The Superbugs Are Here, But There’s Still Hope

Carbon nanodot scaffolding with polyamines kills drug-resistant bacteria, Winston-Salem State University researchers found.


We’ve been warned about it for years—the advent of the superbug. Superbugs are scary because they are treatment resistant or immune to antibiotics. But don’t despair yet! Science is on it.

According to a press release issued by Elsevier, a new study found that the tiny molecular scaffolding that holds molecules together could hold the answers to defeating antibiotic-resistant bacteria.

The study suggests that carbon nanodot scaffolding assembled with small molecules called polyamines could kill some of the dangerous drug-resistant bacteria.

According to the press release, the World Health Organization (WHO) said that antimicrobial resistance is one of the biggest public health threats we face today. In 2013 alone, there were about 480,000 cases of multidrug-resistant tuberculosis and the problem is only increasing.

Previous research has shown that some large, positively charged compounds called polycationic dendrimers are antimicrobial. The researchers of this study suggested that by adding similar, but smaller polycationic molecules onto a material called carbon nanodots could be even more effective at killing superbugs.

"We urgently need new and better antimicrobial materials if we are to tackle drug-resistant bacteria," lead author Dr. Maria Ngu-Schwemlein said in the press release. "Our study shows that carbon nanodots can serve as a molecular scaffold for building antimicrobial materials. It's exciting because carbon nanodots are relatively easy and cheap to make, they're non-toxic and soluble in water."

Dr. Ngu-Schwemlein is from the Winston-Salem State University.

Researchers use carbon nanodots in many ways, including imaging, sensing and drug delivery. They can be easily constructed from starch and are non-toxic, which makes them perfect for medicine.

Chemical groups coat the nanodots and can turn them into scaffolding that holds molecules together to enhance their potential. Researchers used them to make PAMAM (polyamidoamines) molecules, which vary in size and have some antimicrobial properties.

In an effort to make smaller, more antimicrobial molecules, researchers built two molecules—CND-PAM1 and CND-PAM2. The research team tested them both and found that even at very low concentrations both could kill Escherichia coli and Staphylococcus aureus.

Researchers also tested the molecules’ ability to kill other drug-resistant bacteria strains, including pneumonia, which the molecules were four times more effective at killing than the non-drug-resistant strain.

The study also found that the molecules with scaffolding helped existing antibiotics work better.

"We hope our research will lead to more effective antibiotics, and that it will inspire other researchers to use carbon nanodots as scaffolding for a variety of applications," Dr. Ngu-Schwemlein said.

This study was published in Bioorganic & Medicinal Chemistry Letters, volume 26.

It was funded in part by the National Institute of General Medical Sciences, part of the National Institutes of Health.

The authors disclosed no conflicts of interest.