Controlling neuronal growth and connectivity via directed self-assembly of proteins

2013 ◽  
Vol 1498 ◽  
pp. 207-212
Author(s):  
Daniel Rizzo ◽  
Ross Beighley ◽  
James D. White ◽  
Cristian Staii
Keyword(s):  
Self Assembly ◽  
Gold Surface ◽  
Nerve Tissue ◽  
3 Dimensional ◽  
Force Microscopy ◽  
Self Assembling ◽  
Atomic Force ◽  
Will Self ◽  
Neuron Growth

ABSTRACTMaterials that offer the ability to influence tissue regeneration are of vital importance to the field of Tissue Engineering. Because valid 3-dimensional scaffolds for nerve tissue are still in development, advances with 2-dimensional surfaces in vitro are necessary to provide a complete understanding of controlling regeneration. Here we present a method for controlling nerve cell growth on Au electrodes using Atomic Force Microscopy -aided protein assembly. After coating a gold surface in a self-assembling monolayer of alkanethiols, the Atomic Force Microscope tip can be used to remove regions of the self-assembling monolayer in order to produce well-defined patterns. If this process is then followed by submersion of the sample into a solution containing neuro-compatible proteins, they will self assemble on these exposed regions of gold, creating well-specified regions for promoted neuron growth.

scholarly journals Nanosized Particles Assembled by a Recombinant Virus Protein Are Able to Encapsulate Negatively Charged Molecules and Structured RNA

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 858
Author(s):  
Hemalatha Mani ◽  
Yi-Cheng Chen ◽  
Yen-Kai Chen ◽  
Wei-Lin Liu ◽  
Shih-Yen Lo ◽  
...  
Keyword(s):  
Self Assembly ◽  
Rna Binding ◽  
Core Protein ◽  
Average Diameter ◽  
Virus Protein ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hcv Core Protein

RNA-based molecules have recently become hot candidates to be developed into therapeutic agents. However, successful applications of RNA-based therapeutics might require suitable carriers to protect the RNA from enzymatic degradation by ubiquitous RNases in vivo. Because of their better biocompatibility and biodegradability, protein-based nanoparticles are considered to be alternatives to their synthetic polymer-based counterparts for drug delivery. Hepatitis C virus (HCV) core protein has been suggested to be able to self-assemble into nucleocapsid-like particles in vitro. In this study, the genomic RNA-binding domain of HCV core protein consisting of 116 amino acids (p116) was overexpressed with E. coli for investigation. The recombinant p116 was able to assemble into particles with an average diameter of approximately 27 nm, as visualized by electron microscopy and atomic force microscopy. Measurements with fluorescence spectroscopy, flow cytometry, and fluorescence quenching indicated that the p116-assembled nanoparticles were able to encapsulate small anionic molecules and structured RNA. This study demonstrates methods that exploit the self-assembly nature of a virus-derived protein for nanoparticle production. This study also suggests that the virus-derived protein-assembled particles could possibly be developed into potential carriers for anionic molecular drugs and structured RNA-based therapeutics.

scholarly journals The Inhibitory Effect of Resveratrol on Elastin Amyloidogenesis

2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
Antonietta Pepe ◽  
Florian Delaunay ◽  
Angelo Bracalello ◽  
Brigida Bochicchio
Keyword(s):  
Molecular Structure ◽  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Inhibitory Effect ◽  
Degenerative Diseases ◽  
Force Microscopy ◽  
Atomic Force ◽  
Circular Dichroïsm

The role of polyphenols in the prevention of degenerative diseases is emerging in the last years. In this report, we will investigate in vitro the inhibitory effect of resveratrol on elastin amyloidogenesis. The effect of resveratrol on molecular structure was investigated by circular dichroism spectroscopy, while the inhibitory effect on self-assembly was evaluated by turbidimetry as a function of temperature and by atomic force microscopy.

scholarly journals Microstructural differences of fibrin and self-assembling peptide hydrogels in dental pulp stem cell behavior: the effect of chlorite-oxidized oxyamylose

