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Anita J Hill - One of the best experts on this subject based on the ideXlab platform.
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effects of crowding and environment on the evolution of conformational ensembles of the multi stimuli responsive intrinsically disordered protein rec1 Resilin a small angle scattering investigation
Journal of Physical Chemistry B, 2016Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Namita Roy Choudhury, Jitendra P Mata, Robert B Knott, Naba K. DuttaAbstract:In this study, we explore the overall structural ensembles and transitions of a biomimetic, multi-stimuli-responsive, intrinsically disordered protein (IDP), Rec1-Resilin. The structural transition of Rec1-Resilin with change in molecular crowding and environment is evaluated using small-angle neutron scattering and small-angle X-ray scattering. The quantitative analyses of the experimental scattering data using a combination of computational models allowed comprehensive description of the structural evolution, organization, and conformational ensembles of Rec1-Resilin in response to the changes in concentration, pH, and temperature. Rec1-Resilin in uncrowded solutions demonstrates the equilibrium intrinsic structure quality of an IDP with radius of gyration Rg ∼ 5 nm, and a scattering function for the triaxial ellipsoidal model best fit the experimental dataset. On crowding (increase in concentration >10 wt %), Rec1-Resilin molecules exert intermolecular repulsive force of interaction, the Rg value reduc...
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Effects of Crowding and Environment on the Evolution of Conformational Ensembles of the Multi-Stimuli-Responsive Intrinsically Disordered Protein, Rec1-Resilin: A Small-Angle Scattering Investigation
2016Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Robert Knott, Jitendra P. Mata, Namita R. Choudhury, Naba K. DuttaAbstract:In this study, we explore the overall structural ensembles and transitions of a biomimetic, multi-stimuli-responsive, intrinsically disordered protein (IDP), Rec1-Resilin. The structural transition of Rec1-Resilin with change in molecular crowding and environment is evaluated using small-angle neutron scattering and small-angle X-ray scattering. The quantitative analyses of the experimental scattering data using a combination of computational models allowed comprehensive description of the structural evolution, organization, and conformational ensembles of Rec1-Resilin in response to the changes in concentration, pH, and temperature. Rec1-Resilin in uncrowded solutions demonstrates the equilibrium intrinsic structure quality of an IDP with radius of gyration Rg ∼ 5 nm, and a scattering function for the triaxial ellipsoidal model best fit the experimental dataset. On crowding (increase in concentration >10 wt %), Rec1-Resilin molecules exert intermolecular repulsive force of interaction, the Rg value reduces with a progressive increase in concentration, and molecular chains transform from a Gaussian coil to a fully swollen coil. It is also revealed that the structural organization of Rec1-Resilin dynamically transforms from a rod (pH 2) to coil (pH 4.8) and to globular (pH 12) as a function of pH. The findings further support the temperature-triggered dual-phase-transition behavior of Rec1-Resilin, exhibiting rod-shaped structural organization below the upper critical solution temperature (∼4 °C) and a large but compact structure above the lower critical solution temperature (∼75 °C). This work attempted to correlate unusual responsiveness of Rec1-Resilin to the evolution of conformational ensembles
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structural ensembles reveal intrinsic disorder for the multi stimuli responsive bio mimetic protein rec1 Resilin
Scientific Reports, 2015Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Namita Roy Choudhury, Robert Knott, Nathan P Cowieson, Naba K. DuttaAbstract:Rec1-Resilin is the first recombinant Resilin-mimetic protein polymer, synthesized from exon-1 of the Drosophila melanogaster gene CG15920 that has demonstrated unusual multi-stimuli responsiveness in aqueous solution. Crosslinked hydrogels of Rec1-Resilin have also displayed remarkable mechanical properties including near-perfect rubber-like elasticity. The structural basis of these extraordinary properties is not clearly understood. Here we combine a computational and experimental investigation to examine structural ensembles of Rec1-Resilin in aqueous solution. The structure of Rec1-Resilin in aqueous solutions is investigated experimentally using circular dichroism (CD) spectroscopy and small angle X-ray scattering (SAXS). Both bench-top and synchrotron SAXS are employed to extract structural data sets of Rec1-Resilin and to confirm their validity. Computational approaches have been applied to these experimental data sets in order to extract quantitative information about structural ensembles including radius of gyration, pair-distance distribution function, and the fractal dimension. The present work confirms that Rec1-Resilin is an intrinsically disordered protein (IDP) that displays equilibrium structural qualities between those of a structured globular protein and a denatured protein. The ensemble optimization method (EOM) analysis reveals a single conformational population with partial compactness. This work provides new insight into the structural ensembles of Rec1-Resilin in solution.
