Bacteria loaded with glucose polymer and photosensitive ICG silicon-nanoparticles for glioblastoma photothermal immunotherapy

Bacteria can bypass the blood-brain barrier (BBB), suggesting the possibility of employment of bacteria for combating central nervous system diseases. Herein, we develop a bacteria-based drug delivery system for glioblastoma (GBM) photothermal immunotherapy. The system, which we name as ‘Trojan bacteria’, consists of bacteria loaded with glucose polymer and photosensitive ICG silicon-nanoparticles. In an orthotopic GBM mouse model, we demonstrate that the intravenously injected bacteria bypass the BBB, targeting and penetrating GBM tissues. Upon 808 nm-laser irradiation, the photothermal effects produced by ICG allow the destruction of bacterial cells and the adjacent tumour cells. Furthermore, the bacterial debris as well as the tumour-associated antigens promote antitumor immune responses that prolong the survival of GBM-bearing mice. Moreover, we demonstrate the residual bacteria are effectively eliminated from the body, supporting the potential therapeutic use of this system.


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Group sizes for experiments were chosen on the basis of prior experience and literature precedence, so that sufficient numbers were used to ensure reproducibility and determine standard deviations. The number of animals was at least 3. For each sample, two technical replicates were carried out. If there was 20% or greater variation between technical replicates, an additional two technical replicates were carried out. . Sample sizes employed in this study were referenced previously published studies (Nature Communications 2022, 13: 1255.
No data were excluded from the analyses.
All experimental findings were reliably reproduced. At least three independent samples were performed for each experiment. All experiments were performed as technical or biological replications as appropriate for the experiment design. Details of experimental replicates are given in the figure legends Samples were organized into groups according to date of collection. Microorganisms were cultured and maintained in the same environment and randomly allocated to each group.
All the data collection and analysis were from blinded with randomized samples.
Antibodies for flow cytometry are described in detail in Supplementary Table 1 All primary antibodies were mouse-specific as per the company's data sheet. All used antibodies have been previously published and the references can be found on data sheets No commonly misidentified cell lines were used.
The housing conditions for the mice (female, 10-12 weeks old) were 25°C and 65% humidity adjusted by the ventilation equipment and air filtration system. All animals are provided with 12 h of light and 12 h of darkness daily. Weekly cleaning of the cages and changing of the corn cob bedding are carried out by specialized staff. The animals are fed with irradiated feed and water, and the animals are fed with autoclaved tap water.
no wild animals were used in the study. no field collected samples were used in the study.
all animal experimental procedures were performed according to the Guideline for Animal Experimentation with the approval of the animal care committee of Soochow University.
Human blood samples were provided by a healthy volunteer.
Human blood samples were provided by a healthy volunteer following written informed consent.
The study protocols using human blood samples were approved by the ethics committee of Soochow University. The authors state that all human blood experiments were performed in strict accordance with the relevant laws and institutional guidelines.
Tumors, spleen and the carotid lymph nodes were harvested from sacrificed mice. The tumors and lymph nodes were cut into small pieces and resuspended in DMEM. The supernatant from the clipped lymph nodes was collected, centrifuged at 490 x g for 5 min, and resuspended. The tumour pieces were incubated with digestive enzyme for 1 h at 37°C on a shaker (90 rpm) and then filtered through a cell strainer. The supernatant from the digested tumor tissues was collected, centrifuged at 490 x g for 5 min, and resuspended. The spleen was mechanically dissociated and resuspended in DMEM. The suspension was filtered through a cell strainer, centrifuged and resuspended. Lymphocytes were stained with anti-CD11c-FITC, anti-MHC II-PerCP for DC maturation analysis, while the single tumour cell suspensions labeled with anti-CD45-PercP, anti-CD3-FITC, anti-CD4-APC and anti-CD8a-PE was used to examine CD8a+ T cell response. And single tumour cell suspensions labeled with labeled with anti-CD45-PercP, anti-CD3-FITC, anti-NK1.1-PE was used to examine NK cell response. Meanwhile to examine macrophage cell response, single tumour cell suspensions were labeled with anti-CD11b-PE, anti-F4/80-FITC. The cells were then washed twice and analysed using flow cytometer.