March 25, 2025: Newcastle University scientists, supported by funding from Versus Arthritis, have created an innovative bioprinting method that produces cell-filled gels closely resembling human tissues, earning patents in both the US and Europe.

The pioneering technique, known as Reactive Jet Impingement (ReJI) bioprinting, involves jetting two different liquids at each other—one containing cells in a cross-linking solution and the other a polymer solution. These solutions combine mid-air to create a cell-filled hydrogel that can be printed on nearly any surface. This approach enhances cell density to approximately ten times that of conventional bioprinting technologies and operates at a much faster rate. The resulting tissues are significantly more like human tissue samples.

Their discovery shows such potential that they have launched a spin-out company, Jetbio, to attract investment and introduce the ReJI printer to laboratories worldwide.

Professor Dalgarno, of Newcastle University's School of Engineering, said, “Drug discovery is a complicated and extremely costly process involving multiple rounds of testing before they reach clinical trials. In clinical investigations, only one in ten of the compounds tested proceeds to reach the market. These rates of failure make it clear that we must improve our models so that they are more representative of drug response in humans. There is currently a lot of interest in developing better human in vitro models of diseases and tissues so we have better ways of testing drugs.”

The landscape of drug discovery is changing and interest in new technology is growing.  With the potential for the British start-up to tap into a rapidly expanding global market, the Jetbio team was invited to showcase the technology to ministers and senior figures in public health.

The changing landscape of drug discovery

Lucy Donaldson, director of research at Versus Arthritis which funded the research through the Tissue Engineering and Regenerative Therapies Centre Versus Arthritis,  said, “The JetBio team are in the vanguard of research driving forward new technologies that promise to improve both the quality and speed of drug development. These advances can potentially bring new drugs to the population sooner – and that applies to treatments for arthritis, cancer, and cardiovascular disease. This is a very exciting leap forward.”

A crucial step in the drug development process is testing on in-vitro cell cultures, which traditionally involve growing cells on a flat surface, such as a microscope slide. In vitro refers to tests or processes conducted outside the body under artificial conditions, like on a slide or in a test tube. However, these 2D models do not accurately reflect the human body, where cells naturally interact with each other in a 3D environment.

Introducing Jetbio’s technology into labs to print cells in a 3D matrix, which more closely replicates human tissues, could significantly improve testing accuracy. This advancement has the potential to transform what is currently a lengthy process with high failure rates, explained Professor Dalgarno from Newcastle University's School of Engineering.

The coffee machine-sized printers also hold promise for regenerative medicine. Arthritis, which affects 10 million people in the UK and over 500 million globally, currently has limited treatment options. This condition significantly impacts people’s ability to lead pain-free, active lives. For arthritis patients, the goal is to refine the technology to enable faster and more personalized cell culturing for use in Autologous Chondrocyte Implantation (ACI), a procedure where surgeons repair cartilage damage by implanting specialized cells into cartilage defects. This technology could enhance the precision and success rates of such implants.

The printers also have potential applications for a wide range of medical conditions. A notable example is the EC-funded REBORN project, where the Newcastle team is developing an in vitro heart chamber model. By combining ReJI bioprinting with other bioprocessing techniques, they aim to create a tissue-engineered "sleeve" that can be connected to small pumps to simulate a beating heart. The sleeve’s unique structure contains cardiomyocyte and fibroblast cells, mirroring those found in heart tissue, and is being developed to support the testing of new treatments for cardiac conditions.

Funding from the NC3Rs has supported showcasing the printers to the scientific community through workshops held in Bristol, Newcastle, and Cambridge in February. The printers are now set to be deployed in the labs of these three universities.