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Niezabitowska E, Gray DM, Gallardo-Toledo E, Owen A, Rannard SP, McDonald TO. Understanding the Degradation of Core-Shell Nanogels Using Asymmetrical Flow Field Flow Fractionation. J Funct Biomater 2023; 14:346. [PMID: 37504841 PMCID: PMC10381601 DOI: 10.3390/jfb14070346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/16/2023] [Accepted: 06/28/2023] [Indexed: 07/29/2023] Open
Abstract
Nanogels are candidates for biomedical applications, and core-shell nanogels offer the potential to tune thermoresponsive behaviour with the capacity for extensive degradation. These properties were achieved by the combination of a core of poly(N-isopropylmethacrylamide) and a shell of poly(N-isopropylacrylamide), both crosslinked with the degradable crosslinker N,N'-bis(acryloyl)cystamine. In this work, the degradation behaviour of these nanogels was characterised using asymmetric flow field flow fractionation coupled with multi-angle and dynamic light scattering. By monitoring the degradation products of the nanogels in real-time, it was possible to identify three distinct stages of degradation: nanogel swelling, nanogel fragmentation, and nanogel fragment degradation. The results indicate that the core-shell nanogels degrade slower than their non-core-shell counterparts, possibly due to a higher degree of self-crosslinking reactions occurring in the shell. The majority of the degradation products had molecule weights below 10 kDa, which suggests that they may be cleared through the kidneys. This study provides important insights into the design and characterisation of degradable nanogels for biomedical applications, highlighting the need for accurate characterisation techniques to measure the potential biological impact of nanogel degradation products.
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Affiliation(s)
- Edyta Niezabitowska
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK
| | - Dominic M Gray
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK
| | - Eduardo Gallardo-Toledo
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L3 5TR, UK
- Centre of Excellence in Long-Acting Therapeutics (CELT), University of Liverpool, Liverpool L3 5TR, UK
| | - Andrew Owen
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L3 5TR, UK
- Centre of Excellence in Long-Acting Therapeutics (CELT), University of Liverpool, Liverpool L3 5TR, UK
| | - Steve P Rannard
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK
- Materials Innovation Factory, University of Liverpool, Liverpool L7 3NY, UK
| | - Tom O McDonald
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK
- Department of Materials, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
- Henry Royce Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
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Fehér B, Zhu K, Nyström B, Varga I, Pedersen JS. Effect of Temperature and Ionic Strength on Micellar Aggregates of Oppositely Charged Thermoresponsive Block Copolymer Polyelectrolytes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13614-13623. [PMID: 31577150 DOI: 10.1021/acs.langmuir.9b01896] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The self-assembly of two oppositely charged diblock copolymers that have a common thermosensitive nonionic block of poly(N-isopropylacrylamide) (pNIPAAM) has been investigated. The effect of the mixing ratio and total polymer concentrations on the self-assembly of the components and on the phase stability of the mixtures was studied by dynamic light scattering, electrophoretic mobility, and turbidimetry measurements in water at 20 °C. The effect of the competing electrostatic and hydrophobic interactions on the nanostructure of negatively charged electrostatically self-assembled micelles bearing a pNIPAAM corona was investigated by small-angle X-ray scattering (SAXS). The electrostatic and hydrophobic interactions were controlled independently by tuning the ionic strength (from pure water to 50 mM NaCl) and the temperature (20-50 °C) of the investigated mixtures. The SAXS data could be fitted by a spherical micelle model, which has a smoothly decaying radial profile and a Gaussian star term that describes the internal structure of the micellar structures and possible attractive interactions between the polymer chains. At high temperature, a cluster structure factor was included for describing the formation of bulky clusters of the formed micelles. At low temperature and ionic strength, the formation of micelles with a coacervate core and hydrated pNIPAAM shell was observed. The structural evolution of the self-assembled micelles with increasing ionic strength and temperature could be followed, and finally at high ionic strength and temperature, the formation of inverted micelles with a hydrophobic core and polyelectrolyte shell could be identified.
