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Topics Covered
Background
Delsa Nano Zeta Potential and
Submicron Particle Size Analyzer
Functionality of Dendrimers
as Molecular Nanomaterials
Modifying Terminal Groups of
Dendrimer Molecules
Mesurement of Zeta Potential and
Particle Diameter of PAMAM Dendrimer
Background
Beckman
Coulter, Inc. is a leading manufacturer of biomedical testing instrument
systems, tests and supplies that simplify and automate laboratory processes.
Spanning the biomedical testing continuum - from pioneering medical research and
clinical trials to laboratory diagnostics and point-of-care testing - Beckman
Coulter's 200,000 installed systems provide essential biomedical information
to enhance health care around the world
Delsa Nano Zeta Potential and Submicron Particle Size Analyzer
The DelsaNano series is a new generation of instruments that use
photon correlation spectroscopy (PCS), which determines particle size by
measuring the rate of fluctuations in laser light intensity scattered by
particles as they diffuse through a fluid, for size analysis measurements and/or
electrophoretic light scattering (ELS), which determines electrophoretic
movement of charged particles under an applied electric field from the Doppler
shift of scattered light, for zeta potential determination.
This series has a broad range of capabilities, including conventional static
and automatic titration measurements for both size and zeta potential
distributions of suspended particles in a wide range of size and concentration.
The DelsaNano also can measure zeta potential of a solid surface
or film.
Functionality of Dendrimers as Molecular Nanomaterials
Dendrimers are representative organic and polymeric nanomaterials used to construct novel devices by accumulative
molecular nanomaterials. Dendrimer
is a branched polymer whose structure can be precisely controlled. A dendrimer
molecule consists of a core and a surface. It is believed that the core
determines the size, shape, orientation, and diversity, and that the surface,
composed of reactive and nonreactive terminal groups, expresses their
functionality.
Modifying Terminal Groups of Dendrimer Molecules
Modification of these terminal groups is being applied to both bioscience and
materials science fields. In designing dendrimer
molecules, the particle diameter is evaluated as a fundamental physical
property. Zeta potential is also significant in determining the surface
functionality with terminal group modification.
Mesurement of Zeta Potential and Particle Diameter of PAMAM Dendrimer
In this study, the DelsaNano C, a submicron particle size
analyzer, was used to measure the zeta potential and particle diameter of
the 1,4-diaminobutane core PAMAM (aliphatic amidoamine-type) dendrimer
(hexylamide surface) from Aldrich. The sample has a molecular weight of 83,200
Dalton with 256 terminal groups. The sample concentration was 5 wt% in methanol.
The particle
size distribution is shown in Figure 1 and the zeta potential distribution
is shown in Figure 2. It was determined that the average particle diameter was
8.5 nm and the zeta potential was +7.2 mV because of the positive terminal amino
group.
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Figure 1. Dendrimer particle size distribution.
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Figure 2. Dendrimer zeta potential distribution.
Source: Beckman Coulter
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