Photosensitized NO Release from Water-Soluble Nanoparticle Assemblies

Abstract

The photoluminescence from CdSe/ZnS core/shell quantum dots, modified to make them water-soluble by exchanging the surface ligands with dihydrolipoic acid, is partially quenched by adding the chromium(III) complex trans-Cr(cylcam)(ONO)2 + (1, BF4 - salt). This quenching, attributed to the formation of electrostatic assemblies due to ion pairing of 1 with the negatively charged QD surface, is accompanied by the release of NO owing to photosensitized reaction of the Cr(III) nitrito complex.

Applications of Nanoparticles in Biology

“…Ford et al have designed a water-soluble nanocontainer for NO storage based on electrostatic assembly of DHLA-coated quantum dots and cationic dinitro complexes that uses energy transfer from the core to release NO. [104] In another approach, doping of Ag/Au nanoparticles serves as an antenna to absorb the energy from a laser beam of ''biologically friendly'' near-infrared (NIR) region, causing local heating and disruption of microcapsules. More recently, Bhatia et al designed multifunctional superparamagnetic nanoparticles for remote release of bound drugs (Fig.…”

Photo-Controlled Release of NO and CO with Inorganic and Organometallic Complexes

“…As a result, various strategies have been designed to make such species more susceptible to longer wavelength excitation [45,48,51,52,54,76,80,85,90,[116][117][118][119]. With certain platforms, it has proved possible to achieve the NO release at longer wavelength by extending the conjugation of the ligand frame and by adding key substituent groups at strategic positions [65,85,90].…”

“…Subsequent studies have shown that the TPE technique with photoNORM conjugates can be used to deliver NO to cells [78] and to tissue [51]. Another strategy that has been applied is to use semiconductor quantum dots (QDs) and related nanoparticles as the light-gathering antenna to sensitize photoNORMs [51,80,119,122].…”

“…Furthermore, the QD surfaces can, in principle, be decorated not only with a photochemical precursor of a bioactive small molecule but also with targeting moieties to make these multifunctional nano-carriers [123]. With these properties in mind, Neuman and co-workers carried out proof of concept studies demonstrating that CdSe/ZnS core/shell QDs photosensitize NO release from CrONO in aqueous solutions (Figure 18) [119,122]. In these studies, the QD/CrONO conjugates were an electrostatic assembly of the cationic CrONO on the negatively charged surface of QDs, and subsequent work [124] noted a clear correlation between the quenching of the QD PL and the spectral overlap integral consistent with a Forster resonance energy transfer (FRET) mechanism for the sensitization of the photoreaction.…”

Immobilized ruthenium complexes and aspects of their reactivity

“…Ford et al have developed a strategy for the photosensitized release of NO using CdSe/ZnS water-soluble quantum dots (QD) as antennae for energy transfer to trans-[Cr(cyclam)(ONO) 2 ] + , a known photochemical NO precursor [153,154]. Under irradiation, NO production is ∼15-fold enhanced with a QD/complex ratio of 10 −3 regarding the amount of NO produced from the trans-[Cr(cyclam)(ONO) 2 ] + solution only.…”