6 research outputs found
Effect of Surfactants on the Self-Assembly of a Model Elastin-like Block Corecombinamer: From Micelles to an Aqueous Two-Phase System
Recent
advances in genetic engineering now allow the synthesis
of protein-based block corecombinamers derived from elastin-like peptide
sequences with complete control of chemistry and molecular weight,
thereby resulting in unique physical and biological properties. The
individual blocks of the elastin-like block corecombinamers (ELbcRâs)
display different phase behaviors in aqueous solution, which leads
to the thermally triggered self-assembly of nano-objects ranging from
micelles to vesicles. Herein, the interaction of cationic surfactant
dodecyl trimethylammonium bromide (DTAB), anionic surfactant dodecyl
sodium sulfate (SDS), and nonionic surfactant octyl-ÎČ-glucopyranoside
(OG) with an ELbcR has been investigated by dynamic light scattering
(DLS), the ζ potential and cryo-transmission electron microscopy
(cryo-TEM). At 65 °C and neutral pH in aqueous solution, the
ELbcR (E50A40) is associated into micelles with a diameter of 150
nm comprising a hydrophobic (A) core and a hydrophilic (E) anionic
(from the glutamic acid residues) corona. The size of these self-assemblies
can be controlled by adjusting the cosurfactant concentrations. Although
the effects of surfactants on the self-assembly behavior of ELbcRâs
depend on the hydrocarbon chain length and headgroup of the surfactants,
a general tendency to increase in size, which in some cases leads
to flocculation and a phase-separated state, is observed. These results
support the use of surfactants as a highly interesting means of controlling
the self-assembly of ELbcRâs in aqueous solution as well as
their use in drug delivery and purification processes
Biocompatible ELR-Based Polyplexes Coated with MUC1 Specific Aptamers and Targeted for Breast Cancer Gene Therapy
The search for new and biocompatible
materials with high potential
for improvement is a challenge in gene delivery applications. A cell
type specific vector made of elastin-like recombinamer (ELR) and aptamers
has been specifically designed for the intracellular delivery of therapeutic
material for breast cancer therapy. A lysine-enriched ELR was constructed
and complexed with plasmid DNA to give positively charged and stable
polyplexes. Physical characterization of these polyplexes showed a
particle size of around 140 nm and a zeta potential of approximately
+40 mV. The incorporation of MUC1-specific aptamers into the polyplexes
resulted in a slight decrease in zeta potential but increased cell
transfection specificity for MCF-7 breast cancer cells with respect
to a MUC1-negative tumor line. After showing the transfection ability
of this aptamer-ELR vector which is facilitated mainly by macropinocytosis
uptake, we demonstrated its application for suicide gene therapy using
a plasmid containing the gene of the toxin PAP-S. The strategy developed
in this work about using ELR as polymeric vector and aptamers as supplier
of specificity to deliver therapeutic material into MUC1-positive
breast cancer cells shows promising potential and continues paving
the way for ELRs in the biomedical field
Singularity of quantitative research: from collecting information to producing results
International audienc
Multifunctional Compartmentalized Capsules with a Hierarchical Organization from the Nano to the Macro Scales
Inspired by the cellsâ structure,
we present compartmentalized
capsules with temperature and magnetic-based responsiveness and hierarchical
organization ranging from the nano- to the visible scales. Liquefied
alginate macroscopic beads coated with a layer-by-layer (LbL) chitosan/alginate
shell served as containers both for model fluorophores and microcapsules,
which in their turn encapsulated either another fluorophore or magnetic
nanoparticles (MNPs). The microcapsules were coated with a temperature-responsive
chitosan/elastin-like recombinamer (ELR) nanostructured shell. By
varying the temperature from 25 to 37 °C, the two-hour release
of rhodamine encapsulated within the microcapsules and its diffusion
through the external compartment decreased from 84% and 71%. The devices
could withstand handling and centrifugal stress, with 50% remaining
intact at a rotation speed of 2000<i>g</i>. MNPs attributed
magnetic responsiveness toward external magnetic fields. Such a customizable
system can be envisaged to transport bioactive agents and cells in
tissue engineering applications
Layer-by-Layer Film Growth Using Polysaccharides and Recombinant Polypeptides: A Combinatorial Approach
Nanostructured films consisting of
polysaccharides and elastin-like
recombinamers (ELRs) are fabricated in a layer-by-layer manner. A
quartz-crystal microbalance with dissipation monitoring (QCM-D) is
used to follow the buildup of hybrid films containing one polysaccharide
(chitosan or alginate) and one of several ELRs that differ in terms
of amino acid content, length, and biofunctionality <i>in situ</i> at pH 4.0 and pH 5.5. The charge density of the ingredients at each
pH is determined by measuring their ζ-potential, and the thickness
of a total of 36 different films containing five bilayers is estimated
using the Voigt-based viscoelastic model. A comparison of the values
obtained reveals that thicker films can be obtained when working at
a pH close to the acidity constant of the polysaccharide used (near-p<i>K</i><sub>a</sub> conditions), suggesting that the construction
of such films is more favorable when based on the presence of hydrophobic
interactions between ELRs and partially neutralized polysaccharides.
Further analysis shows that the molecular weight of the ELRs plays
only a minor role in defining the growth tendency. When taken together,
these results point to the most favorable conditions for constructing
nanostructured films from natural and distinct recombinant polypeptides
that can be tuned to exhibit specialized biofunctionality for tissue-engineering,
drug-delivery, and biotechnological applications
Immunomodulatory Nanoparticles from Elastin-Like Recombinamers: Single-Molecules for Tuberculosis Vaccine Development
This study investigates both the physicochemical properties
and immunogenicity of a genetically engineered elastin-like block
corecombinamer (ELbcR) containing a major membrane protein sequence
from <i>Mycobacterium tuberculosis</i>. The recombinant
production of this ELbcR allows the production of large quantities
of safe, antigenic particle-based constructs that directly and reversibly
self-assemble into highly biocompatible, multivalent, monodisperse,
and stable nanovesicles with a diameter of 55 nm from the same gene
product using a highly efficient and cost-effective inverse transition
cycling (ITC) procedure. The compositional complexity of these vesicles
is retained after secondary processes such as endotoxin removal, sterilization,
and lyophilization. An initial pro-chemotactic cytokine response (IL-1ÎČ)
followed by a pro-Th2/IL-5 response was observed in mice plasma following
subcutaneous administration of the antigen-loaded nanovesicles in
mice. This biphasic model of cytokine production was coupled with
humoral isotype switching from IgM- to IgG-specific antibodies against
the antigen, which was only observed in the presence of both the antigen
and the polymer in the same construct and in the absence of additional
adjuvants