Did you know that a new type of button battery is much safer for children to swallow (although we don’t recommend it)?

Around 5,000 children a year in America are rushed to hospital after swallowing batteries.

When the batteries contact body fluids, it activates an electric current that damages tissue.

Scientists from Harvard and MIT covered the anodes of button batteries with a silicone polymer containing silver particles.

At normal pressure, the silicone expands. The silver particles embedded in it are spaced far apart from each other and do not conduct electricity.

When pressure is applied by putting the battery in its casing in an electrical device, it compresses the silicone mixture, bringing the silver particles into contact with each other so they can conduct electricity.

If a child ingests the battery, it will not be compressed inside its oesophagus. The silver particles are spaced far apart and do not conduct electricity, thus protecting the child from tissue damage.

The authors are currently investigating the safety implications of children sticking the batteries up their nose and ears.

 

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Background

Accidentally swallowing batteries can be very dangerous.

Around 5,000 children are rushed to emergency departments in the USA each year, with an average of 1 death per year.

Besides choking, the batteries can cause damage to the digestive tract, particularly the oesophagus and vocal chords.

Tissue damage is caused by leakage of caustic alkaline electrolytes, and more significantly, activation of electric currents when in contact with body fluids.

Legislation was introduced in 2008 to restrict children’s access to batteries (i.e. they must be locked in a casing inside devices), however this has seen only a modest reduction in battery ingestions.

Therefore, alternative approaches are required.

Materials and Methods

Scientists from Harvard and MIT in Boston, USA developed a new coating that insulates the battery when ingested (prevents current flow). They visualised the coating using electron microscopy, then tested it in saline solution and in a pig’s oesophagus.

Results

Silver particles were mixed into a silicone polymer, which was applied to the anodes of button batteries.

At normal pressure, the silicone expands. The silver particles embedded in it are spaced far apart from each other and do not conduct electricity.

When pressure is applied by putting the battery in the casing of an electric device, it compresses the silicone mixture, bringing the silver particles into contact with each other so they can conduct electricity.

If a child ingests the battery, it will not be compressed inside its oesophagus. The silver particles are spaced far apart and do not conduct electricity.

Instead, the silicone acts as an insulator, preventing current flow from the battery (even in the presence of fluid), protecting the child from internal tissue damage.

Discussion

The silicone insulation also helps protect/insulate the batteries from water and prolongs their shelf-life.

The authors state they are currently investigating the safety implications of children sticking the batteries up their nose and ears.

Article

Simple battery armour to protect against gastrointestinal injury from accidental ingestion

Laulicht et al., 2014 Proc. Nat. Acad. Sci. USA 111:16490-5

Keywords

Battery, batteries, electric, electricity, current, silver, conduct, conduction, silicone, polymer, ingestion, swallow, compress, compression, pressure, expand, pressure, oesophagus, emergency

Subject

Science, chemistry, ST1-12MW, ACSSU031, ST1-13MW, ST1-16P, ST2-16P, ST3-6PW, ACSSU097, ACSSU219, ST3-13MW, ST3-16P, ST4-10PW, ACSSU117, SC4-11PW, ACSSU155, SC5-11PW, ACSSU190, SC5-17CW, ACSSU187