Dendritic branching concepts

The origins of the present three-dimensional (3D), dendritic branching concepts can be traced back to the initial introduction of infinite network theory by Flory [29-32]... 

This manuscript describes the dendritic macromolecules for optical and optoelectronic apph-cations, particularly stimulated emission, laser emission, and nonlinear optics. Dendrimers have been designed and synthesized for these applications based on simple concepts. A coreshell structure, through the encapsulation of active imits by dendritic branches, or a cone-shaped structure, through the step-by-step reactions of active imits, can provide particular benefits for the optical high-gain media and nonlinear optical materials. It also described experimental results that support the methods presented for designing and fabricating functionalized dendrimers for optoelectronic applications, and theoretical results that reveal the intermolecular electronic effect of the dendritic structure. 

Other types of branched peptide dendrimers, known as multiple antigen peptides (MAPs), have been synthesized to mimic proteins for applications, for instance as synthetic vaccines, serodiagnostics, peptide inhibitors and intracellular delivery vehicles. Since this concept has been recently described in detail elsewhere [11], only the conceptual framework will be briefly presented here. Tam and coworkers have developed a dendritic core based on lysine units for the construction of MAPs [12-15] (Fig. 3). Carrying antigens at their periphery these MAPs have been designed to increase antigenicity and immunogenicity of peptides. 

Concept The structural motif of a defined branching of branches leads to dendritic molecules reaching the nanometer scale. The development of this concept has given rise to a great variety of macromolecules which... 

FIGURE 1 — 1. This is an artist s concept of how a neuron is organized in order to send synaptic information. It does this via a long axon, which sends its information into numerous branches called terminal axon fibers. Each of these axon terminals can potentially make presynaptic contacts with other neurons. Also shown is the cell body, which is the command center of the nerve, contains the nucleus of the cell, and processes both incoming and outgoing information. The dendrites are organized largely to capture information from other neurons (see also Fig. 1—2). 

Macromolecules that contain two or more topologically distinct components are complex architectures that can lead to emergent properties or behaviors that are different to those of either of the individual molecular architectures. Dendronized polymers [16-19] are examples of such complex molecular architectures and are composed of a linear polymer backbone and perfectly branched dendritic side chains on each repeat unit (Scheme 1). The molar masses of such polymers emphasize the shift in thinking brought about by Staudinger s concept of macromolecules [1,2]. Individual dendronized polymers are nanoscopic objects [20-25] whose organization in bulk is determined by hierarchical processes that occur on a different set of length scales compared to conventional polymers [16,26]. By virtue of the size and shape of dendronized polymers, interest in this complex macromolecular architecture has moved toward how to extract functionality from these nanoscale molecular objects. 

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