MRI-monitored long-term therapeutic hydrogel system for brain tumors without surgical resection.

To overcome the unresolved issues of conventional therapeutic approaches such as radiation therapy, chemotherapy, combinational chemotherapy, and surgical treatment, we designed an injectable 'MRI-monitored long-term therapeutic hydrogel (MLTH)' system as an alternative/adjuvant approach for brain tumors. The MLTH system consists of a thermosensitive/magnetic poly(organophosphazene) hydrogel (the magnetic hydrogel) as a biodegradable imaging platform and an anticancer drug as a therapeutic agent via a simple physical mixing. The MLTH system has adequate properties for the MRI-monitored long-term therapy as follows: injectability, localizability due to fast gelation at body temperature, biocompatibility, biodegradability, sustained drug release, and MR imaging function. Since the MLTH system only requires a very small-sized pin hole injected into the area of brain tumors stereotactically, we suggest that the MLTH system can be an alternative/adjuvant approach to treat the malignant brain tumors without any surgical resection. Furthermore, we expect that the MLTH system can minimize the side effects from either an intravenous injection or surgical operation because one of the aims of MLTH is to focus on the sustained local delivery of anticancer drugs via a one- or two-time intratumoral injections. Thus, we assessed successfully the MRI-monitored long-term therapeutic potentialities of the MLTH system for brain tumors and estimated the inhibition efficacy of tumor growth via an MRI-monitored long-term therapy in this study.