Abstract: Disclosed are apparatus and methods that provide the ability to electrical stimulate a physical system, and actively eliminate interference with signal acquisition (artifacts) that arises from the stimulation. The technique implemented in the circuits and methods for eliminating interference connects a discharge path to a physical interface to the system to remove charge that is built-up during stimulation. By placing the discharge path in a feedback loop that includes a recording preamplifier and AC-coupling circuitry, the physical interface is brought back to its pre-stimulation offset voltage. The disclosed apparatus and methods may be used with piezoelectric transducers, ultrasound devices, optical diodes, and polarizable and non-polarizable electrodes. The disclosed apparatus can be employed in implantable devices, in vitro or in vivo setups with vertebrate and invertebrate neural tissue, muscle fibers, pancreatic islet cells, osteoblasts, osteoclasts, bacteria, algae, fungi, protists, and plants.

Abstract: Apparatus and processes are disclosed that provide a microfabricated microtool having a mechanically actuated manipulating mechanism. The microtool comprises a tweezer having flexible arms, and an actuating mechanism. A biological, electrical, or mechanical component is grasped, cut, sensed, or measured by the flexible arms. The actuating mechanism requires no electric power and is achieved by the reciprocating motion of a smooth, rigid microstructure applied against the flexible arms of the microtool. In certain implementations, actuator motion is controlled distally by a tethered cable. A process is also disclosed for producing a microtool, and in particular, by micropatterning. Photolithography may be used to form micro-molds that pattern the microtool or components of the microtool. In certain implementations, the tweezer and actuating mechanism are produced fully assembled. In other implementations, the tweezer and actuating mechanism are produced separately and assembled together.