Network Formation and Sieving Performance of Self-Assembling Hydrogels

Abstract

Self-assembling hydrogels, consisting of aqueous solutions of poly(ethylene glycol)s end-capped with perfluorocarbon groups (Rf−PEGs), were studied for their electrophoretic sieving performance. These materials form physical gels, with the end groups aggregated in hydrophobic cores. The gels display high sieving performance, expressed as a large mobility dependence on DNA size, for short double-stranded DNA fragments even at relatively low polymer concentrations (∼3 wt %). This interesting characteristic can be attributed to the dense packing of interconnected micelles that build up the hydrogel network. The physically connected micelles act as a permanent network on the time scale of DNA migration over the distance between micelle cores. A mobility plateau was observed for intermediate DNA sizes that were probably too large to sieve through the network of interconnected micelles and yet too small to reptate. This plateau was followed by a reptation regime for larger DNA sizes, that has similar resolving characteristics to that observed for entangled linear PEO solutions.

Humidity-Dependent Wetting Properties of High Hysteresis Surfaces

“…To facilitate drastic structural rearrangements of the surface material, a promising approach is to use physical rather than covalent bonds − The relative lengths of the polymer midblock and the endgroups determine the phase behavior of the polymers in aqueous media: single-phase gel, single-phase micellar solution, coexisting gel and micellar solution, or an insoluble hydrogel. Previous work has shown that a 6 kg/mol PEG molecule with 10 fluorinated carbons (termed 6KC10) when dip-coated from ethanol onto a surface premodified with a fluorinated SAM yields an insoluble gel layer that is impervious to decay at high shear rates in water.…”

DNA sequencing and genotyping in miniaturized electrophoresis systems

“…The "porosity" of the self-assembled surfactant network Electrophoresis 2004, 25, 3564-3588 was said to be easily controlled with the choice of monomer concentration, denaturant, and temperature. A related family of self-assembling hydrogels consisting of aqueous solutions of PEG, end-capped with perfluorocarbon groups, has been applied for dsDNA fragment sizing [212]. The aggregation of hydrophobic fluorocarbon cores acts as physical cross-linking points, so that physical gels form at relatively low surfactant concentrations (as low as 2% w/w) and can provide highresolution dsDNA sieving.…”