The development of new drugs is not without tests. Scientists first offer them to animals, but the ultimate consumer of medicines is humans. But here there is no full guarantee that the proposed medicine is harmless to the subject. It is important for specialists to know what side effects are possible from taking a developed medication, what needs to be changed. A solution has been found. Lawrence Livermore National Laboratory recently introduced a heart-on-a-chip at Lawrence Livermore National Laboratory. Specialists have learned how to generate tissue that performs the basic functions of the main human organ – the heart, artificially. Nobody has achieved such success before them. The heart tissue grown in Lawrence’s laboratory makes it possible to measure the intensity of its contractions and the electrical signals passing in it. Samples that were created earlier, could perform no more than one function of the heart. Tissues were grown from human heart cells under laboratory conditions for 9 days. The researchers obtained the first results 2 days after the start of the experiment. A two-dimensional structure, which could already be reduced, was obtained from cardiomyocytes, the muscle cells of the heart. Further, experts studied how norepinephrine acts on the heart, it is used in the treatment of heart failure and low blood pressure. Scientists have recorded that the heart was contracting more often from the drug and more frequent electrical signals came. Under the action of norepinephrine, a similar reaction is observed in the heart muscle. The continuation of the experiments allowed us to achieve an amazing effect – the preservation of electrical impulses in the tissues when the contraction itself was completed. Previously, it was not possible to achieve a similar effect on any artificial simulator. Thus, in the future, the new platform may partially abandon animal testing.