Tiny thermometer directly monitors changes in temperature when ions pass through a nanopore. (Credit: Osaka University)

Nanopores, which are tiny openings in a membrane so small that only a single DNA strand or virus particle can pass through, are an exciting new platform for building sensors. A direct measurement of the thermal effects caused by these ions can help make nanopores more practical as sensors.

A team of researchers has created a thermocouple made of gold and platinum nanowires with a point of contact just 100 nm in size that served as the thermometer. It was used to measure the temperature directly next to a nanopore cut into a 40-nm-thick film suspended on a silicon wafer.

Joule heating occurs when electrical energy is converted into heat by the resistance in a wire. When studying a 300-nm-sized nanopore, the researchers recorded the ionic current of a phosphate buffered saline as a function of applied voltage. They demonstrated nearly ohmic behavior over a wide range of experimental conditions.

With smaller nanopores, the heating effect became more pronounced, because less fluid from the cooler side could pass through to equalize the temperature. As a result, the heating could cause a non-negligible effect, with nanopores experiencing a temperature increase of a few degrees under standard operating conditions.

For more information, visit here  .

Topics:
Biological sciences Measuring Instruments Medical Medical equipment and supplies Medical, health and wellness Monitoring Nanotechnology Nanotechnology Sensors Sensors and actuators Thermoelectrics

More From SAE Media Group

    Magazine cover
    Medical Design Briefs Magazine

    This article first appeared in the April, 2022 issue of Medical Design Briefs Magazine (Vol. 12 No. 4).

    Read more articles from this issue here.

    Read more articles from the archives here.