Chiromagnetic nanoparticles and gels

Abstract

Chiral inorganic nanostructures have high circular dichroism, but real-time control of their optical activity has so far been achieved only by irreversible chemical changes. Field modulation is a far more desirable path to chiroptical devices. We hypothesized that magnetic field modulation can be attained for chiral nanostructures with large contributions of the magnetic transition dipole moments to polarization rotation. We found that dispersions and gels of paramagnetic CoO nanoparticles with chiral distortions of the crystal lattices exhibited chiroptical activity in the visible range that was 10 times as strong as that of nonparamagnetic nanoparticles of comparable size. Transparency of the nanoparticle gels to circularly polarized light beams in the ultraviolet range was reversibly modulated by magnetic fields. These phenomena were also observed for other nanoscale metal oxides with lattice distortions from imprinted amino acids and other chiral ligands. The large family of chiral ceramic nanostructures and gels can be pivotal for new technologies and knowledge at the nexus of chirality and magnetism.

Tunable Chiroptical Properties from the Plasmonic Band to Metal–Ligand Charge Transfer Band of Cysteine‐Capped Molybdenum Oxide Nanoparticles

“…[5] Among them, chiral metal oxide NPs with ligand induced chirality has triggered tremendous interests for their essential applications in chiral catalysis,b iomaterials,o ptics and understanding of light-matter interactions.T od ate,Y . Yeom et al [7] synthesized Co 3 O 4 chiromagnetic NPs and their gels that can be used for real-time magnetic field modulation. Yeom et al [7] synthesized Co 3 O 4 chiromagnetic NPs and their gels that can be used for real-time magnetic field modulation.…”

Remote Magnetic Nanoparticle Manipulation Enables the Dynamic Patterning of Cardiac Tissues

“…Magnetic procedures to manipulate and remotely control cellular behavior represent a promising approach for fabrication of tissuelike constructs. To date, magnetic fabrication of biological structures has been illustrated by the assembly of biomembranes made of organized yeast, [11] the formation of "artificial retinas" by magnetic field modulation of chiromagnetic nanoparticles, [12] or the engineering of vocal folds, [13] among others. [10] Magnetic techniques are advantageous due to their high precision and accuracy.…”

“…[5] However, these techniques often involve elaborate, macroscale stimulation systems and are not always suitable for the fabrication of detailed microarchitectures in vitro as each pattern requires new molds, posts, or frames. To date, magnetic fabrication of biological structures has been illustrated by the assembly of biomembranes made of organized yeast, [11] the formation of "artificial retinas" by magnetic field modulation of chiromagnetic nanoparticles, [12] or the engineering of vocal folds, [13] among others.Here, we report a new platform for engineering tissue morphologies with controlled geometries. Magnetic procedures to manipulate and remotely control cellular behavior represent a promising approach for fabrication of tissuelike constructs.…”

Chiral Semiconductor Nanoparticles for Protein Catalysis and Profiling

“…The anisotropyfactor of d/l-QDs was as high as 0.01. [10] Recently,c hiral metal oxides (Co 3 O 4 NPs, [11] MoO 3 NPs, [12] and WO 3Àx NPs [13] ), which exhibited intense optical activities in the visible range,h ave been synthesized using chiral ligands.S ome chiral metal sulfide nanomaterials such as HgS [14] and CdS [15] have also been prepared. Mechanistic investigations indicate the generation of hydroxylr adicals as the reactive species that cause the cutting of proteins.…”

“…[8] Chiral inorganic NPs have triggered great interest due to their easy synthesis and their tremendous applications including chiral sensing, [9] chiral separation, enantioselective catalysis,a nd advanced photonic devices. [10] Recently,c hiral metal oxides (Co 3 O 4 NPs, [11] MoO 3 NPs, [12] and WO 3Àx NPs [13] ), which exhibited intense optical activities in the visible range,h ave been synthesized using chiral ligands.S ome chiral metal sulfide nanomaterials such as HgS [14] and CdS [15] have also been prepared. These chiral NPs with deformations of the crystal lattices may be extended to other nanomaterials with tailorable chiroptical properties.…”