Dr Who technology finds medical application

A MEDICAL version of Dr Who’s sonic screwdriver has been developed that could be used to diagnose a host of conditions ranging from cancer to abnormal pregnancy.

The device uses sound waves to isolate tiny liquid-filled bubbles called exosomes that are released by cells and contain tell-tale molecules linked to various disorders.

Scientists working on the technology hope to produce a portable scanner that can look for exosomes within a blood sample and provide rapid diagnosis.

Like the sonic screwdriver, it would be a multi-purpose tool capable of identifying many different conditions.

Professor Tony Jun Huang, one of the scientists from Duke University in North Carolina, US, said: “We want to make extracting high-quality exosomes as simple as pushing a button and getting the desired samples within 10 minutes.”

The same researchers have already shown that the sound wave technology can fish rare circulating cancer tumour The Doctor often used his sonic screwdriver to get outo scrapes cells out of blood samples. In their latest study, the scientists successfully captured exosomes using a two-stage approach. First, pressure from sound waves passing through liquid is used to remove cells and platelets from blood. Then higher frequency sound waves are employed to separate out exosomes from the sample.

Previous research has demonstrated that exosome contents can serve as markers for different types of cancer, neurodegenerative conditions, kidney disease, foetal abnormalities and other disorders.

But standard methods of isolating exosomes require spinning blood samples in large and non-portable high speed centrifuges.

As well as the operation taking nearly 24 hours, high centrifugal forces can damage the tiny vesicles, which measure 30 to 150 nanometres across and whose bubble-skin surface consists of a delicate fatty membrane. A nanometre is equivalent to a millionth of a millimetre.

Sound waves were much gentler and only applied a force to the exosomes for a second or less, said the researchers, whose work is reported in the journal Proceedings of the National Academy of Sciences.