Exposure to acute and prolonged microgravity triggers numerous physiological adaptations. To date, the underlying molecular mechanisms are not well understood, and several pathways have been proposed. Among other candidates, specific ion channels are hypothesized to be gravity dependent, but it has not been possible to conclusively demonstrate gravity dependency of specific protein entities. Therefore, we developed a miniaturized two-electrode voltage clamp (TEVC) that allowed electrophysiological experiments on Xenopus laevis oocytes using the GraviTower Bremen Prototype (GTB-Pro). The GTP-Pro is capable of flying experiments on a vertical parabolic trajectory, providing microgravity for a few seconds. As an interesting first candidate, we examined whether the nonselective mechanosensitive ion channel PIEZO1 is gravity dependent. The results showed no difference between PIEZO1-overexpressing and control oocytes under acute microgravity conditions.

Light microscopes became essential tools in everyday lab work a long time ago. However, most commercial microscopes are costly, and they are often bulky and heavy. Therefore, microscopes are rarely seen in mobile applications or used by interested amateurs. Here, we present an affordable, portable single-lens microscope. It essentially uses a Raspberry Pi single-board computer, a camera, a touchscreen display, and an LED ring at its core. Apart from brightfield microscopy, contrast-enhancing methods by oblique, dark-field, and Rheinberg illumination are possible, as well. The microscope is ideal for applications that do not require high-end optical components. Due to its low cost and flexible use, it is also suitable for hands-on experiences of the fascinating world not visible by the human eye.

Articular cartilage separates the bones in articulating joints (e.g. hips, knees, shoulder, etc.) and allows for almost effortless movement. The predominant cell types found in articular cartilage are termed chondrocytes and are responsible for building, maintaining and degrading the tissue. The pathological breakdown of articular cartilage results in osteoarthritis, which is a wide-spread disease in western civilizations and has a major socio-economic impact. An active lifestyle and adequate mechanical stimulation are essential for cellular health and tissue maintenance. However, to date the molecular mechanisms on how chondrocytes (cartilage cells) integrate mechanical forces into a cellular response (mechanotransduction) are not fully understood. Our aim is, therefore, to better understand the effects of mechanotransduction on cartilage degeneration and regeneration.

Adequate mechanical stimulation is essential for cellular health and tissue maintenance, including articular cartilage, which lines the articulating bones in joints. Chondrocytes, which are the sole cells found in articular cartilage, are responsible for matrix synthesis, maintenance and degradation. It is generally believed that chondrocytes require mechanical stimuli through daily physical activity for adequate cartilage homeostasis. However, to date, the molecular mechanisms of cellular force sensing (mechanotransduction) are not fully understood. Among other mechanisms, the cytoskeleton is thought to play a key role. Despite that gravity is a very small force at the cellular level, cytoskeletal adaptations have been observed under altered gravity conditions of a parabolic flight in multiple cell types. In this study, we developed a novel hardware which allowed to chemically fix primary bovine chondrocytes at 7 time points over the course of a 31-parabola flight.

Due to the limited self-repair capacity of articular cartilage, the surgical restoration of defective cartilage remains a major clinical challenge. The cell-based approach, which is known as autologous chondrocyte transplantation (ACT), has limited success, presumably because the chondrocytes acquire a fibroblast-like phenotype in monolayer culture. This unwanted dedifferentiation process is typically addressed by using three-dimensional scaffolds, pellet culture, and/or the application of exogenous factors. Alternative mechanical unloading approaches are suggested to be beneficial in preserving the chondrocyte phenotype.We examined if the random positioning machine (RPM) could be used to expand chondrocytes in vitro such that they maintain their phenotype.

Mechanical unloading by microgravity (or weightlessness) conditions triggers profound adaptation processes at the cellular and organ levels. Among other mechanisms, mechanosensitive ion channels are thought to play a key role in allowing cells to transduce mechanical forces. Previous experiments performed under microgravity have shown that gravity affects the gating properties of ion channels. We developed a new method to record a calcium dependent current in native eggs from the African clawed frog (Xenopus laevis oocytes) under microgravity conditions during a parabolic flight.

It is not fully understood how cells detect external mechanical forces, but mechanosensitive ion channels play important roles in detecting and translating physical forces into biological responses (mechanotransduction). With the “OoClamp” device, we developed a tool to study electrophysiological processes, including the gating properties of ion channels under various gravity conditions. The “OoClamp” device uses an adapted patch clamp technique and is operational during parabolic flight and centrifugation up to 20 g. In the framework of the REXUS/BEXUS program, we have further developed the “OoClamp” device with the goal of conducting electrophysiological experiments aboard a flying sounding rocket.

Random Positioning Machines (RPMs) are used as a ground-based model to simulate microgravity (or weightlessness). Thereby, the biological samples are continuously rotated about two axes. The simulation of microgravity requires that the RPM’s rotation is faster than the biological process under study, but not so fast that undesired side effects appear. We have built several RPM in various sizes and with various features.

Muscle atrophy is of great medical concern, not only for astronauts in space but also for immobilized patients or elderly people on earth. Random Positioning Machines (RPM) are ground based devices frequently used to expose cells to simulated microgravity. The RPM consists of two gimbal mounted frames which rotate constantly to average the earth gravity vector over time to zero. Many studies on myoblasts have been carried out to study muscle development but only a few data are available concerning myoblast differentiation under simulated microgravity. The goal of this project was to improve the means of cell cultivation on the RPM and to study myoblast differentiation under simulated microgravity.

The Federal Institute for Material Science and Technology (EMPA) uses – at its branch in Thun – a tribometer to determine the specific abrasion properties of two samples rubbing on each other. Our task was to expand and modernize the tribometer, so friction force and the normal force can be measured in high temperature experiments. In addition we integrate an automatic control for the temperature and the rotation speed of the samples.