2020 ◽  
Author(s):  
Mostafa EzEldeen ◽  
Burak Toprakhisar ◽  
Denise Murgia ◽  
Nick Smisdom ◽  
Olivier Deschaume ◽  
...  
Keyword(s):  
Dental Pulp ◽  
Microstructural Stability ◽  
Microscopy Imaging ◽  
Force Microscopy ◽  
Regenerative Endodontics ◽  
Self Assembling ◽  
Atomic Force ◽  
Peptide Hydrogels

Abstract Tailored hydrogels mimicking the native extracellular environment could aid in overcoming the high variability in regenerative endodontics outcomes. This study aimed to evaluate the effect of the chemokine-binding and antimicrobial polymer, chlorite-oxidized oxyamylose (COAM), on the microstructural properties of fibrin and self-assembling peptide (SAP) hydrogels. Further, to assess the influence of the microstructural differences between the hydrogels on the in vitro behavior of dental pulp stem cells (DPSCs).Structural and mechanical characterization of the hydrogels with and without COAM was performed by atomic force microscopy and scanning electron microscopy to characterize their microstructure (roughness and fiber length, diameter, straightness and alignment) and by nanoindentation to measure their stiffness (elastic modulus). DPSCs were encapsulated in hydrogels with and without COAM. Cell viability and circularity was determined using confocal microscopy imaging, and proliferation was determined using DNA quantification. Inclusion of COAM did not alter the microstructure of the fibrin hydrogels at the fiber level, while affecting the SAP hydrogel microstructure (homogeneity) leading to fiber aggregation. The stiffness of the SAP hydrogels was 7-fold higher than the fibrin hydrogels. The viability and attachment of DPSCs and DNA content was significantly higher in fibrin hydrogels than in SAP hydrogels. The microstructural stability after COAM inclusion and the favorable DPSCs’ response observed in fibrin hydrogels suggest this system as a promising carrier for COAM and for application in endodontic regeneration.

Self-assembling layers created by membrane proteins on gold

2007 ◽  
Vol 35 (3) ◽  
pp. 522-526 ◽  
Author(s):  
D.S. Shah ◽  
M.B. Thomas ◽  
S. Phillips ◽  
D.A. Cisneros ◽  
A.P. Le Brun ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Self Assembly ◽  
Three Dimensions ◽  
Membrane Systems ◽  
Electrical Measurements ◽  
Supported Bilayers ◽  
Force Microscopy ◽  
Planar Surfaces ◽  
Self Assembling ◽  
Atomic Force

Membrane systems are based on several types of organization. First, amphiphilic lipids are able to create monolayer and bilayer structures which may be flat, vesicular or micellar. Into these structures membrane proteins can be inserted which use the membrane to provide signals for lateral and orientational organization. Furthermore, the proteins are the product of highly specific self-assembly otherwise known as folding, which mostly places individual atoms at precise places in three dimensions. These structures all have dimensions in the nanoscale, except for the size of membrane planes which may extend for millimetres in large liposomes or centimetres on planar surfaces such as monolayers at the air/water interface. Membrane systems can be assembled on to surfaces to create supported bilayers and these have uses in biosensors and in electrical measurements using modified ion channels. The supported systems also allow for measurements using spectroscopy, surface plasmon resonance and atomic force microscopy. By combining the roles of lipids and proteins, highly ordered and specific structures can be self-assembled in aqueous solution at the nanoscale.

scholarly journals Chlorite oxidized oxyamylose differentially influences the microstructure of fibrin and self assembling peptide hydrogels as well as dental pulp stem cell behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mostafa EzEldeen ◽  
Burak Toprakhisar ◽  
Denise Murgia ◽  
Nick Smisdom ◽  
Olivier Deschaume ◽  
...  
Keyword(s):  
Dental Pulp ◽  
Microstructural Stability ◽  
Force Microscopy ◽  
Regenerative Endodontics ◽  
Self Assembling ◽  
Atomic Force ◽  
Human Dental Pulp ◽  
Peptide Hydrogels

