Part I of the tutorial focused on utilizing electrochemical devices, which convert electronic addressing signals into chemical signal substances, in order to regulate the functions and physiology of cells and tissues. The prime devices to achieve such regulation are the ionic resistor, diode and transistor-based on polyelectrolytes and PEDOT. Such iontronics were described in detail, including how they have been applied to various biological systems for precise control of physiology. The tutorial initially reviewed the field of organic bioelectronics; the devices utilized and application targets chosen.