Tissue Engineering

Pipetting of cell culture media in 24 well plate depicted in front of confocal microscopy image of red and blue stained cells

Tissue engineering and regenerative medicine are interdisciplinary fields aimed at developing biological substitutes to restore, maintain, improve tissue function, or replace diseased and damaged tissues. Both hard tissues (e.g., bone, cartilage) and soft tissues (e.g., skin, cardiovascular valves) can be fabricated by tissue engineering. Cells, scaffolds, and growth-stimulating signals are three key components for engineering tissue substitutes. Whereas tissue engineering cultures tissue in vitro, regenerative medicine combines tissue engineering with other strategies, including cell-based therapy, gene therapy, and immunomodulation, to induce in vivo tissue regeneration. Biomimetic tissue constructs are also developed as in vitro models for drug screening and disease modeling.

Tissue engineering involves cultivating new tissue in the lab by combining scaffolds, native tissue cells, and bioactive molecules to emulate the biological processes of the body.

Tissue scaffolds are analogous to the functions of extracellular matrix (ECM) in native tissues. Tissue scaffolds provide a structural and physical environment for cells to grow, migrate, and respond to signals; mechanical properties to the resulting tissue; and bioactive cues to the residing cells for activity regulation.

Three major approaches have evolved to develop tissue scaffolds that mimic native ECM functions:

  • Seeding cells on pre-made porous scaffolds from degradable biomaterials, including decellularized ECM from allogenic and xenogenic tissues, natural polymers, bioglasses, and synthetic polymers
  • Cell sheet engineering by seeding cells on thermo-responsive polymer-coated culture dishes and detaching the polymer sheet once the cells become confluent
  • Cell encapsulation in a hydrogel matrix made of natural or synthetic polymers, such as bioinks, in 3D bioprinting

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