to treat the skin, which can lead to unwanted side effects.
The barrier layer of skin allows for the tiny STAR particles to poke through when rubbed on the skin and let the medications enter the body through the micropores without pain.
The study’s investigators believe the STAR particles could be a more effective method for delivering medicine directly to where it is needed and could improve treatments for patients dealing with a variety of skin diseases.
Dr. Prausnitz suggests doctors must weigh the costs of exposing the whole body to a drug such as methotrexate in psoriasis, for example, versus treating the disease topically, which may be less effective. He adds this is where STAR particles could provide value.
“Based on our studies, you could feasibly combine methotrexate with STAR particles into a cream and localize the therapy where it is needed,” Dr. Tadros said. “The STAR particles in the cream would enable drugs to get into skin and treat diseases locally, right where it needs to be treated, and without exposing the whole body to the drug.”
Each STAR particle is roughly a millimeter in size with sharp and strong microneedle structures protruding from the surface that are 100 to 300 microns long.
The research team used a laser to make the particles from ceramic materials such as titanium dioxide, a common ingredient in sunscreens and other cosmetic products.
Dr. Prausnitz and Dr. Tadros suggest that skin creams that deliver drug therapies could widen the range of compounds administered topically.
Additionally, non-medicinal creams infused with the STAR particles have been tested on humans, who reported experiencing a mild tingling sensation but no pain or skin irritation.
Dr. Prausnitz hopes the STAR particles can be used not only in dermatology but for cosmetic purposes as well, where the particles could potentially deliver anti-aging treatments without injections or other invasive procedures.
“Our research philosophy is to develop an understanding of biomedical science and engineering technology, and then bring them together to create something that is practical and can benefit patients,” Dr. Prausnitz said.