All the oligonucleotides were synthesized and purified by Shanghai Sangon Biotechnology Co. Ltd. (Shanghai, China), and their sequences are listed in Table S1. All oligonucleotide stock solutions were prepared by dissolving DNA strands in Tris-HCl buffer (10 mmol L-1 Tris, 10 mmol L-1 MgCl2, pH 8.0) and stored at -20 °C refrigerator before use. All the DNA strands were annealed at 95 °C for 5 min and slowly cooled down to room temperature to obtain stable structures. 1-Ethyl-3-[3-(dimethylamino)-propyl] carbodiimide hydrochloride (EDC) and N?hydroxysuccinimide (NHS) were purchased from Aladdin Reagent Co. Ltd. (Shanghai, China). Sodium hydroxide (NaOH), Na2HPO4·12H2O, NaH2PO4·2H2O, AgNO3 and KCl were purchased from Sinopharm Chemical Reagent Co. Ltd (Shanghai, China). 2-(N Morpholino) ethanesulfonic acid (MES), Gel-Red, loading buffer and 5×TBE buffer were purchased from Sangon Biotechnology Co. Ltd. (Shanghai, China). BCA Protein Quantification Kit was provided by Beyotime Biotechnology (Shanghai, China). Dulbecco’s modified eagle medium (DMEM) was acquired from Aladdin Reagent Co. Ltd. (Shanghai, China). Carboxyl magnetic nanoparticles (COOH-MNPs, 200 nm) was purchased from PuriMag Biotech Co. Ltd. (Xiamen, China). Exo III, phi29 DNA polymerase were purchased from Sangon Biotechnology Co. Ltd. (Shanghai, China). T4 DNA ligase and deoxynucleotides (dNTPs) were purchased from Takara Biotechnology Co. (Dalian, China). Thioflavine T (ThT) was obtained from Yuanye Bio-Technology Co. Ltd. (Shanghai, China). Anti?CD63 rabbit monoclonal antibody(ab193349) was purchased from Abcam Co. Ltd. (Shang, China). Anti-CD9 rabbit monoclonal antibody (20597-1-ap), anti-TSG101 rabbit monoclonal antibody (28283-1-AP) and β-actin monoclonal antibody (66009-1-Ig) were purchased from Proteintech Group Co. Ltd. (Chicago, USA). ELISA (human CD63) kit was purchased from Shanghai Hengyuan Biological Technology (Shanghai, China). All chemicals were analytical grade and directly used without further purification.
