Fig. 3: Preparation and characterization of HSV-1-based silk-hydrogels (Virus@gel).

a The image of the solution-to-gel process of silk-gels. b The image of HSV-1 encapsulated in the silk-hydrogels (Virus@gel) demonstrated the characteristics of gelation and injectability. c SEM image of Virus@gel. d 3D Confocal imaging of HSV-1 labeled with DyLight 550 inside silk-hydrogels. e, f The flow cytometry analysis (e) and the representative fluorescence images (f) of GFP-positive Hepa1-6 cells in the sustained release experiment. Scale bar: 100 μm. n = 3. Data were shown as means ± SEM. g The cell viability after PBS, PBS@gel, HSV-1, or Virus@gel treatment was determined by flow cytometry analysis using Annexin V-APC and PI staining (n = 3; Data were shown as means ± SEM). h–j Mice bearing Hepa1-6 tumors were intratumoral injected with HSV-1 or Virus@gel. h The accumulation of DyLight 550-labeled HSV-1 at the tumor site at the defined time points. Red circles indicated the tumor sites. Red arrows indicated the diffusion of the virus outside the tumors. i The representative fluorescence imaging of the frozen tumor sections 8 days after HSV-1 or Virus@gel intratumoral administration. GFP signals indicated cells infected by HSV-1. Scale bar: 100 μm. j RT-qPCR analysis of the intratumoral HSV-1 genomic DNA levels represented by gD at the defined time points (n = 8; Data were shown as means ± SEM).