Phosphate buffered saline (pbs)

Primers and phosphate-buffered saline (PBS) were purchased from Sangon Biotech Co., Ltd. (Shanghai, China). Fe₃O₄@TiO₂ was obtained from Nanjing Xiuyuan Biotechnology Co., Ltd. (Jiangsu, China). Monoclonal anti-CD63 antibody, monoclonal calnexin antibody, and monoclonal TSG101 antibody were purchased from Abcam Co., Ltd. (Shanghai, China). A solution of 28 wt% ammonium hydroxide (NH₃•H₂O) and PKH26 Red Fluorescent Cell Linker Mini Kit were obtained from Sigma Co., Ltd. (Shanghai, China)., A 0.22-μm syringe-driven filter was purchased from Millipore (United States). Deionized water was processed by Ultrapure Millipore water (18.2 MΩ cm). High glucose Dulbecco’s modified Eagle’s medium (DMEM) and penicillin–streptomycin solution were purchased from Hyclone (UT, United States). Exosome-depleted fetal bovine serum (FBS) media supplement was purchased from System Biosciences, SBI (CA, United States).
All cell lines were purchased from the Shanghai Cell Bank, Chinese Academy of Sciences (Shanghai, China). Healthy human and lung cancer patient plasma samples were supplied by Nanjing University-affiliated Drum Tower Hospital. The samples were centrifuged at 1,500 g for 10 min at 4°C. The supernatant was collected and centrifuged at 2,000 g for 10 min at 4°C to remove platelets. The supernatant was centrifuged at 15,000 g for 30 min and stored at −80°C.

To evaluate cell membrane integrity after quenching, the cells after quenching were stained with fluorescent dyes SYTO 9 (Invitrogen, Carlsbad, USA) and propidium iodide (PI) (Invitrogen). The quenched cell pellets were washed twice with sterile phosphate-buffered saline (PBS) (Sangon Biotech, Shanghai, China) and resuspended in 2 ml of PBS. Cell suspensions (1 ml) were diluted by adding 20 ml of PBS and incubated at 30°C for 1 h, mixing every 15 min. The incubated cell pellets were washed twice and resuspended in 10 ml of PBS. Equal volumes of SYTO 9 and PI were added to the bacterial suspension at a final concentration of 3 μl/ml, and the mixture was incubated at room temperature in the dark for 15 min. The stained bacterial suspension (5 μl) was pipetted onto a glass slide and covered with a coverslip. The stained, quenched cells were visualized by confocal laser scanning microscopy (Nikon A1R MP, Tokyo, Japan) with a 543-nm He-Ne laser (red channel) and a 488-nm Ar laser (green channel).

Luria–Bertani (LB) broth powder was purchased from Meilunbio (Dalian, China). 666-15 was purchased from Topscience (Shanghai, China). Antibiotics were purchased from MedChem Express (MCE, United States). Thiazolyl blue tetrazolium bromide (MTT) and phosphate-buffered saline (PBS) were purchased from Sangon Biotech (Shanghai, China). The bacterial total RNA extraction kit and DNA extraction kit were purchased from TIANGEN (Beijing, China). RT Master Mix and SYBR Green qPCR Master Mix were purchased from MedChem Express (MCE, United States). The lipopolysaccharide (LPS) detection kit was purchased from Cloud-Clone (Wuhan, China). Propidium iodide (PI) was purchased from Thermo Fisher Scientific, USA. 3,3-Dipropylthiadi-carbocyanine iodide [DiSC₃(5)] was purchased from AAT Bioquest, USA. The LIVE/DEAD BacLight bacterial viability kit was purchased from Invitrogen, USA.