Disclosed herein are synthetic leathers, artificial epidermal layers, artificial dermal layers, layered structures, products produced therefrom and methods of producing the same.

Hematopoietic stem cells are extremely difficult to maintain or expand in vitro. Two observations in traditional long-term bone marrow cultures strongly suggest that macrophages may be at the root of the problem: First, micromolar concentrations of hydrocortisone improve the longevity of long-term bone marrow cultures and hydrocortisone is known as a potent inhibitor of macrophage production of pro-inflammatory cytokines, chemokines, enzymes, nitrogen oxide and reactive oxygen species and redirects macrophages to the anti-inflammatory differentiation pathway; Second, the decline of hematopoiesis in long-term bone marrow cultures coincides with the development of large numbers of adherent and non-adherent macrophages including foreign body giant cells. These adherent macrophages and foreign body giant cells exhibit well-spread morphology, contain numerous lysosomes and phagolysosomes in the cytoplasm and are metabolically active. We hypothesize that hydrocortisone fails to suppress all aspects of macrophage pro-inflammatory activation/differentiation, resulting in the production of inhibitors or toxins of hematopoiesis. Macrophage adhesion in cell culture depends on serum proteins pre-adsorbed to the tissue-culture-treated polystyrene (TC-PS), which adsorbs proteins via mostly hydrophilic interactions. TC-PS is used in almost all tissue culture devices currently available. Cellular adhesion provides a strong stimulus for metabolic, mitotic and certain gene activities. Therefore, we seek to reduce macrophage adhesion and activation by culturing bone marrow cells in tissue culture devices composed of or covered with polymers with very different protein-binding characteristics than TC-PS such as polyethylene (PE) and other polyolefins, the latter bind proteins via exclusively hydrophobic interactions. As a result, polyolefins bind different proteins and in lower quantities than TC-PS. Furthermore, PE does not contain additional chemical features like the phenolic rings of polystyrene that might contribute to protein binding and macrophage adhesion/activation. Using these new culture devices, we developed a drastically different long-term bone marrow culture, the “Low Macrophage-Adhesion/Activation” (LoMAC) bone marrow culture. In LoMAC bone marrow culture, hematopoiesis continues for months to over a year and hematopoietic stem cells are amplified gradually. In stark contrast to traditional long-term bone marrow cultures, de novo erythropoiesis and megakaryocytopoiesis proceed robustly in the LoMAC bone marrow culture and B-lymphocyte and natural killer cell progenitors can be continuously derived. Thus, these new culture devices and the associated LoMAC c

Embodiments of the present disclosure generally relate to methods and compositions for controlling cellular expression. More specifically, embodiments described herein relate to hydrogel-encapsulated/dispersed cells, methods of forming hydrogel-encapsulated/dispersed cells, and methods of using hydrogel-encapsulated/dispersed cells for controlling production of, for example, secretomes. In an embodiment, a composition for controlling production of secretomes is provided. The composition includes, a hydrogel comprising, in polymerized form, one or more photoreactive monomers and a thiol linker, wherein at least one of the one or more photoreactive monomers comprises a methylene functional group; and one or more cells dispersed or encapsulated within the hydrogel.

Disclosed are methods of assessing the ability of a candidate therapeutic agent to reverse, reduce or prevent intestinal injury by a potential toxic agent using a three-dimensional, engineered, bioprinted, biological intestinal tissue model. Also disclosed are methods of assessing the effect of an agent on intestinal function, the method comprising contacting the agent with a three-dimensional, engineered, bioprinted, biological intestinal tissue model.

The present disclosure provides feeder hydrogel particles that can function to support the growth, proliferation, and/or activation of a target cell in culture. The present disclosure also provides methods of culturing target cells with feeder hydrogel particles.

A substrate for producing cell aggregates provided with a plurality of spots which comprises a polymer containing a recurring unit derived from a monomer represented by the following formula (I):

##STR00001##

wherein U.sup.a1, U.sup.a2, R.sup.a1 and R.sup.a2 are as defined herein, on a substrate having an ability to inhibit adhesion of cells, wherein a ratio of a total area of the spots to a surface area of the substrate is 30% or more, a diameter of each spot is 50 to 5,000 μm, and a distance between the spots is 30 to 1,000 μm, a method for producing the same, and a method for producing cell aggregates using such a substrate and a method of improving cell utilization efficiency at the time of producing the cell aggregates.

The present disclosure provides a method of producing uniformly sized organoids/multicellular spheroids using a microfluidic device having an array of microwells. The method involves several successive steps. First, a microfluidic device containing parallel rows of microwells that are connected with a supplying channel is filled with a wetting agent. The wetting agent is a liquid that is immiscible in water. For example, the wetting agent may be an organic liquid such as oil. In the next step, the agent in the supplying channel and the microwells is replaced with a suspension of cells in an aqueous solution that contains a precursor for a hydrogel. Next, the aqueous phase in the supplying channel is replaced with the agent, which leads to the formation of an array of droplets of cell suspension in the hydrogel precursor solution, which were compartmentalized in the wells. The droplets are then transformed into cell-laden hydrogels. Subsequently, the agent in the supplying channel is replaced with the cell culture medium continuously flowing through the microfluidic device and the cells within the hydrogels are transformed into multicellular spheroids.

The present disclosure provides methods for bulk droplet vitrification of cells, compositions including the vitrified droplets, and systems for performing the methods for bulk droplet vitrification cells.

The present disclosure discloses a crosslinked hydrogel for muscle stem cell culture and a preparation method and use thereof, and belongs to the technical field of biological food materials. The preparation method includes: dissolving collagen to prepare a solution and adding a certain amount of alginate and heparan sulfate proteoglycan for being uniformly mixed with the collagen solution; and adding ε-PL and TGase into the solution, uniformly stirring, and putting a slurry into a mold for crosslinking to obtain the hydrogel. The hydrogel is prepared by linking the collagen, the polylysine and the heparan sulfate proteoglycan using the TGase to form covalent crosslinking, and forming a compact three-dimensional “egg box” network structure through a physical electrostatic interaction between the polylysine and the alginate. The hydrogel can enhance the absorption to nutrient substances by the muscle stem cells and facilitate the growth of the muscle stem cells. The double-network crosslinked hydrogel has the potential to be a scaffold for the growth of muscle stem cells for cultured meat from stem cells.

Embodiments described herein relate generally to devices, apparatuses, and systems with embedded electrodes for rowing, maintaining, and/or using 3D tissues in vitro. The devices, apparatuses, and systems described herein can provide scalable, automated tissue stimulation.