Small tissue chips with big opportunities for space medicine

Abstract

The spaceflight environment, including microgravity and radiation, may have considerable effects on the health and performance of astronauts, especially for long-duration and Martian missions. Conventional on-ground and in-space experimental approaches have been employed to investigate the comprehensive biological effects of the spaceflight environment. As a class of recently emerging bioengineered in vitro models, tissue chips are characterized by a small footprint, potential automation, and the recapitulation of tissue-level physiology, thus promising to help provide molecular and cellular insights into space medicine. Here, we briefly review the technical advantages of tissue chips and discuss specific on-chip physiological recapitulations. Several tissue chips have been launched into space, and more are poised to come through multi-agency collaborations, implying an increasingly important role of tissue chips in space medicine.

Keywords: Drug development; Microfluidics; Microgravity; Radiation; Spaceflight.

Fig 1.

a. Tissue chips are a promising tool for understanding the biological effects of spaceflight environments, including microgravity and radiation. Photograph credit (iss056e201352): NASA/Roscosmos. b. Astronaut Christina Koch operated kidney chips in the International Space Station (ISS). The reduced footprint and improved automated manipulation of liquids make tissue chips compelling. Reproduced with permission (Yeung et al., 2020). Copyright 2020, John Wiley and Sons. c. Overview of tissue chips for recapitulating multiple tissue-level physiological functions. Microchannels and in-chip microstructures are labeled in red and blue. Multiple tissues can be incorporated into one chip.

Fig. 2.

Two tissue chips for recapitulating the blood vessel and the bone marrow. a. Macroscopic view of a blood vessel chip, the size of which is compared with a quarter. Schematic of the tissue chip design, including glass support layer and several hydrogel layers. b. Immunostaining of endothelial cells after 14-day in-chip culture. c. Blockage of sickle RBCs in the engineered vessel leads to local leakage. a-c, Reproduced with permission (Qiu et al., 2018). Copyright 2018, Springer Nature. d. Schematic of a bone marrow chip using subcutaneous implantation for producing engineered bone marrow (eBM). e. Bone marrow tissues before (0 week) and after 8 weeks of implantation. The chip enables media perfusion and the delivery of biochemical cues. Scale bars, 2 mm. d-e, Reproduced with permission (Torisawa et al., 2014). Copyright 2014, Springer Nature.