C O M M U N I C A T I O N S
of MPC-3 is very similar to that of the model compound 2 under
the same experimental conditions (Supporting Information) sug-
gesting that neither the aliphatic chain nor the metal core alter the
nature of the photoreactivity of the photoactive unit. A kinetic
analysis of the photochemical profiles revealed only 30% quenching
in the case of MPC-3.
In summary, we have reported the first example of NO
photodelivery from ad-hoc modified metal nanoparticles. These
hybrid nanosystems exhibit a combination of indispensable proper-
ties for biological applications, such as ultrasmall sizes, water
solubility and thermal stability under physiological conditions,
photoactivation with low-energy light, photogeneration of nontoxic
intermediates.17 These features make MPC-3 very appealing point
sources of NO that, hopefully, are expected to find wide applications
in biomedical research where controlled release of small amounts
of NO is required.
Figure 3. Absorption spectra of the carboxy-terminated Pt nanoparticles
in aqueous phosphate buffer solution before (a) and after (b) the exchange
reaction with 3. The spectrum of the free 3 in acetonitrile (c) is also shown,
in arbitrary absorbance, for sake of comparison.
Acknowledgment. Financial support from University of Catania
is greatly appreciated.
Supporting Information Available: Experimental procedures,
TEM measurements, calculation of the surface coverage, and photo-
chemical profiles. This material is available free of charge via the
References
Figure 4. NO photorelease (λexc ) 420 nm) from a neutral buffered aqueous
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