Rapid Eradication of Human Breast Cancer Cells through Trackable Light-Triggered CO Delivery by Mesoporous Silica Nanoparticles Packed with a Designed photoCORM

The surprising discovery of salutary effects of low doses of carbon monoxide (CO) in mammalian physiology has raised intense research interest in CO delivery to biological targets under controlled conditions. In recent attempts, photoactive metal carbonyl complexes (photoCORMs) have been employed to trigger CO release at the target sites. In this work, a designed photoCORM namely, fac-[Re(CO)3(pbt) (PPh3)](CF3SO3) (1, pbt =2-(2-pyridyl)benzothiazole) has been synthesized and characterized by spectroscopic methods and crystallography. This photoCORM not only releases CO upon illumination with low-power UV light (305 nm, 5 mW cm–2) but also exhibits a “turn-off” of its orange luminescence (λem = 605 nm) upon release of one CO ligand. The latter property provides a convenient way to track the CO release event. The photoCORM 1 has been entrapped within the pores of the narrow channels of 100 nm mesoporous Al-MCM-41 nanoparticles and the loaded {Re-CO}@Al-MCM-41 MSNs have been characterized by powder X-ray dif...