A novel approach for the prevention of ionizing radiation-induced bone loss using a designer multifunctional cerium oxide nanozyme

The disability,mortality and costs due to ionizing radiation(IR)-induced osteoporotic bone fractures are sub-stantial and no effective therapy exists.Ionizing radiation increases cellular oxidative damage,causing an imbalance in bone turnover that is primarily driven via heightened activity of the bone-resorbing osteoclast.We demonstrate that rats exposed to sublethal levels of IR develop fragile,osteoporotic bone.At reactive surface sites,cerium ions have the ability to easily undergo redox cycling:drastically adjusting their electronic con-figurations and versatile catalytic activities.These properties make cerium oxide nanomaterials fascinating.We show that an engineered artificial nanozyme composed of cerium oxide,and designed to possess a higher fraction of trivalent(Ce^(3+))surface sites,mitigates the IR-induced loss in bone area,bone architecture,and strength.These investigations also demonstrate that our nanozyme furnishes several mechanistic avenues of protection and selectively targets highly damaging reactive oxygen species,protecting the rats against IR-induced DNA damage,cellular senescence,and elevated osteoclastic activity in vitro and in vivo.Further,we reveal that our nanozyme is a previously unreported key regulator of osteoclast formation derived from macrophages while also directly targeting bone progenitor cells,favoring new bone formation despite its exposure to harmful levels of IR in vitro.These findings open a new approach for the specific prevention of IR-induced bone loss using synthesis-mediated designer multifunctional nanomaterials.

Papillary fibroblast-recruiting injectable self-healing multifunctional hydrogels for wound regeneration

The recruitment of key cells to regeneration sites is a promising strategy to promote functional wound healing.Dermal fibroblasts exhibit a heterogeneous population of cells during homeostasis and in response to injury.Papillary fibroblasts play central regulatory roles in the regeneration of skin appendages during wound healing.Inspired by the phenomenon where bait for grass carp can attract grouped grass carps to a fishing spot soon,“Grass Carp Fishing”multifunctional hydrogels,that is,codelivery of an antibody of leucine-rich repeats and immunoglobulin-like domains 1(Lrig1)on the surface of papillary fibroblasts and insulinlike growth factor 1(IGF1)with recruitment function,can recruit papillary fibroblasts.In the experiments,carboxymethyl chitosan showed positive effects in promoting cell proliferation and neovascularization,while dopamine-grafted gelatin was effective in stabilizing the structure and prolonging the degradation time.The sustained release of Lrig1 antibodies and IGF1 from injectable self-healing multifunctional hydrogels persistently accelerated the migration and proliferation of Lrig1+fibroblasts.The in vivo results from a full-thickness cutaneous wound model showed that injectable self-healing multifunctional hydrogel accelerated wound healing and skin regeneration through the recruitment of Lrig1+papillary fibroblasts in wound tissue.Our findings reveal an injectable self-healing multifunctional hydrogel for regeneration,a promising approach to promoting skin wound healing.

静电纺纤维滴鼻液实现脑室内给药

Adequate drug delivery across the blood–brain barrier(BBB) is a critical factor in treating central nervous system(CNS) disorders. Inspired by swimming fish and the microstructure of the nasal cavity, this study is the first to develop swimming short fibrous nasal drops that can directly target the nasal mucosa and swim in the nasal cavity, which can effectively deliver drugs to the brain. Briefly, swimming short fibrous nasal drops with charged controlled drug release were fabricated by electrospinning, homogenization,the π-π conjugation between indole group of fibers, the benzene ring of leucine-rich repeat kinase 2(LRRK2) inhibitor along with charge-dipole interaction between positively charged poly-lysine(PLL)and negatively charged surface of fibers;this enabled these fibers to stick to nasal mucosa, prolonged the residence time on mucosa, and prevented rapid mucociliary clearance. In vitro, swimming short fibrous nasal drops were biocompatible and inhibited microglial activation by releasing an LRRK2 inhibitor. In vivo, luciferase-labelled swimming short fibrous nasal drops delivered an LRRK2 inhibitor to the brain through the nasal mucosa, alleviating cognitive dysfunction caused by sepsis-associated encephalopathy by inhibiting microglial inflammation and improving synaptic plasticity. Thus, swimming short fibrous nasal drops is a promising strategy for the treatment of CNS diseases.

Multichannel high extinction ratio polarized beam splitters based on metasurfaces

Separating lights into different, paths according to the polarization states while keeping their respective path's polarizations with high purification is keen for polarization multiplex in optical communications. Metallic nanowire gratings with multi-slits in a period are proposed to achieve polarized beam splitters (PBSs) in reflection and diffraction. The setting of multi-slits largely reduces the reflection of photons with a transverse magnetific field via the plasmonic waveguiding effect, which leads to highly polarized output lights with extinction ratio larger than 20 dB in each channel. The proposed reflection/diffraction PBSs enrich the approaches to control the polarization states with the advantages of wide incident angles and flexible beam splitting angles.

Dielectric metalens for miniaturized imaging systems:progress and challenges

Lightweight, miniaturized optical imaging systems are vastly anticipated in these fields of aerospace exploration, industrial vision, consumer electronics, and medical imaging. However, conventional optical techniques are intricate to downscale as refractive lenses mostly rely on phase accumulation. Metalens, composed of subwavelength nanostructures that locally control light waves, offers a disruptive path for small-scale imaging systems. Recent advances in the design and nanofabrication of dielectric metalenses have led to some high-performance practical optical systems. This review outlines the exciting developments in the aforementioned area whilst highlighting the challenges of using dielectric metalenses to replace conventional optics in miniature optical systems. After a brief introduction to the fundamental physics of dielectric metalenses, the progress and challenges in terms of the typical performances are introduced. The supplementary discussion on the common challenges hindering further development is also presented, including the limitations of the conventional design methods, difficulties in scaling up, and device integration. Furthermore, the potential approaches to address the existing challenges are also deliberated.