Fig. 1

A nano-modified virus as a treatment for hepatocellular carcinoma (HCC). a A carrier with a liver-focused accumulation of iron oxide nanoparticles (ION)-conjugated recombinant adeno-associated viral type 2 (AAV2) concept involves the administration of a single tail vein injection to facilitate immune-promoting photodynamic virotherapy. Following systemic delivery, the tumor cells are infected with AAV2-KillerRed, leading to the expression of the KillerRed photosensitizer, which can be activated by light to initiate photodynamic virotherapy. Upon illumination, the KillerRed protein generates reactive oxygen species (ROS), causing intracellular damage and promoting cell death, ultimately resulting in a reduction in tumor size. Simultaneously, ION improves the ratio of M1/M2 type macrophages, enhancing their immunomodulatory function. b The conjugation of ION and AAV2 is schematically depicted, illustrating the process involving 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC)/N-hydroxysulfosuccinimide (Sulfo-NHS) coupling. c The percentage of cells expressing GFP was assessed six days after transduction using Ironized AAV2 at a molar ratio of 1/20. This evaluation was conducted following incubation for either one day or seven days in either a PBS solution or a complete culture medium, at temperatures of 4 °C or 37 °C. Flow cytometry was employed for analysis, and the data presented represents the mean of measurements taken in six independent replicates, with the results reported as mean ± standard deviation. d Representative confocal images are shown, displaying RAW 264.7 M0 macrophages treated with ION under different conditions. Bar = 100 μm. e Cell viability of BNL-1MEA cells cocultured with treated macrophages incubated with ION at pH 7.4 or 6.7, as determined by MTS assays (*, p < 0.05, two-tailed unpaired Student’s t test). The bars represent the mean ± standard deviation (n = 4)