Magnetic Bucket Brigade Transport Networks for Cell Transport

Abstract

Controlled transport of biological cells in biomedical applications such as sorting, cell sequencing, and assembly of multicellular structures is a technological challenge. Research areas such as drug delivery or tissue engineering can benefit from precise cell location resulting in faster response rates or more complex tissue structures. Using computational methods, different soft magnetic elements with curved edges are designed to form a transport network, enabling transport and all functionalities for the manipulation of microbeads and cells on surfaces by rotational magnetic fields. Building blocks with bimodal functionalities due to segments of differently curved edges permit breakpoints as well as switchable transport via splitting and combining elements. Connecting the elements, networked paths are realized which allow variable movement patterns of magnetic carriers and cells. The direction of magnetic field rotation is altered to direct the beads and cells into different transport lines, and the exact timing is not critical. The networks are used to achieve deterministic movement of microbeads and cells with minimal intervention. Programmed transport over one millimeter with cell transport velocities of several micrometers per s is demonstrated. Based on scalable microchip technology, the networks can be integrated with CMOS‐compatible materials and straightforwardly combined with sensing and diagnostic structures.

Integrated Hybrid Tweezer for Particle Trapping with Combined Optical and Acoustic Forces

“…Second, to determine the thickness of the silicon nitride layer, which acts as both a cladding of the LN acoustic waveguide and controlling of acoustic radiation, we calculated the first-order pressure and the time-averaged second-order velocity to represent the acoustic radiation force and Stokes drag force based on Equations ( 3) and (5). By fixing the thickness of LN at 20 µm and varying the thickness of silicon nitride, we obtained the amplitude of first-order pressures and the y-component of time-averaged second-order velocities along the y-axis at x = 2.5 µm, as shown in Figure 4a,b.…”

“…For particles with sizes in the micrometers and nanometers, there are many types of tweezers, such as optical tweezers (can be used in molecular sensing, precision molecular manipulation, and cell assembly [1,2]), acoustic tweezers (can be used in particle separation, material manufacture, cell transportation, sorting, and enrichment [3]), magnetic tweezers (can be used in parallel single-molecule fluorescence detection measurements and cell transport [4,5]), dielectrophoretic tweezers (can be used in medical diagnostics, material characterization, drug discovery, cell therapeutics, and particle filtration [6]), and plasmonic tweezers (can be used in biomanipulation, spectrographic sensing and imaging, and particle transport and sorting [7]), etc. Various methods based on optics [8][9][10][11][12][13][14][15][16][17][18][19], acoustics [20][21][22][23][24], magnetism [4,5,25], dielectrophoresis [6], and plasma [7,26] for the remote driving of particles, have been developed. In 1986, Ashkin proved that particles could be trapped by the gradient force generated by a light beam [27].…”

Stray Magnetic Field Variations and Micromagnetic Simulations: Models for Ni0.8Fe0.2 Disks Used for Microparticle Trapping

“…We employ simulations based on the Object Orientated Micromagnetic Framework (OOMMF) [35] to calculate local stray fields from the magnetic disks. While micromagnetic simulations such as OOMMF are commonly used to describe particles trapped and transported by thin-film structures [27][28][29][36][37][38][39], we focus on the variations that arise from repeated OOMMF simulation runs and notice differences that arise in resulting disk fields. Additionally, as methods based on the OOMMF rely on 2D summation over a discretely defined magnetization landscape for an individual field calculation and are, hence, computationally slow, we discuss a fitting method for faster computation of fields.…”

Magnetic Lateral Ladder for Unidirectional Transport of Microrobots: Design Principles and Potential Applications of Cells‐on‐Chip

“…Microrobotics is an active research area in biomedical engineering that aims to develop micromanipulations capable of selectively interacting with individual cells. [1][2][3][4][5] These microrobots in size, ranging from 1 μm to tens of μm, can be controlled by various driving forces [6][7][8][9][10][11][12] to carry out specific functions in different experiments, such as selective transportation, [6,[13][14][15][16][17][18] trapping, [19][20][21][22][23] separation, [24][25][26][27][28][29] and mixing. [30][31][32] Due to their small size, microrobot's performances rely on the directional movement of their specific body shape to achieve their functions [33][34][35][36][37][38][39][40][41][42][43][44] rather than having complex components such as their macroscopic counterparts.…”