The present invention provides a system for artificially inducing and regulating tissue interactions among multiple tissues. A construct for transplantation into a living body, which comprises a structure and a cell mass linked to each other, the structure being an object having a three-dimensional structure and capable of mimicking or resembling a structure and/or a function of the living body.

The present invention is drawn to the generation of micropatterns of biomolecules and cells on standard laboratory materials through selective ablation of a physisorbed biomolecule with oxygen plasma. In certain embodiments, oxygen plasma is able to ablate selectively physisorbed layers of biomolecules (e.g., type-I collagen, fibronectin, laminin, and Matrigel) along complex non-linear paths which are difficult or impossible to pattern using alternative methods. In addition, certain embodiments of the present invention relate to the micropatterning of multiple cell types on curved surfaces, multiwell plates, and flat bottom flasks. The invention also features kits for use with the subject methods.

The present invention pertains to hepatocytes, liver progenitor cells, cholangiocytes, liver sinusoidal endothelial progenitor cells, liver sinusoidal endothelial cells, hepatic stellate progenitor cells, hepatic stellate cells, and liver cellular tissue models, as well as to methods for preparing these cells. The present invention also pertains to a cell fraction comprising liver progenitor cells, liver sinusoidal endothelial progenitor cells, or hepatic stellate progenitor cells. The present invention also pertains to a pharmaceutical composition or kit comprising the above-mentioned cells, a liver cellular tissue model, or a cell fraction. The present invention also pertains to: a method for screening liver disease treatment agents; a method for evaluating the hepatotoxicity of drugs, hepatocytes for infectious disease models, and a method for preparing the same; infectious disease model tissues and a method for preparing the same; as well as a method for screening infectious liver disease treatment agents.

Engineered, living, three-dimensional liver tissue constructs comprising: one or more layers, wherein each layer contains one or more liver cell types, the one or more layers cohered to form a living, three-dimensional liver tissue construct. In some embodiments, the constructs are characterized by having at least one of: at least one layer comprising a plurality of cell types, the cell types spatially arranged relative to each other to create a planar geometry; and a plurality of layers, at least one layer compositionally or architecturally distinct from at least one other layer to create a laminar geometry. Also disclosed are arrays and methods of making the same. Also disclosed are engineered, living, three-dimensional liver tissue constructs for use in the augmentation or restoration of one or more liver functions, by in vivo delivery of tissue or utilization of tissue in an extracorporeal device.

Immunotolerant engineered human tissue constructs are provided that are suitable for implantation into subjects. In some embodiments, the immunotolerance is controllable by an inducible system. Methods of making and using the immunotolerant engineered tissue constructs are provided.

Methods for producing hepatocyte and/or cholangiocyte lineage cells from pluripotent stem cells, the method comprising (a) specifying the extended nodal agonist treated induced endodermal cell population to obtain a cell population comprising hepatocyte and/or cholangiocyte progenitors by contacting the extended nodal agonist treated induced endodermal cell population with specification media comprising a FGF agonist and a BMP4 agonist and/or active conjugates and/or fragments thereof; (b) inducing maturation, and optionally further lineage specification and/or expansion of the hepatocyte and/or cholangiocyte progenitors of the cell population to obtain a population comprising hepatocyte lineage cells such as hepatoblasts, hepatocytes and/or cholangiocytes, the inducing maturation step comprising generating aggregates of the cell population. Optionally, the method also comprises activating the cAMP pathway within the aggregates and forming co-aggregates.

The invention is directed to three-dimensional, engineered, bioprinted biological tissue constructs exhibiting a liver disorder, methods of making the constructs, and use of the constructs in assays, such as drug testing and molecular diagnostic testing, including methods of assessing the ability of a candidate therapeutic agent to reverse, reduce, or prevent a liver disorder, and methods for biomarker discovery.

Certain populations of small cells present in adult human tissue can undergo activation/development to form human pluripotent stem cell populations. These small cells are generally less than six micrometers in diameter and are CD49f-positive, and are referred to herein as human early stage precursors or CD49f.sup.+ cells. Accordingly, provided are cell populations and compositions with enriched CD49f.sup.+ cells from adult human tissue samples and methods and compositions for promoting activation/development of these CD49f.sup.+ cells. Upon differentiation, the activated stem cells can be used for various therapeutic purposes.

The present invention is drawn to the generation of micropatterns of biomolecules and cells on standard laboratory materials through selective ablation of a physisorbed biomolecule with oxygen plasma. In certain embodiments, oxygen plasma is able to ablate selectively physisorbed layers of biomolecules (e.g., type-I collagen, fibronectin, laminin, and Matrigel) along complex non-linear paths which are difficult or impossible to pattern using alternative methods. In addition, certain embodiments of the present invention relate to the micropatterning of multiple cell types on curved surfaces, multiwell plates, and flat bottom flasks. The invention also features kits for use with the subject methods.

Provided are methods and compositions for co-culturing hepatocytes in the presence of growth-arrested stromal cells, resulting in maintenance of hepatocyte function and phenotype for an extended period of time in culture comprising at least 30 days.