Hierarchical Homochiral Assembly of Polyhedral Cage-Type Nanoclusters

Hierarchical chiral self-assembly is of profound significance for biomolecules for their biological functions.Atom-precise metal nanoclusters(NCs)offer better opportunities to construct hierarchical superlattices.Nevertheless,achieving hierarchical homochiral assembly of nanocrystals protected by achiral ligands has proven to be a formidable task,with existing examples primarily limited to heterochiral assembly.Here we put forward a hierarchical assembly strategy towards precisely fabricating highly ordered homochiral superstructures.First,clusterin-nanocage type copper-hydride NCs act as synthons,of which entity is featured with a hexagonal close-packed Cu_(9)kernel embedded in a C_(3)-symmetric trigonal-prismatic metallacage,leading to a chiral core-shell primary structure with either P or M conformation.Then four homochiral NCs combined with guests through synergistic noncovalent interactions spontaneously organize into a supramolecular tetrahedral secondary structure within a unit cell.Finally,these nanoscopic supramolecular motifs pack into tertiary hierarchical superlattice of chiral cubic crystalline phase.Additionally,the crystalline material shows excellent robustness,and fascinating blueexcitable near-infrared thermally activated delayed fluorescence behavior.This work not only exhibits that nanocage-type NCs can be smart as proteins to translate chiral primary structure into tertiary chiral hierarchical complexity,but also provides new insights into structure-to-superstructure,enabling bottom-up creation of higher-level hierarchical homochiral superlattice structures.

Functional analysis of a miRNA‐like small RNA derived from Bombyx mori cytoplasmic polyhedrosis virus

Bombyx mori cytoplasmic polyhedrosis virus(BmCPV)is a major pathogen of the economic insect silkworm,Bombyx mori.Virus‐encoded microRNAs(miRNAs)have been proven to play important roles in host–pathogen interactions.In this study we identified a BmCPV‐derived miRNA‐like 21 nt small RNA,BmCPV‐miR‐1,from the small RNA deep sequencing of BmCPV‐infected silkworm larvae by stem‐loop quantitative real‐time PCR(qPCR)and investigated its functions with qPCR and lentiviral expression systems.Bombyx mori inhibitor of apoptosis protein(BmIAP)gene was predicted by both target prediction software miRanda and Targetscan to be one of its target genes with a binding site for BmCPV‐miR‐1 at the 5′untranslated region.It was found that the expression of BmCPV‐miR‐1 and its target gene BmIAP were both up‐regulated in BmCPV‐infected larvae.At the same time,it was confirmed that BmCPV‐miR‐1 could up‐regulate the expression of BmIAP gene in HEK293T cells with lentiviral expression systems and in BmN cells by transfecting mimics.Furthermore,BmCPV‐miR‐1 mimics could up‐regulate the expression level of BmIAP gene in midgut and fat body in the silkworm.In the midgut of BmCPV‐infected larvae,BmCPV‐miR‐1 mimics could be further up‐regulated and inhibitors could lower the virus‐mediated expression of BmIAP gene.With the viral genomic RNA segments S1 and S10 as indicators,BmCPV‐miR‐1 mimics could up‐regulate and inhibitors down‐regulate their replication in the infected silkworm.These results implied that BmCPV‐miR‐1 could inhibit cell apoptosis in the infected silkworm through up‐regulating BmIAP expression,providing the virus with a better cell circumstance for its replication.

Photocatalytic hydrogen production from acidic aqueous solution in BODIPY-cobaloxime-ascorbic acid homogeneous system

Iodinated boron dipyrromethene(BODIPY) dyes with 8-hydroxyl-quinoline or phenylamine moiety at the meso-position on the BODIPY core were used as efficient photosensitizers(PSs) of three-component light-driven production of H_2 system from acidic aqueous solution in conjunction with a cobaloxime[CoⅢ(dmgH)_2 PyCl](dmgH = dimethylglyoximate, and py = pyridine) as proton-reducing catalyst and ascorbic acid(H_2 A) as sacrificial electron donor. This is the first example of BODIPYs as homogeneous hydrogen-generating PSs employed in the acidic aqueous conditions. That they are active in the acidic solutions and inactive in the basic conditions may indicate that the extent of competition between intramolecular and intermolecular electron transfer reactions exists. Efficient bimolecular electron transfer reaction between PS and molecular catalyst is needed to make H_2 production, while the intramolecular electron transfer of PS may curb H_2 production. The results underscore that the chemical modification of BODIPYs can be performed, thus allowing for the transformation of acid and base conditions for the light-driven H_2 production.