S-nitrosocysteine-decorated PbS QDs/TiO2 nanotubes for enhanced production of singlet oxygen.

Nitric oxide (NO) is an endogenous diatomic molecule important in regulation of numerous physiological functions. The photorelease of NO in a controlled manner can potentially be used in photodynamic therapy (PDT). We present here a method to combine S-nitrosocysteine with TiO(2) nanotube-doped PbS quantum dots (PbS QDs) as a nitric oxide-releasing vehicle to promote production of singlet oxygen. The PbS QDs with a diameter ∼3.6 nm (PbS/TNTs) were attached to the TiO(2) nanotube by using a thiolactic acid linker. S-nitrosocysteine-decorated PbS/TiO(2) nanotubes were prepared by dipping PbS/TNTs in a cysteine solution followed by nitrosylation. The results suggest that this hybrid nanomaterial is capable of photoreleasing nitric oxide and producing singlet oxygen using near-IR light.