Directed cell growth and alignment on protein-patterned 3D hydrogels with stereolithography: In this tissue engineering application, PEG-based hydrogels with different fibronectin patterns were fabricated and the influence of the protein patterns on shape and direction of seeded cells was studied

The stereolithography apparatus (SLA) is a computer-assisted, three-dimensional (3D) printing system that is gaining attention in the medical field for the fabrication of patient-specific prosthetics and implants. An attractive class of implantable biomaterials for the SLA is photopolymerisable hydrogels because of their resemblance to soft tissues and intrinsic support of living cells. However, most laser-based SLA machines lack the minimum feature size required to imitate cell growth and alignment patterns in complex tissue architecture. In this study, we demonstrate a simple method for aligning cells on 3D hydrogels by combining the micro-contact printing (μCP) technique with the stereolithographic process. Fibronectin modified with acrylate groups was printed on glass coverslips with unpatterned, 10, 50, and 100 μm wide line patterns, which were then transferred to hydrogels through chemical linkages during photopolymerisation. Fibroblasts cultured on protein-printed 3D hydrogels aligned in the direction of the patterns, as confirmed by fast Fourier transform and cell morphometrics.