1
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Development and characterization of chitosan/gelatin electrosprayed microparticles as food grade delivery vehicles for anthocyanin extracts. Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2017.11.011] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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2
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Gómez-Mascaraque LG, Llavata-Cabrero B, Martínez-Sanz M, Fabra MJ, López-Rubio A. Self-assembled gelatin-ι-carrageenan encapsulation structures for intestinal-targeted release applications. J Colloid Interface Sci 2018; 517:113-123. [PMID: 29421671 DOI: 10.1016/j.jcis.2018.01.101] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 01/29/2018] [Accepted: 01/29/2018] [Indexed: 11/26/2022]
Abstract
In this work, natural biopolymeric encapsulation structures were developed through the self-assembly of gelatin and ι-carrageenan in aqueous solutions. The interactions of this binary system and of a ternary system containing a polyphenol-rich extract were deeply explored for the development of intestinal delivery systems. The processing of the structures (extrusion vs. freeze-drying) greatly influenced release properties, explained by the specific interactions between gelatin and polyphenols, thus allowing for tuning the processing conditions depending on the desired target application. Release was further controlled by incorporating a divalent salt, giving raise to extract-loaded ι-carrageenan/gelatin capsules with adequate release profiles for intestinal targeted delivery. These results demonstrate the potential of exploiting biopolymer interactions for designing bioactive delivery systems using environmentally friendly processes which do not involve the use of toxic or harsh solvents or cross-linkers.
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Affiliation(s)
- Laura G Gómez-Mascaraque
- Food Safety and Preservation Department, IATA-CSIC, Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Beatriz Llavata-Cabrero
- Food Safety and Preservation Department, IATA-CSIC, Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Marta Martínez-Sanz
- Food Safety and Preservation Department, IATA-CSIC, Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - María José Fabra
- Food Safety and Preservation Department, IATA-CSIC, Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Amparo López-Rubio
- Food Safety and Preservation Department, IATA-CSIC, Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain.
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3
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Wisotzki EI, Tempesti P, Fratini E, Mayr SG. Influence of high energy electron irradiation on the network structure of gelatin hydrogels as investigated by small-angle X-ray scattering (SAXS). Phys Chem Chem Phys 2017; 19:12064-12074. [DOI: 10.1039/c7cp00195a] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Small-angle X-ray scattering revealed ranging structural differences in physically entangled and irradiation-crosslinked gelatin hydrogels.
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Affiliation(s)
- Emilia I. Wisotzki
- Leibniz Institute of Surface Modification (IOM)
- Permoserstrasse 15
- 04318 Leipzig
- Germany
- Faculty of Physics and Earth Science
| | - Paolo Tempesti
- Department of Chemistry “Ugo Schiff” and CSGI
- University of Florence
- via della Lastruccia 3
- Sesto Fiorentino (FI)
- Italy
| | - Emiliano Fratini
- Department of Chemistry “Ugo Schiff” and CSGI
- University of Florence
- via della Lastruccia 3
- Sesto Fiorentino (FI)
- Italy
| | - Stefan G. Mayr
- Leibniz Institute of Surface Modification (IOM)
- Permoserstrasse 15
- 04318 Leipzig
- Germany
- Faculty of Physics and Earth Science
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4
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Liu Y, Winter HH, Perry SL. Linear viscoelasticity of complex coacervates. Adv Colloid Interface Sci 2017; 239:46-60. [PMID: 27633928 DOI: 10.1016/j.cis.2016.08.010] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/31/2016] [Accepted: 08/31/2016] [Indexed: 01/15/2023]
Abstract
Rheology is a powerful method for material characterization that can provide detailed information about the self-assembly, structure, and intermolecular interactions present in a material. Here, we review the use of linear viscoelastic measurements for the rheological characterization of complex coacervate-based materials. Complex coacervation is an electrostatically and entropically-driven associative liquid-liquid phase separation phenomenon that can result in the formation of bulk liquid phases, or the self-assembly of hierarchical, microphase separated materials. We discuss the need to link thermodynamic studies of coacervation phase behavior with characterization of material dynamics, and provide parallel examples of how parameters such as charge stoichiometry, ionic strength, and polymer chain length impact self-assembly and material dynamics. We conclude by highlighting key areas of need in the field, and specifically call for the development of a mechanistic understanding of how molecular-level interactions in complex coacervate-based materials affect both self-assembly and material dynamics.
