Challenges in the development of immunoisolation devices

Abstract Cells have broad therapeutic potential but many require systemic immune suppression to prevent rejection. Immunoisolation devices seek to protect therapeutic cells locally, without causing global disruption to the immune system. In general, these devices use a barrier to physically separate the transplanted cells from the elements in the body, which would normally cause rejection. Nutrients and waste products exchange across this barrier to maintain cell viability and allow cell-secreted drugs to cross to provide therapy. In this chapter, we discuss the types of cells that can be used in these devices and factors that can affect the survival of the transplanted cells. We will elaborate on mechanisms the immune system uses to reject tissue, and how this information can be leveraged in the design of immunoisolation devices. We will discuss recent engineering approaches that have been implemented to promote the viability and functionality of the encapsulated cells. Lastly, we will take an in-depth look into strategies to prevent biomaterial-mediated host-rejection of immunoisolation devices through fibrosis.