American scientists have made a step forward in translating cell therapy from early experiments to the serial practice. They have used the technique of inkjet printing for high-speed production of stem cell aggregates that can differentiate into any tissue. The novelty is presented in the journal Biomicrofluidics.
The authors of the technique, researchers from Harvard Medical School, focused on early development stage of embryonic stem cells culture when cells form the so-called embroid bodies. Embroid bodies are spherical conglomerates composed of pluripotent ESCs which can reproduce in the laboratory the earliest stages of embryo development. Given the appropriate ‘incentives’, embroid bodies can turn into other cell type cultures, such as neurons etc., therefore, they can be used in regenerative medicine for growing tissues and organs.
For the technology to be expanded, it should produce correctly formed uniform embroid bodies of the right size and shape without mechanical injury and with reproducible parameters in each case. The new technology of automated bioprinting with stem cells proves to ensure the above mentioned better than traditional "hang-drop" method with manual pipetting.
To generate embroid bodies with "hang-drop" method and hand-held pipettes, one needs 10 minutes to prepare a single drop, which then develops to embroid body, and the results are not very well reproduced over and over again. To solve this problem, the researchers replaced the pipette and hands with a bioprinter that prints on the turned over Petri dish lid orderly rows of microscopic droplets with embryonic stem cell suspension. Printing speed reaches 160 drops per second. After the printing, the Petri dish lid is flipped, and cell suspensions are left for 24 hours in a hanging position to form embroid bodies. The new technique allows for controlling droplet size, getting reproducible parameters of embroid bodies, and is much faster.
The scientists have tested their technique on mouse cells, but it can be applied to human embryonic stem cells as well. Now the Harvard team plans to compare the functioning of cells grown with the old and new methods.