AbstractTailored hydrogels mimicking the native extracellular environment could help overcome the high variability in outcomes within regenerative endodontics. This study aimed to evaluate the effect of the chemokine-binding and antimicrobial polymer, chlorite-oxidized oxyamylose (COAM), on the microstructural properties of fibrin and self-assembling peptide (SAP) hydrogels. A further goal was to assess the influence of the microstructural differences between the hydrogels on the in vitro behavior of human dental pulp stem cells (hDPSCs). Structural and mechanical characterization of the hydrogels with and without COAM was performed by atomic force microscopy and scanning electron microscopy to characterize their microstructure (roughness and fiber length, diameter, straightness, and alignment) and by nanoindentation to measure their stiffness (elastic modulus). Then, hDPSCs were encapsulated in hydrogels with and without COAM. Cell viability and circularity were determined using confocal microscopy, and proliferation was determined using DNA quantification. Inclusion of COAM did not alter the microstructure of the fibrin hydrogels at the fiber level while affecting the SAP hydrogel microstructure (homogeneity), leading to fiber aggregation. The stiffness of the SAP hydrogels was sevenfold higher than the fibrin hydrogels. The viability and attachment of hDPSCs were significantly higher in fibrin hydrogels than in SAP hydrogels. The DNA content was significantly affected by the hydrogel type and the presence of COAM. The microstructural stability after COAM inclusion and the favorable hDPSCs' response observed in fibrin hydrogels suggest this system as a promising carrier for COAM and application in endodontic regeneration.

scholarly journals Exploring the Self-Assembly of Encapsulin Protein Nanocages from Different Structural Classes

2021 ◽  
Author(s):  
India Boyton ◽  
Sophia C Goodchild ◽  
Dennis Diaz ◽  
Aaron Elbourne ◽  
Lyndsey Collins-Praino ◽  
...  
Keyword(s):  
Self Assembly ◽  
Structural Integrity ◽  
Guanidine Hydrochloride ◽  
Significant Loss ◽  
Spectroscopic Techniques ◽  
Design Modification ◽  
Force Microscopy ◽  
Future Design ◽  
Self Assembling ◽  
Atomic Force

Encapsulins, self-assembling icosahedral protein nanocages derived from prokaryotes, represent a versatile set of tools for nanobiotechnology. However, a comprehensive understanding of the mechanisms underlying encapsulin self-assembly, disassembly, and reassembly is lacking. Here, we characterise the disassembly/reassembly properties of three encapsulin nanocages that possess different structural architectures: T = 1 (24 nm), T = 3 (32 nm), and T = 4 (42 nm). Using spectroscopic techniques and electron microscopy, encapsulin architectures were found to exhibit varying sensitivities to the denaturant guanidine hydrochloride (GuHCl), extreme pH, and elevated temperature. While all encapsulins showed the capacity to reassemble following GuHCl-induced disassembly (within 75 min), only the smallest T = 1 nanocage reassembled after disassembly in basic pH (within 15 min). Furthermore, atomic force microscopy revealed that all encapsulins show a significant loss of structural integrity after undergoing sequential disassembly/reassembly steps. These findings provide insights into encapsulins disassembly/reassembly dynamics, thus informing their future design, modification, and application.

Combinatorial Approach to Materials Fabrication from Higher Hierarchies of Rosette Nanotubes

2007 ◽  
Vol 1057 ◽  
Author(s):  
Grigory Tikhomirov ◽  
Hicham Fenniri
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Combinatorial Approach ◽  
X Ray ◽  
Force Microscopy ◽  
Rosette Nanotubes ◽  
Self Assembling ◽  
Atomic Force ◽  
Transmission Electron

ABSTRACTThe self-assembly of six self-complimentary Guanine – Cytosine hybrid heterocycles bearing hydrophobic substituents has been studied using combinatorial approach in eight solvents under different conditions. The parameters that were varied include: the structure of the self-assembling module, its concentration, the solvent, temperature, and time of self-assembly. scanning electron microscopy (SEM) was used as a screening tool. A wide variety of interesting morphologies was found. The most interesting structures were studied by atomic force microscopy (AFM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray powder diffraction (XRD).

scholarly journals Hydroxyapatite Formation Coexists with Amyloid-like Self-Assembly of Human Amelogenin

2020 ◽  
Vol 21 (8) ◽  
pp. 2946 ◽  
Author(s):  
Jing Zhang ◽  
Jian Wang ◽  
Chengwei Ma ◽  
Junxia Lu
Keyword(s):  
Self Assembly ◽  
Tooth Enamel ◽  
Protein Assembly ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dynamic Components ◽  
The Right

