Fabrication of ZIF-8, NV-ZIF, and NV-ZIFMCF

1. Stirring NV (1 mg. mL^-1) and 2-methylimidazole (2.5 M, 0.9 mL) for 30 minutes.
2. Slowly added zinc nitrate solution (0.5 M, 0.1 mL). Continue stirring for 20 minutes.
3. Centrifuge (7000 rpm, 10 min), dicard supernatant and resuspend pellet in DI water three times to remove any residues, repeat two more times.
4. Let cells grow in T-175 culture flasks to full confluency, then detached and washed in PBS three times by centrifuging at 500 × g.
5. Suspend in a hypotonic lysing buffer consisting of 20 mM Tris-HCl pH 7.5, 10 mM KCl, 2 mM MgCl₂ and 1 EDTA-free mini protease inhibitor tablet per 10 mL of solution and disrupted using a Dounce homogenizer with a tight-fitting pestle.
6. The entire solution was subjected to 20 passes before spinning down at 3,200 × g for 5 min.
7. The supernatant was saved while the pellet was resuspended in hypotonic lysing buffer and subjected to another 20 passes and spun down again.
8. The supernatants were pooled and centrifuged at 20,000 × g for 20 min, after which the pellet was discarded and the supernatant was centrifuged again at 100,000 × g.
9. The pellet containing the plasma membrane material was then washed again in 10 mM Tris-HCl pH 7.5 and 1 mM EDTA.
10. The final pellet was collected and used as a purified cancer cell membrane. 
11. NV-ZIF_MCF was fabricated by mixing 1:1 weight ratio of NV-ZIF and extracted cancer cell membrane in deionized water. 
12. The mixture was transferred into a syringe and successively extruded through 1.0 μm, 800.0 nm and 450.0 nm polycarbonate membrane. 
13. The obtained NV-ZIF_MCF in solution was further purified by centrifugation to remove the free cancer cell membrane.

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