2.7 Rheological properties of BMSC-laden GelMA/Gel bioinks
7 w/v% GelMA, 3 w/v% gelatin and BMSCs at the density of
1×106 per ml were mixed to prepare BMSC-laden
GelMA/Gel bioinks for 3D bioprinting. The rheological properties of
GelMA/Gel inks and BMSC-laden GelMA/Gel bioinks were investigated at 20
℃ using a rheometer (MCR 302, 176 Anton Paar, Austria) equipped with a
parallel plate unit with a 20 mm diameter. In accordance with the
preliminary strain sweep test results, GelMA/Gel inks and BMSC-laden
GelMA/Gel bioinks with or without UV crosslinking were loaded onto a
parallel plate and subjected to a maximum strain (γ) of 1.0% under
continuous oscillation. In the frequency sweep mode, the storage moduli
(G’) and loss moduli (G”) of GelMA/Gel inks and BMSC-laden GelMA/Gel
bioinks were measured in the range of 0.1 - 100 rad/s. Furthermore, the
shear thinning behavior of GelMA/Gel inks and BMSC-laden GelMA/Gel
bioinks was studied. The viscosity of each sample was measured over the
temperature range of 15-50 ℃ at 1 s-1 shear rate.
Thixotropic tests were conducted in two repeated steps by varying the
shear rate. First, a low shear rate
(1 s-1) was applied for 120 s. Then, a high shear rate
(500 s-1) was applied for 60 s.