Grayscale 4D Biomaterial Customization at High Resolution and Scale
Hydrogel biomaterials have proven indispensable for three-dimensional (3D) cell culture but have fallen short in replicating the innate physiochemical complexity of real tissue. Though traditional photolithography affords localized material manipulation, robust methods that govern when, where, and to what extent such phototailoring occurs throughout materials would be profoundly enabling towards fabricating more-realistic 3D tissue constructs. Here, we introduce "grayscale image z-stack-guided multiphoton optical-lithography" (GIZMO) as a generalizable and intuitive strategy to rapidly photomodulate materials in full 3D non-binary patterns at submicron resolutions spanning large volumes (>mm3). Highlighting its versatility, we employ GIZMO to variably photopattern biomolecule release from, protein immobilization to, and degradation within hydrogels based on biologically derived or synthetic grayscale image stacks with unprecedented complexity. We anticipate that GIZMO will enable new opportunities to probe and manipulate cell fates, as well as to engineer complex functional tissue.