Fabrication and wireless micromanipulation of magnetic-biocompatible microrobots using microencapsulation for microrobotics and microfluidics applications

Abstract

It is important to fabricate biocompatible and chemical-resistant microstructures that can be powered and controlled without a tether in fluid environment for applications when contamination must be avoided, like cell manipulation, and applications where connecting the power source to the actuator would be cumbersome, like targeted delivery of chemicals. In this work, a novel fabrication method was described to encapsulate magnetic composite into pure SU-8 structures, enabling the truly microscale ferromagnetic microrobots biocompatible and chemical resistant. The microrobots were developed using the simple multilayer photolithography that allows us to mass produce and were actuated contact-free by external magnetic field to complete micromanipulations of micro-objects. The microrobots were actuated moving along a preplanned path to transport a glass microsphere object at an approximately average speed of 1.1 mm/sec and can be operated to rotate, aim at targets and collect objects.

A simple method for producing freestanding 3D microstructures by integrated photomask micromolding

“…But in practice, the only limitation of the minimum feature size is the limitation of micromanufacturing microcavities on chrome glass and/or the resolution limit of the material (depending on the bigger one). According to a previous publication [16], the resolution limit of SU-8 with a 1050 mm 2 s −1 kinematic viscosity is 2 μm; and the manufacturing limitation of the local micro/nano micromanufacturing company we can access is 5 μm. Therefore, the minimum feature size that IPM can achieve is 5 μm.…”

“…Micromolding has become a ubiquitous fabrication method due to its numerous advantages-high fabrication throughput, a large breadth of available material properties, low cost and a wide variety of producible geometries [16]. However, there is a primary challenge in micromolding, which is the elimination of unwanted connecting film between parts that results from overfilling mold cavities as shown in figure 1.…”

Fabrication and Applications of Magnetic Polymer Composites for Soft Robotics

“…Likewise, a model for the microrobots' surface-tension-based interaction is proposed. Microstructures that are powered and controlled wirelessly in fluid environments are crucial for applications where contamination must be avoided, such as cell manipulation, and for applications where connecting the power source to the actuator would be cumbersome, such as targeted delivery of chemicals [72]. A novel production methodology was suggested to enclose magnetic composite materials within pure SU-8 structures, hence facilitating the development of microscale ferromagnetic microrobots that possess both biocompatibility and chemical resistance.…”

Photopatternable Magnetic Hollowbots by Nd-Fe-B Nanocomposite for Potential Targeted Drug Delivery Applications

“…Magnetic forces offer an attractive option for actuation in microelectromechanical systems (MEMS) and microscale systems because they scale favorably at micro- and nano-scale lengths [ 17 , 18 ]. The contact-free nature of magnetic actuation makes it ideal for applications where contamination must be avoided, such as interactions with cells or other biological samples [ 19 ], or where connecting the power source to the actuator would be cumbersome, such as freestanding microrobots [ 20 ]. And, unlike systems based on electrostatic or dielectric forces, magnetic actuators can operate in liquid or gas and are unaffected by the ionic concentration of the surrounding medium.…”