2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Swiss and Dutch researchers have developed material that allows the use of rotational 3D printing to create volumetric models of organs from hydrogels with living cells. The method differs from traditional layer-by-layer 3D printing in that the object is created simultaneously throughout the entire volume in one stage, which reduces the printing time to several tens of seconds, say the authors of the article in Advanced Materials.
In almost all 3D printing methods, an object is formed by layering material. This allows you to create objects of almost any shape, including a complex internal structure, but it causes the main disadvantage of 3D printing - a lot of time spent even on creating small objects.
There are also uncommon methods that allow you to form a printed object simultaneously over the entire volume and thereby significantly save time. One of these methods is somewhat reminiscent of computed tomography - during it, a vessel with a liquid material hardening under the action of irradiation rotates and is irradiated with light from a projector. At the same time, the projections of the 3D model from a certain angle are displayed on the projector one by one. The intensity of the radiation is selected in such a way that the object solidifies only in that volumetric area where light from different projections is combined. After printing, the remaining liquid precursor can be drained from the vessel and the printed object removed from it.
A team of researchers led by Riccardo Levato of the University of Utrecht used this technique to print organ models from a hydrogel with living cells. They created a hydrogel precursor consisting of a phosphate-buffered gelatin-methacryloyl hydrogel and a photoinitiator. They placed various cells in it with a concentration of 106 to 107 units per milliliter.
The authors experimented with printing volumetric models of some organs from several types of cells. During the experiments, they managed to create several models, spending several tens of seconds on printing. To test the applicability of the method, they measured the viability and metabolic activity of cells on the day of printing and one week after that.
It turned out that after a week, cell survival remained almost the same (about 85 percent), and metabolic activity doubled or more, depending on the sample and the type of cells. In addition, comparison with printing with the same formulations by other methods showed that these parameters are comparable when using rotary 3D printing.
In 2017, another group of researchers presented a method of volumetric projection 3D printing, in which a vessel containing a liquid does not have to be rotated. The installation, created by the scientists, uses a spatial modulator that splits the laser beam into three separate beams that hit the container of liquid on three sides, thereby achieving a similar effect with the solidification of certain areas.