3D printing of shape-morphing and antibacterial anisotropic nanocellulose hydrogels

We report on a procedure for the preparation, printing and curing of antibacterial poly(N-isopropylacrylamide) nanocellulose-reinforced hydrogels. These composites present a highly anisotropic microstructure which allows to control and modulate the resulting mechanical properties. The incorporation of such nanoparticles enables us to modify both the strength and the humidity-dependent swelling direction of printed parts, offering a fourth-dimensional property to the resulting composite. Antibacterial properties of the hydrogels were obtained by incorporating the functionalized peptide e-polylysine, modified with the addition of a methacrylate group to ensure UV-immobilization. We highlight the relevance of well-adapted viscoelastic properties of our material for 3D printing by direct ink writing of self-supporting complex structures reaching inclination angles of 45 degrees. The addition of cellulose nanoparticles, the overall ink composition and the printing parameters strongly determine the resulting degree of orientation. The achieved control over the anisotropic swelling properties paves the way to complex three-dimensional structures with programmable actuation.

Automated summary

The research presents a method for preparing, printing, and curing antibacterial poly(N-isopropylacrylamide) nanocellulose-reinforced hydrogels with an anisotropic microstructure to control mechanical properties. Incorporating nanoparticles allows for modifying strength and swelling direction, creating a fourth-dimensional property. Control over anisotropic swelling properties enables complex three-dimensional structures with programmable actuation.