Gravitational sedimentation of gold nanoparticles

Colleen M. Alexander, James C. Dabrowiak, Jerry Goodisman

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

We study the gravitational sedimentation of citrate- or ascorbate-capped spherical gold nanoparticles (AuNP) by measuring the absorption-vs.-time curve produced as the particles sediment through the optical beam of a spectrophotometer, and comparing the results with a calculated sedimentation curve. TEM showed the AuNP had gold-core diameters of 12.1 ± 0.6, 65.0 ± 5.2, 82.5 ± 5.2 or 91.8 ± 6.2. nm, and gave diameter distribution histograms. The Mason-Weaver sedimentation-diffusion equation was solved for various particle diameters and the solutions were weighted with the TEM histogram and the size-dependent extinction coefficient, for comparison with absorbance-vs.-time curve obtained from freshly prepared suspensions of the AuNP. For particles having average gold-core diameters of 12.1 ± 0.6, 65.0 ± 5.2 and 82.5 ± 5.2. nm, very good agreement exists between the theoretical and observed curves, showing that the particles sediment individually and that the diameter of the gold core is the important factor controlling sedimentation. For the largest particles, observed and calculated curves generally agree, but the former shows random effects consistent with non-homogeneous domains in the sample. Unlike TEM, the simple and unambiguous sedimentation experiment detects all the particles in the sample and can in principle be used to derive the true size histogram. It avoids artifacts of TEM sampling and shear forces of ultracentrifugation. We also show how information about the size histogram can be obtained from the sedimentation curve.

Original languageEnglish (US)
Pages (from-to)53-62
Number of pages10
JournalJournal of Colloid and Interface Science
Volume396
DOIs
StatePublished - 2013

Fingerprint

Sedimentation
Gold
Nanoparticles
Transmission electron microscopy
Sediments
Spectrophotometers
Citric Acid
Suspensions
Sampling
Experiments

Keywords

  • Extinction coefficient
  • Gold nanoparticles
  • Gravitational sedimentation
  • Histogram

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Colloid and Surface Chemistry

Cite this

Gravitational sedimentation of gold nanoparticles. / Alexander, Colleen M.; Dabrowiak, James C.; Goodisman, Jerry.

In: Journal of Colloid and Interface Science, Vol. 396, 2013, p. 53-62.

Research output: Contribution to journalArticle

Alexander, Colleen M. ; Dabrowiak, James C. ; Goodisman, Jerry. / Gravitational sedimentation of gold nanoparticles. In: Journal of Colloid and Interface Science. 2013 ; Vol. 396. pp. 53-62.
@article{2d7d7e95e69b460e85aa99d93654066a,
title = "Gravitational sedimentation of gold nanoparticles",
abstract = "We study the gravitational sedimentation of citrate- or ascorbate-capped spherical gold nanoparticles (AuNP) by measuring the absorption-vs.-time curve produced as the particles sediment through the optical beam of a spectrophotometer, and comparing the results with a calculated sedimentation curve. TEM showed the AuNP had gold-core diameters of 12.1 ± 0.6, 65.0 ± 5.2, 82.5 ± 5.2 or 91.8 ± 6.2. nm, and gave diameter distribution histograms. The Mason-Weaver sedimentation-diffusion equation was solved for various particle diameters and the solutions were weighted with the TEM histogram and the size-dependent extinction coefficient, for comparison with absorbance-vs.-time curve obtained from freshly prepared suspensions of the AuNP. For particles having average gold-core diameters of 12.1 ± 0.6, 65.0 ± 5.2 and 82.5 ± 5.2. nm, very good agreement exists between the theoretical and observed curves, showing that the particles sediment individually and that the diameter of the gold core is the important factor controlling sedimentation. For the largest particles, observed and calculated curves generally agree, but the former shows random effects consistent with non-homogeneous domains in the sample. Unlike TEM, the simple and unambiguous sedimentation experiment detects all the particles in the sample and can in principle be used to derive the true size histogram. It avoids artifacts of TEM sampling and shear forces of ultracentrifugation. We also show how information about the size histogram can be obtained from the sedimentation curve.",
keywords = "Extinction coefficient, Gold nanoparticles, Gravitational sedimentation, Histogram",
author = "Alexander, {Colleen M.} and Dabrowiak, {James C.} and Jerry Goodisman",
year = "2013",
doi = "10.1016/j.jcis.2013.01.005",
language = "English (US)",
volume = "396",
pages = "53--62",
journal = "Journal of Colloid and Interface Science",
issn = "0021-9797",
publisher = "Academic Press Inc.",

