Printable Poly(N-acryloyl glycinamide) Nanocomposite Hydrogel Formulations

Printable synthetic polymer formulations leading to hydrogels with high strengths, swelling resistance, and bioactivities are required to control the mechanical and functional characteristics of biological scaffolds. Here, we present nanocomposite hydrogels prepared with the upper critical solution (UCST)-type polymer ink poly(N-acryloyl glycinamide) (PNAGA) and different concentrations of carbon nanotubes (CNTs). Nanofiller CNTs are recommended for increasing the bioactivities of hydrogel scaffolds. Printing methods were established in which the CNTs were included before and after the fabrication of the ink. The methods were compared to each other and their temperatures and shear-thinning properties were determined from the rheologies. A self-thickening method was utilized for 3D printing of nanocomposite constructs, and the printabilities varied with the CNT content and preparation method. After photopolymerization of the printed constructs, the nanocomposite hydrogel exhibited a slightly higher mechanical strength (15,500 Pa, E-mod = 0.697 +/- 0.222 MPa), great elasticity (elongation similar to 500%) and an electrical conductivity (5.2 center dot 10(-4) +/- 1.5 center dot 10(-4) S center dot m(-1)) comparable to that of the neat PNAGA hydrogel. Since high-strength constructs can be 3D printed with good resolution and low cytotoxicity, these nanocomposite hydrogel scaffolds could be used in biological and tissue engineering applications.

Automated summary

Printable synthetic polymer formulations are needed to control the mechanical and functional characteristics of biological scaffolds. In this study, nanocomposite hydrogels were prepared using the upper critical solution (UCST)-type polymer ink poly(N-acryloyl glycinamide) (PNAGA) and carbon nanotubes (CNTs). The hydrogel scaffolds showed increased bioactivities with the addition of CNTs. Different printing methods were compared, and their rheologies were determined. The printed constructs exhibited high mechanical strength, great elasticity, and electrical conductivity, making them suitable for biological and tissue engineering applications.