19 research outputs found
A designer peptide as a template for growing Au nanoclusters
A peptide was designed to generate a sub-nanometric template that guides the growth of fluorescent gold nanoclusters. The peptide was endorsed with nucleating moieties and a three-dimensional structure that arrests the growth of ultrasmall nanoparticles. The nanoclusters are not cytotoxic and can be found in the cytosol of cells
Achieving Controlled Biomolecule-Biomaterial Conjugation
The conjugation of biomolecules can impart materials with the bioactivity necessary to modulate specific cell behaviors. While the biological roles of particular polypeptide, oligonucleotide, and glycan structures have been extensively reviewed, along with the influence of attachment on material structure and function, the key role played by the conjugation strategy in determining activity is often overlooked. In this review, we focus on the chemistry of biomolecule conjugation and provide a comprehensive overview of the key strategies for achieving controlled biomaterial functionalization. No universal method exists to provide optimal attachment, and here we will discuss both the relative advantages and disadvantages of each technique. In doing so, we highlight the importance of carefully considering the impact and suitability of a particular technique during biomaterial design
Amino Acid Sequence in Constitutionally Isomeric Tetrapeptide Amphiphiles Dictates Architecture of One-Dimensional Nanostructures
The switching of
two adjacent amino acids can lead to differences
in how proteins fold thus affecting their function. This effect has
not been extensively explored in synthetic peptides in the context
of supramolecular self-assembly. Toward this end, we report here the
use of isomeric peptide amphiphiles as molecular building blocks to
create one-dimensional (1D) nanostructures. We show that four peptide
amphiphile isomers, with identical composition but a different sequence
of their four amino acids, can form drastically different types of
1D nanostructures under the same conditions. We found that molecules
with a peptide sequence of alternating hydrophobic and hydrophilic
amino acids such as VEVE and EVEV self-assemble into flat nanostructures
that can be either helical or twisted. On the other hand, nonalternating
isomers such as VVEE and EEVV result in the formation of cylindrical
nanofibers. Furthermore, we also found that when the glutamic acid
is adjacent to the alkyl tail the supramolecular assemblies appear
to be internally flexible compared to those with valine as the first
amino acid. These results clearly demonstrate the significance of
peptide side chain interactions in determining the architectures of
supramolecular assemblies
Research data supporting "Residue-Specific Solvation Directed Thermodynamic and Kinetic Control over Peptide Self-Assembly with 1D/2D Structure Selection"
Experimental research raw data supporting the publication by Lin, Y. et al, 2019, "Residue-Specific Solvation Directed Thermodynamic and Kinetic Control over Peptide Self-Assembly with 1D/2D Structure Selection", ACS Nano. DOI: 10.1021/acsnano.8b08117.
Molecular simulation data is available upon reasonable request from [email protected] research raw data supporting the publication by Lin, Y. et al, 2019, "Residue-Specific Solvation Directed Thermodynamic and Kinetic Control over Peptide Self-Assembly with 1D/2D Structure Selection", ACS Nano. DOI: 10.1021/acsnano.8b08117. Molecular simulation data is available upon reasonable request from [email protected]
Self-Healing, Self-Assembled β‑Sheet Peptide–Poly(γ-glutamic acid) Hybrid Hydrogels
Self-assembled
biomaterials are an important class of materials
that can be injected and formed <i>in situ</i>. However,
they often are not able to meet the mechanical properties necessary
for many biological applications, losing mechanical properties at
low strains. We synthesized hybrid hydrogels consisting of a polyÂ(γ-glutamic
acid) polymer network physically cross-linked via grafted self-assembling
β-sheet peptides to provide non-covalent cross-linking through
β-sheet assembly, reinforced with a polymer backbone to improve
strain stability. By altering the β-sheet peptide graft density
and concentration, we can tailor the mechanical properties of the
hydrogels over an order of magnitude range of 10–200 kPa, which
is in the region of many soft tissues. Also, due to the ability of
the non-covalent β-sheet cross-links to reassemble, the hydrogels
can self-heal after being strained to failure, in most cases recovering
all of their original storage moduli. Using a combination of spectroscopic
techniques, we were able to probe the secondary structure of the materials
and verify the presence of β-sheets within the hybrid hydrogels.
Since the polymer backbone requires less than a 15% functionalization
of its repeating units with β-sheet peptides to form a hydrogel,
it can easily be modified further to incorporate specific biological
epitopes. This self-healing polymer−β-sheet peptide hybrid
hydrogel with tailorable mechanical properties is a promising platform
for future tissue-engineering scaffolds and biomedical applications
Residue-Specific Solvation-Directed Thermodynamic and Kinetic Control over Peptide Self-Assembly with 1D/2D Structure Selection
Understanding the self-organization and structural transformations of molecular ensembles is important to explore the complexity of biological systems. Here, we illustrate the crucial role of cosolvents and solvation effects in thermodynamic and kinetic control over peptide association into ultrathin Janus nanosheets, elongated nanobelts, and amyloid-like fibrils. We gained further insight into the solvation-directed self-assembly (SDSA) by investigating residue-specific peptide solvation using molecular dynamics modeling. We proposed the preferential solvation of the aromatic and alkyl domains on the peptide backbone and protofibril surface, which results in volume exclusion effects and restricts the peptide association between hydrophobic walls. We explored the SDSA phenomenon in a library of cosolvents (protic and aprotic), where less polar cosolvents were found to exert a stronger influence on the energetic balance at play during peptide propagation. By tailoring cosolvent polarity, we were able to achieve precise control of the peptide nanostructures with 1D/2D shape selection. We also illustrated the complexity of the SDSA system with pathway-dependent peptide aggregation, where two self-assembly states (i.e., thermodynamic equilibrium state and kinetically trapped state) from different sample preparation methods were obtained
Residue-Specific Solvation-Directed Thermodynamic and Kinetic Control over Peptide Self-Assembly with 1D/2D Structure Selection
Electrospinning Bioactive Supramolecular Polymers from Water
Electrospinning
is a high-throughput, low-cost technique for manufacturing
long fibers from solution. Conventionally, this technique is used
with covalent polymers with large molecular weights. We report here
the electrospinning of functional peptide-based supramolecular polymers
from water at very low concentrations (<4 wt %). Molecules with
low molecular weights (<1 kDa) could be electrospun because they
self-assembled into one-dimensional supramolecular polymers upon solvation
and the critical parameters of viscosity, solution conductivity, and
surface tension were optimized for this technique. The supramolecular
structure of the electrospun fibers could ensure that certain residues,
like bioepitopes, are displayed on the surface even after processing.
This system provides an opportunity to electrospin bioactive supramolecular
materials from water for biomedical applications