2 research outputs found
Branched Wormlike Micelles Formed by Self-Assembled Comblike Amphiphilic Copolyelectrolytes
The structure of the self-assemblies
formed by amphiphilic comblike
copolyelectrolytes dispersed in water has been investigated by scattering
techniques (light and neutron) and by transmission electronic microscopy.
The comblike polymers consisted of a polystyrene backbone grafted
with a fixed amount of pendant <i>N</i>,<i>N</i>-dimethyl quaternary ammonium alkyl groups of various lengths ranging
from C12 up to C18. In aqueous solution, the polymers self-assembled
into small spherical aggregates at low concentrations and into cylindrical
aggregates above a critical concentration with a diameter that increased
with the length of the alkyl side chains. The length of the cylindrical
aggregates increased with increasing concentration, and branching
occurred at higher concentration, which induced gelation above a critical
percolation concentration. Growth and branching were favored by increasing
the ionic strength of the solution. The dynamics slowed down with
decreasing temperature and increasing alkyl length, and the assemblies
of polymers with C16 and C18 pendant chains were kinetically frozen
at 20 Ā°C
Amino AcidāNucleotideāLipids: Effect of Amino Acid on the Self-Assembly Properties
Hybrid amphiphiles
composed of a lipid covalently linked to biomolecules
are attracting considerable attention, owing to their unique physicochemical
and biological properties. Herein, we have synthesized novel amino
acidānucleotideālipids (ANLs), presenting phenylalanine
and thymidine residues and saturated or unsaturated diacyl glycerol
lipid moieties to investigate the effect of the specific aminoacid
moieties on both aggregation properties and interactions of ANLs with
single strand polyA RNA. Physicochemical studies (DLS, cryo-TEM, and
small angle X-ray scattering) indicate that phenylanaline amino acids
inserted at the 5ā² position of the nucleotide-lipids stabilize
multilamellar systems, whereas unilamellar vesicles are formed preferentially
in the case of nucleotideālipids (NLs). Both NLs and ANLs exhibit
weak interactions with complementary polyA RNA as revealed by isothermal
titration calorimetry investigations. The multilamellar vesicles obtained
with ANLs could be used as a versatile carrier, suitable for both
hydrophobic and hydrophilic therapeutic molecules