Abstract
Measuring the size and charge of objects suspended in solution, such as dispersions of colloids or macromolecules, is a significant challenge. Measurements based on light scattering are inherently biased to larger entities, such as aggregates in the sample1, because the intensity of light scattered by a small object scales as the sixth power of its size. Techniques that rely on the collective migration of species in response to external fields (electric or hydrodynamic, for example) are beset with difficulties including low accuracy and dispersion-limited resolution2,3,4. Here, we show that the size and charge of single nanoscale objects can be directly measured with high throughput by analysing their thermal motion in an array of electrostatic traps5. The approach, which is analogous to Millikan's oil drop experiment, could in future be used to detect molecular binding events6 with high sensitivity or carry out dynamic single-charge resolved measurements at the solid/liquid interface.
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References
Bowen, W. R., Hall, N. J., Pan, L. C., Sharif, A. O. & Williams, P. M. The relevance of particle size and zeta-potential in protein processing. Nature Biotechnol. 16, 785–787 (1998).
Varenne, A. & Descroix, S. Recent strategies to improve resolution in capillary electrophoresis—a review. Anal. Chim. Acta 628, 9–23 (2008).
Laue, T. M. & Stafford, W. F. Modern applications of analytical ultracentrifugation. Annu. Rev. Bioph. Biom. 28, 75–100 (1999).
Giddings, J. C. Field-flow fractionation—analysis of macromolecular, colloidal and particulate materials. Science 260, 1456–1465 (1993).
Krishnan, M., Mojarad, N., Kukura, P. & Sandoghdar, V. Geometry-induced electrostatic trapping of nanometric objects in a fluid. Nature 467, 692–695 (2010).
Anker, J. N. et al. Biosensing with plasmonic nanosensors. Nature Mater. 7, 442–453 (2008).
Millikan, R. A. The isolation of an ion, a precision measurement of its charge, and the correction of Stokes's law. Science 32, 436–448 (1910).
Daaboul, G. G. et al. High-throughput detection and sizing of individual low-index nanoparticles and viruses for pathogen identification. Nano Lett. 10, 4727–4731 (2010).
Sharp, K. A. & Honig, B. Calculating total electrostatic energies with the nonlinear Poisson–Boltzmann equation. J. Phys. Chem. 94, 7684–7692 (1990).
Overbeek, J. T. G. The role of energy and entropy in the electrical double-layer. Colloid Surf. 51, 61–75 (1990).
Ospeck, M. & Fraden, S. Solving the Poisson–Boltzmann equation to obtain interaction energies between confined, like-charged cylinders. J. Chem. Phys. 109, 9166–9171 (1998).
Keen, S., Leach, J., Gibson, G. & Padgett, M. J. Comparison of a high-speed camera and a quadrant detector for measuring displacements in optical tweezers. J. Opt. A 9, S264–S266 (2007).
Howard, J. Mechanics of Motor Proteins and the Cytoskeleton 19 (Sinauer Associates, 2001).
Tothova, J., Vasziova, G., Glod, L. & Lisy, V. Langevin theory of anomalous Brownian motion made simple. Eur. J. Phys. 32, 645–655 (2011).
Li, T., Kheifets, S., Medellin, D. & Raizen, M. G. Measurement of the instantaneous velocity of a Brownian particle. Science 328, 1673–1675 (2010).
Savin, T. & Doyle, P. S. Role of a finite exposure time on measuring an elastic modulus using microrheology. Phys. Rev. E 71, 041106 (2005).
Wong, W. P. & Halvorsen, K. The effect of integration time on fluctuation measurements: calibrating an optical trap in the presence of motion blur. Opt. Express 14, 12517–12531 (2006).
Savin, T. & Doyle, P. S. Static and dynamic errors in particle tracking microrheology. Biophys. J. 88, 623–638 (2005).
Eichmann, S. L. & Bevan, M. A. Direct measurements of protein-stabilized gold nanoparticle interactions. Langmuir 26, 14409–14413 (2010).
Hoang, H. T. et al. Analysis of single quantum-dot mobility inside 1D nanochannel devices. Nanotechnology 22, 275201 (2011).
Hunter, R. J. The significance of stagnant layer conduction in electrokinetics. Adv. Colloid Interface Sci. 100–102, 153–167 (2003).
Zhang, H., Hassanali, A. A., Shin, Y. K., Knight, C. & Singer, S. J. The water-amorphous silica interface: analysis of the Stern layer and surface conduction. J. Chem. Phys. 134, 024705 (2011).
Beunis, F., Strubbe, F., Neyts, K. & Petrov, D. Beyond Millikan: the dynamics of charging events on individual colloidal particles. Phys. Rev. Lett. 108, 016101 (2012).
Kirkwood, J. G. & Shumaker, J. B. Forces between protein molecules in solution arising from fluctuations in proton charge and configuration. Proc. Natl Acad. Sci. USA 38, 863–871 (1952).
Novo, C., Funston, A. M. & Mulvaney, P. Direct observation of chemical reactions on single gold nanocrystals using surface plasmon spectroscopy. Nature Nanotech. 3, 598–602 (2008).
Semrau, S., Pezzarossa, A. & Schmidt, T. Microsecond single-molecule tracking (μsSMT). Biophys. J. 100, L19–L21 (2011).
Sahl, S. J., Leutenegger, M., Hilbert, M., Hell, S. W. & Eggeling, C. Fast molecular tracking maps nanoscale dynamics of plasma membrane lipids. Proc. Natl Acad Sci. USA 107, 6829–6834 (2010).
Ueno, H. et al. Simple dark-field microscopy with nanometer spatial precision and microsecond temporal resolution. Biophys. J. 98, 2014–2023 (2010).
Celebrano, M., Kukura, P., Renn, A. & Sandoghdar, V. Single-molecule imaging by optical absorption. Nature Photon. 5, 95–98 (2011).
De Jonge, N. & Ross, F. M. Electron microscopy of specimens in liquid. Nature Nanotech. 6, 349–356 (2011).
Acknowledgements
M.K. acknowledges support from the European Commission in the form of a Marie Curie Research Fellowship. T. Savin and R. Klemm are thanked for fruitful discussions and D. Weitz for hospitality at the time of writing. The authors thank V. Sandoghdar for sustained support.
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N.M. performed the experiments, analysed data and participated in writing of the manuscript. M.K. conceived the project, performed the theoretical analysis, analysed data and wrote the manuscript.
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Mojarad, N., Krishnan, M. Measuring the size and charge of single nanoscale objects in solution using an electrostatic fluidic trap. Nature Nanotech 7, 448–452 (2012). https://doi.org/10.1038/nnano.2012.99
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DOI: https://doi.org/10.1038/nnano.2012.99
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