Video Microscopy of Dynamically Aggregated Paramagnetic Particle Chains in an Applied Rotating Magnetic Field

Anil K. Vuppu, Antonio Garcia, Mark Hayes

Research output: Contribution to journalArticle

85 Citations (Scopus)

Abstract

A rotating unidirectional magnetic field generated by a motor-mounted permanent magnet was used to dynamically aggregate paramagnetic particles from suspension to form chains. Video microscopy and image processing were used to analyze the data. Good synchronicity was observed between the chains and the field .up to 8 Hz frequency. Chain growth is facilitated at very low rotational frequencies initially after starting from static conditions, after which the mean chain length decreases in response to increasing viscous drag forces. As the frequency is increased from low values, the mean chain length decreases initially rapidly and later more slowly at higher frequencies, thus resulting in two regimes: the fast and the slow decrease regimes. Typical structures such as linear chains and S-shaped chains are observed as well as unusual U-shaped structures. The formation of dynamic S-shaped structures can be predicted based on the flexibility of the chains and the principle of conservation of angular momentum. Formation of single-chain aggregates is observed in microwells that are up to 50 μm wide, whereas in larger microwells multichain formation was noticed. The motor-mounted permanent magnet arrangement has applications in the development of portable microchip biosensors. The arrangement proved sufficient and reliable in forming chains, which display behavior similar to that observed under more elaborate and controlled conditions.

Original languageEnglish (US)
Pages (from-to)8646-8653
Number of pages8
JournalLangmuir
Volume19
Issue number21
DOIs
StatePublished - Oct 14 2003

Fingerprint

Chain length
Permanent magnets
Microscopic examination
Magnetic fields
microscopy
Angular momentum
magnetic fields
Biosensors
Drag
Conservation
Suspensions
Image processing
permanent magnets
viscous drag
bioinstrumentation
image processing
conservation
flexibility
angular momentum

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Video Microscopy of Dynamically Aggregated Paramagnetic Particle Chains in an Applied Rotating Magnetic Field. / Vuppu, Anil K.; Garcia, Antonio; Hayes, Mark.

In: Langmuir, Vol. 19, No. 21, 14.10.2003, p. 8646-8653.

Research output: Contribution to journalArticle

@article{579e30417d764244bfcf97355f48db87,
title = "Video Microscopy of Dynamically Aggregated Paramagnetic Particle Chains in an Applied Rotating Magnetic Field",
abstract = "A rotating unidirectional magnetic field generated by a motor-mounted permanent magnet was used to dynamically aggregate paramagnetic particles from suspension to form chains. Video microscopy and image processing were used to analyze the data. Good synchronicity was observed between the chains and the field .up to 8 Hz frequency. Chain growth is facilitated at very low rotational frequencies initially after starting from static conditions, after which the mean chain length decreases in response to increasing viscous drag forces. As the frequency is increased from low values, the mean chain length decreases initially rapidly and later more slowly at higher frequencies, thus resulting in two regimes: the fast and the slow decrease regimes. Typical structures such as linear chains and S-shaped chains are observed as well as unusual U-shaped structures. The formation of dynamic S-shaped structures can be predicted based on the flexibility of the chains and the principle of conservation of angular momentum. Formation of single-chain aggregates is observed in microwells that are up to 50 μm wide, whereas in larger microwells multichain formation was noticed. The motor-mounted permanent magnet arrangement has applications in the development of portable microchip biosensors. The arrangement proved sufficient and reliable in forming chains, which display behavior similar to that observed under more elaborate and controlled conditions.",
author = "Vuppu, {Anil K.} and Antonio Garcia and Mark Hayes",
year = "2003",
month = "10",
day = "14",
doi = "10.1021/la034195a",
language = "English (US)",
volume = "19",
pages = "8646--8653",
journal = "Langmuir",
issn = "0743-7463",
publisher = "American Chemical Society",
number = "21",

}

TY - JOUR

T1 - Video Microscopy of Dynamically Aggregated Paramagnetic Particle Chains in an Applied Rotating Magnetic Field

AU - Vuppu, Anil K.

AU - Garcia, Antonio

AU - Hayes, Mark

PY - 2003/10/14

Y1 - 2003/10/14

N2 - A rotating unidirectional magnetic field generated by a motor-mounted permanent magnet was used to dynamically aggregate paramagnetic particles from suspension to form chains. Video microscopy and image processing were used to analyze the data. Good synchronicity was observed between the chains and the field .up to 8 Hz frequency. Chain growth is facilitated at very low rotational frequencies initially after starting from static conditions, after which the mean chain length decreases in response to increasing viscous drag forces. As the frequency is increased from low values, the mean chain length decreases initially rapidly and later more slowly at higher frequencies, thus resulting in two regimes: the fast and the slow decrease regimes. Typical structures such as linear chains and S-shaped chains are observed as well as unusual U-shaped structures. The formation of dynamic S-shaped structures can be predicted based on the flexibility of the chains and the principle of conservation of angular momentum. Formation of single-chain aggregates is observed in microwells that are up to 50 μm wide, whereas in larger microwells multichain formation was noticed. The motor-mounted permanent magnet arrangement has applications in the development of portable microchip biosensors. The arrangement proved sufficient and reliable in forming chains, which display behavior similar to that observed under more elaborate and controlled conditions.

AB - A rotating unidirectional magnetic field generated by a motor-mounted permanent magnet was used to dynamically aggregate paramagnetic particles from suspension to form chains. Video microscopy and image processing were used to analyze the data. Good synchronicity was observed between the chains and the field .up to 8 Hz frequency. Chain growth is facilitated at very low rotational frequencies initially after starting from static conditions, after which the mean chain length decreases in response to increasing viscous drag forces. As the frequency is increased from low values, the mean chain length decreases initially rapidly and later more slowly at higher frequencies, thus resulting in two regimes: the fast and the slow decrease regimes. Typical structures such as linear chains and S-shaped chains are observed as well as unusual U-shaped structures. The formation of dynamic S-shaped structures can be predicted based on the flexibility of the chains and the principle of conservation of angular momentum. Formation of single-chain aggregates is observed in microwells that are up to 50 μm wide, whereas in larger microwells multichain formation was noticed. The motor-mounted permanent magnet arrangement has applications in the development of portable microchip biosensors. The arrangement proved sufficient and reliable in forming chains, which display behavior similar to that observed under more elaborate and controlled conditions.

UR - http://www.scopus.com/inward/record.url?scp=0142185110&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0142185110&partnerID=8YFLogxK

U2 - 10.1021/la034195a

DO - 10.1021/la034195a

M3 - Article

AN - SCOPUS:0142185110

VL - 19

SP - 8646

EP - 8653

JO - Langmuir

JF - Langmuir

SN - 0743-7463

IS - 21

ER -