Magnetic Nanoparticles Slow Corrosive Bacteria in Biofilms

Bacteriophages combined with nanoparticle clusters are drawn into biofilms with a magnet. Photo courtesy of the Alvarez Group.

Magnetic nanoparticle clusters are showing potential to punch through biofilms to reach and purge bacteria that can foul water treatment systems with problems such as corrosion, according to scientists at Rice University (Houston, Texas) and the University of Science and Technology of China (Hefei, China).

The nanoclusters developed through Rice’s engineering research center carry bacteriophages—viruses that infect bacteria and propagate —and deliver them to targets that resist chemical disinfection.

The phages were combined with nanoclusters of carbon, sulfur, and iron oxide that were further modified with amino groups. The amino coating prompted the phages to bond with the clusters head-first, which left their infectious tails exposed and able to infect bacteria. A weak magnetic field draws the clusters—and the phages—into biofilms to their targets

Without the pull of a magnetic host, these phages would disperse in solution, largely fail to penetrate biofilms, and allow bacteria to grow in solution and corrode metal—a costly problem for water distribution systems.

The researchers say biofilms can be beneficial in some wastewater treatment or industrial fermentation reactors because of their enhanced reaction rates and resistance to exogenous stresses.

“However, biofilms can be very harmful in water distribution and storage systems since they can shelter pathogenic microorganisms that pose significant public health concerns and may also contribute to corrosion and associated economic losses,” says Rice student and study co-author Pingfeng Yu.

Source: Rice University,