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Needle-free jet injection enables the delivery of drugs into skin or soft tissue by puncturing them with a high-velocity liquid jet. However, precise and efficient drug delivery requires generating such liquid jets with both a controlled velocity and a high throughput, which remains challenging with current spring-and gas-actuated jet injectors. Here, we propose a depth-controlled and high-throughput injection method by adapting laser-induced forward transfer (LIFT), a high-resolution two-dimensional printing technique, for direct three-dimensional liquid delivery into soft tissues.The velocity of thin liquid jets is laser actuated from 10 to 85 m/s so that doses as small as 10 pL, not achievable with other injectors, are injected at a 1 Hz repetition rate into a 300 μm thick soft gelatin substrate with a 25 μm depth precision and 12 μm lateral resolution. We further investigate the potential of this liquid delivery technique as a direct three-dimensional cell-delivery vehicle and show that depth-controlled particle delivery requires high-delivery efficiency. Our direct three-dimensional liquid delivery system opens up more possibilities for pinpoint drug delivery in soft tissues or tissue-engineered constructs.

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A new feeding concept for electrical transportation systems is presented, based on supercapacitive energy storage. Supercapacitors are new and powerful components for energy storage. Compared with batteries, the amount of energy supercapacitors can store is low and does not allow large vehicle autonomy. Because supercapacitors have the property to be re-loadable in a few seconds, a sequential supply system has been developed, considering repetitive feeding at the stops. To solve the problem of the high power amount needed to reach short refill times, a solution is proposed, which consists of using an intermediary supercapacitive tank placed at fixed stations, which is refilled between the bus arrivals with a much lower power. In addition to the description of the needed power electronic converters, theoretical and experimental results are presented, defining the controlled profile of the instantaneous power level, in order to achieve a fast energy transfer between two supercapacitive tanks.