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Affiliation(s)
- Yalin Liu
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - H Henning Winter
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Sarah L Perry
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA.
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5
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Pathak J, Rawat K, Aswal VK, Bohidar HB. Hierarchical Internal Structures in Gelatin-Bovine Serum Albumin/β-Lactoglobulin Gels and Coacervates. J Phys Chem B 2016; 120:9506-12. [PMID: 27526229 DOI: 10.1021/acs.jpcb.6b05378] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, we report the comparative study of gels and complex coacervates of bovine serum albumin (BSA) and beta-lactoglobulin (β-Lg) with gelatin close to their common pI. Surface patch binding produced a range of new soft matter phases (interpolymer complexes) such as opaque coacervates (charge neutralized complexes) and transparent gels (overcharged complexes). We emphasize on the comparative study of the microstructure of coacervates and gels formed at different mixing ratios using small angle scattering (SANS) data. It was found that phase states were entirely defined by the mixing ratio r = [GB]:[β-Lg or BSA]. Thermo-viscoelastic profiles of aforesaid samples revealed a smaller storage modulus and lower melting temperature for coacervates compared to gels. Thermally activated samples generated additional phases that were also probed by SANS and rheology. Thus, it is established that intermolecular association between globular proteins and a random coil polypeptide can generate various soft matter states that may facilitate harvesting of novel biomaterials.
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Affiliation(s)
- Jyotsana Pathak
- School of Physical Sciences, Jawaharlal Nehru University , New Delhi 110067, India
| | - Kamla Rawat
- Special Center for Nanosciences, Jawaharlal Nehru University , New Delhi 110067, India.,Inter University Accelerator Centre , New Delhi 110067, India
| | - V K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre , Mumbai 400 085, India
| | - H B Bohidar
- School of Physical Sciences, Jawaharlal Nehru University , New Delhi 110067, India.,Special Center for Nanosciences, Jawaharlal Nehru University , New Delhi 110067, India
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Yang Z, Hemar Y, Hilliou L, Gilbert EP, McGillivray DJ, Williams MAK, Chaieb S. Nonlinear Behavior of Gelatin Networks Reveals a Hierarchical Structure. Biomacromolecules 2015; 17:590-600. [DOI: 10.1021/acs.biomac.5b01538] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Zhi Yang
- School
of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Yacine Hemar
- School
of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Institute
of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
- The Riddet Institute, Palmerston North 4442, New Zealand
| | - Loic Hilliou
- Institute
for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal
| | - Elliot P. Gilbert
- Bragg
Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Duncan J. McGillivray
- School
of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Institute
of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
- The MacDiarmid Institute, Palmerston
North 4442, New Zealand
| | - Martin A. K. Williams
- Institute
of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
- The Riddet Institute, Palmerston North 4442, New Zealand
- The MacDiarmid Institute, Palmerston
North 4442, New Zealand
| | - Sahraoui Chaieb
- Division
of Physical Sciences and Engineering, King Abdullah University of Sciences and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
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7
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Derkach SR. Interfacial layers of complex-forming ionic surfactants with gelatin. Adv Colloid Interface Sci 2015; 222:172-98. [DOI: 10.1016/j.cis.2014.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/14/2014] [Accepted: 05/15/2014] [Indexed: 11/30/2022]
