Cellular Mechanotransduction by Osteoblasts in Microgravity explores bone morphogenic protein (BMP) and the signaling pathways it communicates through, as it is one of the main pathways involved in osteogenesis. Osteoporosis causes bones to become weak and brittle as individuals age. On Earth, degeneration occurs over decades, making the study of osteoporosis a slow process. This investigation plans to leverage microgravity to accelerate the degeneration of cells. Despite a deep understanding of the physiological context of bone formation in bone biomechanics, the mechanism of cellular mechanotransduction and its implication in osteoporosis is not entirely clear.
Two aims are being tested in this investigation, cellular tension and its role in altering BMP and mechanical compression in signaling in cells with low cell tension as it relates to BMP. The CubeLab in this investigation will facilitate the cell’s survival throughout the flight including ascent and descent. The CubeLab will utilize a 12-well culture vessel to house and feed the cells and a three-axis autonomous microscope will be used for on-demand imagining.
Reduced gravitational force in microgravity conditions presents a unique research environment to reproduce the absence of mechanical loading and provides an accelerated means to alter cell growth and function in a natural way (i.e., without the use of pharmacological inhibitors or genetic perturbation). As a result, BMP signaling activity increases with cells under compression in microgravity. By accelerating our understanding of the signals without having to wait decades to see it occur as it would on Earth. This investigation will advance our knowledge in cell physiology under true microgravity conditions and also push the frontier of single-cell and cell biology experiments on the International Space Station.
Research carried out in this proposed work has the potential to translate to an insightful understanding of the mechanosensing of osteoblasts, along with other research carried out on Earth, thereby helping a large population of people who may suffer from osteoporosis. This work is also relevant to other age-related diseases as there is data pointing to a correlation of cell mechanics with aging cells.
Space Tango is partnering with the University of California San Diego to investigate slurries comprised of air, sand, and water to mimic mudflow activities in microgravity. In water-air-particle slurry, hydrophobic particles (such as ash) tend to attach to air bubbles and form different slurry structures before flow, during flow, and transport. On Earth, due to gravitational pull, the settling of hydrophobic sand particles occurs at different rates due to density and size. To further our understanding, this investigation will explore how different types of sand particles (fine, medium, and coarse) attach to particles in microgravity and the resulting slurry that occurs.
The CubeLab used in this investigation is designed to push each type of sand mixture through a clear viewing chamber to witness the behavior of the hydrophobic particles. Each type of sand will be put through different flow rates ranging from 0.5cm/s to 10cm/s. Space Tango developed an automated high-speed camera to support real-time video capture of these flow rates while on the International Space Station.
Gravitational settling of hydrophobic sand particles occurs at different rates due to density and size terrestrially. This investigation studies the formation and stability of the bubble-sand structure in the absence of sedimentation in the unique environment of microgravity. Without gravity, the investigation will be able to observe the hydrophobic particles that attach to air bubbles forming different slurry structures. The results of this investigation will facilitate the understanding, modeling, predicting, and development of innovative solutions to prevent catastrophic post-fire mudflows.
Dynamic control of multi-phase flow offers exciting manipulation capability for wide space and Earth applications where phase-change thermal transport and precision control of multi-phase fluid motion. Control of multi-phase flow would improve efficiency and energy saving for applications such as liquid purification, water harvesting, and heating and cooling applications both terrestrially and in space.
Space Tango engineered photo-responsive surfactants, which reversibly switch their molecular structures upon illuminations of appropriate wavelengths and change the interfacial tension of the fluids on demand. The CubeLab in this investigation will apply the appropriate wavelength to a bubble and then cause a gradient in the tension to form a Marangoni flow in the fluid. The Marangoni flow exerts a new force on a bubble in the opposing direction, causing it to depart from the substrate into the bulk fluid. This leads to the bubble being “pinched off” with control, promoting bubble departures during boiling to enhance thermal transport.
The use of microgravity is essential in this investigation to enable large-length scales exceeding the limited capillary lengths possible on Earth. Microgravity creates a long time scale for bubble/droplet departure, therefore greatly reducing the challenges of microscopic and high-speed visualization. Microgravity also allows for direct experimental observation of the proposed light-controlled motion without buoyancy and natural convection, which is essential to ensure accurate fundamental understanding and comparison.