The ITOP and Regenerative Medicine
Director of the Wake Forest Institute for Regenerative Medicine (WFIRM), Anthony Atala and his group have been working on 3D printed tissues for a long time, and his popular TED talk in 2011: “Printing a Human Kidney”, certainly raised the expectations for what 3D printing could do for regenerative medicine. Now, five years later, Atala’s group created the integrated tissue-organ printer (ITOP), an innovative bioprinting system. The results of their study were published in the journal Nature Biotechnology.
Even though conventional tissue engineering approaches have generated bone cartilage, and muscle tissues, they have failed to do so in a reproducible manner and with the necessary complexity that vascularization requires. Thus, bone cartilage and muscle tissues created through these engineering approaches fail to perform as expected in the clinic. With new innovations in bioprinting like the groundbreaking, ITOP, scientists can now produce human-scale tissue and organ constructs with the right architecture and structural integrity. In this first proof of concept, after transplanting bone, cartilage and skeletal muscle tissues into mice and rats, researchers demonstrated how the bioprinted living tissues engrafted, matured and became vascularized over time.
How 3D Bioprinters Works
To overcome previous bioprinting limitations, researchers have developed a system that is capable of depositing concurrently different kinds of polymers with complementing properties. By using the right polymer mixtures, they can precisely tune the mechanical properties of the structure they want to print and overcome previous size and shape limitations. The technologic advancement that allows this printing parallelization, involved designing multi-dispensing modules and sophisticated nozzles capable of printing biomaterials and cells with 2 µm and 50 µm resolutions, respectively.
New 3D bioprinting technology also required designing a lattice of microchannels that are permissive to nutrient and oxygen diffusion and allowed cross-linking of the cell-hydrogel constructs after passage through the nozzle system. In more simple terms, the ITOP is able to generate a structure of viable cells held together with “bio-ink” and engineered with a lattice of micro-channels that ensures these cells are well-nourished.
Promising Results
After transplantation, the evaluation of a bioprinted mandible bone, ear-shaped cartilage and organized skeletal muscle revealed tissue maturation and vascularization. This suggests that these printed tissue constructs might be suitable for transplantation to patients.
The highlight of this revolutionary study was how the bioprinted tissue was accepted in the animal models. Hence, the results are indeed promising and may very well regenerate modern medicine and end the need for organ donations.
References:
Kang, H.-W. et al. A 3D bioprinting system to produce human-scale tissue constructs with structural integrity. Nat. Biotechnol. (2016). doi:10.1038/nbt.3413
Image courtesy of dreamtimes.com.
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