Researchers at the University of California San Diego have developed a tiny “pop-up” sensor that can measure the electronic signals traveling in heart cells. The technology consists of tiny spike-like protrusions that can penetrate cell membranes without causing damage, and that can detect electrical signals within individual cells and between cells in 3D tissue samples. The device could provide new insights into heart diseases such as myocardial infarction and cardiac arrhythmias.
Heart tissue is intrinsically dependent on electrical activity for proper function, and its precise measurement at the single cell level and intercellular level could provide a wealth of information on the basis of numerous heart diseases. However, inserting tiny electrodes into individual cells is difficult and can cause damage. This latest technology is said to offer a less invasive way to achieve this.
“Studying the propagation of an electrical signal between different cells is important to understand the mechanism of cell function and disease,” said Yue Gu, one of the scientists who led the development of the new sensor. “Irregularities in this signal can indicate, for example, cardiac arrhythmias. If the signal cannot travel properly from one part of the heart to the other, then part of the heart cannot receive the signal and therefore cannot contract. ”
Illustration of the device’s connection to heart cells (above). The sensors can simultaneously monitor electrical signals in several individual cells (bottom left) and at two locations in one cell (bottom right). Image adapted from Nature Nanotechnology
The device is based on an array of tiny field effect transistors that the researchers coated with a double layer of phospholipid. This coating allows them to penetrate inside the cell without causing a foreign body reaction that would interfere with long-term measurements of electrical activity. The tiny probes are sensitive enough to measure electrical signals within a cell, but they can also track signals traveling through multiple cells.
The device has a “pop-up” structure because the researchers glued the transistors onto a pre-stretched elastomeric film, and when the tension was released, the transistors straightened up into a 3D structure. “It’s like a pop-up book,” said Gu. “It starts as a 2D structure, and when you press it, it pops open in some places and becomes a 3D structure.”
So far, the UCSD team has tested the technology on cardiac cell cultures in the laboratory and has already gained some knowledge about the speed with which signals propagate through individual cells and cell groups. However, the device could also have potential for research into neurological diseases and allow researchers to study the electrical impulses in neurons.
Study in nature nanotechnology: Three-dimensional transistor arrays for intra- and intercellular recording
