May the Force Be with You (Or Not): The Immune System under Microgravity.

All terrestrial organisms have evolved and adapted to thrive under Earth's gravitational force. Due to the increase of crewed space flights in recent years, it is vital to understand how the lack of gravitational forces affects organisms. It is known that astronauts who have been exposed to microgravity suffer from an array of pathological conditions including an impaired immune system, which is one of the most negatively affected by microgravity. However, at the cellular level a gap in knowledge exists, limiting our ability to understand immune impairment in space. This review highlights the most significant work done over the past 10 years detailing the effects of microgravity on cellular aspects of the immune system.

Engineered Microvessel for Cell Culture in Simulated Microgravity.

As the number of manned space flights increase, studies on the effects of microgravity on the human body are becoming more important. Due to the high expense and complexity of sending samples into space, simulated microgravity platforms have become a popular way to study these effects on earth. In addition, simulated microgravity has recently drawn the attention of regenerative medicine by increasing cell differentiation capability. These platforms come with many advantages as well as limitations. A main limitation for usage of these platforms is the lack of high-throughput capability due to the use of large cell culture vessels. Therefore, there is a requirement for microvessels for microgravity platforms that limit waste and increase throughput. In this work, a microvessel for commercial cell culture plates was designed. Four 3D printable (polycarbonate (PC), polylactic acid (PLA) and resin) and castable (polydimethylsiloxane (PDMS)) materials were assessed for biocompatibility with adherent and suspension cell types. PDMS was found to be the most suitable material for microvessel fabrication, long-term cell viability and proliferation. It also allows for efficient gas exchange, has no effect on cell culture media pH and does not induce hypoxic conditions. Overall, the designed microvessel can be used on simulated microgravity platforms as a method for long-term high-throughput biomedical studies.