Pioneering 'Heart on a Chip' will aid drug screening

As a result, these 'organ on a chip' devices could replace the use of animals to screen drugs for safety and usefulness.

This 'organ on a chip' is said to represent a major step forward in the development of accurate, faster methods of testing for drug toxicity. It is reckoned to cost about $5bn on average to develop a drug and 60% of that figure comes from upfront costs in the research and development phase. According to Professor Healey, using a model of a human organ could significantly cut the cost and time of bringing a new drug to market.

The heart cells were derived from human-induced pluripotent stem cells, the adult stem cells that can be coaxed to become many different types of tissue.

The researchers designed their cardiac microphysiological system with a 3D structure comparable to the geometry and spacing of connective tissue fibre in a human heart. The team added the differentiated human heart cells into the loading area and the system’s confined geometry helped align the cells in multiple layers and in a single direction.Microfluidic channels on either side of the cell area serve as models for blood vessels, mimicking the exchange by diffusion of nutrients and drugs with human tissue.

The system replicates how tissue in the body actually gets exposed to nutrients and drugs. Within 24 hours after the heart cells were loaded into the chamber, they began beating on their own at a normal physiological rate of 55 to 80bpm. The researchers noted that their 'heart on a chip' could be adapted to model human genetic diseases or to screen for an individual’s reaction to drugs. The engineered heart tissue remained viable and functional over multiple weeks, which is enough time to be used to test various drugs according to Professor Healey.