An increasing number of things in our daily lives learn to think and feel. The future could look like this: Sensors integrated into clothing by default measure our pulse rate or body temperature. Reasonably priced blood analysis chips for one-time use facilitate medical tests. Toys are interactive, teddy bears can hold a conversation. Food prices and best-before dates are tagged electronically. All products can be located at any time and are provided with electronic theft protection.The electronic components and circuits that are needed to make this future vision a reality have to be produced via inexpensive techniques. In particular for packaging and disposable products, the materials of the electronic parts are required to be environmentally compatible and non-toxic. Conventional silicon chip-based electronics, as a matter of fact, often consist of materials that are harmful to the environment. Besides, the production of these materials in the clean room is relatively time-consuming and complex. At KIT 's Institute of Nanotechnology (INT), researchers develop electronic components and circuits that can be printed cost-effectively with ink-jet printers. Paper or plastics e.g., in the form of thin transparent or flexible films can be used as suitable carrier materials. Electrochemically controlled transistors are the core elements of printed electronics. The special electrolytes required by these transistors were developed by the KIT research team. The newly developed electrolyte is liquid when applied and after a few seconds hardens into an elastic transparent solid. The electrolyte is characterized by an exceptionally good ion conductivity and high polarizability and serves as electronic insulator at the same time. The components of the electrolyte - a polymer, a plasticizer, an electrolyte salt, and a solvent - all are nontoxic, environmentally compatible, durable, and temperature-stable.