Microrheology with modulated optical nanoprobes (MOONs)

Fabrication, Assembly, and Application of Patchy Particles

“…Over the last two decades, many fabrication methods for Janus particles have been developed, [14] including scalable ones, and the particles are now being implemented in new technologies such as emulsions, [44,45] electronic paper, [46][47][48] tunable liquid optics, [49] sensors [50] and microrheological probes. [51][52][53] Fabrication methods for various types of Janus particles, ranging from bicompartmental and dumbbell-like to half-rasberry, arconand snowman-like particles, have been comprehensively reviewed by Perro and co-workers. [14] A more recent review by Walther and Müller [54] concentrates more specifically on compartmentalized polymeric Janus particles with various shapes, such as spheres, fibers, and disks.…”

Magnetic interaction of Janus magnetic particles suspended in a viscous fluid

“…A Janus (anisotropic) magnetic particle is composed of two different magnetic materials, e.g., a magnetic particle with a nonmagnetic cap, a non-magnetic particle with a magnetic cap, and a particle with a magnetic hemisphere [8][9][10]. By coating one hemisphere of a particle with a thin layer of metal and the other hemisphere with a fluorescent material, the particle rotates in response to a rotating external field.…”

“…By coating one hemisphere of a particle with a thin layer of metal and the other hemisphere with a fluorescent material, the particle rotates in response to a rotating external field. Such a particle can be utilized as a rheological probe [8]. Janus particles with a magnetic hemisphere are able to load chemical or biological payloads such as dyes, fluorophores, proteins, or cells.…”

Sudden Breakdown in Linear Response of a Rotationally Driven Magnetic Microparticle and Application to Physical and Chemical Microsensing

“…This is the technique used in this paper. An alternative technique 15 is to rotate magnetically modulated optical nanoprobes (MagMOONs) in a plane that is orthogonal to the imaging planessee bottom of Figure 1. MagMOONs are half-coated fluorescent magnetic particles that emit varying intensities of light, depending on their angular orientation.…”

“…6,7,[15][16][17][18][19][20][21][22] By tracking the intensity of the MagMOON as it rotates, the orientation and average rotation rate can be determined, and therefore, phase-locking and phaseslipping can be monitored for spherical particles. 15 One potential application for combined physical and chemical sensing probes is for the study of an environment in which a chemical change induces a physical change or vice versa. An example for this can be found in giant unilamellar vesicles, where introduction of a cross-linking ion causes the formation of a hydrogel.…”