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an16 Resilin an advanced multi stimuli responsive Resilin mimetic protein polymer
Acta Biomaterialia, 2014Co-Authors: Rajkamal Balu, Naba K. Dutta, Christopher M Elvin, Namita Roy Choudhury, Russell E Lyons, Robert Knott, Anita J HillAbstract:Abstract Engineered protein polymers that display responsiveness to multiple stimuli are emerging as a promising class of soft material with unprecedented functionality. The remarkable advancement in genetic engineering and biosynthesis has created the opportunity for precise control over the amino acid sequence, size, structure and resulting functions of such biomimetic proteins. Herein, we describe the multi-stimuli-responsive characteristics of a Resilin-mimetic protein, An16-Resilin (An16), derived from the consensus sequence of Resilin gene in the mosquito Anopheles gambiae . We demonstrate that An16 is an intrinsically disordered protein that displays unusual dual-phase thermal transition behavior along with responsiveness to pH, ion, light and humidity. Identifying the molecular mechanisms that allow An16 to sense and switch in response to varying environments furthers the ability to design intelligent biomacromolecules.
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the effect of hydration on molecular chain mobility and the viscoelastic behavior of Resilin mimetic protein based hydrogels
Biomaterials, 2011Co-Authors: My Y Truong, Naba K. Dutta, Christopher M Elvin, Namita Roy Choudhury, Kate M Nairn, Anita J HillAbstract:The outstanding rubber-like elasticity of Resilin and Resilin-mimetic proteins depends critically on the level of hydration. In this investigation, water vapor sorption and the role of hydration on the molecular chain dynamics and viscoelastic properties of Resilin-mimetic protein, rec1-Resilin is investigated in detail. The dynamic and equilibrium swelling behavior of the crosslinked protein hydrogels with different crosslink density are reported under various controlled environments. We propose three different stages of hydration; involving non-crystallizable water, followed by condensation or clustering of water around the already hydrated sites, and finally crystallizable water. The kinetics of water sorption for this engineering protein is observed to be comparable to hydrophilic polymers with a diffusion coefficient in the range of 10−7 cm2 s−1. From the comparison between the absorption and desorption isotherms at a constant water activity, it has been observed that rec1-Resilin exhibits sorption hysteresis only for the tightly bound water. Investigation of molecular mobility using differential scanning calorimetry, indicates that dehydrated crosslinked rec1-Resilin is brittle with a glass transition temperature (Tg) of >180 °C, which dramatically decreases with increasing hydration; and above a critical level of hydration rec1-Resilin exhibits rubber-like elasticity. Nanoindentation studies show that even with little hydration (<10%), the mechanical properties of rec1-Resilin gels change dramatically. Rheological investigations confirm that the equilibrium-swollen crosslinked rec1-Resilin hydrogel exhibits outstanding elasticity and resilience of ∼92%, which exceeds that of any other synthetic polymer and biopolymer hydrogels.
Naba K. Dutta - One of the best experts on this subject based on the ideXlab platform.
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effects of crowding and environment on the evolution of conformational ensembles of the multi stimuli responsive intrinsically disordered protein rec1 Resilin a small angle scattering investigation
Journal of Physical Chemistry B, 2016Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Namita Roy Choudhury, Jitendra P Mata, Robert B Knott, Naba K. DuttaAbstract:In this study, we explore the overall structural ensembles and transitions of a biomimetic, multi-stimuli-responsive, intrinsically disordered protein (IDP), Rec1-Resilin. The structural transition of Rec1-Resilin with change in molecular crowding and environment is evaluated using small-angle neutron scattering and small-angle X-ray scattering. The quantitative analyses of the experimental scattering data using a combination of computational models allowed comprehensive description of the structural evolution, organization, and conformational ensembles of Rec1-Resilin in response to the changes in concentration, pH, and temperature. Rec1-Resilin in uncrowded solutions demonstrates the equilibrium intrinsic structure quality of an IDP with radius of gyration Rg ∼ 5 nm, and a scattering function for the triaxial ellipsoidal model best fit the experimental dataset. On crowding (increase in concentration >10 wt %), Rec1-Resilin molecules exert intermolecular repulsive force of interaction, the Rg value reduc...
