npj Microgravity最新文献

Microgravity alters key biological processes, impacting cellular structure, function, and metabolism. In the absence of gravity, cells experience changes that disrupt signal transduction, gene expression, and metabolic pathways, affecting growth rates and cellular viability. Ground-based simulators like clinostats replicate microgravity conditions to study these effects, allowing researchers to examine cellular responses in the lab. This study uses Saccharomyces cerevisiae to explore microgravity's impact on yeast metabolism and properties. Yeast cells are exposed to simulated microgravity via a 2D-clinostat and analyzed using dielectrophoresis over 1-24 h. A double-shell model reveals significant morphological and membrane changes under these conditions. Results indicate notable differences in membrane permittivity and conductivity, with microgravity reducing the folding factor in yeast cells, impairing nutrient uptake and energy production. This research enhances the understanding of microgravity's effects on eukaryotic cells and contributes to the field of gravitational biology.

The purpose of this study was to determine the extent to which extracellular vesicles (EVs) circulating in blood after exercise training act as an effective mimetic to maintain skeletal muscle mass during unloading and/or accelerate recovery after disuse. Ten healthy males (27.7 ± 7.1 y) were recruited for a 6-week progressive resistance and endurance training program. EVs were isolated from blood before (EVs) or immediately after training (ExerVs). EVs were intraperitoneally injected into male mice (4×; 3 × 10⁸ particles/injection) during 14 days of hindlimb unloading (HU), then the muscles were collected immediately or 7 days after HU. ExerVs did not maintain muscle mass, fiber size (fCSA), or protein synthesis but significantly reduced collagen I during HU. ExerV administration rapidly restored Type I fCSA and capillary quantity concomitant with reduced collagen during the reloading period. Overall, this study demonstrates that ExerVs may represent a novel strategy to preserve skeletal muscle health during disuse.

Maxillofacial fractures, especially those of the mandible, pose a significant risk in microgravity environments because astronauts experience progressive bone loss during long-duration flights because of skeletal unloading. In this study, we explored the biomechanical response of the mandibular angle to high-impact trauma caused by gravity and microgravity. A human mandibular model was subjected to a force of 2000 N at an angle of 45°, which was directed posterosuperiorly at the right-angle region with simulations comparing healthy and osteoporotic bone (bone loses its density in long flights due to skeletal unloading). The results revealed that although stresses remained the same across all conditions, microgravity caused nearly double the strain and deformation, indicating a high risk of fracture. These findings emphasize the need for biomechanical evaluation and protective strategies in space medicine.

Space-based biomanufacturing has historically focused on long-duration crewed and exploration missions, but its greater potential lies in supporting in-space logistics, manufacturing, and servicing in Earth orbit. This article provides a strategic perspective on how shifting investments, policy, and R&D to orbital biomanufacturing could revolutionize defense, commercial, and civil sectors by enhancing supply chain resiliency, operational flexibility, ethical debris management, and commercial viability in Earth orbit.

As resident immune cells of the central nervous system, microglia exhibit inherent responsiveness to external stimuli and insults. In this study, we demonstrated that a simulated microgravity conditions induces pro-inflammatory activation of BV2 microglial cells, a process tightly regulated by the RhoA GTPase Arhgap18. Specifically, the downregulation of Arhgap18 under simulated microgravity was identified as the upstream mechanism driving microglial activation and triggering neuroinflammation via the Arhgap18/RhoA/ROCK signaling pathway. For in vivo validation, we established a 21-day hindlimb unloading (HU) mouse model, which confirmed that simulated microgravity promotes pro-inflammatory microglial activation in the cerebral cortex and hippocampus. Furthermore, co-culture of N2a neural cells with pro-inflammatory microglia led to distinct morphological alterations in N2a cells and a significant downregulation of synaptic plasticity-related proteins-effects that were recapitulated in the HU mouse model. Collectively, these findings suggest that microgravity may mediate changes in neuronal synaptic plasticity by activating the inflammatory response of microglia.

The growth of compositionally uniform InAs_1-xSb_x bulk crystals remains a formidable challenge due to severe solute segregation and morphological instability under terrestrial conditions. Here, we report the successful growth of a single-crystalline InAs_0.933Sb_0.067 alloy (x = 6.7 mol%) on an InAs seed via the vertical gradient freeze method aboard the China Space Station. Crucially, microgravity enables diffusion-dominated solidification by suppressing buoyancy-driven convection. As a direct consequence, the crystal is free of macroscopic voids and striations, exhibits a tenfold reduction in dislocation density, and maintains Sb compositional uniformity (±0.5 mol%) over its entire ~11 mm diameter and ~2.5 mm growth length. Moreover, the microgravity-grown crystal outperforms its terrestrial counterpart in both crystalline quality and electrical properties. These findings highlight that microgravity provides a unique pathway to overcome the intrinsic limitations of ground-based growth, enabling crystal quality unattainable on Earth - with potential relevance to advanced optoelectronic applications.

With the emergence of long-duration space travel, space exploration missions pose a major concern due to the heightened risk of medical emergencies, such as sudden cardiac arrest. While several cardiopulmonary resuscitation (CPR) methods have been proposed for human spaceflight, their reliability and effectiveness remain uncertain, as these methods lack systematic evaluation through physiological metrics. To address this gap, a high-fidelity CPR simulator was developed to simulate blood circulation and deliver real-time hemodynamic feedback. Herein, we show that in normogravity, the CPR simulator generates compression-decompression waveforms that align with published animal and test bench studies. As an exploratory comparison, we also report relative differences in hemodynamic pressure observed between normogravity and hypogravity conditions. The findings highlight that internal physiological responses are critical for evaluating CPR effectiveness in hypogravity, with the CPR simulator serving as a plausible tool. The current study represents an initial step toward the validation of a gold standard CPR protocol and may contribute to the complex health challenges surrounding long-duration spaceflight.

Space missions require sustainable life support systems capable of producing oxygen and biomass under microgravity. We report the use of acoustic levitation to trap and manipulate the filamentous cyanobacterium Limnospira indica PCC 8005 during parabolic flights. Within a millimeter-scale fluidic chamber, this helical microorganism rapidly assembles into thin layers under a standing ultrasonic wave. Stable trapping in microgravity requires substantially less acoustic power (0.42 mW) than on Earth (1.4 mW), highlighting the potential for energy-efficient bioprocessing in space. Monte Carlo simulations and light attenuation modeling show that layered structuring enhances light penetration, potentially overcoming the "compensation point" limitation in bulk cultures. These findings open new perspectives for photobioreactors using acoustic manipulation to boost photosynthetic efficiency and reduce energy demands for oxygen and biomass production in space.