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8
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Pathak J, Rawat K, Aswal VK, Bohidar HB. Hierarchical surface charge dependent phase states of gelatin-bovine serum albumin dispersions close to their common pI. J Phys Chem B 2014; 118:11161-71. [PMID: 25171436 DOI: 10.1021/jp5068846] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report interaction between bovine serum albumin ([BSA] = 1% (w/v)) and gelatin B ([GB] = 0.25-3.5% (w/v)) occurring close to their common isoelectric pH (pI). This interaction generated distinguishable multiple soft matter phases like opaque coacervates (phase I) and transparent gels (phase II), where the former are composed of partially charge neutralized intermolecular complexes (zeta potential, ζ ≤ 0) and the latter of overcharged complexes (ζ ≥ 0) that organized into a network pervading the entire sample volume. These phase states were completely governed by the protein mixing ratio r = [GB]:[BSA]. Coacervates, when heated above 32 °C, produced thermoirreversible turbid gels (phase III), stable in the region 32 ≥ T ≤ 50 °C. When the transparent gels were heated to T ≥ 34 °C, these turned into turbid solutions that did form a turbid fragile gel (phase IV) upon cooling. Mechanical and thermal behaviors of aforesaid coacervates (phase I) and gels (phase II) were examined; coacervates had lower storage modulus and melting temperature compared to gels. Cole-Cole plots attributed considerable heterogeneity to coacervate phase, but gels were relatively homogeneous. Raman spectroscopy data suggested differential microenvironment for these phases. Coacervates were mostly hydrated by partially structured water with degree of hydration dependent on gelatin concentration whereas for gels hydration was invariant of [GB]. Small-angle neutron scattering (SANS) data gave static structure factor profiles, I(q), versus wavevector q, that were remarkably different. For transparent gels, data could be split into two distinct regions: (i) 0.01 < q < 0.1 Å(-1), I(q) = IOZ(0)/(1 + q(2)ζgel(2))(2) (Debye-Bueche function) with ζgel = 9-13 nm, and (ii) 0.1 < q < 0.35 Å(-1), I(q) = IOZ(0)/(1 + q(2)ξgel(2)) (Ornstein-Zernike function) with ξgel = 3.1 ± 0.6 nm. Similarly, for coacervate, the aforesaid two q-regions were described by (i) I(q) = IPL(0)q(-α) with α = 1.7 ± 0.1 and (ii) I(q) = IOZ(0)/(1 + q(2)ξcoac(2)) with ξcoac = 1.6 ± 0.2 nm, a value close to the persistence length of gelatin chain (lp ≈ 2 nm). Phase transition from one equilibrium state to another, i.e., phase I to II, was hierarchical in the charge state of the protein-protein complex. Within the same charge state, transition from phase I to III and from phase II to IV was thermally activated. The aforesaid mechanisms are captured in a unique ζ-T phase diagram.
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Affiliation(s)
- Jyotsana Pathak
- Polymer and Biophysics Laboratory, School of Physical Sciences, and ‡Special Center for Nanosciences, Jawaharlal Nehru University , New Delhi 110067, India
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9
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Derkach SR. WITHDRAWN: Interfacial layers of complex-forming ionic surfactants with gelatin. Adv Colloid Interface Sci 2014:S0001-8686(14)00194-8. [PMID: 24997869 DOI: 10.1016/j.cis.2014.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 05/14/2014] [Indexed: 10/25/2022]
Abstract
The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/ 10.1016/j.cis.2014.05.001. The duplicate article has therefore been withdrawn.
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Affiliation(s)
- Svetlana R Derkach
- Murmansk State Technical University, 13, Sportivnaya str., Murmansk 13183010, Russia.