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Effects of Crowding and Environment on the Evolution of Conformational Ensembles of the Multi-Stimuli-Responsive Intrinsically Disordered Protein, Rec1-Resilin: A Small-Angle Scattering Investigation
2016Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Robert Knott, Jitendra P. Mata, Namita R. Choudhury, Naba K. DuttaAbstract:In this study, we explore the overall structural ensembles and transitions of a biomimetic, multi-stimuli-responsive, intrinsically disordered protein (IDP), Rec1-Resilin. The structural transition of Rec1-Resilin with change in molecular crowding and environment is evaluated using small-angle neutron scattering and small-angle X-ray scattering. The quantitative analyses of the experimental scattering data using a combination of computational models allowed comprehensive description of the structural evolution, organization, and conformational ensembles of Rec1-Resilin in response to the changes in concentration, pH, and temperature. Rec1-Resilin in uncrowded solutions demonstrates the equilibrium intrinsic structure quality of an IDP with radius of gyration Rg ∼ 5 nm, and a scattering function for the triaxial ellipsoidal model best fit the experimental dataset. On crowding (increase in concentration >10 wt %), Rec1-Resilin molecules exert intermolecular repulsive force of interaction, the Rg value reduces with a progressive increase in concentration, and molecular chains transform from a Gaussian coil to a fully swollen coil. It is also revealed that the structural organization of Rec1-Resilin dynamically transforms from a rod (pH 2) to coil (pH 4.8) and to globular (pH 12) as a function of pH. The findings further support the temperature-triggered dual-phase-transition behavior of Rec1-Resilin, exhibiting rod-shaped structural organization below the upper critical solution temperature (∼4 °C) and a large but compact structure above the lower critical solution temperature (∼75 °C). This work attempted to correlate unusual responsiveness of Rec1-Resilin to the evolution of conformational ensembles
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structural ensembles reveal intrinsic disorder for the multi stimuli responsive bio mimetic protein rec1 Resilin
Scientific Reports, 2015Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Namita Roy Choudhury, Robert Knott, Nathan P Cowieson, Naba K. DuttaAbstract:Rec1-Resilin is the first recombinant Resilin-mimetic protein polymer, synthesized from exon-1 of the Drosophila melanogaster gene CG15920 that has demonstrated unusual multi-stimuli responsiveness in aqueous solution. Crosslinked hydrogels of Rec1-Resilin have also displayed remarkable mechanical properties including near-perfect rubber-like elasticity. The structural basis of these extraordinary properties is not clearly understood. Here we combine a computational and experimental investigation to examine structural ensembles of Rec1-Resilin in aqueous solution. The structure of Rec1-Resilin in aqueous solutions is investigated experimentally using circular dichroism (CD) spectroscopy and small angle X-ray scattering (SAXS). Both bench-top and synchrotron SAXS are employed to extract structural data sets of Rec1-Resilin and to confirm their validity. Computational approaches have been applied to these experimental data sets in order to extract quantitative information about structural ensembles including radius of gyration, pair-distance distribution function, and the fractal dimension. The present work confirms that Rec1-Resilin is an intrinsically disordered protein (IDP) that displays equilibrium structural qualities between those of a structured globular protein and a denatured protein. The ensemble optimization method (EOM) analysis reveals a single conformational population with partial compactness. This work provides new insight into the structural ensembles of Rec1-Resilin in solution.
