Israeli researchers have just announced the successful completion of a molecular computer, which uses enzymatic chemical reactions to perform the necessary logic computations. Itamar Willner and his team at the Hebrew University of Jerusalem built the computer using glucose dehydrogenase (GDH) and horseradish peroxidase (HRP) enzymes, with hydrogen peroxide and glucose molecules representing input values. The presence or absence of these two chemicals correspond to binary 1s and 0s, allowing the computer to perform AND and XOR operations which are determined optically by a camera. Although enzyme computers will always be inherently slow, Willner envisions his invention being used one day to precisely calculate and distribute doses of medicine from inside a patient's body.