Multisensor-integrated organs-on-chips platform for automated and continual in situ monitoring of organoid behaviors.

Organ-on-a-chip systems are miniaturized microfluidic 3D human tissue and organ models designed to recapitulate the important biological and physiological parameters of their in vivo counterparts. They have recently emerged as a viable platform for personalized medicine and drug screening. These in vitro models, featuring biomimetic compositions, architectures, and functions, are expected to replace the conventional planar, static cell cultures and bridge the gap between the currently used preclinical animal models and the human body. Multiple organoid models may be further connected together through the microfluidics in a similar manner in which they are arranged in vivo, providing the capability to analyze multiorgan interactions. Although a wide variety of human organ-on-a-chip models have been created, there are limited efforts on the integration of multisensor systems. However, in situ continual measuring is critical in precise assessment of the microenvironment parameters and the dynamic responses of the organs to pharmaceutical compounds over extended periods of time. In addition, automated and noninvasive capability is strongly desired for long-term monitoring. Here, we report a fully integrated modular physical, biochemical, and optical sensing platform through a fluidics-routing breadboard, which operates organ-on-a-chip units in a continual, dynamic, and automated manner. We believe that this platform technology has paved a potential avenue to promote the performance of current organ-on-a-chip models in drug screening by integrating a multitude of real-time sensors to achieve automated in situ monitoring of biophysical and biochemical parameters.

Bioprinting 3D microfibrous scaffolds for engineering endothelialized myocardium and heart-on-a-chip.

Engineering cardiac tissues and organ models remains a great challenge due to the hierarchical structure of the native myocardium. The need of integrating blood vessels brings additional complexity, limiting the available approaches that are suitable to produce integrated cardiovascular organoids. In this work we propose a novel hybrid strategy based on 3D bioprinting, to fabricate endothelialized myocardium. Enabled by the use of our composite bioink, endothelial cells directly bioprinted within microfibrous hydrogel scaffolds gradually migrated towards the peripheries of the microfibers to form a layer of confluent endothelium. Together with controlled anisotropy, this 3D endothelial bed was then seeded with cardiomyocytes to generate aligned myocardium capable of spontaneous and synchronous contraction. We further embedded the organoids into a specially designed microfluidic perfusion bioreactor to complete the endothelialized-myocardium-on-a-chip platform for cardiovascular toxicity evaluation. Finally, we demonstrated that such a technique could be translated to human cardiomyocytes derived from induced pluripotent stem cells to construct endothelialized human myocardium. We believe that our method for generation of endothelialized organoids fabricated through an innovative 3D bioprinting technology may find widespread applications in regenerative medicine, drug screening, and potentially disease modeling.

Organoid-on-a-chip and body-on-a-chip systems for drug screening and disease modeling.

In recent years, advances in tissue engineering and microfabrication technologies have enabled rapid growth in the areas of in vitro organoid development as well as organoid-on-a-chip platforms. These 3D model systems often are able to mimic human physiology more accurately than traditional 2D cultures and animal models. In this review, we describe the progress that has been made to generate organ-on-a-chip platforms and, more recently, more complex multi-organoid body-on-a-chip platforms and their applications. Importantly, these systems have the potential to dramatically impact biomedical applications in the areas of drug development, drug and toxicology screening, disease modeling, and the emerging area of personalized precision medicine.

Hepatic stellate cells' involvement in progenitor-mediated liver regeneration.

Earlier studies conducted by our laboratory have shown that suppression of transforming growth factor-beta (TGFbeta)-mediated upregulation of connective tissue growth factor (CTGF) by iloprost resulted in a greatly diminished oval cell response to 2-acetylaminofluorene/partial hepatectomy (2AAF/PH) in rats. We hypothesized that this effect is due to decreased activation of hepatic stellate cells. To test this hypothesis, we maintained rats on a diet supplemented with 2% L-cysteine as a means of inhibiting stellate cell activation during the oval cell response to 2AAF/PH. In vitro experiments show that L-cysteine did, indeed, prevent the activation of stellate cells while exerting no direct effect on oval cells. Desmin immunostaining of liver sections from 2AAF/PH animals indicated that maintenance on the L-cysteine diet resulted in an 11.1-fold decrease in the number of activated stellate cells within the periportal zones. The total number of cells proliferating in the periportal zones of livers from animals treated with L-cysteine was drastically reduced. Further analyses showed a greater than fourfold decrease in the magnitude of the oval cell response in animals maintained on the L-cysteine diet as determined by immunostaining for both OV6 and alpha-fetoprotein (AFP). Global liver expression of AFP as measured by real-time PCR was shown to be decreased 4.7-fold in the L-cysteine-treated animals. These data indicate that the activation of hepatic stellate cells is required for an appropriate oval cell response to 2AAF/PH.