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Tunable Thermoresponsiveness of Resilin via Coassembly with Rigid Biopolymers
2015Co-Authors: Jasmin L. Whittaker, Naba K. Dutta, Christopher M Elvin, Robert Knott, Gordon Mcphee, Nicolas H. Voelcker, Anita Hill, Namita Roy ChoudhuryAbstract:The ability to tune the thermoresponsiveness of recombinant Resilin protein, Rec1-Resilin, through a facile coassembly system was investigated in this study. The effects of change in conformation and morphology with time and the responsive behavior of Rec1-Resilin in solution were studied in response to the addition of a rigid model polypeptide (poly-l-proline) or a hydrophobic rigid protein (Bombyx mori silk fibroin). It was observed that by inducing more ordered conformations and increasing the hydrophobicity the lower critical solution temperature (LCST) of the system was tuned to lower values. Time and temperature were found to be critical parameters in controlling the coassembly behavior of Rec1-Resilin in both the model polypeptide and more complex protein systems. Such unique properties are useful for a wide range of applications, including drug delivery and soft tissue engineering applications
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an16 Resilin an advanced multi stimuli responsive Resilin mimetic protein polymer
Acta Biomaterialia, 2014Co-Authors: Rajkamal Balu, Naba K. Dutta, Christopher M Elvin, Namita Roy Choudhury, Russell E Lyons, Robert Knott, Anita J HillAbstract:Abstract Engineered protein polymers that display responsiveness to multiple stimuli are emerging as a promising class of soft material with unprecedented functionality. The remarkable advancement in genetic engineering and biosynthesis has created the opportunity for precise control over the amino acid sequence, size, structure and resulting functions of such biomimetic proteins. Herein, we describe the multi-stimuli-responsive characteristics of a Resilin-mimetic protein, An16-Resilin (An16), derived from the consensus sequence of Resilin gene in the mosquito Anopheles gambiae . We demonstrate that An16 is an intrinsically disordered protein that displays unusual dual-phase thermal transition behavior along with responsiveness to pH, ion, light and humidity. Identifying the molecular mechanisms that allow An16 to sense and switch in response to varying environments furthers the ability to design intelligent biomacromolecules.
Christopher M Elvin - One of the best experts on this subject based on the ideXlab platform.
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effects of crowding and environment on the evolution of conformational ensembles of the multi stimuli responsive intrinsically disordered protein rec1 Resilin a small angle scattering investigation
Journal of Physical Chemistry B, 2016Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Namita Roy Choudhury, Jitendra P Mata, Robert B Knott, Naba K. DuttaAbstract:In this study, we explore the overall structural ensembles and transitions of a biomimetic, multi-stimuli-responsive, intrinsically disordered protein (IDP), Rec1-Resilin. The structural transition of Rec1-Resilin with change in molecular crowding and environment is evaluated using small-angle neutron scattering and small-angle X-ray scattering. The quantitative analyses of the experimental scattering data using a combination of computational models allowed comprehensive description of the structural evolution, organization, and conformational ensembles of Rec1-Resilin in response to the changes in concentration, pH, and temperature. Rec1-Resilin in uncrowded solutions demonstrates the equilibrium intrinsic structure quality of an IDP with radius of gyration Rg ∼ 5 nm, and a scattering function for the triaxial ellipsoidal model best fit the experimental dataset. On crowding (increase in concentration >10 wt %), Rec1-Resilin molecules exert intermolecular repulsive force of interaction, the Rg value reduc...
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Effects of Crowding and Environment on the Evolution of Conformational Ensembles of the Multi-Stimuli-Responsive Intrinsically Disordered Protein, Rec1-Resilin: A Small-Angle Scattering Investigation
2016Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Robert Knott, Jitendra P. Mata, Namita R. Choudhury, Naba K. DuttaAbstract:In this study, we explore the overall structural ensembles and transitions of a biomimetic, multi-stimuli-responsive, intrinsically disordered protein (IDP), Rec1-Resilin. The structural transition of Rec1-Resilin with change in molecular crowding and environment is evaluated using small-angle neutron scattering and small-angle X-ray scattering. The quantitative analyses of the experimental scattering data using a combination of computational models allowed comprehensive description of the structural evolution, organization, and conformational ensembles of Rec1-Resilin in response to the changes in concentration, pH, and temperature. Rec1-Resilin in uncrowded solutions demonstrates the equilibrium intrinsic structure quality of an IDP with radius of gyration Rg ∼ 5 nm, and a scattering function for the triaxial