The SARS-CoV-2 pandemic poses an unprecedented public health crisis. Evidence suggests that SARS-CoV-2 infection causes dysregulation of the immune system. However, the unique signature of early immune responses remains elusive. We characterized the transcriptome of rhesus macaques and mice infected with SARS-CoV-2. Alarmin S100A8 was robustly induced in SARS-CoV-2 infected animal models as well as in COVID-19 patients. Paquinimod, a specific inhibitor of S100A8/A9, could rescue the pneumonia with substantial reduction of viral loads in SARS-CoV-2 infected mice. Remarkably, Paquinimod treatment resulted in almost 100% survival in a lethal model of mouse coronavirus infection using the mouse hepatitis virus (MHV). A group of neutrophils that contributes to the uncontrolled pathological damage and onset of COVID-19 were dramatically induced by coronavirus infection. Paquinimod treatment could reduce these neutrophils and regain antiviral responses, unveiling key roles of S100A8/A9 and aberrant neutrophils in the pathogenesis of COVID-19, highlighting new opportunities for therapeutic intervention.

Inorganic CsPbI3 perovskite quantum dot (PQD) receives increasing attention for the application in the new generation solar cells, but the defects on the surface of PQDs significantly affect the photovoltaic performance and stability of solar cells. Herein, the amino acids are used as dual‐passivation ligands to passivate the surface defects of CsPbI3 PQDs using a facile single‐step ligand exchange strategy. The PQD surface properties are investigated in depth by combining experimental studies and theoretical calculation approaches. The PQD solid films with amino acids as dual‐passivation ligands on the PQD surface are thoroughly characterized using extensive techniques, which reveal that the glycine ligand can significantly improve defect passivation of PQDs and therefore diminish charge carrier recombination in the PQD solid. The power conversion efficiency (PCE) of the glycine‐based PQD solar cell (PQDSC) is improved by 16.9% compared with that of the traditional PQDSC fabricated with Pb(NO3)2 treating the PQD surface, owning to improved charge carrier extraction. Theoretical calculations are carried out to comprehensively understand the thermodynamic feasibility and favorable charge density distribution on the PQD surface with a dual‐passivation ligand.

Flexible wearable sensors are emerging as next-generation tools to collect information from the human body and surroundings in a smart, friendly, and real-time manner. A new class of such sensors with various functionality and amenability for the human body is essential for this goal. Unfortunately, the majority of the wearable sensors reported so far in the literature were of a single function (mostly strain sensors) and just a prototype without thinking of continuous mass production. In this paper, we report a series of multifunctional conductive hydrogel/ thermochromic elastomer hybrid fibers with core–shell segmental configuration and their application as flexible wearable strain and temperature sensors to monitor human motion and body/surrounding temperatures. Specifically, a conductive reduced-graphene-oxide-doped poly­(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylamide (rGO-poly­(AMPS-co-AAm)) hydrogel and a thermochromic elastomer containing silicon rubber and thermochromic microcapsules are chosen as strain-sensitive and thermosensitive materials, respectively. A core–shell segmental structure is realized by programming the extrusion of either conductive hydrogel precursor solution or a thermochromic elastomer prepolymer as a core layer via dual-core coaxial wet spinning. Depending on the assembly order and length of the conductive hydrogel and the thermochromic elastomer, the as-prepared hybrid fibers can be used for different purposes, i.e., human-motion monitoring, body or room temperature detection, and color decoration. The strategy described above, i.e., fabrication of core–shell segmental fibers via the wet-spinning method, is especially suitable for mass production in industry and can be further extended to fabricate flexible wearable devices with more components and more functions such as transistors, sensors, displays, and batteries.

In this paper, a novel bioinspired stem cell‐laden microgel and related in vivo cartilage repair strategy are proposed. In particular, herein the preparation of new stem cell‐laden microgels, which can be injected into the chondral defect site in a minimally invasive way, and more importantly, capable of in situ self‐assembly into 3D macroporous scaffold without external stimuli, is presented. Specifically, thiolated gelatin (Gel‐SH) and vinyl sulfonated hyaluronic acid (HA‐VS) are first synthesized, and then stem cell‐laden gelatin/hyaluronic acid hybrid microgels (Gel‐HA) are generated by mixing Gel‐SH, HA‐VS, and bone mesenchymal stem cells (BMSCs) together via droplet‐based microfluidic approach, followed by gelation through fast and efficient thiol‐Michael addition reaction. The encapsulated BMSCs show high viability, proliferation, and chondrogenic differentiation potential in the microgels. Moreover, the in vitro test proves that BMSC‐laden Gel‐HA microgels are injectable without sacrificing BMSC viability, and more importantly, can self‐assemble into cartilage‐like scaffolds via cell–cell interconnectivity. In vivo experiments further confirm that the self‐assembled microgels can inhibit vascularization and hypertrophy. The Gel‐HA microgels and relevant cartilage repair strategy, i.e., injecting BMSC‐laden microgels separately and reconstructing chondral defect structure by microgel self‐assembly, provides a simple and effective method for cartilage tissue engineering and regenerative medicine.

Inorganic CsPbI3 perovskite quantum dot (PQD) shows a high potential for photovoltaic applications. However, the surface matrix of the PQDs significantly suffers from deterioration during the purification process with antisolvent,...