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10
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Melnyk A, Wolska L, Namieśnik J. Coacervative extraction as a green technique for sample preparation for the analysis of organic compounds. J Chromatogr A 2014; 1339:1-12. [DOI: 10.1016/j.chroma.2014.02.082] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Revised: 02/10/2014] [Accepted: 02/26/2014] [Indexed: 11/28/2022]
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11
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Bode F, da Silva MA, Smith P, Lorenz CD, McCullen S, Stevens MM, Dreiss CA. Hybrid processes in enzymatically gelled gelatin: impact on , macroscopic properties and cellular response. SOFT MATTER 2013; 9:6986-6999. [PMID: 25310528 DOI: 10.1039/c3sm00125c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Physical, chemical and hybrid tilapia fish gelatin hydrogels were investigated by small-angle neutron scattering (), molecular dynamic simulations and their biological effect in cell cultures studied; results from the different experimental techniques were then correlated and linked to the rheological properties of the gels (F. Bode et al., Biomacromolecules, 2011, 12, 3741-3752). Hydrogels were obtained by cross-linking with the microbial enzyme transglutaminase (mTGase) under two conditions: above and below gelatin physical temperature (ca. 23 °C). Hydrogels cross-linked at 37 °C, from the sol-state, are referred to as 'chemical' gels (C); hydrogels cross-linked at 21 °C, thus with concurrent physical , are referred to as 'physical-co-chemical' gels (PC). The data were appropriately described by a combination of a Lorentzian and a power law model. For physical gels, the correlation length (ξ) obtained from the fits decreased linearly with gelatin concentration, from 42 to 26 Å for 3.5 to 10% w/w gelatin, respectively. Independently of temperature, all physical gels at a given concentration showed a similar correlation length ξ (26 ± 2 Å), with no significant difference with the sol-state (23 ± 2 Å). In both C and PC gels, ξ increased with mTGase concentration over the range studied: 40 to 167 Å for 10 and 40 U mTGase per g gelatin in C gels (after 120 min cross-linking) and 40 to 82 Å for 10 and 40 U mTGase per g gelatin for PC gels. ξ reached a plateau at the highest mTGase concentration studied for both types of gels. In addition, kinetic studies on C gels revealed that ξ increased linearly with time in the first two hours and grew faster with increasing mTGase concentration. ξ values in the PC gels were smaller than in the corresponding C gels. Cell proliferation studies showed that the gels were compatible with cell growth and indicated no statistically relevant dependence on mTGase concentration for C gels. For PC gels, cell proliferation decreased with increases in mTGase concentration, by approximately 80% from 10 to 40 U mTGase per g gelatin. With the exception of the highest mTGase concentration studied, PC gels overall showed a slightly (but statistically significant) higher cell proliferation than the corresponding chemical gels.
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Affiliation(s)
- Franziska Bode
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK.
| | - Marcelo Alves da Silva
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK.
| | - Paul Smith
- Theory & Simulation of Condensed Matter Group, Department of Physics, King's College London, Strand, London WC2R 2LS, UK
| | - Christian D Lorenz
- Theory & Simulation of Condensed Matter Group, Department of Physics, King's College London, Strand, London WC2R 2LS, UK
| | - Seth McCullen
- Department of Materials, Department of Bioengineering and Institute for Biomedical Engineering, Imperial College London, Exhibition Road, London SW72AZ, UK
| | - Molly M Stevens
- Department of Materials, Department of Bioengineering and Institute for Biomedical Engineering, Imperial College London, Exhibition Road, London SW72AZ, UK
| | - Cécile A Dreiss
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK.
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12
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Rawat K, Aswal VK, Bohidar HB. DNA–Gelatin Complex Coacervation, UCST and First-Order Phase Transition of Coacervate to Anisotropic ion gel in 1-Methyl-3-octylimidazolium Chloride Ionic Liquid Solutions. J Phys Chem B 2012. [DOI: 10.1021/jp3102089] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Kamla Rawat
- Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - V. K. Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400094, India
| | - H. B. Bohidar
- Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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13
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Anisotropic domain growth and complex coacervation in nanoclay-polyelectrolyte solutions. Adv Colloid Interface Sci 2011; 167:12-23. [PMID: 21763636 DOI: 10.1016/j.cis.2011.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 06/14/2011] [Accepted: 06/19/2011] [Indexed: 11/23/2022]
Abstract
In this review, the generalized domain growth in a coacervating solution is discussed. Associative electrostatic interaction between nanoclay (Laponite) and gelatin-A (a polyelectrolyte) is shown to drive complex coacervation at room temperature (25°C). Phase separation kinetics, leading to spontaneous coacervation transition occurring below spinodal temperature (315K) was studied by depolarized dynamic light scattering. Depolarization and axial ratio data clearly revealed that the domains formed of soluble complexes undergo time-dependent anisotropic growth during the initial period of phase separation (t<500s). The equatorial axis of these domains was observed to grow following a power-law behavior: a(t)~t(β) and β=0.25 ± 0.04 independent of quench depth that was not deep. In contrast, the polar axis shrunk with time following: b(t)~t(-δ) and δ=0.15 ± 0.05 independent of quench depth. These domains preferentially grew as oblate ellipsoids during this time. Effect of gravity on domain growth was not observed in our experiments. These results answer the basic issue of binding between discotic colloidal particles and polyelectrolytes in dispersion phase and the resultant phase separation kinetics.