ellipsoidal model best fit the experimental dataset. On crowding (increase in concentration >10 wt %), Rec1-Resilin molecules exert intermolecular repulsive force of interaction, the Rg value reduces with a progressive increase in concentration, and molecular chains transform from a Gaussian coil to a fully swollen coil. It is also revealed that the structural organization of Rec1-Resilin dynamically transforms from a rod (pH 2) to coil (pH 4.8) and to globular (pH 12) as a function of pH. The findings further support the temperature-triggered dual-phase-transition behavior of Rec1-Resilin, exhibiting rod-shaped structural organization below the upper critical solution temperature (∼4 °C) and a large but compact structure above the lower critical solution temperature (∼75 °C). This work attempted to correlate unusual responsiveness of Rec1-Resilin to the evolution of conformational ensembles
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structural ensembles reveal intrinsic disorder for the multi stimuli responsive bio mimetic protein rec1 Resilin
Scientific Reports, 2015Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Namita Roy Choudhury, Robert Knott, Nathan P Cowieson, Naba K. DuttaAbstract:Rec1-Resilin is the first recombinant Resilin-mimetic protein polymer, synthesized from exon-1 of the Drosophila melanogaster gene CG15920 that has demonstrated unusual multi-stimuli responsiveness in aqueous solution. Crosslinked hydrogels of Rec1-Resilin have also displayed remarkable mechanical properties including near-perfect rubber-like elasticity. The structural basis of these extraordinary properties is not clearly understood. Here we combine a computational and experimental investigation to examine structural ensembles of Rec1-Resilin in aqueous solution. The structure of Rec1-Resilin in aqueous solutions is investigated experimentally using circular dichroism (CD) spectroscopy and small angle X-ray scattering (SAXS). Both bench-top and synchrotron SAXS are employed to extract structural data sets of Rec1-Resilin and to confirm their validity. Computational approaches have been applied to these experimental data sets in order to extract quantitative information about structural ensembles including radius of gyration, pair-distance distribution function, and the fractal dimension. The present work confirms that Rec1-Resilin is an intrinsically disordered protein (IDP) that displays equilibrium structural qualities between those of a structured globular protein and a denatured protein. The ensemble optimization method (EOM) analysis reveals a single conformational population with partial compactness. This work provides new insight into the structural ensembles of Rec1-Resilin in solution.
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Tunable Thermoresponsiveness of Resilin via Coassembly with Rigid Biopolymers
2015Co-Authors: Jasmin L. Whittaker, Naba K. Dutta, Christopher M Elvin, Robert Knott, Gordon Mcphee, Nicolas H. Voelcker, Anita Hill, Namita Roy ChoudhuryAbstract:The ability to tune the thermoresponsiveness of recombinant Resilin protein, Rec1-Resilin, through a facile coassembly system was investigated in this study. The effects of change in conformation and morphology with time and the responsive behavior of Rec1-Resilin in solution were studied in response to the addition of a rigid model polypeptide (poly-l-proline) or a hydrophobic rigid protein (Bombyx mori silk fibroin). It was observed that by inducing more ordered conformations and increasing the hydrophobicity the lower critical solution temperature (LCST) of the system was tuned to lower values. Time and temperature were found to be critical parameters in controlling the coassembly behavior of Rec1-Resilin in both the model polypeptide and more complex protein systems. Such unique properties are useful for a wide range of applications, including drug delivery and soft tissue engineering applications
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an16 Resilin an advanced multi stimuli responsive Resilin mimetic protein polymer
Acta Biomaterialia, 2014Co-Authors: Rajkamal Balu, Naba K. Dutta, Christopher M Elvin, Namita Roy Choudhury, Russell E Lyons, Robert Knott, Anita J HillAbstract:Abstract Engineered protein polymers that display responsiveness to multiple stimuli are emerging as a promising class of soft material with unprecedented functionality. The remarkable advancement in genetic engineering and biosynthesis has created the opportunity for precise control over the amino acid sequence, size, structure and resulting functions of such biomimetic proteins. Herein, we describe the multi-stimuli-responsive characteristics of a Resilin-mimetic protein, An16-Resilin (An16), derived from the consensus sequence of Resilin gene in the mosquito Anopheles gambiae . We demonstrate that An16 is an intrinsically disordered protein that displays unusual dual-phase thermal transition behavior along with responsiveness to pH, ion, light and humidity. Identifying the molecular mechanisms that allow An16 to sense and switch in response to varying environments furthers the ability to design intelligent biomacromolecules.
