title: Synthesis and characterization of thermoreversible biopolymer microgels based on hydrogen bonded nucleobase pairing.
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.
authors.affiliation: Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213-3890, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Cao
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Gu
authors.forename: Lorraine
authors.initials: L
authors.lastname: Hsu
authors.forename: Gary D
authors.initials: GD
authors.lastname: Patterson
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Armitage
mesh_terms: D001360:Avidin / Q000737:chemistry; D001483:Base Sequence; D001710:Biotin / Q000737:chemistry; D004247:DNA / Q000138:chemical synthesis / Q000737:chemistry*; D005782:Gels; D006358:Hot Temperature; D006860:Hydrogen Bonding; D008027:Light; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D020135:Peptide Nucleic Acids / Q000138:chemical synthesis / Q000737:chemistry*; D011506:Proteins / Q000138:chemical synthesis / Q000737:chemistry*; D012542:Scattering, Radiation
chemical_list: D005782:Gels; D009841:Oligonucleotides; D020135:Peptide Nucleic Acids; D011506:Proteins; D001360:Avidin; D001710:Biotin; D004247:DNA