Figure 1.

A Herceptin-loaded mixture hydrogel for the therapy of HER2+ breast tumors. A) Injectable and thermosensitive hydrogels formed by mixing a sol of a PLGA-PEG-PLGA triblock copolymer, which is actually a suspension of micelles, and a sediment of an analogue containing a different PEG/PLGA proportion. Their mixtures with rational mix proportions likewise form micelles in aqueous medium at low temperatures, and with an increase of temperature, the micellar aggregation driven by the hydrophobic interaction induces the formation of a percolated micelle network, the so-called sol-gel transition ⁵⁹. B) A schematic of the Herceptin-loaded hydrogel for preventing the local relapse of HER2+ breast tumors after breast-conserving surgery. A HER2+ breast tumor model was first created in nude mice, and the tumors were then excised by imitative breast-conserving surgery. Approximately 1 mm³ of tumor mass was separated from the original tumor and then placed into the excision site to imitate the residual tumor after BCT. After one day of surgery, the Herceptin-loaded hydrogel was hypodermically injected, and the administration site was 5 mm away from the excision site of the tumor. The sustained release of Herceptin was achieved by gel degradation combined with drug diffusion. The pAkt signaling pathway was inhibited by the sustained delivery of Herceptin, and the NK cell-mediated immunity response was activated.