The clinical application of triptolide(TPL)in tumor therapy has been greatly limited by its toxicity and inefficient delivery.Herein,a localized and sustained-release thermo-sensitive hydrogel was developed for the intra-tumor administration of TPL.Based on the amphiphilic structure of poly(N-iso-propylacrylamide-co-acrylic acid)-g-F68 copolymer,it was able to form nano-micelles to efficiently encapsulate TPL,and then turn into a hydrogel at 37 °C.TPL@nano-gel exhibited a sustained drug release profile in vitro and a stronger anticancer effect caused by“two strikes”.The“first strike”was its enhanced cytotoxicity compared to free TPL,due to the enhanced pro-apoptosis effect observed in both MDA-MB-231 and MCF-7 cells caused by the regulation of endogenous mitochondrial pathways.Furthermore,TPL@nano-gel exhibited a“second-strike”through its anti-angiogenesis capabilities medi-ated through VEGFR-2 signaling inhibition.As expected,after intra-tumoral injection at a 0.45 mg/kg TPL-equivalent dose three times over 14 days in 4T1 tumor-bearing mice,TPL@nano-gel led to lower systemic toxicity and higher antitumor efficacy compared to multiple injections of TPL.In this regard,these findings indicate that this injectable thermo-responsive hydrogel carries great potential for TPL as a safe and effective cancer therapy.