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Affiliation(s)
- Bence Fehér
- Institute of Chemistry , ELTE , Pázmány Péter sétány 1/A , Budapest 1117 , Hungary
- Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO) , Aarhus University , Gustav Wieds Vej 14 , 8000 Aarhus C , Denmark
| | - Kaizheng Zhu
- Department of Chemistry , University of Oslo , P.O. Box 1033, Blindern , N-0315 Oslo , Norway
| | - Bo Nyström
- Department of Chemistry , University of Oslo , P.O. Box 1033, Blindern , N-0315 Oslo , Norway
| | - Imre Varga
- Institute of Chemistry , ELTE , Pázmány Péter sétány 1/A , Budapest 1117 , Hungary
| | - Jan Skov Pedersen
- Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO) , Aarhus University , Gustav Wieds Vej 14 , 8000 Aarhus C , Denmark
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Rimmerman D, Leshchev D, Hsu DJ, Hong J, Abraham B, Henning R, Kosheleva I, Chen LX. Revealing Fast Structural Dynamics in pH-Responsive Peptides with Time-Resolved X-ray Scattering. J Phys Chem B 2019; 123:2016-2021. [PMID: 30763085 PMCID: PMC6533112 DOI: 10.1021/acs.jpcb.9b00072] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Many biomaterials can adapt to changes in the local biological environment (such as pH, temperature, or ionic composition) in order to regulate function or deliver a payload. Such adaptation to environmental perturbation is typically a hierarchical process that begins with a response at a local structural level and then propagates to supramolecular and macromolecular scales. Understanding fast structural dynamics that occur upon perturbation is important for rational design of functional biomaterials. However, few nanosecond time-resolved methods can probe both intra- and intermolecular scales simultaneously with a high structural resolution. Here, we utilize time-resolved X-ray scattering to probe nanosecond to microsecond structural dynamics of poly-l-glutamic acid undergoing protonation via a pH jump initiated by photoexcitation of a photoacid. Our results provide insights into the protonation-induced hierarchical changes in packing of peptide chains, formation of a helical structure, and the associated collapse of the peptide chain.
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Affiliation(s)
- Dolev Rimmerman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Denis Leshchev
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Darren J. Hsu
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Jiyun Hong
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Baxter Abraham
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Robert Henning
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Irina Kosheleva
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Lin X. Chen
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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Badasyan A, Mavrič A, Kralj Cigić I, Bencik T, Valant M. Polymer nanoparticle sizes from dynamic light scattering and size exclusion chromatography: the case study of polysilanes. SOFT MATTER 2018; 14:4735-4740. [PMID: 29796469 DOI: 10.1039/c8sm00780b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dynamic light scattering (DLS) and size exclusion chromatography (SEC) are among the most popular methods for determining polymer sizes in solution. Taking dendritic and network polysilanes as a group of least soluble polymer substances, we critically compare and discuss the difference between nanoparticle sizes, obtained by DLS and SEC. Polymer nanoparticles are typically in poor solution conditions below the theta point and are therefore in the globular conformation. The determination of particle sizes in the presence of attractive interactions is not a trivial task. The only possibility to measure, aggregation-free, the true molecular size of polymer nanoparticles in such a solution regime, is to perform the experiment with a dilute solution of globules (below the theta point and above the miscibility line). Based on the results of our polysilane measurements, we come to a conclusion that DLS provides more reliable results than SEC for dilute solutions of globules. General implications for the size measurements of polymer nanoparticles in solution are discussed.
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Affiliation(s)
- Artem Badasyan
- University of Nova Gorica, Materials Research Laboratory, Vipavska 13, SI-5000 Nova Gorica, Slovenia.
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Perevyazko I, Trützschler AK, Gubarev A, Lebedeva E, Traeger A, Schubert US, Tsvetkov N. Molecular and structural analysis via hydrodynamic methods: Cationic poly(2-aminoethyl-methacrylate)s. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.10.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Lutz-Bueno V, Liebi M, Kohlbrecher J, Fischer P. Intermicellar Interactions and the Viscoelasticity of Surfactant Solutions: Complementary Use of SANS and SAXS. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2617-2627. [PMID: 28221812 DOI: 10.1021/acs.langmuir.6b04466] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In ionic surfactant micelles, basic interactions among distinct parts of surfactant monomers, their counterion, and additives are fundamental to tuning molecular self-assembly and enhancing viscoelasticity. Here, we investigate the addition of sodium salicylate (NaSal) to hexadecyltrimethylammonium chloride and bromide (CTAC and CTAB) and 1-hexadecylpyridinium chloride and bromide (CPyCl and CPyBr), which have distinct counterions and headgroup structures but the same hydrophobic tail. Different contrasts are obtained from small-angle neutron scattering (SANS), which probes differences between the nucleus of atoms, and X-rays SAXS, which probes differences in electron density. If combined, this contrast allows us to define specific intramicellar length scales and intermicellar interactions. SANS signals are sensitive to the contrast between the solvent (D2O) and the hydrocarbonic tails in the micellar core (hydrogen), and SAXS can access the inner structure of the polar shell because the headgroups, counterions, and penetrated salt have higher electron densities compared to the solvent and to the micellar core. The number density, intermicellar distances, aggregation number, and inter/intramicellar repulsions are discussed on the basis of the dependence of the structure factor and form factor on the micellar aggregate morphology. Therefore, we confirm that micellar growth can be tuned by variations in the flexibility and size of the the headgroup as well as the ionic dissociation rate of its counterion. Additionally, we show that the counterion binding is even more significant to the development of viscoelasticity than the headgroup structure of a surfactant molecule. This is a surprising finding, showing the importance of electrostatic charges in the self-assembly process of ionic surfactant molecules.
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Affiliation(s)
- Viviane Lutz-Bueno
- Institute of Food, Nutrition and Health, ETH Zurich , 8092 Zurich, Switzerland
| | | | | | - Peter Fischer
- Institute of Food, Nutrition and Health, ETH Zurich , 8092 Zurich, Switzerland
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