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Santinath Singh S, Aswal VK, Bohidar HB. Internal structures of agar-gelatin co-hydrogels by light scattering, small-angle neutron scattering and rheology. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2011; 34:62. [PMID: 21706280 DOI: 10.1140/epje/i2011-11062-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 05/16/2011] [Accepted: 05/30/2011] [Indexed: 05/31/2023]
Abstract
Internal structures of agar-gelatin co-hydrogels were investigated as a function of their volumetric mixing ratio, [Formula: see text] , 1.0 and 2.0 using dynamic light scattering (DLS), small-angle neutron scattering (SANS) and rheology. The degree of non-ergodicity ( X = 0.2 ± 0.02) , which was extracted as a heterodyne contribution from the measured dynamic structure factor data remained less than that of homogeneous solutions where ergodicity is expected (X = 10. The static structure factor, I(q) , results obtained from SANS were interpreted in the Guinier regime (low-q , which implied the existence of ≈ 250 nm long rod-like structures (double-helix bundles), and the power law (intermediate-q regions) yielded I (q) ~ q(−α) with α = 2.3 , 1.8 and 1.6 for r = 0.5 , 1.0 and 2.0. This is indicative of the presence of Gaussian chains at low r , while at r = 2 there was a propensity of rod-shaped structures. The gel strength and transition temperatures measured from frequency sweep and temperature ramp studies were suggestive of the presence of a stronger association between the two biopolymer networks at higher r . The results indicate that the internal structures of agar-gelatin co-hydrogels were highly dependent on the volumetric mixing ratio.
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Affiliation(s)
- S Santinath Singh
- Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India.
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15
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Kizilay E, Maccarrone S, Foun E, Dinsmore AD, Dubin PL. Cluster Formation in Polyelectrolyte−Micelle Complex Coacervation. J Phys Chem B 2011; 115:7256-63. [DOI: 10.1021/jp109788r] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ebru Kizilay
- Department of Chemistry and ‡Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Simona Maccarrone
- Department of Chemistry and ‡Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Elaine Foun
- Department of Chemistry and ‡Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Anthony D. Dinsmore
- Department of Chemistry and ‡Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Paul L. Dubin
- Department of Chemistry and ‡Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
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16
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Aimé C, Rietveld IB, Coradin T. Hydrazine-induced thermo-reversible optical shifts in silver–gelatin bionanocomposites. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.02.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Saxena A, Kaloti M, Bohidar H. Rheological properties of binary and ternary protein–polysaccharide co-hydrogels and comparative release kinetics of salbutamol sulphate from their matrices. Int J Biol Macromol 2011; 48:263-70. [DOI: 10.1016/j.ijbiomac.2010.11.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/11/2010] [Accepted: 11/16/2010] [Indexed: 10/18/2022]
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18
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19
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Dowling MB, Lee JH, Raghavan SR. pH-responsive jello: gelatin gels containing fatty acid vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:8519-8525. [PMID: 19317424 DOI: 10.1021/la804159g] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We describe a new way to impart pH-responsive properties to gels of biopolymers such as gelatin. This approach involves the embedding of pH-sensitive nanosized vesicles within the gel. The vesicles employed here are those of sodium oleate (NaOA), a fatty-acid-based amphiphile with a single C18 tail. In aqueous solution, NaOA undergoes a transition from vesicles at a pH approximately 8 to micelles at a pH higher than approximately 10. Here, we combine NaOA and gelatin at pH 8.3 to create a vesicle-loaded gel and then bring the gel in contact with a pH 10 buffer solution. As the buffer diffuses into the gel, the vesicles within the gel get transformed into micelles. Accordingly, a vesicle-micelle front moves through the gel, and this can be visually identified by the difference in turbidity between the two regions. Vesicle disruption can also be done in a spatially selective manner to create micelle-rich domains within a vesicle-loaded gel. A possible application of the above approach is in the area of pH-dependent controlled release. A vesicle-to-micelle transition releases hydrophilic solutes encapsulated within the vesicles into the bulk gel, and in turn these solutes can rapidly diffuse out of the gel into the external bath. Experiments with calcein dye confirm this concept and show that we can indeed use the pH in the bath to tune the release rate of solutes from vesicle-loaded gels.