David H. Pashley - One of the best experts on this subject based on the ideXlab platform.
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susceptibility of a polycaprolactone based root canal filling material to degradation using an agar well diffusion assay
American Journal of Dentistry, 2008Co-Authors: N Hiraishi, David H. Pashley, Marco Ferrari, N M King, Fernanda Tranchesi Sadek, Franklin R. TayAbstract:PURPOSE To examine whether Resilon, a polycaprolactone-based thermoplastic root filling material was susceptible to biodegradation by cholesterol esterase using agar-well diffusion assay of serially-diluted aqueous Resilon emulsions that were dispersed in agar. METHODS Emulsions of Resilon and polycaprolactone were prepared and dispersed in agar on culture plates. Two different concentrations of a cholesterol esterase (0.3 and 1.2 U/mL) were prepared and fed to wells prepared in the agar plates using an agar-well diffusion assay for examination of the degradation of polymeric materials. RESULTS Degradation of the emulsified Resilon was manifested as the formation of clear zones of different sizes around the agar wells. No clear zones were observed in agar wells that contain sterile distilled water as the negative control.
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evaluation of the quality of the apical seal in resilon epiphany and gutta percha ah plus filled root canals by using a fluid filtration approach
Journal of Endodontics, 2007Co-Authors: Rakesh Raina, Robert J. Loushine, Franklin R. Tay, Norman R Weller, David H. PashleyAbstract:This in vitro fluid filtration study compared the apical leakage of root canals that were obturated with Resilon/Epiphany (Resilon Research LLC, Madison, CT) or gutta-percha/AH Plus (GP/AH; DENTSPLY Tulsa, Tulsa, OK) sealer using warm vertical condensation. Fluid flow rate through the filled roots was measured 7 days after the obturations by using a fluid filtration device. Measurements were made before root resection and after 3 to 11 mm of resections. Before any removal of root length, there were no significant differences between the roots filled with Resilon/Epiphany or GP/AH. Analysis of individual root resection results revealed that differences in the fluid flow rate of the two systems occurred only when 9 or 10 mm of the roots were resected with more than half the root length resected when GP/AH Plus leaked more than Resilon/Epiphany. There were no significant differences in the fluid flow rate up to and including 8 mm of root resection. It is concluded Resilon/Epiphany sealed 17-mm root canals as well as gutta-percha and AH Plus sealer and that it does not create a monoblock root filling that does not leak.
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Susceptibility of a polycaprolactone-based root canal filling material to degradation. Evidence of biodegradation from a simulated field test.
American journal of dentistry, 2007Co-Authors: Franklin Chi Meng Tay, Robert J. Loushine, David H. Pashley, Sergio Kuttler, Franklin Garcia-godoy, Nigel M. King, Marco FerrariAbstract:PURPOSE To examine if Resilon, a polycaprolactone-based root filling material, was susceptible to microbial biodegradation by using a simulated field test that consisted of incubating the material in wet dental sludge under mesophilic and aerobic conditions. METHODS Pressed disks prepared from Resilon, polycaprolactone (positive control) and gutta-percha (negative control) were incubated in wet dental sludge for up to 4 months and examined for topographical changes using scanning electron microscopy. RESULTS Gutta-percha exhibited minimal changes in surface integrity, while polycaprolactone and Resilon exhibited severe surface pitting and erosion. In the latter, disappearance of the polymer matrix was accompanied by exposure of mineral and bioactive glass fillers. Bacteria and hyphae-like structures were present on the disk surfaces.
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an in vitro assessment of the sealing ability of resilon epiphany using fluid filtration
Journal of Endodontics, 2006Co-Authors: Stephen G Biggs, Kenneth I Knowles, Jose L Ibarrola, David H. PashleyAbstract:The aim of this in vitro study was to compare the sealing ability of Resilon/Epiphany to gutta-percha and Roth or AH Plus sealers. Leakage of the obturated roots was measured using the fluid filtration technique. There were eight groups of 12 teeth each. Group 1: obturated with Resilon/Epiphany; group 2: obturated with gutta-percha/Roth, allowed to set for 3 wk; group 3: obturated with gutta-percha/Roth; group 4: obturated with Resilon/Epiphany using a single cone; group 5: obturated with Resilon cones without using primer/sealer (positive control); group 6: obturated with gutta-percha/AH Plus; group 7: same as group 6, but allowed to set for 8 h; and group 8: sealed on the outside with three layers of nail varnish (negative control). The results showed that only the positive control (group 5) leaked significantly more (p < 0.05) than the other groups. There was no effect of time on leakage. Resilon/Epiphany was no better than gutta-percha/Roth or gutta-percha/AH Plus at sealing root canals.
