Metal Nanoclusters for Fluorescence Imaging

The importance of metal nanoclusters (MNCs) and their remarkable opto-physical properties as inorganic fluorescent quantum dots for bio-imaging and applications in medical diagnosis were studied. Their significance as good replacements for oftentimes, less-effective organic analogues was demonstrated. Silver and copper nanoclusters were prepared by reducing their metal ions with sodium borohydride in aqueous solutions. Atomic force microscopy results showed that silver and copper nanoclusters with an average size of approximately 1.40 nm were synthesized from their salts. The presence of these MNCs was confirmed by confocal microscopy which also illustrated their luminescent and photostability properties. Fluorescence spectroscopy results showed that these samples possessed emissions at 435 and 617 nm for the AgNCs, and at 636 nm for the CuNCs excited at 315 and 255 nm respectively. Electrospray ionization mass spectrometer confirmed the presence of species with a metal core of Ag4 and Cu7 having a molecular mass of 529 and 559. Cyclic voltammetry data confirmed the presence of Ag (I) ions and Ag (0) in the sample solution. XPS similarly confirmed the elemental presence of these metals. Fluorescent quantum yield was ≈70 % which is remarkable for quantum dots. It was recommended that MNCs can present better effects as fluorescent probes for both bio-imaging and medical diagnosis

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1-18
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