Now that it has become possible to 3D print cell-friendly gels quickly and in various shapes and sizes, the next question becomes how the gel can help the development or direction of the cells. In this study, volumetric bioprinting was adapted for the creation of three-dimensional, biologically functional areas within the printed gel.
Volumetric bioprinting, with which an object a few centimeters in size can be printed in mere seconds, offers many possibilities for the printing of cells. The speed of the process combined with the cell-friendliness of the gel are great advantages. However, when the print is finished, the cells may not be placed exactly where they are needed, nor is it possible to alter the gel much to aid the development, growth or specialization of cells to create functional tissues. Overcoming this hurdle, then, is important, because in our body cells know where to go and where to stay following signals that they sense in specific regions or tissues.
Adding functionality to the printed gel
To make it possible to make chemical changes to the print after the initial printing process, the researchers played with the porosity of the gel, as well as the compounds in it that bind with other molecules in the gel. “With this technique it is possible to engraft biomolecules to our printed constructs within minutes in a high spatial resolution,” first author Marc Falandt explains. “First we printed our gelatin-based constructs with the volumetric printer, then by infusing these constructs with biomolecules and photoinitiator, we could create complex 3D motives inside the gelatin structures. This method gives us three-dimensional control of the location where you want your biomolecules to be trapped. Something that was not possible before.”
Helping cells find their way by giving them a chemical map
With this innovation, it is now possible to create volumetric prints that can have growth factors or bioactive proteins “painted” into them in any desired 3D shape. For example, signal molecules that guide the direction and formation of blood vessels can be placed in such a way that they create a trail that attracts new vessels only where and when needed inside the 3D printed object.
These signals could then attract the right cells, or help stem cells to fulfill their regenerative potential. Falandt: “This work really takes the first steps into the development and characterization of smart materials that allow biochemical editing in 3D. In combination with the fast volumetric bioprinting technique, this approach is extremely promising for the creation of a biofabricated scaffolds that could guide cell behavior and development. It could allow us to closely mimic the complex biochemical environment of native tissues and organs with our 3D bioprints.
Advanced Materials Technologies
Experimental study
Lab-produced tissue samples
Spatial-Selective Volumetric 4D Printing and Single-Photon Grafting of Biomolecules within Centimeter-Scale Hydrogels via Tomographic Manufacturing
23-May-2023
C.G. and S.v.V. are stakeholders in the company BIO INX, the authors declare to have no known competing financial or commercial interests that could have influenced the work reported in this paper. All the other co-authors declare no conflicts of interest.