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Bakirov A, Kopishev E, Kadyrzhan K, Donbaeva E, Zhaxybayeva A, Duisembiyev M, Suyundikova F, Suleimenov I. The Method of Direct and Reverse Phase Portraits as a Tool for Systematizing the Results of Studies of Phase Transitions in Solutions of Thermosensitive Polymers. Gels 2024; 10:395. [PMID: 38920941 PMCID: PMC11203281 DOI: 10.3390/gels10060395] [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: 04/21/2024] [Revised: 05/29/2024] [Accepted: 06/07/2024] [Indexed: 06/27/2024] Open
Abstract
It is shown that a more than significant amount of experimental data obtained in the field of studying systems based on thermosensitive hydrophilic polymers and reflected in the literature over the past decades makes the issue of their systematization and classification relevant. This, in turn, makes relevant the question of choosing the appropriate classification criteria. It is shown that the basic classification feature can be the number of phase transition stages, which can vary from one to four or more depending on the nature of the temperature-sensitive system. In this work, the method of inverse phase portraits is proposed for the first time. It was intended, among other things, to identify the number of phase transition stages. Moreover, the accuracy of this method significantly exceeds the accuracy of the previously used method of direct phase portraits since, for the first time, the operation of numerical differentiation is replaced by the operation of numerical integration. A specific example of the application of the proposed method for the analysis of a previously studied temperature-sensitive system is presented. It is shown that this method also allows for a quantitative comparison between the results obtained by the differential calorimetry method and the turbidimetry method. Issues related to increasing the resolution of the method of direct phase portraits are discussed.
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Affiliation(s)
- Akhat Bakirov
- Department of Chemistry and Technology of Organic Substances, Natural Compounds and Polymers, Faculty of Chemistry and Chemical Technology, Al Farabi Kazakh National University, Almaty 050040, Kazakhstan;
- Department of Telecommunication Engineering, Institute of Communications and Space Engineering, Gumarbek Daukeev Almaty University of Power Engineering and Communications, Almaty 050040, Kazakhstan;
| | - Eldar Kopishev
- Department of Chemistry, Faculty of Natural Sciences, L.N. Gumilyov Eurasian National University, Astana 010000, Kazakhstan; (E.D.); (A.Z.); (M.D.); (F.S.)
| | - Kaisarali Kadyrzhan
- Department of Telecommunication Engineering, Institute of Communications and Space Engineering, Gumarbek Daukeev Almaty University of Power Engineering and Communications, Almaty 050040, Kazakhstan;
| | - Elvira Donbaeva
- Department of Chemistry, Faculty of Natural Sciences, L.N. Gumilyov Eurasian National University, Astana 010000, Kazakhstan; (E.D.); (A.Z.); (M.D.); (F.S.)
| | - Aigerim Zhaxybayeva
- Department of Chemistry, Faculty of Natural Sciences, L.N. Gumilyov Eurasian National University, Astana 010000, Kazakhstan; (E.D.); (A.Z.); (M.D.); (F.S.)
| | - Marat Duisembiyev
- Department of Chemistry, Faculty of Natural Sciences, L.N. Gumilyov Eurasian National University, Astana 010000, Kazakhstan; (E.D.); (A.Z.); (M.D.); (F.S.)
| | - Faiziya Suyundikova
- Department of Chemistry, Faculty of Natural Sciences, L.N. Gumilyov Eurasian National University, Astana 010000, Kazakhstan; (E.D.); (A.Z.); (M.D.); (F.S.)
| | - Ibragim Suleimenov
- National Engineering Academy of the Republic of Kazakhstan, Almaty 050010, Kazakhstan
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Hassler JF, Lawson M, Arroyo EC, Bates FS, Hackel BJ, Lodge TP. Discovery of Kinetic Trapping of Poloxamers inside Liposomes via Thermal Treatment. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:14263-14274. [PMID: 37755825 PMCID: PMC10853007 DOI: 10.1021/acs.langmuir.3c01499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
Poloxamers, a class of biocompatible, commercially available amphiphilic block polymers (ABPs) comprising poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) blocks, interact with phospholipid bilayers, resulting in altered mechanical and surface properties. These block copolymers are useful in a variety of applications including therapeutics for Duchenne muscular dystrophy, as cell membrane stabilizers, and for drug delivery, as liposome surface modifying agents. Hydrogen bonding between water and oxygen atoms in PEO and PPO units results in thermoresponsive behavior because the bound water shell around both blocks dehydrates as the temperature increases. This motivated an investigation of poloxamer-lipid bilayer interactions as a function of temperature and thermal history. In this study, we applied pulsed-field-gradient NMR spectroscopy to measure the fraction of chains bound to 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) liposomes between 10 and 50 °C. We measured an (11 ± 3)-fold increase in binding affinity at 37 °C relative to 27 °C. Moreover, following incubation at 37 °C, it takes weeks for the system to re-equilibrate at 25 °C. Such slow desorption kinetics suggests that at elevated temperatures polymer chains can pass through the bilayer and access the interior of the liposomes, a mechanism that is inaccessible at lower temperatures. We propose a molecular mechanism to explain this effect, which could have important ramifications on the cellular distribution of ABPs and could be exploited to modulate the mechanical and surface properties of liposomes and cell membranes.
