Study of Azobenzene-modified Black Phosphorus for Potential Tumor Therapy

Exploring the interaction between black phosphorus (BP)-based hybrid systems and target proteins is of great significance for understanding the biological effects of 2D nanomaterials at the molecular level. Density functional theory (DFT) calculations revealed that different terminal groups of the azobenzene (AB) motif in BP@AB hybrids can affect the extent of interfacial charge transfer between the BP sheet and AB-derivatives, which determines the electrostatic interaction with proteins and hence biofunctions of BP@AB hybrids. With the advantage of AB modification, BP@AB hybrids displayed antitumor effects and induced production of cellular reactive oxygen species and apoptosis in cancer cells. Through the proteomics profiling, cellular ribosome and lipid metabolic processes were screened out as the target pathways of the BP@AB-NH₂ in HeLa cells, while the BP@AB-S-S-AB system mainly targets the ERBB and PPAR signaling pathways. Molecular docking simulations revealed that due to the positive charge, ribosomal pathway proteins enriched in negatively charged amino acids such as lysine and arginine are preferentially adsorbed and bound by BP@AB-NH₂ hybrids. Whereas for BP@AB-S-S-AB, receptors containing narrow and long pocket domains are more likely to bind with BP@AB-S-S-AB by van der Waals forces for the rod-like hybrids. Different biomolecule targeting and action modes of BP@AB hybrids have been rationalized by different electrostatic environments and matching of geometric configurations, shedding insight for designing efficient and targeted modification of a 2D nanomaterial-based strategy for cancer therapy.