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. Author manuscript; available in PMC: 2009 Dec 17.
Published in final edited form as: J Am Chem Soc. 2008 Dec 17;130(50):17095–17105. doi: 10.1021/ja8068853

Figure 6.

Figure 6

Real-time sensing single TNFα molecules using SMNOBS and probing binding reactions of single protein molecules (TNFα with MAB):

(A) Snap shots of real-time optical images of single AgMMUA-MAB nanoparticles incubated with TNFα at (a) 0, (b) 10, (c) 20, (d) 30, (e) 60, and (f) 240 min; Scale bar is 10 μm, showing the distances among nanoparticles, but not the sizes of single nanoparticles because they are under optical diffraction limit.

(B) LSPR spectra of a representative single AgMMUA-MAB nanoparticle circled in (A) incubated with TNFα at (a)-(f) (0-240 min), showing the red shift of peak wavelength of 29 nm over 30 min of incubation time.

(C) Plots of peak wavelength (λmax) of single nanoparticles in (A) versus incubation time, showing stochastic binding equilibrium times at: (i-ii) 30, (iii) 120, (vi) 30-60, (v)120, and (vi) 30 min, respectively. Acquisition time of each image and spectra of single nanoparticles at a given time in (A) and (B) is 90 s. Points are experimental data and the lines are added to show the trend of data points.