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International Journal of Bioprinting 3D-printed thermosensitive hydrogel based microrobots

Figure 8. (a) 3D printing window of PNAGA-100-encapsuled DOX. (b) 3D structures of PNAGA-100-DOX printed via 2PP method. (c) DOX release
measurement of PNAGA-100 under 25°C and 45°C, respectively. (d) Evaluation of thermosensitive properties of PNAGA-100.

concentration benefits the formation in a longer term microstructures that encapsule DOX as drugs were
and orderly hydrogen network when the temperature 3D-printed via the 2PP method. Figure 8a shows the 3D
is increased, and thus exhibits better thermosensitive printing window of PNAGA-100-DOX with varying laser
performance than PNAGA-50. However, in the region with powers and scan speeds. Taking laser power of 90 mW and
a high concentration of NAGA (above 10 wt%) referred scan speed of 3000 μm/s as an example, 3D structures of
to as Region 2 in Figure 7, high-strength and robust PNAGA-100-DOX in the shape of a five-pointed star with
supramolecular PNAGA hydrogels, which are equipped clear outlines were printed, proving that 3D printing of
with nonthermosensitive and nonswellable features, PNAGA-100-based thermosensitive microstructure with
were obtained . As a result, PNAGA-100 with medium DOX via 2PP method can be successfully achieved with
[27]
NAGA concentration manifests better thermosensitive perfect 3D configuration (Figure 8b). Second, PNAGA-100-
performance than PNAGA-200 and PNAGA-300 with DOX based microstructures were incubated in DI water at
high-strength supramolecular networks. In terms of 45°C and 25°C, respectively. The DOX release amount was
practical applications, different PNAGA systems can be evaluated by measuring the absorbance using a microplate
selected based on the requirements by varying the NAGA reader. As displayed in Figure 8c, the DOX release amounts
concentrations. of PNAGA-100 at 45°C are about two to three times higher
than that at 25°C under each incubation time, which agrees
3.5. Drug release well with its thermosensitive performance (Figure 8d). At
Taking into account the excellent thermosensitive 45°C, higher DOX release amounts were observed, which
performance of PNAGA-100, the drug release may be due to the swelling state of PNAGA-100, benefiting
measurements were assessed with PNAGA-100 under the expansion of the porous structures on the surface of
45°C and 25°C, respectively. Firstly, PNAGA-100 PNAGA-100-based hydrogels and thus contributing to

Volume 9 Issue 3 (2023) 279 https://doi.org/10.18063/ijb.709