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White JM, Crabtree AA, Bates FS, Calabrese MA. Effect of chain architecture on the structure, dynamics, and rheology of thermoresponsive poloxamer hydrogels and associated blends. Macromolecules 2023; 56:6834-6847. [PMID: 38774522 PMCID: PMC11104561 DOI: 10.1021/acs.macromol.3c01107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2024]
Abstract
Poloxamers, ABA triblock polymers composed of a poly(propylene oxide) (PPO) midblock (B) and poly(ethylene oxide) (PEO) endblocks (A), are widely studied for biomedical applications. Aqueous poloxamer 407 (P407; also referred to as F127) undergoes a solution-to-gel transition with increasing temperature, driven by the formation and ordering of micelles onto periodic lattices; however, the gel temperature and resulting modulus has limited tunability. Here, reverse P407 (RP407), a BAB polymer of the same composition and molar mass but the inverted architecture, is synthesized via anionic polymerization. The micellization and gelation temperatures of RP407 are higher than that of P407 and the PPO endblocks allow for intermicelle bridging; however, both single-component solutions favor body-centered cubic (BCC) packings. Further, aqueous RP407 displays a "soft gel" region with interesting rheological behavior, including viscoelastic aging and thermal hysteresis. Combining P407 and RP407 yields solutions with intermediate transition temperatures and alters the size and micelle packing. While the single-component solutions produce BCC packings, the blends form close-packed structures and larger micelles of higher aggregation numbers. Blends of P407 with an analogous AB diblock (E111P32) display similar behavior, whereas RP407/diblock blends form intermediate-sized BCC-packed micelles. These differences in packing and aggregation alter the local environments within the gels, which could have implications for applications such as drug delivery and protein stabilization.
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Affiliation(s)
- Joanna M White
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN, 55455
| | - Adelyn A Crabtree
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN, 55455
| | - Frank S Bates
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN, 55455
| | - Michelle A Calabrese
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN, 55455
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Crabtree A, Boehnke N, Bates F, Hackel B. Consequences of poly(ethylene oxide) and poloxamer P188 on transcription in healthy and stressed myoblasts. Proc Natl Acad Sci U S A 2023; 120:e2219885120. [PMID: 37094151 PMCID: PMC10161009 DOI: 10.1073/pnas.2219885120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 03/26/2023] [Indexed: 04/26/2023] Open
Abstract
Poly(ethylene oxide) (PEO) and poloxamers, a class of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers, have many personal and medical care applications, including the stabilization of stressed cellular membranes. Despite the widespread use, the cellular transcriptional response to these molecules is relatively unknown. C2C12 myoblasts, a model muscle cell, were subjected to short-term Poloxamer 188 (P188) and PEO181 (8,000 g/mol) treatment in culture. RNA was extracted and sequenced to quantify transcriptomic impact. The addition of moderate concentrations (14 µM) of either polymer to unstressed cells caused substantial differential gene expression, including at least twofold modulation of 357 and 588 genes, respectively. In addition, evaluation of the transcriptome response to osmotic stress without polymer treatment revealed dramatic change in RNA expression. Interestingly, the addition of polymer to stressed cells-at concentrations that provide physiological protection-did not yield a significant difference in expression of any gene relative to stress alone. Genome-scale expression analysis was corroborated by single-gene quantitative real-time PCR. Changes in protein expression were measured via western blot, which revealed partial alignment with the RNA results. Collectively, the significant changes to expression of multiple genes and resultant protein translation demonstrates an unexpectedly broad biochemical response to these polymers in healthy myoblasts in vitro. Meanwhile, the lack of substantial transcriptional response to polymer treatment in stressed cells highlights the physical nature of that protective mechanism.
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Affiliation(s)
- Adelyn A. Crabtree
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN55455
| | - Natalie Boehnke
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN55455
| | - Frank S. Bates
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN55455
| | - Benjamin J. Hackel
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN55455
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Hassler JF, Crabtree A, Liberman L, Bates FS, Hackel BJ, Lodge TP. Effect of Bottlebrush Poloxamer Architecture on Binding to Liposomes. Biomacromolecules 2023; 24:449-461. [PMID: 36563027 DOI: 10.1021/acs.biomac.2c01274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Poloxamers─triblock copolymers consisting of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO)─have demonstrated cell membrane stabilization efficacy against numerous types of stress. However, the mechanism responsible for this stabilizing effect remains elusive, hindering engineering of more effective therapeutics. Bottlebrush polymers have a wide parameter space and known relationships between architectural parameters and polymer properties, enabling their use as a tool for mechanistic investigations of polymer-lipid bilayer interactions. In this work, we utilized a versatile synthetic platform to create novel bottlebrush analogues to poloxamers and then employed pulsed-field-gradient NMR and an in vitro osmotic stress assay to explore the effect of bottlebrush architectural parameters on binding to, and protection of, model phospholipid bilayers. We found that the binding affinity of a bottlebrush poloxamer (BBP) (B-E1043P515, Mn ≈ 26 kDa) is about 3 times higher than a linear poloxamer with a similar composition and number of PPO units (L-E93P54E93, Mn ≈ 11 kDa). Furthermore, BBP binding is sensitive to overall molecular weight, side-chain length, and architecture (statistical versus block). Finally, all tested BBPs exhibit a protective effect on cell membranes under stress at sub-μM concentrations. As the factors controlling membrane affinity and protection efficacy of bottlebrush poloxamers are not understood, these results provide important insight into how they adhere to and stabilize a lipid bilayer surface.
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