Tooth enamel is formed in an extracellular environment. Amelogenin, the major component in the protein matrix of tooth enamel during the developing stage, could assemble into high molecular weight structures, regulating enamel formation. However, the molecular structure of amelogenin protein assembly at the functional state is still elusive. In this work, we found that amelogenin is able to induce calcium phosphate minerals into hydroxyapatite (HAP) structure in vitro at pH 6.0. Assessed using X-ray diffraction (XRD) and 31P solid-state NMR (SSNMR) evidence, the formed HAP mimics natural enamel closely. The structure of amelogenin protein assembly coexisting with the HAP was also studied using atomic force microscopy (AFM), transmission electron microscopy (TEM) and XRD, indicating the β-amyloid structure of the protein. SSNMR was proven to be an important tool in detecting both the rigid and dynamic components of the protein assembly in the sample, and the core sequence 18EVLTPLKWYQSI29 was identified as the major segment contributing to the β-sheet secondary structure. Our research suggests an amyloid structure may be an important factor in controlling HAP formation at the right pH conditions with the help of other structural components in the protein assembly.

Peptides Co-Assembling into Hydrangea-Like Microstructures

2020 ◽  
Vol 20 (5) ◽  
pp. 3239-3245
Author(s):  
Zhen Guo ◽  
Zhiwei Shen ◽  
Yujiao Wang ◽  
Tingyuan Tan ◽  
Yi Zhang
Keyword(s):  
Self Assembly ◽  
Hydrophobic Interactions ◽  
Supramolecular Assembly ◽  
Force Microscopy ◽  
Peptide Assembly ◽  
Atomic Force ◽  
Potential Applications ◽  
Cellular Microenvironments ◽  
Functional Biomaterials

Supramolecular assembly in vitro is a simple and effective way to produce multi-level biostructures to mimic the self-assembly of biomolecules in organisms. The study on peptide assembly behaviors would benefit a lot to understand what goes on in life, as well as in the construction of plenty of functional biomaterials that have potential applications in various fields. Since cellular microenvironments are crowded and contain various biomolecules, studying protein and peptide co-assembly is of great interest. Here, we introduced the co-assembly of 5-FAM-ELVFFAE-NH2 (EE-7) and (CY5)-KLVFFAK-NH2 (KK-7), which are sequences derived from the core of the amyloid β (Aβ) peptide, a key protein in Alzheimer’s diseases. Morphologic studies employing atomic force microscopy and scanning electron microscopy indicated that the co-assembled entities had a novel hydrangea-like microstructure, in contrast to micro-sheet structures formed from monocomponent EE-7 or KK-7, respectively. Fluorescence co-localization experiments confirmed that the hydrangealike microstructures were indeed made of both EE-7 and KK-7. We suggest that the formation of the hydrangea-like microstructures is driven by both the electrostatic and hydrophobic interactions between EE-7 and KK-7. A molecular mechanism has been provided to explain the formation of the hydrangea-like microstructures.

Atomic Force Microscopy Studies of Alkyl-Phosphonate SAMs on Mica

2008 ◽  
Vol 589 ◽  
pp. 257-262 ◽  
Author(s):  
A. Paszternák ◽  
A. Pilbáth ◽  
Z. Keresztes ◽  
Ilona Felhősi ◽  
J. Telegdi ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Ethanol Solution ◽  
Layer Formation ◽  
Mica Surface ◽  
Phosphonic Acids ◽  
Force Microscopy ◽  
Alkyl Chains ◽  
Self Assembling ◽  
Atomic Force

The layer formation of phosphonic acids on mica surface as a model system, from aqueous and ethanol solutions has been investigated. The aggregation behavior (critical micelle concentration, cmc) of molecules in the solution phase has been determined by surface tension measurements in order to select the appropriate concentration for the layer formation experiments. Layer formation of self-assembling molecules of alkyl-phosphonic acids has been followed by atomic force microscopy (AFM). Nucleation, growth and coalescence of densely packed islands of phosphonates from ethanol solution have been recorded on mica surface. The structure of islands depends on the length of alkyl-chains. Self-assembly of phosphonates has been also observed from aqueous solution, as presented by octyl-phosphonic acid (OcPA). The height of OcPA islands is 1.46 􀁲 0.22 nm, which is practically equal with the length of molecule (1.4 nm). This shows that OcPA molecules form monolayer height domains on the mica surface.

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