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Affiliation(s)
- Matthew B Dowling
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742-2111, USA
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20
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Leick S, Degen P, Köhler B, Rehage H. Film formation and surface gelation of gelatin molecules at the water/air interface. Phys Chem Chem Phys 2009; 11:2468-74. [DOI: 10.1039/b819708c] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Chodankar S, Aswal VK, Kohlbrecher J, Vavrin R, Wagh AG. Structural study of coacervation in protein-polyelectrolyte complexes. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 78:031913. [PMID: 18851071 DOI: 10.1103/physreve.78.031913] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 07/07/2008] [Indexed: 05/26/2023]
Abstract
Coacervation is a dense liquid-liquid phase separation and herein we report coacervation of protein bovine serum albumin (BSA) in the presence of polyelectrolyte sodium polystyrene sulfonate (NaPSS) under varying solution conditions. Small-angle neutron scattering (SANS) measurements have been performed on above protein-polyelectrolyte complexes to study the structural evolution of the process that leads to coacervation and the phase separated coacervate as a function of solution pH , protein-polyelectrolyte ratio and ionic strength. SANS study prior to phase separation on the BSA-NaPSS complex shows a fractal structure representing a necklace model of protein macromolecules randomly distributed along the polystyrene sulfonate chain. The fractal dimension of the complex decreases as pH is shifted away from the isoelectric point ( approximately 4.7) of BSA protein, which indicates the decrease in the compactness of the complex structure due to increase in the charge repulsion between the protein macromolecules bound to the polyelectrolyte. Concentration-dependence studies of the polyelectrolyte in the complex suggest coexistence of two populations of polyelectrolytes, first one fully saturated with proteins and another one free from proteins. Coacervation phase has been obtained through the turbidity measurement by varying pH of the aqueous solution containing protein and polyelectrolyte from neutral to acidic regime to get them to where the two components are oppositely charged. The spontaneous formation of coacervates is observed for pH values less than 4. SANS study on coacervates shows two length scales related to complex aggregations (mesh size and overall extent of the complex) hierarchically branched to form a larger network. The mesh size represents the distance between cross-linked points in the primary complex, which decreases with increase in ionic strength and remains the same on varying the protein-polyelectrolyte ratio. On the other hand, the overall extent of the complex shows a similar structure irrespective of varying ionic strength and protein-polyelectrolyte ratio. A large fraction ( approximately 50%) of protein-polyelectrolyte complexes is also found to be free in the supernatant after the coacervation.
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Affiliation(s)
- S Chodankar
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400 085, India
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Gupta AN, Bohidar HB. Temporal evolution of self-organization of gelatin molecules and clusters on quartz surface. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:051912. [PMID: 18233692 DOI: 10.1103/physreve.76.051912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Indexed: 05/25/2023]
Abstract
Aqueous gelatin solutions when spread on hydrophilic substrates form self-organized structures where the gelatin molecules and clusters are arranged as self-similar objects giving a mass fractal dimension df=1.67 and 1.72 for solutions made with KCl and NaCl salts as estimated from atomic force microscopic studies. The dehydration driven self-organization of particles changed the df values to 1.78 and 1.81, respectively, after 24 h. This further changed to 1.83 and 1.85 after a time lapse of 10 days. The dynamics of formation of these structures are modeled through spin-exchange kinetics in the nonequilibrium steady state regime in order to understand their complex behavior. Kawasaki spin exchange dynamics has been applied to a diffusion limited aggregation type fractal object, and the growth of the domains was observed by minimizing the free energy. The fractal dimension of such a system changed from 1.70 to 1.82 which inferred the loss of fractal behavior and the generation of a more compact object. The experimentally observed temporal evolution of these complex structures could be adequately described through the results obtained from the computer simulation data.
