3D-printed PNAGA thermosensitive hydrogelbased microrobots: An effective cancer therapy by temperature-triggered drug release.

Hydrogels with temperature-responsive capabilities are increasingly utilized and researched owing to their prospective applications in the biomedical field. In this work, we developed thermosensitive poly-N-acryloyl glycinamide (PNAGA) hydrogels-based microrobots by using the advanced two-photon polymerization printing technology. N-acryloyl glycinamide (NAGA) concentration-dependent thermosensitive performance was presented and the underlying mechanism behind was discussed. Fast swelling behavior was achieved by PNAGA-100 at 45°C with a growth rate of 22.5%, which is the highest value among these PNAGA hydrogels. In addition, a drug release test of PNAGA-100-based thermosensitive hydrogels was conducted. Our microrobots demonstrate higher drug release amount at 45°C (close to body temperature) than at 25°C, indicating their great potential to be utilized in drug delivery in the human body. Furthermore, PNAGA-100-based thermosensitive microrobots are able to swim along the route as designed under the magnetic actuator after incubating with Fe@ZIF-8 crystals. Our biocompatible thermosensitive magnetic microrobots open up new options for biomedical applications and our work provides a robust pathway to the development of high-performance thermosensitive hydrogel-based microrobots.