Tuning PNIPAm self-assembly and thermoresponse: roles of hydrophobic end-groups and hydrophilic comonomer

2019 ◽  
Vol 10 (25) ◽  
pp. 3469-3479 ◽  
Author(s):  
Monica L. Ohnsorg ◽  
Jeffrey M. Ting ◽  
Seamus D. Jones ◽  
Seyoung Jung ◽  
Frank S. Bates ◽  
...  
Keyword(s):  
Cloud Point ◽  
Systematic Study ◽  
Self Assembly ◽  
Design Rules ◽  
End Groups

Systematic study of hydrophobic and hydrophilic modifications to poly(N-isopropylacrylamide) elucidates design rules for control over cloud point and aqueous self-assembly.

Aromatic identity, electronic substitution, and sequence in amphiphilic tripeptide self-assembly

Soft Matter ◽  
2018 ◽  
Vol 14 (45) ◽  
pp. 9168-9174 ◽  
Author(s):  
Jugal Kishore Sahoo ◽  
Calvin Nazareth ◽  
Michael A. VandenBerg ◽  
Matthew J. Webber
Keyword(s):  
Self Assembly ◽  
Short Peptides ◽  
Design Rules ◽  
Sequence Variations

The design rules for self-assembly of short peptides are assessed using a combination of chemical and sequence variations.

Peptide α-helices for synthetic nanostructures

2007 ◽  
Vol 35 (3) ◽  
pp. 487-491 ◽  
Author(s):  
M.G. Ryadnov
Keyword(s):  
Self Assembly ◽  
De Novo ◽  
Three Dimensional ◽  
Functional Materials ◽  
Protein Assemblies ◽  
Helical Peptides ◽  
Design Rules ◽  
Natural Protein ◽  
Self Assembling ◽  
Recent Developments

Supramolecular structures arising from a broad range of chemical archetypes are of great technological promise. Defining such structures at the nanoscale is crucial to access principally new types of functional materials for applications in bionanotechnology. In this vein, biomolecular self-assembly has emerged as an efficient approach for building synthetic nanostructures from the bottom up. The approach predominantly employs the spontaneous folding of biopolymers to monodisperse three-dimensional shapes that assemble into hierarchically defined mesoscale composites. An immediate interest here is the extraction of reliable rules that link the chemistry of biopolymers to the mechanisms of their assembly. Once established these can be further harnessed in designing supramolecular objects de novo. Different biopolymer classes compile a rich repertoire of assembly motifs to facilitate the synthesis of otherwise inaccessible nanostructures. Among those are peptide α-helices, ubiquitous folding elements of natural protein assemblies. These are particularly appealing candidates for prescriptive supramolecular engineering, as their well-established and conservative design rules give unmatched predictability and rationale. Recent developments of self-assembling systems based on helical peptides, including fibrous systems, nanoscale linkers and reactors will be highlighted herein.

scholarly journals Biocatalysis of d,l-Peptide Nanofibrillar Hydrogel

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2995 ◽  
Author(s):  
Tiziano Carlomagno ◽  
Maria C. Cringoli ◽  
Slavko Kralj ◽  
Marina Kurbasic ◽  
Paolo Fornasiero ◽  
...  
Keyword(s):  
Self Assembly ◽  
Solid Phase ◽  
Building Blocks ◽  
Cd Spectroscopy ◽  
Tem Analysis ◽  
Design Rules ◽  
Self Assembling ◽  
Transmission Electron ◽  
Oscillatory Rheometry ◽  
The Many

Self-assembling peptides are attracting wide interest as biodegradable building blocks to achieve functional nanomaterials that do not persist in the environment. Amongst the many applications, biocatalysis is gaining momentum, although a clear structure-to-activity relationship is still lacking. This work applied emerging design rules to the heterochiral octapeptide sequence His–Leu–DLeu–Ile–His–Leu–DLeu–Ile for self-assembly into nanofibrils that, at higher concentration, give rise to a supramolecular hydrogel for the mimicry of esterase-like activity. The peptide was synthesized by solid-phase and purified by HPLC, while its identity was confirmed by 1H-NMR and electrospray ionization (ESI)-MS. The hydrogel formed by this peptide was studied with oscillatory rheometry, and the supramolecular behavior of the peptide was investigated with transmission electron microscopy (TEM) analysis, circular dichroism (CD) spectroscopy, thioflavin T amyloid fluorescence assay, and attenuated total reflectance (ATR) Fourier-transform infrared (FT-IR) spectroscopy. The biocatalytic activity was studied by monitoring the hydrolysis of p-nitrophenyl acetate (pNPA) at neutral pH, and the reaction kinetics followed an apparent Michaelis–Menten model, for which a Lineweaver–Burk plot was produced to determine its enzymatic parameters for a comparison with the literature. Finally, LC–MS analysis was conducted on a series of experiments to evaluate the extent of, if any, undesired peptide acetylation at the N-terminus. In conclusion, we provide new insights that allow gaining a clearer picture of self-assembling peptide design rules for biocatalysis.

