Nanozyme controlled photothermal heat generation on nanoceria decorated MoS2 nanoflowers for enhanced cytotoxicity in cancer chemo-photothermal therapy
Nishakavya Saravanan, Prasanna Ganesh, Sudhagar Pitchaimuthu, Anandhakumar Sundaramurthy
Abstract
In recent years, the fabrication of nanomaterials with built-in ability to mimick biological enzymes (nanozymes) is gaining popularity for biomedical applications , especially for cancer photothermal therapy , based on non-toxic and photo-thermal heat generating 2D materials . The use of 2D inter-layered MoS 2 nanoflowers (NFs) is especially interesting as it results in nanozymes that are photostable and biocompatible for normal cells under physiological conditions . In this work, we have synthesized MoS 2 nanoflowers (NFs) decorated with CeO 2 nanoparticles (NPs) using two linker molecules of cysteine and polyethylenimine connected through carbodiimide chemistry. The electron microscopy investigations revealed the formation of flower shaped MoS 2 of 400 ± 100 nm in size decorated with spherical shaped CeO 2 NPs of 15±5 nm in size. The fabricated nanozymes were investigated by UV–visible (UV–vis), FTIR spectroscopy , Raman spectroscopy and dynamic light scattering . The NFs decorated with long-chain PEI molecules demonstrated higher photo-thermal heat generation when compared to nanozymes decorated with low molecular weight PEI. Notably, the photo-thermal heat generation, biocompatibility , anti-cancer activity of nanozymes are significantly influenced by molecular weight of PEI, concentration of nanozymes , time duration of near-infrared (NIR) light exposure, power density of NIR light and folic acid (FA) conjugation. The nanozymes conjugated with FA on their surface exhibited excellent anti-cancer activity against human colon cancer cells under NIR light exposure at 808 nm and 0.5 W/cm 2 . Hence, the nanozymes demonstrated here have huge potential as nanophoto-thermal agents in cancer photothermal therapy .