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A Comparison of Cohesive Strength and Stiffness of Resilon and Gutta-Percha
Journal of Endodontics, 2006Co-Authors: Chad Williams, Robert J. Loushine, R. Norman Weller, David H. Pashley, Franklin R. TayAbstract:Abstract The purpose of this study was to compare the cohesive strength and stiffness of Resilon and gutta-percha under dry conditions and after 1 month of water storage to determine if they are stiff enough to reinforce roots. Dog-bone shaped specimens were created and pulled to failure at 3 mm/min in a Vitrodyne universal tester. The apparent modulus of elasticity, percent elongation, and yield stress were measured. Cohesive strength was defined as the yield stress. The data were analyzed using a two-way ANOVA for each outcome (α = 0.05). The results of this study show that the cohesive strength (that is the tensile stress when they begin to flow or break) and modulus of elasticity (or stiffness) of gutta-percha and Resilon are relatively low. Although the results showed statistically significant differences between the physical properties of gutta-percha and Resilon under varied conditions, these differences were not clinically significant. In conclusion, the stiffness of Resilon and gutta-percha is too low to reinforce roots after root canal therapy.
Namita Roy Choudhury - One of the best experts on this subject based on the ideXlab platform.
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effects of crowding and environment on the evolution of conformational ensembles of the multi stimuli responsive intrinsically disordered protein rec1 Resilin a small angle scattering investigation
Journal of Physical Chemistry B, 2016Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Namita Roy Choudhury, Jitendra P Mata, Robert B Knott, Naba K. DuttaAbstract:In this study, we explore the overall structural ensembles and transitions of a biomimetic, multi-stimuli-responsive, intrinsically disordered protein (IDP), Rec1-Resilin. The structural transition of Rec1-Resilin with change in molecular crowding and environment is evaluated using small-angle neutron scattering and small-angle X-ray scattering. The quantitative analyses of the experimental scattering data using a combination of computational models allowed comprehensive description of the structural evolution, organization, and conformational ensembles of Rec1-Resilin in response to the changes in concentration, pH, and temperature. Rec1-Resilin in uncrowded solutions demonstrates the equilibrium intrinsic structure quality of an IDP with radius of gyration Rg ∼ 5 nm, and a scattering function for the triaxial ellipsoidal model best fit the experimental dataset. On crowding (increase in concentration >10 wt %), Rec1-Resilin molecules exert intermolecular repulsive force of interaction, the Rg value reduc...
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structural ensembles reveal intrinsic disorder for the multi stimuli responsive bio mimetic protein rec1 Resilin
Scientific Reports, 2015Co-Authors: Rajkamal Balu, Christopher M Elvin, Anita J Hill, Namita Roy Choudhury, Robert Knott, Nathan P Cowieson, Naba K. DuttaAbstract:Rec1-Resilin is the first recombinant Resilin-mimetic protein polymer, synthesized from exon-1 of the Drosophila melanogaster gene CG15920 that has demonstrated unusual multi-stimuli responsiveness in aqueous solution. Crosslinked hydrogels of Rec1-Resilin have also displayed remarkable mechanical properties including near-perfect rubber-like elasticity. The structural basis of these extraordinary properties is not clearly understood. Here we combine a computational and experimental investigation to examine structural ensembles of Rec1-Resilin in aqueous solution. The structure of Rec1-Resilin in aqueous solutions is investigated experimentally using circular dichroism (CD) spectroscopy and small angle X-ray scattering (SAXS). Both bench-top and synchrotron SAXS are employed to extract structural data sets of Rec1-Resilin and to confirm their validity. Computational approaches have been applied to these experimental data sets in order to extract quantitative information about structural ensembles including radius of gyration, pair-distance distribution function, and the fractal dimension. The present work confirms that Rec1-Resilin is an intrinsically disordered protein (IDP) that displays equilibrium structural qualities between those of a structured globular protein and a denatured protein. The ensemble optimization method (EOM) analysis reveals a single conformational population with partial compactness. This work provides new insight into the structural ensembles of Rec1-Resilin in solution.
