Chiral magnetic hybrid materials constructed from macromolecules and their chiral applications

Defect-engineered chiral metal-organic frameworks

Chirality has an important impact on chemical and biological research, as most active substances are chiral. In recent decades, metal-organic frameworks (MOFs), which are assembled from metal ions or clusters and organic linkers via metal-ligand bonding, have attracted considerable scientific interest due to their high crystallinity, exceptional porosity and tunable pore sizes, high modularity, and diverse functionalities. Since the discovery of the first functional chiral metal-organic frameworks (CMOFs), CMOFs have been involved in a variety of disciplines such as chemistry, physics, optics, medicine, and pharmacology. The introduction of defect engineering theory into CMOFs allows the construction of a class of defective CMOFs with high hydrothermal stability and multi-stage pore structure. The introduction of defects not only increases the active sites but also enlarges the pore sizes of the materials, which improves chiral recognition, separation, and catalytic reactions, and has been widely investigated in various fields. This review describes the design and synthesis of various defective CMOFs, their characterization, and applications. Finally, the development of the materials is summarized, and an outlook is given. This review should provide researchers with an insight into the design and study of complex defective CMOFs.

Biomimetic Chiral Nanomaterials with Selective Catalysis Activity

Chiral nanomaterials with unique chiral configurations and biocompatible ligands have been booming over the past decade for their interesting chiroptical effect, unique catalytical activity, and related bioapplications. The catalytic activity and selectivity of chiral nanomaterials have emerged as important topics, that can be potentially controlled and optimized by the rational biochemical design of nanomaterials. In this review, chiral nanomaterials synthesis, composition, and catalytic performances of different biohybrid chiral nanomaterials are discussed. The construction of chiral nanomaterials with multiscale chiral geometries along with the underlying principles for enhancing chiroptical responses are highlighted. Various biochemical approaches to regulate the selectivity and catalytic activity of chiral nanomaterials for biocatalysis are also summarized. Furthermore, attention is paid to specific chiral ligands, materials compositions, structure characteristics, and so on for introducing selective catalytic activities of representative chiral nanomaterials, with emphasis on substrates including small molecules, biological macromolecule, and in-site catalysis in living systems. Promising progress has also been emphasized in chiral nanomaterials featuring structural versatility and improved chiral responses that gave rise to unprecedented chances to utilize light for biocatalytic applications. In summary, the challenges, future trends, and prospects associated with chiral nanomaterials for catalysis are comprehensively proposed.

Chiral Inorganic Nanomaterials for Photo(electro)catalytic Conversion

Chiral inorganic nanomaterials due to their unique asymmetric nanostructures have gradually demonstrated intriguing chirality-dependent performance in photo(electro)catalytic conversion, such as water splitting. However, understanding the correlation between chiral inorganic characteristics and the photo(electro)catalytic process remains challenging. In this perspective, we first highlight the chirality source of inorganic nanomaterials and briefly introduce photo(electro)catalysis systems. Then, we delve into an in-depth discussion of chiral effects exerted by chiral nanostructures and their photo-electrochemistry properties, while emphasizing the emerging chiral inorganic nanomaterials for photo(electro)catalytic conversion. Finally, the challenges and opportunities of chiral inorganic nanomaterials for photo(electro)catalytic conversion are prospected. This perspective provides a comprehensive overview of chiral inorganic nanomaterials and their potential in photo(electro)catalytic conversion, which is beneficial for further research in this area.

Synthesis and Application of Fluorescent Polymer Micro- and Nanoparticles

Fluorescent polymer particles have witnessed an increasing interest in recent years, owing to their fascinating physicochemical properties as well as wide-ranging applications. In this review, the state-of-the-art research progress of fluorescent polymer particles in the past five years is summarized. First, the synthesis protocols for fluorescent polymer particles, including emulsion polymerization, precipitation polymerization, dispersion polymerization, suspension polymerization, nanoprecipitation, self-assembly, and post-polymerization modification, are presented in detail. Then, the applications of the resulting beguiling particles in anticounterfeiting, chemical sensing, and biomedicine, are illustrated. Finally, the challenges and opportunities that exist in the field are pointed out. This review aims to offer important guidance and stimulate more research attention to this rapidly developing field.

Sieving nanometer enantiomers using bound states in the continuum from the metasurface

Enantioseparation of chiral molecules is an important aspect of life sciences, chemical syntheses, and physics. Yet, the prevailing chemical techniques are not effective. Recently, a few types of plasmonic apertures have been theoretically proposed to distinguish between chiral molecules that vary based on their handedness under circularly polarized illumination. Both analytic calculations and numerical simulation demonstrated that enantioselective optical sieving could be obtained at the nanoscale using a large chiral optical force based on plasmonic resonance enhanced near-field chiral gradients in the aperture. Nevertheless, scaling this scheme to chiral entities of a few nanometer size (i.e., proteins and DNA) faces formidable challenges owing to the fabrication limit of a deeply sub-nanometer aperture and the intense power levels needed for nanoscale trapping. In contrast, by extending the Friedrich-Wintgen theory of the bound states in the continuum (BIC) to photonics, one may explore another mechanism to obtain enantioselective separation of chiral nanoparticles using all-dielectric nanostructures. Here, we present a metasurface composed of an array of silicon (Si) nanodisks embedded with off-set holes, which supports a sharp high-quality (Q) magnetic dipolar (MD) resonance originating from a distortion of symmetry-protected BIC, so called quasi-BIC. We, for the very first time, show that such a quasi-BIC MD resonance can markedly improve the chiral lateral force on the paired enantiomers with linearly polarized illumination. This quasi-BIC MD resonance can enhance the chirality density gradient with alternating sign at each octant around the Si nanodisk, while exhibiting a small gradient for the electromagnetic (EM) density. This offers a chiral lateral force that is 1 order larger in magnitude compared to the non-chiral lateral forces on sub-2 nm chiral objects with a chirality parameter of ±0.01. Moreover, the quasi-BIC MD resonance can excite four pairs of diverse optical potential wells (-13k B T) that are distributed uniformly along the outer edge of the resonator, enabling a simultaneous separation of four paired enantiomers. Our proposed dielectric metasurface may move forward the techniques of enantioseparation and enantiopurification, taking a novel perspective to advanced all-optical enantiopure synthesis.

Biological applications of chiral inorganic nanomaterials

Chirality is common in nature and plays the essential role in maintaining physiological process. Chiral inorganic nanomaterials with intense optical activity have attracted more attention due to amazing properties in recent years. Over the past decades, many efforts have been paid to the preparation and chirality origin of chiral nanomaterials; furthermore, emerging biological applications have been investigated widely. This review mainly summarizes recent advances in chiral nanomaterials. The top-down and bottom-up preparation methods and chirality origin of chiral nanomaterials are introduced; besides, the biological applications, such as sensing, therapy, and catalysis, will be introduced comprehensively. Finally, we also provide a perspective on the biomedical applications of chiral nanomaterials.

Building Permanently Optically Active Particles from Absolutely Achiral Polymer

Chirality in polymer particles represents one of the most dynamic areas of nanoscale materials today. The chirality of most chiral polymeric particles (CPPs) derived from achiral monomers/polymers has a strong...