First 3D-printed heart-on-a-chip with sensing developed

Harvard scientists have developed the first entirely 3D-printed heart-on-a-chip with integrated sensing using a fully automated procedure, which may provide an alternative to traditional animal testing for drugs.

The new approach to manufacturing may one day allow researchers to rapidly design organs-on-chips, also known as microphysiological systems, that match the properties of a specific disease or even an individual patient's cells.

The 3D-printed heart-on-a-chip, developed by researchers at Harvard University, can be quickly fabricated in customised form factors allowing researchers to easily collect reliable data for short-term and long-term studies.

"This new programmable approach to building organs-on-chips not only allows us to easily change and customise the design of the system by integrating sensing but also drastically simplifies data acquisition," said Johan Ulrik Lind, postdoctoral fellow at the Harvard John A Paulson School of Engineering and Applied Sciences (SEAS).

"Our microfabrication approach opens new avenues for in vitro tissue engineering, toxicology and drug screening research," said Kit Parker, Professor at SEAS.

Organs-on-chips mimic the structure and function of native tissue and have emerged as a promising alternative to traditional animal testing.

Researchers have developed microphysiological systems that mimic the microarchitecture and functions of lungs, hearts, tongues and intestines.

However, the fabrication and data collection process for organs-on-chips is expensive and laborious.

Currently, these devices are built in clean rooms using a complex, multi-step lithographic process and collecting data requires microscopy or high-speed cameras.

"Our approach was to address these two challenges simultaneously via digital manufacturing," said Travis Busbee, graduate student at Harvard.

"By developing new printable inks for multi-material 3D printing, we were able to automate the fabrication process while increasing the complexity of the devices," said Busbee.

The researchers developed six different inks that integrated soft strain sensors within the micro-architecture of the tissue.

In a single, continuous procedure, the team 3D printed those materials into a cardiac microphysiological device - a heart on a chip - with integrated sensors.

The chip contains multiple wells, each with separate tissues and integrated sensors, allowing researchers to study many engineered cardiac tissues at once.

"Researchers are often left working in the dark when it comes to gradual changes that occur during cardiac tissue development and maturation because there has been a lack of easy, non-invasive ways to measure the tissue functional performance," said Lind.
"These integrated sensors allow researchers to continuously collect data while tissues mature and improve their contractility," he said.

The research was published in Nature Materials.