Using frog foam to deliver antibiotics

March 23, 2016, Society for General Microbiology
Tungara frog (species Engystomops pustulosus) from Trinidad. Credit: Dr Paul Hoskisson

Today, at the Microbiology Society's Annual Conference in Liverpool, scientists will show that the foam made by Trinidadian frogs represents a new, non-toxic antibiotic delivery system that may help to prevent infections.

While mating, Tungara frogs (Engystomops pustulosus) release a protein cocktail that they beat into a with their back legs. The frogs - less than 5 centimetres long - lay their eggs in these foam nests to protect them from disease, predators and environmental stresses.

Researchers from the University of Strathclyde have been analysing the frog foam, showing that it is highly stable and capable of taking up drugs before releasing them at a stable rate. The group's work reveals that the foam can release model dyes at a steady rate over a period of 72-168 hours, while foam loaded with the antibiotic vancomycin was shown to prevent in vitro growth of the pathogenic bacterium Staphylococcus aureus for a period of 48 hours. The foam proteins were tested in vitro against keratinocytes, a type of skin cell, for 24 hours. These cells were still alive and viable after 24 hours of exposure, demonstrating that the foam is not toxic to human cells.

Sarah Brozio from the University of Strathclyde, who undertook the research, said: "Foams are usually very short-lived so they're not considered for long-term drug release, even though they have great potential for topical treatments. This foam comes from a tiny frog and yet offers us a whole new approach that could prevent wound infections, and with increasing antibiotic resistance it's important that all new tactics are explored. "

Currently, the team have engineered E. coli bacteria to produce two of the foam's protein constituents, including Ranaspumin-2, which on its own produces a short-lived foam that is also non-toxic to human cells. The researchers are working to produce a completely synthetic form of the foam that is as stable as the frog-produced version.

Drug delivery systems that target specific areas of the body improve treatment for patients and can reduce side effects. The group envisages that the foam's long-lasting, durable characteristics could be used to treat severe burns, which frequently become infected and require the use of intravenous antibiotics.

Dr Paul Hoskisson, who leads the research team, said: "Foams are unusual in nature and are typically made of inactivated proteins, yet this foam is stable and importantly compatible with , making it potentially ideal for pharmaceutical applications. While foams like these are a long way from hitting the clinic, they could help in burns and wound treatment, providing support and protection for healing tissue and delivering drugs at the same time - all from a humble little frog."

Explore further: Liquid foam: Plastic, elastic and fluid

Related Stories

Liquid foam: Plastic, elastic and fluid

November 30, 2015

What differentiates complex fluids from mere fluids? What makes them unique is that they are neither solid nor liquid. Among such complex fluids are foams. They are used as a model to understand the mechanisms underlying ...

Uncovering liquid foam's bubbly acoustics

October 17, 2013

Liquid foams fascinate toddlers singing in a bubble bath. Physicists, too, have an interest in their acoustical properties. Borrowing from both porous material and foam science, Juliette Pierre from the Paris Diderot University, ...

Levitating foam liquid under the spell of magnetic fields

November 11, 2013

Foams fascinate, partly due to their short lifespan. Foams change as fluid drains out of their structure over time. It is precisely their ephemeral nature which has, until now, prevented scientists from experimentally probing ...

Wood-derived foam materials

April 29, 2015

Since most foam materials are made of petrochemical plastics, they aren't very climate-friendly. But now an alternative is in sight – a novel foam material produced entirely from wood, which is not harmful to the environment ...

Recommended for you

Newly designed molecule binds nitrogen

February 22, 2018

Wheat, millet and maize all need nitrogen to grow. Fertilisers therefore contain large amounts of nitrogenous compounds, which are usually synthesised by converting nitrogen to ammonia in the industrial Haber-Bosch process, ...

A protein that self-replicates

February 22, 2018

ETH scientists have been able to prove that a protein structure widespread in nature – the amyloid – is theoretically capable of multiplying itself. This makes it a potential predecessor to molecules that are regarded ...

Squid skin could be the solution to camouflage material

February 22, 2018

Cephalopods—which include octopuses, squid, and cuttlefish—are masters of disguise. They can camouflage to precisely match their surroundings in a matter of seconds, and no scientist has quite been able to replicate the ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.