“…Since the cost of drug discovery is constantly increasing due to the limited predictability of conventional monolayer culture methods and animal models, this technology has great potential to promote drug discovery and development as well as to model human physiology and disease.This Special Issue is themed to provide insight and advancements in organ-on-chip microdevices. There are fifteen papers including three review papers, covering a novel material to fabricate microfluidic organs-on-chips [1], methods to deliver mechanical stimuli [2,3], methods to measure mechanical forces [4,5], methods to evaluate cellular functions in 3D cultures [6][7][8], and specific organ models; lung chips [3,9], liver chips [10,11], blood vessel chips [12][13][14][15] including models of the outer blood-retina barrier [14] and ischemia-reperfusion injury [15].Inside the body, cells are exposed to biomechanical forces, including fluidic shear stress and mechanical strain, which regulate cell function and contribute to disease. Kaarj et al reviewed methods to produce mechanical stimuli focusing on the technical details of devices [2].…”