Prev. Article Next Article Table of Contents

Article

Synthesis and Characterization of Thermoreversible Biopolymer Microgels Based on Hydrogen Bonded Nucleobase Pairing

Supporting Info

Rong Cao, Zhenyu Gu, Lorraine Hsu, Gary D. Patterson, and Bruce A. Armitage*

Contribution from the Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213-3890

J. Am. Chem. Soc., 2003, 125 (34), pp 10250–10256

DOI: 10.1021/ja035211t

Publication Date (Web): July 31, 2003

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

army@cyrus.andrew.cmu.edu

Abstract

We describe the synthesis and characterization of a thermoreversibly cross-linked biopolymer microgel based on protein, DNA, and peptide nucleic acid (PNA) components. The DNA assembles into a trifunctional three-way junction (TWJ) with single-stranded overhangs. PNA oligomers complementary to these overhangs and bearing terminal biotin groups hybridize to the DNA TWJ and simultaneously bind to the tetrafunctional protein avidin, leading to a cross-linked system. Dynamic light scattering experiments reveal that micron-sized particles are formed. Static light scattering was used to characterize the internal structure of these microgels, which were found to have a fractal dimension of 1.85, indicative of a loose network structure. Heating disrupts the weakest component in the system, namely the PNA−DNA hybrid, resulting in dissolution of the microgel, while cooling restores the hydrogen bonding leading to reassembly of the microgel. Variation of the nucleotide sequence permits tuning of the gelation temperature with fine control.

View: Full Text HTML | Hi-Res PDF