On a day that has seen the UK’s newspapers run front page stories on the benefits and successes of science’s golden child – the CAR-T cell, other news has surfaced of another equally successful breakthrough in the field of regenerative medicine.
First published in Nature Biotechnology, a team at Wake Forest Baptist Medical Centre has developed a new technique that 3D-prints living body parts, which when implanted into animals function normally.
Although similar techniques where biodegradable scaffolding is built and then ‘soaked’ in cells are already in use for human patients, the science of tissue regeneration in the past has been limited by the enormous challenge of keeping the cells alive. Generally speaking once the tissues become thicker than 0.2 millimetres the cells become starved of nutrients and oxygen.
To combat this limitation the team, led by Professor Anthony Atala, has developed a ground breaking new technique that creates tissues laden with micro-channels more akin to a sponge, which allows the nutrients to be delivered and penetrate the tissue.
In a joint publication with Hyun-Wook Kang, Sang Jin Lee, In Kap Ko, Carlos Kengla and James J Yoo, Professor Atala writes that the challenge of producing “3D, vascularised cellular constructs of clinically relevant size, shape and structural integrity” can be overcome by their “integrated tissue-organ printer (ITOP)”.
ITOP can create stable tissue constructs of any shape at a human-scale. Explaining how the technology works, the paper details:
“Mechanical stability is achieved by printing cell-laden hydrogels together with biodegradable polymers in integrated patterns and anchored on sacrificial hydrogels. The correct shape of the tissue construct is achieved by representing clinical imaging data as a computer model of the anatomical defect and translating the model into a program that controls the motions of the printer nozzles, which dispense cells to discrete locations.”
The real genius though is the addition of microchannels into the tissue that facilitates the diffusion of nutrients to printed cells (the sponge like quality) thus overcoming the 0.2 mm thickness limit of tissue constructs.
The technology has been demonstrated in mandible and calvarial bone, cartilage and skeletal muscle, with the future aims to produce tissues for human complex tissues and solid organs.
Speaking to the BBC, Professor Atala explains how this works in the real world,
“Let’s say a patient presented with an injury to their jaw bone and there’s a segment missing. We’d bring the patient in, do the imaging and then we would take the imaging data and transfer it through our software to drive the printer to create a piece of jawbone that would fit precisely in the patient.”
Although this breakthrough has got many in the field excited, Professor Atala has cautioned that additional research is needed before ITOP tissue constructs can be used in patients, but mused that “it will be less than a decade before surgeons like me are trialling customised printed organs and tissues. I can’t wait!”
Image Credit: Nature BioTechnology