Fabrication and magnetic control of bacteria-inspired robotic microswimmers

Abstract

A biomimetic, microscale system using the mechanics of swimming bacteria has been fabricated and controlled in a low Reynolds number fluidic environment. The microswimmer consists of a polystyrene microbead conjugated to a magnetic nanoparticle via a flagellar filament using avidin-biotin linkages. The flagellar filaments were isolated from the bacterium, Salmonella typhimurium. Propulsion energy was supplied by an external rotating magnetic field designed in an approximate Helmholtz configuration. Further, the finite element analysis software, COMSOL MULTIPHYSICS, was used to develop a simulation of the robotic devices within the magnetic controller. The robotic microswimmers exhibited flagellar propulsion in two-dimensional magnetic fields, which demonstrate controllability of the biomimetically designed devices for future biomedical applications.

Magnetization directions and geometries of helical microswimmers for linear velocity-frequency response

“…A number of types of microrobots em ploying different propulsion techniques have been developed, including chemically powered microrobots dependent on external fuels to create phoretic flows [10][11][12][13][14][15][16][17][18], externally con trolled biotic systems [19], dielectrophoretically manipulated robots [20], and magnetically actuated robots, including those that require a nearby surface [21][22][23][24] and those that can swim in bulk fluids [25][26][27][28][29][30][31][32][33][34][35]. In this paper, we focus on magnetically actuated microswimmers in bulk fluids which can be propelled when rotated by an external magnetic field [28][29][30][31][32][33][34][35].…”

Pulling and pushing a cargo with a catalytically active carrier

“…This determines ρ(ξ, η) and the slip velocity follows fromv s = −[(b/h η )∂ η ρ(ξ, η)] ξ=±ξ0êη withê η = {(cosh ξ cos η − 1) cos φ , (cosh ξ cos η − 1) sin φ , − sinh ξ sin η}/C.Due to the linearity of the Stokes equations the hydrodynamic flow field u = u I + u II [Eqs. (4) and(5)] is the superposition of the one corresponding to u I (|r| → ∞) = −V with stick BCs on Σ and the one corresponding to a quiescent flow far away, i.e., u II (|r| → ∞ = 0 with slip BCs v s on Σ. The solution for the first problem is known[28] and corresponds to a hydrodynamic force on the composite F I = −12πµRλV, where 1)(2n + 3) × 1 − 4 sinh 2 (n + 1/2)ξ 0 − (2n + 1) 2 sinh 2 ξ 0 2 sinh(2n + 1)ξ 0 + (2n + 1) sinh 2ξ 0 .…”

Development of a Biomedical Micro/Nano Robot for Drug Delivery

“…[7][8][9][10] To address these problems for micro-robots and drug delivery vehicle, we propose miniature, and energyefficient bio-mimetic propulsion concepts of interfacing bacteria with liposome by means of antibody, with the ultimate goal of using bacteria with liposome for actuation, control, sensing, and moving towards target. [11][12][13][14][15][16] Figure 1 shows a schematic diagram illustrating bacteria attached to liposome by means of an antibody. The research work presented here intends to investigate the stochastic nature of bacterial propulsion of liposome, which is important for developing next-generation bio-hybrid swimming microrobots finding applications in diverse fields ranging from biomedical to environmental applications.…”