Junyang Li

Bullous keratopathy, a condition severely impacting vision and potentially leading to corneal blindness, necessitates corneal transplantation. However, the shortage of donor corneas and complex surgical procedures drive the exploration of tissue‐engineered corneal endothelial layers. This study develops a transparent, amphiphilic, and cell‐free membrane for corneal endothelial replacement. The membrane, securely attached to the posterior surface of the cornea, is created by mixing hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethylacrylate (EGDMA) in a 10:1 ratio. A 50 µL volume is used to obtain a 60 µm hydrophobic membrane on both sides, with one side treated with a polyvinylpyrrolidone (PVP) solution. The resulting membrane is transparent, foldable, biocompatible, amphiphilic, and easily handled. When exposed to 20% sulfur hexafluoride (SF₆), the hydrophilic side of the membrane adheres tightly to the corneal Descemet's membrane, preventing water absorption into the corneal stroma, and thus treating bullous keratopathy. Histological test confirms its effectiveness, showing normal corneal structure and low inflammation when implanted in rabbits for up to 100 d. This study showcases the potential of this membrane as a viable option for corneal endothelial replacement, offering a novel approach to address donor tissue scarcity in corneal transplantation.

Hematopoietic syndrome of acute radiation syndrome (h-ARS) is an acute illness resulted from the damage of bone marrow (BM) microenvironment after exposure to radiation. Currently, the clinical management of h-ARS is limited to medication-assisted treatment, while there is still no specific therapy for the hematopoietic injury from high-dose radiation exposure. Our study aimed to assemble biomimetic three-dimensional (3D) BM microniches by co-culture of hematopoietic stem and progenitor cells (HSPCs) and mesenchymal stem cells (MSCs) in porous, injectable and viscoelastic microscaffolds in vitro. The biodegradable BM microniches were then transplanted in vivo into the BM cavity for the treatment of h-ARS. We demonstrated that the maintenance of HSPCs was prolonged by co-culture with MSCs in the porous 3D microscaffolds with 84 μm in pore diameter and 11.2 kPa in Young's modulus compared with 2D co-culture system. Besides, the minimal effective dose and therapeutic effects of the BM microniches were investigated on a murine model of h-ARS, which showed that the intramedullary cavity-injected BM microniches could adequately promote hematopoietic reconstitution and mitigate death from acute lethal radiation with a dose as low as 1000 HSPCs. Furthermore, the mRNA expression of Notch1 and its downstream target gene Hes1 of HSPCs were increased when co-cultured with MSCs, while the Jagged1 expression of the co-cultured MSCs was upregulated, indicating the significance of Notch signaling pathway in maintenance of HSPCs. Collectively, our findings provide evidence that biomimetic and injectable 3D BM microniches could maintain HSPCs, promote hematopoiesis regeneration and alleviate post-radiation injury, which provides a promising approach to renovate conventional HSPCs transplantation for clinical treatment of blood and immune disorders.

In recent years, cyclic peptides have attracted much attention due to their chemical and enzymatic stability, low toxicity, and easy modification. In general, the self-assembled nanostructures of cyclic peptides tend to form nanotubes in a cyclic stacking manner through hydrogen bonding. However, studies exploring other assembly strategies are scarce. In this context, we proposed a new assembly strategy based on cyclic peptides with covalent self-assembly. Here, cyclic peptide-(DPDPDP) was rationally designed and used as a building block to construct new assemblies. With cyclo-(DP)₃ as the structural unit and 2,2′-diamino-N-methyldiethylamine as the linker, positively charged nanospheres ((CP)₆NS) based on cyclo-(DP)₃ were successfully constructed by covalent self-assembly. We assessed their size and morphology by scanning electron microscopy (SEM), TEM, and DLS. (CP)₆NS were found to have a strong positive charge, so they could bind to siRNA through electrostatic interactions. Confocal microscopy analysis and cell viability assays showed that (CP)₆NS had high cellular internalization efficiency and low cytotoxicity. More importantly, real-time polymerase chain reaction (PCR) and flow cytometry analyses indicated that (CP)₆NS-siRNA complexes potently inhibited gene expression and promoted tumor cell apoptosis. These results suggest that (CP)₆NS may be a potential siRNA carrier for gene therapy.

This study revealed the enhanced therapeutic effects and mechanisms of Exendin-4–engineered MSCs for type 2 diabetes treatment.

Automatic train operation (ATO) is an important part of automatic train control (ATC) systems in urban rail transit. Using computers to simulate the complicated circumstances of train movement to test the operations of certain ATO systems in urban rail transit is an economical, reliable, and safe method. This paper proposes a testing platform for ATO systems, which may be applied to the development of both software and hardware of ATO systems. Specifically, this work firstly studies the theory of traction calculation model of urban rail transit and develops a simulation testing system by building virtual equipment PXI and a software platform based on the programming language LabVIEW8.2. Comprehensive operation results show that the proposed ATO testing platform is capable of simulating the urban rail transit circumstances and accomplishing a variety of testing tasks.