Steering and control of miniaturized untethered soft magnetic grippers with haptic assistance

Untethered miniature robotics have recently shown promising results in several scenarios at the microscale, such as targeted drug delivery, microassembly, and biopsy procedures. However, the vast majority of these small-scale robots have very limited manipulation capabilities, and none of the steering systems currently available enable humans to intuitively and effectively control dexterous miniaturized robots in a remote environment. In this paper, we present an innovative micro teleoperation system with haptic assistance for the intuitive steering and control of miniaturized self-folding soft magnetic grippers in 2-D space. The soft grippers can be wirelessly positioned using weak magnetic fields and opened/closed by changing their temperature. An image-guided algorithm tracks the position of the controlled miniaturized gripper in the remote environment. A haptic interface provides the human operator with compelling haptic sensations about the interaction between the gripper and the environment, as well as enables the operator to intuitively control the target position and grasping configuration of the gripper. Finally, magnetic and thermal control systems regulate the position and grasping configuration of the gripper. The viability of the proposed approach is demonstrated through two experiments involving 26 human subjects. Providing haptic stimuli elicited statistically significant improvements in the performance of the considered navigation and micromanipulation tasks. Note to Practitioners-The ability to accurately and intuitively control the motion of miniaturized grippers in remote environments can open new exciting possibilities in the fields of minimally-invasive surgery, micromanipulation, biopsy, and drug delivery. This paper presents a micro teleoperation system with haptic assistance through which a clinician can easily control the motion and open/close capability of miniaturized wireless soft grippers. It introduces the underlying autonomous magnetic and thermal control systems, their interconnection with the master haptic interface, and an extensive evaluation in two real-world scenarios: following of a predetermined trajectory, and pick-and-place of a microscopic object.

Fabrication and characterization of RF nanoantenna on a nanoliter-scale 3D microcontainer

We report the design and fabrication of a nanoantenna structure on the surface of a 3D nanoliter-scale container for the development of communicable nanoliter-scale chemical delivery systems. The porous container was self-assembled, after which the nanoantenna was fabricated on the top of the microcontainer using focused ion beam (FIB) ion-induced metal deposition. The nanoantenna was structured as a rectangular metal coil composed of platinum (Pt) nanowires (70 nm in width). The response of the nanoantenna structure was simulated using finite element software and showed a strong resonant feature at 10.8 GHz, which was confirmed by high frequency measurements.

Patternable nanowire sensors for electrochemical recording of dopamine

Spatially resolved electrochemical recording of neurochemicals is difficult due to the challenges associated with producing nanometer-scale patternable and integrated sensors. We describe the lithographic fabrication and characterization of patternable gold (Au) nanowire (NW) based sensors for the electrochemical recording of dopamine (DA). We demonstrate a straightforward NW-size-independent approach to align contact pads to NWs. Sensors, with NW widths as small as 30 nm, exhibited considerable insensitivity to scan rates during cyclic voltammetry, a nonlinear increase in oxidation current with increasing NW width, and the selectivity to measure submaximal synaptic concentrations of DA in the presence of interfering ascorbic acid. The electrochemical sensitivity of Au NW electrode sensors was much larger than that of Au thin-film electrodes. In chronoamperometric measurements, the NW sensors were found to be sensitive for submicromolar concentration of DA. Hence, the patternable NW sensors represent an attractive platform for electrochemical sensing and recording.

Hyperthermia with magnetic nanowires for inactivating living cells

We describe a method to induce hyperthermia in cells, in-vitro, by remotely heating Ni nanowires (NWs) with radio frequency (RF) electromagnetic fields. Ni NWs were internalized by human embryonic kidney cells (HEK-293). Only cells proximal to NWs or with internalized NWs changed shape on exposure to RF fields indicative of cell death. The cell death occurs as a result of hyperthermia, since the RF field remotely heats the NWs as a result of magnetic hysteresis. This is the first demonstration of hyperthermia induced by NWs; since the NWs have anisotropic and strong magnetic moments, our experiments suggest the possibility of performing hyperthermia at lower field strengths in order to minimize damage to untargeted cells in applications such as the treatment of cancer.

Forming electrical networks in three dimensions by self-assembly

Self-assembly of millimeter-scale polyhedra, with surfaces patterned with solder dots, wires, and light-emitting diodes, generated electrically functional, three-dimensional networks. The patterns of dots and wires controlled the structure of the networks formed; both parallel and serial connections were generated.