Hypothermic 3d bioprinting of living tissues supported by perfusable vasculature

A composition comprising:

• a hydrogel matrix comprising a plurality of layers, each layer comprising a cross-linked polymer network formed from a photosensitive polymer having a molecular weight greater than 2,000 Daltons, wherein the hydrogel matrix has a elastic modulus of from about 1 kilopascal to about 200 kilopascals;
• a first elongated void in the hydrogel matrix providing a first tubular channel;
• a second elongated void in the hydrogel matrix providing a second tubular channel;
• wherein the first tubular channel and the second tubular channel are perfusable;
• wherein the first tubular channel does not intersect the second tubular channel;
• and
• wherein the second tubular channel interpenetrates the first tubular channel.

A process for manufacturing a multi-layer hydrogel matrix construct, comprising:

• a) creating a 3D model of the multi-layer hydrogel matrix construct using a design software, wherein the 3D model of the multi-layer hydrogel matrix construct comprises a first computational algorithm that yields a first elongated void in the multi-layer hydrogel matrix construct providing a first tubular channel, and a second computational algorithm that yields a second elongated void in the multi-layer hydrogel matrix construct providing a second tubular channel, wherein the second computational algorithm results in the second tubular channel interpenetrating the first tubular channel;
• b) converting the 3D model to a format suitable for use in a 3D printing software to yield a formatted 3D model;
• c) importing the formatted 3D model into the 3D printing software, wherein the 3D printing software is programmed to slice the formatted 3D model into multiple 2D xy images;
• d) supplying a prepolymerization solution to a vat associated with a build platform of a 3D printer, wherein the vat is transparent, and wherein the prepolymerization solution comprises a photosensitive polymer having a molecular weight of greater than 2,000 Daltons and at least two vinyl groups per molecule of polymer, a light-absorbing additive material to control light penetration, and a photoinitiator;
• e) positioning a mobile Z-axis stage of the 3D printer at a distance from the vat, wherein the Z-axis stage includes a surface sufficient for gelled material to adhere thereto, wherein the distance between the surface and an inner bottom surface of the vat is equivalent to a desired layer thickness of the multi-layer hydrogel matrix construct;
• f) projecting a pattern being onto the inner bottom surface of the vat, wherein the pattern corresponds to one of the multiple 2D xy images;
• g) polymerizing a layer of the multi-layer hydrogel matrix construct consistent with the pattern;
• and
• h) repeating steps d through g one or more times, wherein the mobile Z-axis stage is moved so that the distance moved is equivalent to the desired thickness of each subsequent layer, and wherein the same or a different pattern is displayed for each subsequent layer.