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. Author manuscript; available in PMC: 2010 Mar 1.
Published in final edited form as: Nat Chem. 2009 Sep 1;1(6):461–465. doi: 10.1038/nchem.334

Figure 3. Determination of the optimum ratio of fluorophore to NP.

Figure 3

Change in fluorescence intensities of GFP (250 nM) at 510 nm were measured after the addition of cationic NPs (0–2 μM) with an excitation wavelength of 475 nm. The absorption effect from gold core was subtracted by using non-interacting tetra(ethylene glycol)-functionalized gold NPs. Inset shows the change of Fluorescence intensity of GFP (100 nM) at 510 nm upon addition of cationic NP3 in 5 mM sodium phosphate buffer. The red solid lines represent the best curve fitting using the model of single set of identical binding sites and the arrow indicates the optimum binding ratio used for our study.