Abstract: A method of making a 3D-printed biomaterial is described. The method includes depositing a hydrogel comprising cells and a cryoprotectant from a 3D printer onto a freezing plate to form a frozen hydrogel filament; depositing additional hydrogel comprising cells and a cryoprotectant from a 3D printer in contact with a previously placed frozen hydrogel filament to form a 3D-printed biomaterial comprising a plurality of frozen hydrogel filaments; and removing the 3D-printed biomaterial from the freezing plate. 3D-printed biomaterials made by the method are also described.

Abstract: A method of shrinking a hydrogel is described. The method includes contacting a polyionic hydrogel with a polyionic solution including an ionic polymer having a net opposite charge from that of the polyionic hydrogel for an amount of time sufficient to decrease the volume of the polyionic hydrogel. Hydrogel compositions made using this method, and methods of using these hydrogels in 3D printing are also described.

Abstract: Described are systems and methods for multi-material printing. The systems and methods can utilize a stereolithographic printing device, a moving stage, and a microfluidic device. The microfluidic device can include a plurality of reservoirs, each reservoir housing a different ink for printing, and a microfluidic chip. The microfluidic chip can include a chamber that comprises a plurality of inlets, a printing region, and one or more outlets as well as an elastic membrane.

Abstract: Described are systems and methods for multi-material printing. The systems and methods can utilize a stereolithographic printing device, a moving stage, and a microfluidic device. The microfluidic device can include a plurality of reservoirs, each reservoir housing a different ink for printing, and a microfluidic chip. The microfluidic chip can include a chamber that comprises a plurality of inlets, a printing region, and one or more outlets as well as an elastic membrane.

Abstract: Methods fabricate an endothelialized myocardium usable for screening of a drug. A microfibrous hydrogel scaffold is manufactured with additive manufacturing that concurrently bioprints endothelial cells directly within the microfibrous hydrogel scaffold. A bioink is bioprinted into an arrangement of one or more microfibers. The bioink includes at least one crosslinking component and suspended endothelial cells. The crosslinking component or components are crosslinked to yield the microfibrous hydrogel scaffold having the endothelial cells embedded directly within. The microfibrous hydrogel scaffold is seeded with cardiomyocytes to yield the endothelialized myocardium with a controlled anisotropy. The endothelialized myocardium can be incubated until the endothelialized myocardium matures into spontaneously beating myocardial tissue having contractions aligned with the controlled anisotropy.

Abstract: A bioreactor and methods for use can include a microfibrous scaffold, that can be made of a composite bioink, and that can have endothelial cells directly embedded within the scaffold using an additive manufacturing process. The scaffold can further be seeded with cardiomyocytes. The hydrogel scaffold can be composed of a plurality of serpentine layers, with each serpentine layers, which can be placed on each other in a cross-hatch configuration, so that the primary axes of successive layers are perpendicular. This configuration can establish an aspect ratio for the scaffold, which can be selectively varied. For greater strength, the successive layers that have a primary axis in the same direction can be placed in the scaffold so that they are slight offset from each other. The scaffold can be placed in the bioreactor with perfusion, for use in cardiovascular drug screening and other nanomedicine endeavors.

Abstract: Described are systems and methods for in vivo multi-material bioprinting. The in vivo multi-material bioprinting can be used to fabricate biomedical constructs within a patient minimally invasively. The systems and methods can utilize a multi-material bioprinter, which includes a biocompatible portion. The biocompatible portion can include a single printhead for in vivo bioprinting. The single printhead can include a plurality of outlets, each linked to one of a plurality of reservoirs. Each of the plurality of reservoirs can each house a different bioink for bioprinting. Each of the plurality of outlets can be activated to release a respective bioink.

Abstract: Described are systems and methods for multi-material printing. The systems and methods can utilize a stereolithographic printing device, a moving stage, and a microfluidic device. The microfluidic device can include a plurality of reservoirs, each reservoir housing a different ink for printing, and a microfluidic chip. The microfluidic chip can include a chamber that comprises a plurality of inlets, a printing region, and one or more outlets as well as an elastic membrane.

Abstract: A bioreactor and methods for use can include a microfibrous scaffold, that can be made of a composite bioink, and that can have endothelial cells directly embedded within the scaffold using an additive manufacturing process. The scaffold can further be seeded with cardiomyocytes. The hydrogel scaffold can be composed of a plurality of serpentine layers, with each serpentine layers, which can be placed on each other in a cross-hatch configuration, so that the primary axes of successive layers are perpendicular. This configuration can establish an aspect ratio for the scaffold, which can be selectively varied. For greater strength, the successive layers that have a primary axis in the same direction can be placed in the scaffold so that they are slight offset from each other. The scaffold can be placed in the bioreactor with perfusion, for use in cardiovascular drug screening and other nanomedicine endeavors.