Pinprick solution for heart tests

Kent-based in-vitro diagnostic company Vivacta has developed a point-of-care device that can measure the rate of heart muscle decay from a pinprick of blood.

The technology (pictured below) combines piezofilm detection with immunoassay testing, a method of clinical chemistry testing that detects analytes by directing antibodies to bind to the specific ones. An example of an analyte is troponin, one of the proteins that makes up the heart muscle and is detected in blood in increasing concentrations when part of the muscle dies.

The device, comprising a single-use cartridge that is put into an A5-sized instrument, is claimed to deliver the results of the concentration of the analyte in under five minutes.

'You prick a patient's finger and the cartridge will draw 30 microlitres of blood into the cartridge,' said chief executive Neil Butler.

'The blood flows into a capillary channel and picks up what we call a label, which has antibodies all over it. This will find the analyte of interest and bind with it.'

Laminated on the capillary channel is piezofilm, a plastic with piezoelectric and pyro- electric characteristics, which has the same antibodies on its surface that bind to the analyte-bound labels in the capillary.

When the cartridge is inserted into the device, an LED is flashed through the piezofilm and any label bound to the surface absorbs the light energy and turns it into heat. 'The heat gets dumped into the piezofilm which sees it as a temperature change and generates a voltage,' said Butler. The voltage is the quantitive measurement of the binding event, which is directly proportional to the concentration of the analyte in the solution.

Vivacta intends to launch a test for Thyroid Function where the analyte thyroid stimulating hormone (TSH) needs to be detected at concentrations 10 times lower than for troponin.