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Tunable Thermoresponsiveness of Resilin via Coassembly with Rigid Biopolymers
2015Co-Authors: Jasmin L. Whittaker, Naba K. Dutta, Christopher M Elvin, Robert Knott, Gordon Mcphee, Nicolas H. Voelcker, Anita Hill, Namita Roy ChoudhuryAbstract:The ability to tune the thermoresponsiveness of recombinant Resilin protein, Rec1-Resilin, through a facile coassembly system was investigated in this study. The effects of change in conformation and morphology with time and the responsive behavior of Rec1-Resilin in solution were studied in response to the addition of a rigid model polypeptide (poly-l-proline) or a hydrophobic rigid protein (Bombyx mori silk fibroin). It was observed that by inducing more ordered conformations and increasing the hydrophobicity the lower critical solution temperature (LCST) of the system was tuned to lower values. Time and temperature were found to be critical parameters in controlling the coassembly behavior of Rec1-Resilin in both the model polypeptide and more complex protein systems. Such unique properties are useful for a wide range of applications, including drug delivery and soft tissue engineering applications
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an16 Resilin an advanced multi stimuli responsive Resilin mimetic protein polymer
Acta Biomaterialia, 2014Co-Authors: Rajkamal Balu, Naba K. Dutta, Christopher M Elvin, Namita Roy Choudhury, Russell E Lyons, Robert Knott, Anita J HillAbstract:Abstract Engineered protein polymers that display responsiveness to multiple stimuli are emerging as a promising class of soft material with unprecedented functionality. The remarkable advancement in genetic engineering and biosynthesis has created the opportunity for precise control over the amino acid sequence, size, structure and resulting functions of such biomimetic proteins. Herein, we describe the multi-stimuli-responsive characteristics of a Resilin-mimetic protein, An16-Resilin (An16), derived from the consensus sequence of Resilin gene in the mosquito Anopheles gambiae . We demonstrate that An16 is an intrinsically disordered protein that displays unusual dual-phase thermal transition behavior along with responsiveness to pH, ion, light and humidity. Identifying the molecular mechanisms that allow An16 to sense and switch in response to varying environments furthers the ability to design intelligent biomacromolecules.
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the effect of hydration on molecular chain mobility and the viscoelastic behavior of Resilin mimetic protein based hydrogels
Biomaterials, 2011Co-Authors: My Y Truong, Naba K. Dutta, Christopher M Elvin, Namita Roy Choudhury, Kate M Nairn, Anita J HillAbstract:The outstanding rubber-like elasticity of Resilin and Resilin-mimetic proteins depends critically on the level of hydration. In this investigation, water vapor sorption and the role of hydration on the molecular chain dynamics and viscoelastic properties of Resilin-mimetic protein, rec1-Resilin is investigated in detail. The dynamic and equilibrium swelling behavior of the crosslinked protein hydrogels with different crosslink density are reported under various controlled environments. We propose three different stages of hydration; involving non-crystallizable water, followed by condensation or clustering of water around the already hydrated sites, and finally crystallizable water. The kinetics of water sorption for this engineering protein is observed to be comparable to hydrophilic polymers with a diffusion coefficient in the range of 10−7 cm2 s−1. From the comparison between the absorption and desorption isotherms at a constant water activity, it has been observed that rec1-Resilin exhibits sorption hysteresis only for the tightly bound water. Investigation of molecular mobility using differential scanning calorimetry, indicates that dehydrated crosslinked rec1-Resilin is brittle with a glass transition temperature (Tg) of >180 °C, which dramatically decreases with increasing hydration; and above a critical level of hydration rec1-Resilin exhibits rubber-like elasticity. Nanoindentation studies show that even with little hydration (<10%), the mechanical properties of rec1-Resilin gels change dramatically. Rheological investigations confirm that the equilibrium-swollen crosslinked rec1-Resilin hydrogel exhibits outstanding elasticity and resilience of ∼92%, which exceeds that of any other synthetic polymer and biopolymer hydrogels.