Implantable biohybrid artificial organs

TLDR

Biohybrid artificial organs combine synthetic materials and living cells to replace organ or tissue function, yet knowledge of immune rejection mechanisms with semipermeable membranes remains limited. The review focuses on implantable immunoisolation devices that protect tissue from immune rejection via semipermeable membranes. The review examines device design and performance for maintaining cell viability and function, addressing oxygen supply limitations, tissue density, neovascularization, and immune rejection protection. Recent studies show that membrane properties help prevent immune rejection and demonstrate substantial progress toward clinically useful implantable immunoisolation devices.

Abstract

Biohybrid artificial organs encompass all devices which substitute for an organ or tissue function and incorporate both synthetic materials and living cells. This review concerns implantable immunoisolation devices in which the tissue is protected from immune rejection by enclosure within a semipermeable membrane. Two critical areas are discussed in detail: (i) Device design and performance as it relates to maintenance of cell viability and function. Attention is focussed on oxygen supply limitation and how it is affected by tissue density and the development of materials that induce neovascularization at the host tissue-membrane interface; and (ii) Protection from immune rejection. Our current knowledge of the mechanisms that may be operative in immune rejection in the presence of a semipermeable membrane barrier is limited. Nonetheless, recent studies shed light on the role played by membrane properties in preventing immune rejection, and many studies demonstrate substantial progress towards clinically useful implantable immunoisolation devices.