Scientists say they have made a “nanomedicine breakthrough” by creating “antifungal nanofibers” from recycled plastic materials that are able to target and attack specific fungal infections. This is according to a study published in the journal Nature Communications.
Researchers from the International Business Machines Corporation (IBM), based in the US, and the Institute of Bioengineering and Nanotechnology (IBN) in Singapore, say they created the technology by converting plastic materials such as polyethylene terephthalate (PET) – commonly used in plastic bottles – into non-toxic biocompatible materials that act as “antifungal agents.”
Fungal infections are extremely common all over the world and cover a broad number of conditions. Mild fungal infections include athlete’s foot, a rash or a mild respiratory illness. But other fungal infections, such as fungal pneumonia or bloodstream infection, can be severe.
According to the researchers, a person is more likely to develop a fungal infection if they possess an altered immune system as a result of antibiotic treatment, or have conditions such as HIV/AIDS or cancer.
Although there are antifungal drugs available to treat these infections, there is the issue of drug resistance.
The investigators explain that traditional antifungal drugs work by attempting to get into cells to attack the infection. However, the drugs find it difficult to target and break through the membrane wall of the fungi.
They also note that fungi are similar to mammalian cells in terms of metabolism. This means the antifungal drugs that are currently used have difficulty determining the difference between infected and healthy cells.
With these factors in mind, the investigators looked to develop a new antifungal agent that could combat the issue of drug resistance.
The scientists transformed PET into completely new antifungal molecules using a hydrogen-bonding process that causes them to self-assemble.
The researchers explain that the way these molecules stick together is “like molecular velcro in a polymer-like fashion to form nanofibers.” They note that this process is important because the antifungal agents only work in their “fiber or polymer-like form.”
Explaining how the agents, or “nanofibers” work, the researchers say they possess a positive charge that is able to specifically target a fungal membrane that is negatively charged, and attach to these alone through “electrostatic interaction.”
Dr. Yi Yan Yang, of IBN and leader of the study, says:
“The ability of these molecules to self-assemble into nanofibers is important because unlike discrete molecules, fibers increase the local concentration of cationic charges and compound mass.
This facilitates the targeting of the fungal membrane and its subsequent lysis, enabling the fungi to be destroyed at low concentrations.”
The assembly of the antifungal nanofibers was simulated in order to predict which different structures could destroy fungi.
From this, the researchers found that the lowest concentration that stops the visible growth of fungi – known as the minimum inhibitory concentration (MIC) – proved the most effective against a variety of fungal infections.
Further research revealed that the nanofibers erased 99.9% of Candida Albicans (C. albicans) – a fungus that is a cause of oral and genital infections in humans, as well as the third most common bloodstream infection in the US.
The fungi was eradicated after 1 hour of incubation and demonstrated no sign of resistance after 11 treatments.
Comparing these results to traditional antifungal drugs, the researchers note that traditional therapeutics developed resistance after 6 hours and were only able to suppress additional fungal growth.
Further studies also looked at the activity of the nanofibers in mouse models. This was done using a C. albicans biofilm infection linked to use of contact lenses.
The researchers found that the nanofibers were able to significantly reduce the number of fungi, prevented new structural growth of fungi in the cornea, and decreased inflammation in the eye.
Commenting on the findings, Prof. Jackie Y. Ying, executive director of IBN, says:
“A key focus of IBN’s nanomedicine research efforts is the development of novel polymers and materials for more effective treatment and prevention of various diseases.
Our latest breakthrough with IBM allows us to specifically target and eradicate drug-resistant and drug-sensitive fungi strains and fungal biofilms, without harming surrounding healthy cells.”
Earlier this year, Medical News Today reported on a study detailing the discovery of a new type of gene switch found in C. albicans.