Distributed Force Control for Microrobot Manipulation via Planar Multi‐Spot Optical Tweezer

Abstract

manipulation of cells, [3,4] microrobots, trapped in the focal position of the laser beam can be utilized as end-effectors of the OT. [5] Therefore, developing optical micro-machines to enable dexterous indirect manipulation of OT can have a wide range of applications. For example, four streptavidin-functionalized polystyrene beads, controlled by a time-shared multiplexed OT, have been attached to a biotinylated red blood cell and served as micro-tools to analyze the underlying molecular mechanisms involved in cell flickering. [6] In life science, laser-driven spinning birefringent spheres have been used to generate microfluidic-induced shear force for control of the growth of individual axons (nerve fibers) precisely, paving the way for nerve repair and regeneration. [7] To enable more dexterous indirect optical trapping and optical manipulation, optical micro robotics with novel synthetic structures can be used to increase the flexibility of OT systems and facilitate the deployment of general robotic solutions for biomedical science. [8] With recent advances in two-photon polymerization and other emerging micro/nanofabrication techniques, steerable non-spherical particles can now be fabricated. [9] Therefore, optically driven microrobots with complex structures can be used for arbitrary translational and angular positioning in 3D space. For example, anisotropic shapes have been considered for the design of micro-particles to create a remotely driven micro-motor based on radiation pressure for micromechanical systems. [10] An indirect optical trapping method using light driven micro-rotors to create a new form of near-field hydrodynamic micro-manipulation has been proposed, [11] with which the 2D trapping of absorbing particles, the control of position and orientation of yeast cells, and the independent control over multiple objects simultaneously have been demonstrated. Apart from using OT to realize reconfigurable hydrodynamic manipulation via the control of optically driven micro-motors, optoelectronic tweezer has been developed to combine dielectrophoresis with OT, which is capable of exerting a stronger manipulation force for a given intensity of light for microrobot control. [12] A shaped particle based on a tapered cylinder fabricated by two-photon polymerization has been proposed for acting as a passive force clamp, [13] which facilitates the design of optically trapped objects with specific force profiles. However, the motions of the passive force clamp are mainly for planar translation. For micro-manipulation which demands Optical tweezers (OT) represent a versatile tool for micro-manipulation. To avoid damages to living cells caused by illuminating laser directly on them, microrobots controlled by OT can be used for manipulation of cells or living organisms in microscopic scale. Translation and planar rotation motion of microrobots can be realized by using a multi-spot planar OT. However, out-of-plane manipulation of microrobots is difficult to achieve with a planar OT. This paper presents a distribut...

Data-Driven Microscopic Pose and Depth Estimation for Optical Microrobot Manipulation

“…The two-photon polymerization (2PP) method was used for the manufacturing process, where the resolution is set to 100 nm and realized by a 3D printing system (Nanoscribe GmbH, Germany). The microplatforms and microrobots for experimental validation were printed on the glass substrate and placed in deionized (DI) water within a spacer …”

Control and Autonomy of Microrobots: Recent Progress and Perspective

“…With a higher frequency, US imaging gives a better axial resolution, yet the imaging depth will be relatively shallow since highfrequency US waves are easier to be attenuated. The imaging contrast is related to the acoustic resistance difference between the target microrobot and the surrounding environment, thus by increasing the acoustic resistance of the microrobot (e.g., air Electrohydrodynamic [216,217] Acoustic Actuation Bulk Wave [218,219] Surface Wave [220][221][222][223][224][225] Traveling Wave [226,227] Light Actuation Photophoresis [228][229][230][231] Optomechanical Response [32,232,233] Optical Tweezer [234][235][236] Magnetic Actuation Magnetic Gradient Force [121,[237][238][239][240] Magnetic Torque [19,35,64,98,241,242] Multi-stimuli Actuation [36,243,244] Table 2. Comparison between different localization modalities for microrobot.…”

Light‐Powered Microrobots: Challenges and Opportunities for Hard and Soft Responsive Microswimmers

“…Intelligent microrobot design for distributed force control can overcome this and enable optical manipulation with six degrees of freedom despite the planar optical trap positions. [71] Another noteworthy light-based approach for microstructure manipulation is the use of optoelectronic tweezers. [72][73][74] Recently, polymeric cogwheel-shaped microrobots controlled by optoelectric tweezers were used for indirect cellular manipulation.…”

“…Intelligent microrobot design for distributed force control can overcome this and enable optical manipulation with six degrees of freedom despite the planar optical trap positions. [ 71 ]…”