Encapsulation strategies for improving the biological behavior of CdS@ZIF-8 nanocomposites

Herein we report encapsulation approaches for Cadmium Sulfide (CdS) encapsulated zeolitic imidazolate framework (ZIF)-8 (CdS@ZIF-8), such as “bottle-around-the-ship” and “ship-in-the-bottle.” In this study, these composites were evaluated for antibacterial and DNA-binding properties. To the best of our knowledge, this is the first report on the synthesis of CdS nanoparticles using ZIF-8 as a capping agent. The as-synthesized nanocomposites were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), Brunauer–Emmett–Teller surface area analysis, field emission-scanning electron microscopy, and high-resolution transmission electron microscopy. Characterization studies revealed that both encapsulation approaches provided different morphologies to the encapsulated framework. The antibacterial activity of the as-fabricated nanocomposite, in which ZIF-8 acts as a capping agent, was more effective against Escherichia coli (E. coli) than Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis). Furthermore, DNA-binding studies of nanocomposites performed by UV absorption spectroscopic titration method in E. coli genomic DNA indicated that DNA binding occurs along with cleavage. Therefore, the designed nanocomposites demonstrate great promise for future anticancer research.