Researchers at the University of California San Diego have developed a high-throughput technique for 3D bioprinting. Using the new technology, the researchers can very quickly print large numbers of custom tissue samples that are suitable for drug screenings. Their printing method can yield a 96-well plate with tissue samples in each well in as little as 30 minutes, which takes closer to 100 hours using previous technologies. This approach would be useful for researchers who need to test the effects of drug candidates on specific human tissues or model diseases.
High-throughput drug screens using human tissue samples can help researchers to weed out ineffective drug candidates, identify promising drug compounds and reduce the number of experimental animals required for preclinical drug research. Bioprinting is a developing technology, whereby a solution of cells and biomaterials is 3D printed into tissue constructs, which has the potential to aid high-throughput drug screening. However, current bioprinting technologies are not typically fast enough to produce a large number of tissue samples within a reasonable time frame.
This new method is geared towards creating tissues samples that contain human cells, and which can provide valuable data. “With human tissues, you can get better data – real human data – on how a drug will work,” said Shaochen Chen, a researcher involved in the study, in a UCSD announcement. “Our technology can create these tissues with high-throughput capability, high reproducibility and high precision. This could really help the pharmaceutical industry quickly identify and focus on the most promising drugs.”
Examples of the geometries that the high-throughput 3D bioprinter can rapidly produce.
The researchers can create a variety of custom tissue structures using the technology, and the printing occurs directly into the wells of a 96-well plate, meaning that the tissue samples are then ready to be assayed right away. An individual sample can be created in as little as 10 seconds. “When you’re scaling this up to a 96-well plate, you’re talking about a world of difference in time savings – at least 96 hours using a traditional method plus sample transfer time, versus around 30 minutes total with our technology,” added Chen.
Using a computer to design the structure of the printed samples beforehand, the researchers can use medical scans to create custom samples that are individual to specific patients. The computer model is then divided into two-dimensional slices and the printing occurs slice-by-slice, rather than the line-by-line approach most commonly used by printers. An array of mirrors and a light-sensitive polymer that solidifies when light reflected by the mirrors strikes it help the system to rapidly create a 3D polymer structure containing live cells.
“An analogy would be comparing the difference between drawing a shape using a pencil versus a stamp,” said Henry Hwang, another researcher involved in the project. “With a pencil, you’d have to draw every single line until you complete the shape. But with a stamp, you mark that entire shape all at once. That’s what the digital micromirror device does in our technology. It’s orders of magnitude difference in speed.”
Study in journal Biofabrication: High throughput direct 3D bioprinting in multiwell plates