Light-Controlled Nitric Oxide Generation from a Novel Self-Assembled Monolayer on a Gold Surface This work was supported by MURST “cofinanziamento di programmi di ricerca di rilevante interesse nazionale” (Project: Mechanisms of Photoinduced Processes in Organized Systems). We also thank Prof. S. Giuffrida for his critical reading of the manuscript, Prof. V. Amico for his useful suggestions, and the referees for constructive comments.

Abstract

Increasing evidence demonstrates that nitric oxide (NO) plays important roles in numerous physiological processes. [1±8] For instance, it is involved in the bioregulation of functions such as vasodilatation, neurotransmission, and hormone secretion in living bodies. In addition to these effects, NO has also been reported to act as efficient anticancer agent that inhibits key metabolic pathways to block the growth of or to kill cells. [9±13] This has stimulated intense interest in com-Figure 6. Photolysis profile: the formation of colloidal silver at different illumination times (l % 410 nm) and the stability of [SiW 12 O 40 ] 4À photocatalyst (l 263 nm). Photolysis of a deaerated solution containing propan-2-ol (0.5 m), [SiW 12 O 40 ] 4À (0.035 mm), Ag (0.1 mm) at pH 5 (l > 320 nm). Experimental SectionK 4 [SiW 12 O 40 ] was synthesized according to literature methods. [18] The metal ions added to the photolysed solution were aqueous solutions of AgNO 3 , PdCl 2 , HAuCl 4 , or H 2 PtCl 6 .In photolysis experiments, an aqueous solution of SiW 12 O 40 4À 0.7 mm and propan-2-ol 0.5 m, at pH 5, was put into a spectrophotometer cell (1 cm path length) deaerated with Ar and covered with a cerum cap. Photolysis was performed with a 1000 W Xe arc lamp, the light intensity of which was mechanically reduced by approximately 40 %, while cut-off filters (up to 320 nm) were used to avoid direct photolysis of organic substrates. The absorption spectra of metal particles or catalyst were taken with a UV/Vis/ NIR Spectrometer (Perkin Elmer Lambda 19), and the degree of reduction of POM in photolyzed, deaerated solutions was calculated from the known extinction coefficient of reduced catalyst, SiW 12 O 40 5À , at 730 nm (0.21 Â 10 4 M À1 cm À1 ). TEM images were obtained using a Philips 200 kV microscope, and the samples were prepared by placing microdrops of colloid solution on a Formvar/carbon coated copper grid.

Poly(norepinephrine): Ultrasmooth Material‐Independent Surface Chemistry and Nanodepot for Nitric Oxide

“…Furthermore, this silane coating provides a thick layer with thickness typically in the micro‐ to millimeter range 30. NO release achieved by SAMs was also reported,31 but the SAM method is limited to noble metals which are not commonly used in medical devices. If the NO loading onto the pNE layer was successful, material‐independent NO immobilization and release would be achievable.…”