© 2004 Robert A. Freitas Jr. and Ralph C. Merkle. All Rights Reserved.

Robert A. Freitas Jr., Ralph C. Merkle, Kinematic Self-Replicating Machines, Landes Bioscience, Georgetown, TX, 2004.

4.1.3 Self-Assembling Dendrimers

Dendrimers [1491-1499], also known as arborols or fractal polymers, are a well-known set of self-assembling structures [1500] that possibly could be used as tools to assist in the assembly of early nanomachines. Dendrimers are large regularly-branching macromolecules resembling fractal patterns, made by an iterative process in which small linear molecules are allowed to bind to each other at a certain number of sites along their length, building up branches upon branches with each iteration working outward from a core molecule having at least two chemically reactive arms, somewhat mimicking tree growth. Different core molecules or building-block chains produce macromolecules with different shapes, and the outer surface can be terminated with chemical groups of specific functionality, producing hundreds of differently-surfaced branched molecules [1501] that have already found use in medical research [1502]. Growth is regulated, so size can be accurately controlled – dendrimers are typically a few nanometers wide but have been constructed with masses exceeding a million protons (~10⁵ atoms) and with diameters larger than 30 nm.

Convergent assembly of specified 6-mer dendrimers via trimerization of precursor dimer “parts” was demonstrated in 1999 [1503]. Dendrimer self-assembly into lattices and other multidendrimeric structures has been studied both computationally [1504, 1505] and experimentally [1506-1509].

DNA-based dendrimers have already been mentioned in Section 4.1.1.

Last updated on 1 August 2005