Jianxiao Gong

Chirality continuum is crucial for advancing fundamental theories - spanning symmetry breaking and topological invariants - and for developing functional materials with tunable chiroptical, spintronic, and magnetic properties. However, achieving chirality continuum, particularly reversible in three-dimensional solids, remains elusive due to the intrinsic difficulties in nanoscale accuracy over extended architectures. Here, we introduce a decoupled design strategy that integrates magnetic field-directed achiral superstructures of luminomagnetic nanoparticles (LMNPs) with post-curing mechanical manipulation. Under a quadrupolar magnetic field, LMNPs self-assemble into nematic superstructures that are fixed within elastomers to form a luminomagnetic gel (LMG). Under macroscopic torsion, the superstructures undergo a transition from achiral to chiral nematic phase, allowing continuous and reversible tuning between left- and right-handed states. This process converts bulk mechanical deformation into nanoscale structural reconfiguration (for instance, 45° twisting in LMG produces 0.00088° of average inter-chain angle reorientation), thereby establishing long-range chiral ordering. The emergent circularly polarized luminescence is robust and reversible, with its intensity and handedness smoothly tuned through adjusting the applied torque. Our work delivers a modular, solid-state platform for reversible chirality continuum, opening avenues for polarization engineering and high-precision/broadband chiroptical technologies.

Regenerating functional bone tissue in critical-sized defects remains a formidable issue. Bone-tissue engineering (BTE) scaffolds are emerging as potential alternatives to bone transplantation for the repair of bone defects. However, developing BTE scaffolds with unique bone-healing properties and natural bone porous structure is challenging. Herein, we presented a biomimetic scaffold with hierarchical porosity via a solvent casting/particulate leaching method. The scaffold comprises osteoinductive whitlockite (WH) nanoparticles evenly dispersed in a poly(lactic-co-glycolic acid) (PLGA) matrix. Highly interconnected pores with hierarchical variations are present in the scaffold, enabling superior solution diffusion and compressive strength. Notably, the WH/PLGA scaffold effectively promoted osteoblast differentiation in vitro and induced bone formation in rat tibia defects, surpassing the performance of both the hydroxyapatite (HAP)/PLGA scaffold and the PLGA scaffold. This study provides a low-cost, facile, and scalable strategy for fabricating BTE scaffolds with favorable mechanical properties, biocompatibility, and bone repair capability.

Novel one-dimensional linear and 3-dimensional topo-epitaxy superstructures were prepared from PbSe nanocrystals dispersed in toluene by oriented attachment-assisted self-assembly at the ethylene glycol/Ar.

Herein, an in situ decomposition–assembly strategy for the versatile fabrication of metal sulfide SPs is developed. In addition to homogeneous Cu ₂ S, CdS, and ZnS products, the proposed system can even be extended to fabricate hybrid Cu ₂ S/Fe ₂ O ₃ SPs.

The engineering of nanoscale features enables the properties of solid-state materials to be tuned. Here, we show the tunable preparation of cuprous sulfide nanocrystals ranging in internal structures from single-domain to multi-domain. The synthetic method utilizes in-situ oxidation to grow nanocrystals with a controlled degree of copper deficiency. Copper-deficient nanocrystals spontaneously undergo twinning to a multi-domain structure. Nanocrystals with twinned domains exhibit markedly altered crystallographic phase and phase transition characteristics as compared to single-domain nanocrystals. In the presence of twin boundaries, the temperature for transition from the ordered phase to the high-copper-mobility superionic phase is depressed. Whereas the superionic phase is stable in the bulk only above ca. 100 °C, cuprous sulfide nanocrystals of ca. 7 nm diameter and a twinned structure are stable in the superionic phase well below ambient temperature. These findings demonstrate twinning to be a structural handle for nanoscale materials design and enable applications for an earth-abundant mineral in solid electrolytes for Li-S batteries.