In a collaborative study, a team of researchers at Singapore's Institute of Bioengineering and Nanotechnology (IBN) and a team at IBM Research lab in Almaden, Calif. (IBM) have developed a new drug that could revolutionize how fungal infections are treated.
In 2010, fungal infections cost $3 billion to treat worldwide, and that number is expected to increase to $6 billion by 2014. This increase is due to an ever-growing population of immune-compromised patients who have diseases like HIV or cancer.
Growing Drug Resistance
“Currently, we have a very limited number of antifungal drugs,” said lead researcher Dr. Yi Yan Yang at IBN in an interview with Healthline. “Most antifungal drugs in the clinic do not kill the fungus, they just suppress its growth. This is why, when the environment is suitable, the fungal infection will come back again.”
That’s not the only problem with current treatments. As with bacteria and antibiotics, fungi are developing resistance to antifungal medications, requiring higher and higher doses of the drug to kill these infections.
This puts the patient at risk because current antifungal drugs have a hard time telling the difference between fungal cells and healthy human cells, so high doses of the drugs can damage a patient’s kidneys and blood cells.
A New Direction of Attack
The new drug candidate solves many of the problems facing current antifungal medications.
Yang’s team made a compound that self-assembles into small, short nanofibers. Using an electrostatic charge, the fibers target the oppositely charged cell membrane of invading fungi. The nanofibers penetrate the fungal cell’s membrane, causing the membrane to burst and killing the invader.
“Our nanostructures can actually kill the fungal cells instead of only suppressing the cells' growth,” said Yang. “Because our antifungal action is through disrupting the membrane of the fungal cells, the fungal cells are not able to develop drug resistance.”
And because of the nanofibers’ electrostatic charge, the drug won't harm animal cells. The membranes of animal cells have a neutral charge, meaning that positively and negatively charged molecules can’t interact with them. So the new drug targets fungi while leaving healthy human cells alone.
In fungal cell cultures in the lab, the new nanofibers were able to destroy more than 99.9 percent of the cells in just one hour. The fungus didn’t develop any resistance to the new drug, even after eleven treatments.
In mice with fungal eye infections, the nanofibers successfully treated the infections without any toxic side effects.
By comparison, Fluoconazole, a common antifungal drug, didn’t destroy the fungi, but prevented the infection from growing further. The fungi also developed resistance to Fluconazole after only six treatments.
To create their drug, the team used polyethylene terephthalate (PET), which is commonly used to make plastic bottles. Americans alone throw away more than 35 billion plastic bottles a year. PET is a cheap and abundant source of raw material, unlike the rare compounds from which many expensive drugs are made today.
“We developed this antifungal agent from recycled PET plastics, so the cost of production of this medication can be very low,” said Yang. “It's also quite green because we use the recycled plastics for human medical applications. We are really pretty excited.”
Right now, the drug is at the basic research stage. In order to make it to patients, the drug will need a sponsor to take it through clinical trials.
Yang is hopeful that a drug company will see the potential in their invention. “We are picking a partnership with pharmaceutical companies to further develop our research,” Yang said.