Toxin-absorbing nanosponges could be used to soak up localized infections

Toxin-absorbing nanoparticles are loaded into a holding gel to make a nanosponge-hydrogel, which can potentially treat local bacterial infections(Credit: W. Gao/Jacobs School of Engineering/UC San Diego)

Back in 2013, we heard that nanoengineers at the University of California, San Diago (UC San Diego) had successfully used nanosponges to soak up toxins in the bloodstream. Fast-forward two years and the team is back with more nanospongey goodness, now using hydrogel to keep the tiny fellas in place, allowing them to tackle infections such as MRSA, without the need for antibiotics.

Let's start with a quick recap. In 2013, a team of researchers announced that they'd successfully managed to create nanosponges – nanoparticles coated in red blood cell membranes – that flow through the bloodstream, removing harmful toxins as they go. The red blood cell coating tricks the immune system into ignoring the nanoparticles, but the disguise also attracts pore-forming toxins that kill cells by perforating their outer membranes.

This breakthrough was ideal if you wanted to deal with harmful toxins in the bloodstream, such as snake venom, but it didn't allow for a sustained attack in a localized region. Since the initial announcement, the team has been working on improving the method, with the new study focusing on adapting it to clear up antibiotic-resistant bacterial infections.

In order to keep the nanosponges tied to a specific area, the team turned to hydrogel – a gel made of water and polymers. The team mixed the nanosponges into the hydrogel, which then holds them in place at an infected spot, allowing for all of the toxins to be removed.

Nanosponges are some three thousand times smaller than red blood cells, allowing billions to be held in every milliliter of hydrogel. The gel's pores are small enough to keep the nanosponges in, but also large enough to allow the toxins to pass through, making it an ideal agent for delivery of the treatment.

As the method doesn't involve antibiotics, it's thought that it won't be affected by existing bacterial antibiotic resistance, and the bacteria shouldn't develop any new resistance in response to the treatment.

The nanosponge/hydrogel combination was tested on MRSA-infected mice, with the team observing significantly smaller lesions on treated as opposed to untreated subjects. The tests also confirmed that hydrogel was effective at holding the nanosponges in place, with 80 percent remaining at the site of infection two days after being injected.

The UC San Diego researchers posted the results of their study in the journal Advanced Materials.

Source: UC San Diego

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