Fig. 4.

Impact of dual chamber syringe mixer nozzle size and hydrogel swelling on synthetic hydrogel viscoelastic properties as determined by cantilever sensors. A PLA 3D printed nozzles of various inner diameters for injecting synthetic hydrogels. B Piezoelectric-excited millimeter cantilever sensors were submerged into synthetic hydrogels. C Phase angle responses of the sensors first in air for 3 min and then submerged in the hydrogels for 7 min. Representative spectra for samples comprising hydrogels synthesized with the three different nozzle sizes and hydrogels synthesized with medium nozzle + swelled in 1X PBS for 24 h at 37 °C. D Phase angle shifts of the corresponding spectra for all samples as outlined in C and which negatively correlated with hydrogel storage moduli. ***p < 0.001 by one way analysis of variance and Tukey’s post hoc analysis (JMP). All data expressed as mean ± SD (n = 3).