α- and β-Cyclodextrin [2]rotaxanes with (diethylenetriamine)platinum(II) stoppers

2005 ◽  
Vol 83 (12) ◽  
pp. 2091-2097 ◽  
Author(s):  
Victor X Jin ◽  
Donal H Macartney ◽  
Erwin Buncel
Keyword(s):  
Self Assembly ◽  
Electrospray Mass Spectrometry ◽  
Platinum Complexes ◽  
H Nmr ◽  
Bridging Ligand ◽  
Dinuclear Platinum ◽  
End Groups ◽  
Group A ◽  
Kinetics Of ◽  
End Group

A series of dinuclear platinum(II) complexes, [(dien)Pt(NH2(CH2)nNH2)Pt(dien)]Cl4 (dien = diethylenetriamine, n = 8, 9, 10, and 12) and their corresponding [2]rotaxanes with α-cyclodextrin (α-CD), [(dien)Pt{NH2(CH2)nNH2·α-CD}Pt(dien)]Cl4, have been synthesized and characterized by 1H, 13C, and 195Pt NMR spectroscopy and electrospray mass spectrometry. The rotaxanes were prepared by reacting the {NH2(CH2)nNH2·α-CD} pseudorotaxanes with [Pt(dien)]Cl, to stopper the included linear α,ω-diaminoalkane chains with the inert Pt(II) end groups. The kinetics of the self-assembly and dissociation of the β-CD rotaxane, [(dien)Pt{NH2(CH2)10NH2·β-CD}Pt(dien)]4+, were investigated by using 1H NMR and are indicative of a slippage mechanism, owing to the comparable sizes of the β-CD cavity and the [Pt(dien)]+ end group. A relatively weak inclusion of the end group in the β-CD cavity precedes a thermally promoted passage of the β-CD over the [Pt(dien)]+ end group onto the hydrophobic polymethylene chain of the bridging ligand of the thread. Key words: rotaxanes, pseudorotaxanes, cyclodextrin, platinum complexes, slippage mechanism.

Design of surface patterns with optimized thermodynamic driving forces for the directed self-assembly of block copolymers in lithographic applications

2017 ◽  
Vol 2 (5) ◽  
pp. 567-580 ◽  
Author(s):  
Grant P. Garner ◽  
Paulina Rincon Delgadillo ◽  
Roel Gronheid ◽  
Paul F. Nealey ◽  
Juan J. de Pablo
Keyword(s):  
Block Copolymers ◽  
Self Assembly ◽  
Driving Forces ◽  
Theoretical Method ◽  
Design Rules ◽  
Surface Patterns

A theoretical method for developing design rules for the directed self-assembly of block copolymers for lithographic applications.

Kinetic and spectroscopic studies on α- and β-cyclodextrin rotaxanes with (µ-N,N′- bis(4-pyridinylmethylene)-α,ω-alkanediimine)bis[pentacyanoferrate(II)] threads

2005 ◽  
Vol 83 (3) ◽  
pp. 195-201 ◽  
Author(s):  
Victor X Jin ◽  
Donal H Macartney ◽  
Erwin Buncel
Keyword(s):  
Chemical Shift ◽  
Metal Complexes ◽  
Key Words ◽  
Rate Constants ◽  
Self Assembly ◽  
Spectroscopic Studies ◽  
Ligand Substitution ◽  
H Nmr ◽  
End Groups ◽  
The Stability

[2]Pseudorotaxanes have been prepared by threading N,N′-bis(4-pyridinylmethylene)-1,2-ethanediimine (L2), -1,4-butanediimine (L4), and -1,6-hexanediimine (L6) ligands through α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD), and have subsequently been converted to the corresponding [2]rotaxane species by coordinating bulky [Fe(CN)5]3– end groups. The stability constants for the [2]pseudorotaxanes were determined by 1H NMR chemical shift titrations and increase with the polymethylene chain length n. The rate constants for both the formation of the [Fe(CN)5(Ln)]3– complexes from the [Fe(CN)5OH2]3– ion and Ln, and the rate constants for the dissociation of Ln from the metal complexes, exhibit significant diminutions in the presence of α- and β-CD, owing to inclusions of the free and coordinated ligands, respectively. The lability of the iron(II)–pyridine bonds also permits the spontaneous self-assembly of the [2]rotaxane upon the addition of cyclodextrin to the iron dimer complexes. The mechanism for this process involves the rate-determining dissociation of a [Fe(CN)5]3– unit from [(NC)5Fe(Ln)Fe(CN)5]6–, followed by CD inclusion of the Ln ligand to form a semirotaxane, and subsequent recomplexation by the [Fe(CN)5OH2]3– ion. Key words: cyclodextrins, rotaxanes, pentacyanoferrate(II), ligand substitution, kinetics.

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