It is the first time that the researchers are successful in introducing an electronic device which can easily monitor the beating of heart cells without giving much harm to them and disturbing their function. RIKEN and a University of Tokyo, Tokyo Women’s Medical University worked together and provided a live sample of heart cells in contact with the nanomesh sensor.
This newly invented device does not only has the ability to track the function of heart cells but also acts as an aid for the future studies of other cells, organs, and tissues. Furthermore, it also provides a path for the future embedded medical devices.
Successful and meaningful cardiac researches are immensely important for everyone. Sunghoon Lee, a professor in Takao Someya’s group at the University of Tokyo, wondered if he and his team could come up with an ultrasoft electronic sensor which can detect and observe the functioning cells. His team then worked and at last was able to make up a sensor that could study heart cells or cardiomyocytes and its beating.
“When researchers study cardiomyocytes in action, they culture them on hard Petri dishes and attach rigid sensor probes. These impede the cells’ natural tendency to move as the sample beats, so observations do not reflect reality well,” said Lee.
“Our nanomesh sensor frees researchers to study cardiomyocytes and other cell cultures in a way more faithful to how they are in nature. The key is to use the sensor in conjunction with a flexible substrate, or base, for the cells to grow on.”
For further carrying out this research Tokyo Women’s Medical University supplied the researchers a fresh sample of cardiomyocytes originated from the human stem cells. The base for these cells was fibrin gel, a very delicate and soft material.
Professor Lee conducted out a complex process and in which he placed the nanomesh sensor on top of the live stem cells. He kept on adding and removing liquid medium when required. This step was an important one to direct the nanomesh sensor.
Professor Lee said: “The fine mesh sensor is difficult to place perfectly. This reflects the delicate touch necessary to fabricate it in the first place. The polyurethane strands which underlie the entire mesh sensor are 10 times thinner than a human hair. It took a lot of practice and pushed my patience to its limit, but eventually, I made some working prototypes.”
For introducing these sensors, the researchers used a method just like a 3D printer, known as electro-spinning. It drives out the polyurethane strands on to a flat sheet. To make it stronger, they covered the spider-web like a sheet with parylene which is a type of plastic. For removing parylene on unnecessary areas, a process called dry etching process with the help of a stencil is done.
After applying gold to them, sensor probes and communication wires are formed. Parylene also serves the function of isolating the probes so that the signals do not interfere with each other. With the help of three probes, it can read out the voltage at three specific areas. The signals called action or field potential are significant for observing the effect of drugs on the heart.
“Drug samples need to get to the cell sample and a solid sensor would either poorly distribute the drug or prevent it reaching the sample altogether. So the porous nature of the nanomesh sensor was intentional, and a driving force behind the whole idea.”
“Whether it’s for drug research, heart monitors or to reduce animal testing, I can’t wait to see this device produced and used in the field. I still get a powerful feeling when I see the close-up images of those golden threads,” says Professor Lee.