Cellular Manipulation Using Rolling Microrobots

Upstream mobility and swarming of light activated micromotors

“…With a magnetic field applied, the micromotors move in a wide range of directions rather than along the direction of the magnetic field. We have observed this previously 24 and attribute it to differences in the magnetic coating on the micromotors or to the formation of aggregates which possess a magnetic moment that is misaligned with their direction of motion.…”

“…A magnetic field acts to make the trajectories of these micromotors more linear due to a suppression of their natural active rotation. 24 Therefore, we applied a magnetic field by placing a permenant magnet near the sample, resulting in less rotation of the micromotors and more persistent motility upstream.…”

“…Swarms of particles have been generated using magnetic fields, 8,9,11 chemical effects, 12,13 electric fields, 14,15 thermal gradients, 16 and acoustic waves. [17][18][19][20] Swarm-like schools of light-active particles have also been formed 21 as well as self-attractive clusters, [22][23][24] although control of such collections of light-active units in flows has not yet been demonstrated.…”

Micro-/nanoscale robotics for chemical and biological sensing

“…68 Rivas' team has recently reported the use of microrobots to physically manipulate cells. 69 Using GLAD, micro-sized silica spheres were coated with a 100 nm nickel layer at a 70° glancing angle as a means of making them magnetic for actuation via rotating magnetic fields.…”

A Review of Single-Cell Microrobots: Classification, Driving Methods and Applications

“…Among them, propulsion and biocompatibility are the main challenges, as in the case of propulsion at microscopic scales where the Reynolds number is very low, making it difficult compared with some micro- and nanoartificial motors based on complex surface biofunctionalization and coating of synthetic materials, such as some particles based on self-thermophoresis propulsion using coated colloids [ 69 ] or biomimetic modifications [ 70 ]. Although it can increase their specificity, the controlled motility for driving tasks [ 71 , 72 ] have many incomparable advantages, such as the ability to encapsulate more drugs within their membranes, interact with other cells and tissues, combine the advantages of previous drug carriers (e.g., drug protection and selectivity) and the ability to penetrate some human tissues and provide specific driving mechanisms to ensure that it triggers drug release [ 73 , 74 ] at the right time and space. And this cellular carrier is more biocompatible than the micro- and nanocarriers mentioned above.…”