The present invention provides, in part, a dexterous endoscope apparatus, referred to herein as a MicroFlex Scope (MFS). The MFS is an novel, small diameter, e.g., less about 1 mm to about 4 mm, about 1 mm to about 3 mm, etc., dexterous endoscope that allows for access, direct visualization, tissue sampling, treatment, etc. of body lumens. In one embodiment, the distal end of the MFS of the invention is an ultra-flexible tip that comprises a plurality of thin, curved shape memory alloy (SMA) actuator elements attached to at least one structural skeleton, e.g., a coil spring skeleton or hinge structure. The SMA actuator elements in each structural skeleton segment are indirectly heated by a heater element and produce force in response to their temperature relative to specific thresholds. In certain embodiments, the heater element may include an integrated heater/sensor element adapted to heat the actuator element and to sense the temperature and bend state of the actuator element. In configurations comprising a plurality of actuator elements, multiplexing/demultiplexing of heating currents and sensor voltages may be accomplished via a parallel bus and demulitplexing circuit. In this regard, a demultiplexing circuit using standard microelectronic fabrication techniques may be designed to achieve individual sensing and control over each actuator element.
