Ferrofluidic Manipulator: Automatic Manipulation of Nonmagnetic Microparticles at the Air–Ferrofluid Interface

Abstract

Manipulation of small-scale matter is a fundamental topic in micro-and nanorobotics. Numerous magnetic robotic systems have been developed for the manipulation of microparticles in an ambient environment, liquid as well as on the air-liquid interface. These systems move intrinsically magnetic or magnetically tagged objects by inducing a magnetic torque or force. However, most of the materials found in nature are nonmagnetic. Here, we report a ferrofluidic manipulator for automatic two-dimensional manipulation of non-magnetic objects floating on top of a ferrofluid. The manipulation system employs eight centimeter-scale solenoids, which can move non-magnetic particles by deforming the air-ferrofluid interface. Using linear programming, we can control the motion of the non-magnetic particles with a predefined trajectory of a line, square, and circle with a precision of 25.1±19.5 µm, 34.4±28.4 µm and 33.4±26.6 µm, respectively. The ferrofluidic manipulator is versatile with the materials and the shapes of the objects under manipulation. We have successfully manipulated particles made of polyethylene, polystyrene, a silicon chip, and poppy and sesame seeds. This work shows a promising venue for the manipulation of living and nonliving matter at the air-liquid interface.

Ferrofluids and bio-ferrofluids: looking back and stepping forward

“…52). 793 The ferrofluid based device controls the motion of non-magnetic particles along predefined paths using a linear-programming-based control algorithm.…”

Navigation of Ultrasound-controlled Swarmbots under Physiological Flow Conditions

“…All in all, microrobots must confront an extremely challenging environment and be carefully guided through a patient's vasculature. To date, efforts in this field have focused on controlling microrobot trajectory inside microchannels and confined spaces (2)(3)(4)(5)(6)(7)(8), and most studies have aimed to manipulate microrobots under static flow conditions (9)(10)(11)(12). Recent work has begun investigating microrobot capabilities when exposed to an external flow (13)(14)(15)(16), but typically considers only low flow velocities, i.e., in the µm/s range.…”

Non-Contact Cooperative Manipulation of Magnetic Microparticles Using Two Robotic Electromagnetic Needles

“…Due to its transparency to human and animal tissues when the field is weak and varying slowly [9] and the capability to address micro-objects wirelessly, magnetic fields have been widely used in robotic micromanipulation. Magnetic-driven microrobotic systems have been demonstrated in performing independent control of multiple magnetic agents in 2D [10] and 3D [11], selective manipulation and extraction [12], [13], swarm motion and patterning [14], [15], as well as carrying out targeted gene delivery [16] and climbing on liquid menisci [17], among a plethora of other reported capabilities [10] [11] [18]. Over the previous two decades, many impressive results have been reported, including contactless ocular operations, targeted drug delivery [7], [19], [20] in-vitro diagnosis [21], endoscopy [22], minimally invasive operation [23], and environmental remediation [24], [25].…”

“…In [26] researchers used nine electromagnetic coils and current minimizing techniques to achieve simultaneous manipulation of two identical microspheres. In [18], researchers proposed a ferrofluidic manipulator consisting of 8 small-scale magnetic coils to manipulate 550 µm diameter spherical non-magnetic particles. Despite the advanced capabilities, most of those magnetic manipulation technologies create global magnetic fields using multiple fixed magnetic sources.…”