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Affiliation(s)
- Amar Nath Gupta
- Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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Gupta AN, Bohidar HB, Aswal VK. Surface patch binding induced intermolecular complexation and phase separation in aqueous solutions of similarly charged gelatin-chitosan molecules. J Phys Chem B 2007; 111:10137-45. [PMID: 17676887 DOI: 10.1021/jp070745s] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The formation of selective surface patch binding induced complex coacervates between polyions, chitosan (cationic polyelectrolyte), and alkali-processed gelatin (polyampholyte), both carrying similar net charge, was investigated for two volumetric mixing ratios: r = [chitosan]/[gelatin] = 1:5 and 1:10. Formation of soluble intermolecular complexes between gelatin and chitosan molecules was observed in a narrow range of pH, though these biopolymers had the same kind of net charge, which was evidenced from electrophoretic measurement. This clearly established the role played by selective surface patch binding driven interactions. The temperature sweep measurements conducted on these coacervate samples through rheology and differential scanning calorimetry (DSC) studies yielded two characteristic melting temperatures located at approximately 68 +/- 3 degrees C and 82 +/- 3 degrees C. In the flow mode, the shear viscosity (eta) of the coacervate samples was found to scale with (power-law model) applied shear rate (gamma*) as eta(gamma*) approximately (gamma*)(-k); this yielded k = 0.76 +/- 0.2 (1 s(-1) < gamma* < 100 s(-1)), indicating non-Newtonian behavior. The static structure factor (I(q)) deduced from small angle neutron scattering (SANS) data in the low q (q is the scattering wavevector) (0.018 A(-1) < q < 0.072 A(-1)) region was fitted to the Debye-Bueche regime, I(q) approximately 1/(1 + zeta(2)q(2))2 that yielded a size of zeta approximately 215 +/- 20 A (for r = 1:10) and zeta approximately 260 +/- 20 A (for r = 1:5) samples, implying change in the size of inhomogeneities present with mixing ratio. In the intermediate q region, called the Ornstein-Zernike regime, I(q) approximately 1/(1 + xi(2)q(2)) gave a correlation length of xi approximately 10.0 +/- 2.0 A independent of the mixing ratio. The results taken together imply the existence of a weakly interconnected and heterogeneous network structure inside the coacervate phase separated by domains of polymer-poor regions.
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Affiliation(s)
- Amar Nath Gupta
- Polymer and Biophysics Lab, School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110 067, India
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Singh SS, Aswal VK, Bohidar HB. Structural studies of agar–gelatin complex coacervates by small angle neutron scattering, rheology and differential scanning calorimetry. Int J Biol Macromol 2007; 41:301-7. [PMID: 17481725 DOI: 10.1016/j.ijbiomac.2007.03.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2007] [Revised: 03/10/2007] [Accepted: 03/23/2007] [Indexed: 11/20/2022]
Abstract
Agar-gelatin complex coacervates are studied by small angle neutron scattering (SANS), rheology (in both flow and temperature scan modes) and differential scanning calorimetry (DSC) in order to probe the microscopic structure of this dense protein-polysaccharide-rich phase. DSC and isochronal temperature sweep (rheology) experiments yielded a characteristic temperature at approximately 35+/-2 degrees C. Rheology data revealed a second characteristic temperature at approximately 75+/-5 degrees C which was absent in DSC thermograms. In the flow mode, shear viscosity (eta) was found to scale with (Carreau model) applied shear rate (gamma ) as: eta(gamma ) approximately (gamma )(-k) with k=1.2+/-0.2 indicating non-Newtonian and shear-thinning features independent of ionic strength. The static structure factor S(q) deduced from SANS data in the low wave vector (0.018 A(-1)<q<0.072 A(-1)) region was fitted to Debye-Bueche function, S(q) approximately 1/(1+zeta(2)q(2))(2) that yielded a size zeta approximately 220+/-20 A identified with the size of the inhomogeneities present. In the high-q region, called the Ornstein-Zernike regime, S(q) approximately 1/(1+xi(2)q(2)) gave correlation length xi approximately 12+/-2A. The results taken together imply the existence of a weakly interconnected and heterogeneous network structure inside the coacervate phase. Structural features of this material are compared with those of agar and gelatin gel, and gelatin coacervate.
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Affiliation(s)
- S Santinath Singh
- Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110016, India
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Mohanty B, Gupta A, Bohidar HB, Bandyopadhyay S. Effect of gelatin molecular charge heterogeneity on formation of intermolecular complexes and coacervation transition. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/polb.21120] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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