Abstract: Methods and compositions for fabricating 3D perfusable networks are described. The methods utilize (1) printable compositions comprising gelatin microgels or Pluronic F-127, and crosslinking initiators; and (2) support materials comprising crosslinkable polymers and gelling agents. In some embodiments, the support material further comprises a co-initiator.

Abstract: Methods and devices are provided for the fabrication of multi-spheroid tissues with precise spatial control over spheroid positioning. In particular, a 3D bioprinter is provided comprising an electromagnet and dual printheads comprising a first nozzle and a second nozzle, wherein the first nozzle extrudes a magnetic ink and the second nozzle manipulates the electromagnet to provide spatial control over construction of a multi-spheroid tissue.

Abstract: A method of bioprinting a bioink printed structure and a bioprinted composition resulting from this method is provided. Biological cells are mixed with biomaterial inks. These biomaterial inks have a biopolymer backbone with grafted thereto a first bio-orthogonal chemical group. The mixed biological cells and biomaterial inks are extruded into a support bath. The next step is diffusing crosslinking molecules which have a second (complementary to the first) bio-orthogonal chemical group, in the support bath, whereby the diffusing crosslinking molecules react via bioorthogonal click-chemistry between the first and second bio-orthogonal chemical groups resulting in covalently crosslinking the biomaterial ink into a printed structure. Embodiments of this invention can be directed towards personalized medicine and printed tissue engineering constructs, as well as drug discovery by printing complex tissue mimics or printing model vasculature for studying cardiovascular disease.

Abstract: A viscoelastic hydrogel based on a protein hetero-assembled with a polymer is provided. The protein cannot self-assemble with itself and the polymer cannot self-assemble with itself. The protein has a first association sequence (1stA) and a first spacer (1stSp). The polymer has a second association sequence (2ndA) and a second spacer (2ndSp). The first association sequence and the second association sequence are physically cross-linked to interact with each other with a 1:1 known and specific stoichiometry to form a three dimensional scaffold. The protein is represented by {1stA(1stSp)}x1stA, where x is ?2, and the polymer is represented by {2ndA(2ndSp)}y2ndA, where y?2.

Abstract: A viscoelastic hydrogel based on a protein hetero-assembled with a polymer is provided. The protein cannot self-assemble with itself and the polymer cannot self-assemble with itself. The protein has a first association sequence (1stA) and a first spacer (1stSp). The polymer has a second association sequence (2ndA) and a second spacer (2ndSp). The first association sequence and the second association sequence are physically cross-linked to interact with each other with a 1:1 known and specific stoichiometry to form a three dimensional scaffold. The protein is represented by {1stA(1stSp)}x1stA, where x is ?2, and the polymer is represented by {2ndA(2ndSp)}y2ndA, where y?2.

Abstract: A two-component, molecular-recognition gelation strategy that enables cell encapsulation without the need for environmental triggers is provided. The two components, which in one example contain WW and polyproline-rich peptide domains that interact via hydrogen bonds, undergo a sol-gel phase transition upon simple mixing. Hence, physical gelation is induced by the mixing of two components at constant environmental conditions, analogous to the formation of chemically crosslinked epoxies by the mixing of two components. Variations in the molecular-level design of the two components are used to predictably tune the association energy and hydrogel viscoelasticity. These hetero-assembly physical hydrogels encapsulate neural progenitor cells at constant physiological conditions within 10 seconds to create uniform 3D cell suspensions that continue to proliferate, differentiate, and adopt well-spread morphologies.

Abstract: Engineered protein coatings are provided for medical implants to promote bone regeneration. The coating is an engineered protein containing an elastin-like structural domain (SEQ ID No: 2) and a cell-adhesive domain derived from an extended fibronectin RGD sequence. The surface of the medical implant is covalently and directly bonded to the coating via photoreactive crosslinking through an insertion and/or addition reaction. The engineered protein coating can be applied directly upon fabrication of the implant, which would eliminate applying the coating in the operating room. The engineered protein coating is also customizable and can include biologics to improve performance. Furthermore, the engineered protein coating could also be spatially patterned on the implant surface.

Abstract: A two-component, molecular-recognition gelation strategy that enables cell encapsulation without the need for environmental triggers is provided. The two components, which in one example contain WW and polyproline-rich peptide domains that interact via hydrogen bonds, undergo a sol-gel phase transition upon simple mixing. Hence, physical gelation is induced by the mixing of two components at constant environmental conditions, analogous to the formation of chemically crosslinked epoxies by the mixing of two components. Variations in the molecular-level design of the two components are used to predictably tune the association energy and hydrogel viscoelasticity. These hetero-assembly physical hydrogels encapsulate neural progenitor cells at constant physiological conditions within 10 seconds to create uniform 3D cell suspensions that continue to proliferate, differentiate, and adopt well-spread morphologies.