5.1.2 Controlled Nanoscale Shapes and Container or Scaffolding
Properties
Systematic shape and unimolecular container or scaffolding behavior appears to be
a nano-periodic property that is specific to each dendrimer family or series. These
properties are determined by the size, shape, and multiplicity of the construction
components used for the core, interior, and surface of the dendrimer (Fig. 12).
Higher multiplicity components and those that contribute to “tethered congestion”
will hasten the development of more rigid shapes, container properties, and less
flexible surface scaffolding as a function of generation.
5.2 Amplification and Functionalization of Dendrimer
Surface Groups
Dendrimers within a generational series can be expected to present their terminal
groups in at least three different modes, namely, flexible, semi-flexible, or rigid
functionalized scaffolding. Based on mathematically defined dendritic branching
rules (i.e., Z ¼ N c N b
G ), the various surface presentations become more congested
and rigid as a function of increasing generation level. It is implicit that this surface
amplification can be designed to control gating properties associated with
unimolecular container development. Furthermore, dendrimers may be viewed as
versatile nanosized objects that can be readily surface-functionalized with a vast
array of chemical and application features. Presently, well over 1,000 diverse
surface functionalities have been attached to dendrimer surfaces [52]. The ability
to control and engineer these parameters provides an endless list of possibilities for
utilizing dendrimers as modules for nanodevice design [11, 48, 50, 117]. Recent
reviews have begun to focus on this area [118–122].
5.3 Nanoscale Dimensions and Shapes Mimic Those
of Proteins
In view of the extraordinary structure control and nanoscale dimensions observed
for dendrimers, it is not surprising to find extensive interest in the use of dendrimers
as globular protein mimics. Based on their systematic, dimensional length scaling
properties and electrophoretic/hydrodynamic [91, 92] behavior, they are widely
recognized as artificial proteins [48, 123]. Substantial effort has been focused
recently on the use of dendrimers for “site isolation” mimicry of proteins [9],
enzyme-like catalysis [124], viral capsid mimicry [125] and other biomimetic
applications [48, 126], drug delivery [119, 123, 127, 128], surface engineering
[129], and light harvesting [130, 131]. These fundamental properties have in fact
Twenty-First Century Polymer Science After Staudinger: The Emergence of. . .
349
Properties
Systematic shape and unimolecular container or scaffolding behavior appears to be
a nano-periodic property that is specific to each dendrimer family or series. These
properties are determined by the size, shape, and multiplicity of the construction
components used for the core, interior, and surface of the dendrimer (Fig. 12).
Higher multiplicity components and those that contribute to “tethered congestion”
will hasten the development of more rigid shapes, container properties, and less
flexible surface scaffolding as a function of generation.
5.2 Amplification and Functionalization of Dendrimer
Surface Groups
Dendrimers within a generational series can be expected to present their terminal
groups in at least three different modes, namely, flexible, semi-flexible, or rigid
functionalized scaffolding. Based on mathematically defined dendritic branching
rules (i.e., Z ¼ N c N b
G ), the various surface presentations become more congested
and rigid as a function of increasing generation level. It is implicit that this surface
amplification can be designed to control gating properties associated with
unimolecular container development. Furthermore, dendrimers may be viewed as
versatile nanosized objects that can be readily surface-functionalized with a vast
array of chemical and application features. Presently, well over 1,000 diverse
surface functionalities have been attached to dendrimer surfaces [52]. The ability
to control and engineer these parameters provides an endless list of possibilities for
utilizing dendrimers as modules for nanodevice design [11, 48, 50, 117]. Recent
reviews have begun to focus on this area [118–122].
5.3 Nanoscale Dimensions and Shapes Mimic Those
of Proteins
In view of the extraordinary structure control and nanoscale dimensions observed
for dendrimers, it is not surprising to find extensive interest in the use of dendrimers
as globular protein mimics. Based on their systematic, dimensional length scaling
properties and electrophoretic/hydrodynamic [91, 92] behavior, they are widely
recognized as artificial proteins [48, 123]. Substantial effort has been focused
recently on the use of dendrimers for “site isolation” mimicry of proteins [9],
enzyme-like catalysis [124], viral capsid mimicry [125] and other biomimetic
applications [48, 126], drug delivery [119, 123, 127, 128], surface engineering
[129], and light harvesting [130, 131]. These fundamental properties have in fact
Twenty-First Century Polymer Science After Staudinger: The Emergence of. . .
349