}

TY - JOUR

T1 - Gravitational sedimentation of gold nanoparticles

AU - Alexander, Colleen M.

AU - Dabrowiak, James C.

AU - Goodisman, Jerry

PY - 2013

Y1 - 2013

N2 - We study the gravitational sedimentation of citrate- or ascorbate-capped spherical gold nanoparticles (AuNP) by measuring the absorption-vs.-time curve produced as the particles sediment through the optical beam of a spectrophotometer, and comparing the results with a calculated sedimentation curve. TEM showed the AuNP had gold-core diameters of 12.1 ± 0.6, 65.0 ± 5.2, 82.5 ± 5.2 or 91.8 ± 6.2. nm, and gave diameter distribution histograms. The Mason-Weaver sedimentation-diffusion equation was solved for various particle diameters and the solutions were weighted with the TEM histogram and the size-dependent extinction coefficient, for comparison with absorbance-vs.-time curve obtained from freshly prepared suspensions of the AuNP. For particles having average gold-core diameters of 12.1 ± 0.6, 65.0 ± 5.2 and 82.5 ± 5.2. nm, very good agreement exists between the theoretical and observed curves, showing that the particles sediment individually and that the diameter of the gold core is the important factor controlling sedimentation. For the largest particles, observed and calculated curves generally agree, but the former shows random effects consistent with non-homogeneous domains in the sample. Unlike TEM, the simple and unambiguous sedimentation experiment detects all the particles in the sample and can in principle be used to derive the true size histogram. It avoids artifacts of TEM sampling and shear forces of ultracentrifugation. We also show how information about the size histogram can be obtained from the sedimentation curve.

AB - We study the gravitational sedimentation of citrate- or ascorbate-capped spherical gold nanoparticles (AuNP) by measuring the absorption-vs.-time curve produced as the particles sediment through the optical beam of a spectrophotometer, and comparing the results with a calculated sedimentation curve. TEM showed the AuNP had gold-core diameters of 12.1 ± 0.6, 65.0 ± 5.2, 82.5 ± 5.2 or 91.8 ± 6.2. nm, and gave diameter distribution histograms. The Mason-Weaver sedimentation-diffusion equation was solved for various particle diameters and the solutions were weighted with the TEM histogram and the size-dependent extinction coefficient, for comparison with absorbance-vs.-time curve obtained from freshly prepared suspensions of the AuNP. For particles having average gold-core diameters of 12.1 ± 0.6, 65.0 ± 5.2 and 82.5 ± 5.2. nm, very good agreement exists between the theoretical and observed curves, showing that the particles sediment individually and that the diameter of the gold core is the important factor controlling sedimentation. For the largest particles, observed and calculated curves generally agree, but the former shows random effects consistent with non-homogeneous domains in the sample. Unlike TEM, the simple and unambiguous sedimentation experiment detects all the particles in the sample and can in principle be used to derive the true size histogram. It avoids artifacts of TEM sampling and shear forces of ultracentrifugation. We also show how information about the size histogram can be obtained from the sedimentation curve.

KW - Extinction coefficient

KW - Gold nanoparticles

KW - Gravitational sedimentation

KW - Histogram

UR - http://www.scopus.com/inward/record.url?scp=84875418311&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84875418311&partnerID=8YFLogxK

U2 - 10.1016/j.jcis.2013.01.005

DO - 10.1016/j.jcis.2013.01.005

M3 - Article

C2 - 23403117

AN - SCOPUS:84875418311

VL - 396

SP - 53

EP - 62

JO - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

SN - 0021-9797

ER -