NPL worked with Ecobrands Ltd to characterise their Zap-It! product, which uses the tiny electric current generated by piezoelectric material to relieve the pain and itching caused by insect bites - such as those from mosquitos.
Zap-It! is a pocket-sized product, marketed by Ecobrands, that is based around a similar piezoelectric mechanism to that used as the ignition source in electronic lighters. It is a medical device, currently available to buy in high street stores across the UK and Europe but, to be sold in the United States of America, it needs FDA (Food and Drug Administration) approval, which requires further test data regarding its electrical output.
Piezoelectric materials, the most well-known of which is quartz, produce a small electric current when their shape is deformed under pressure. By 'clicking' the Zap-It! device, an electrical current is produced that acts on the skin of an insect bite victim to reduce excess production of histamine, and the associated redness and itching. Results from a clinical trial conducted at the London School of Hygiene and Tropical Medicine concluded that more than 90% of test subjects were itch-free within five minutes of using the Zap-It! product.
Ecobrands contacted NPL as they were keen to collect as much accurate data as possible to submit to the FDA and to consider every aspect of their product's safety. A Technology Innovation Fund project was set up to provide this data and potentially open up the US market to the product.
NPL has an international reputation in functional materials characterisation, especially that of piezoelectrics, and so was well positioned to carry out this work for Ecobrands. The majority of the measurements made in the project related to quantifying the electrical output from the device during normal operation. The main challenges came from the fact that the electric pulses produced are very high voltage, low current and are discharged over a short period of time - only 10 millionths of a second. The energy in these pulses depends on the load resistance and the device needed to be tested against a range of loads, representing different skin impedances, to ensure that the device output is safe in all possible conditions.
Robin Baker, Managing Director of Ecobrands, said: "It has been a privilege to have the opportunity to work with the team at NPL to dig deeply into the minutiae of the electrical world of the simple piezo. In my case, to fathom its application on the skin for remedial purposes, and confirm its function within accepted safety limits. With the detailed work Dr. Mark Stewart has produced, I hope Ecobrands will convince the FDA medical board that the product may be sold in the United States."