Scientists have created tiny micromotors which run on stomach acid and can be used to treat bacterial infections of the digestive tract, a nanotechnology first in drug-delivery.
In a new paper published in the journal Nature Communications, engineers at the University of California San Diego describe the positive results of testing their new invention on mice. The tiny delivery systems, about half the width of a human hair, have a magnesium core which reacts with gastric acids of the gut to neutralize stomach acids and to form hydrogen bubbles which propel them forward, allowing the delivery of an antibiotic attached as a layer around the micro core. A further, outer layer of positively-charged polymer allows the nanomachines to adhere to the wall of the stomach.
The process is being hailed as an advance in drug delivery, as it improves upon current methods which rely on proton pump inhibitors to neutralize stomach acids so that antibiotics can do their part in attacking infections of the gut. Proton pump inhibitors come with side effects when taken over long periods of time or in high doses, whereas the magnesium cores and polymer layers of the micromotors can be dissolved by gastric acids without producing harmful physiological effects.
“It’s a one-step treatment with these micromotors, combining acid neutralization with therapeutic action,” said Berta Esteban-Fernández de Ávila, postdoctoral fellow at the UC San Diego Jacobs School of Engineering and study co-author, in a press release.
Researchers tested their method on mice infected with Helicobacter pylori, a bacteria of the digestive tract that causes ulcers. The micromotors delivered the antibiotic clarithromycin to the mice’s stomach and, after five days of treatment, proved to be “slightly more effective” than the current approach involving protein pump inhibitors.
Still in its early stages, the researchers will next test their micromotors using other drug combinations to potentially treat other gastro-intestinal diseases.
“There is still a long way to go, but we are on a fantastic voyage,” says Joseph Wang nanoengineering professor at UC San Diego and lead author of the study, to the New Scientist.
The medical uses of nanotechnology are just beginning to be investigated, as researchers continue to develop methods for scaled-down drug delivery and use nanomachines to improve a targeted, personalized approach to treatment. Nanosensors are finding particular use in medical diagnosis, too, as they present a quicker, cost-effective, portable and accurate way to detect minute quantities of certain compounds in the body.
Natural compounds found in the breath, for example, can be detected on a micro-scale and act as biomarkers for a range of diseases, often presenting themselves much earlier than a disease’s other symptoms — for example, cancers often go undetected at their early stages due to a lack of observable symptoms — and thus their detection could drastically speed up diagnosis.
“As you go smaller, it creates less footprint and more power,” says Frank Gu, professor of chemical engineering at the University of Waterloo in Waterloo, Ontario, to the Toronto Star. “We are at a pivotal point that we are beginning to see how to harvest nanotechnology,” he says.