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Cationic amino-acid functionalized polymethacrylamide vectors for siRNA transfection based on modification of poly(2-isopropenyl-2-oxazoline). J Control Release 2023; 364:687-699. [PMID: 37935258 DOI: 10.1016/j.jconrel.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/01/2023] [Accepted: 11/02/2023] [Indexed: 11/09/2023]
Abstract
Poly(2-isopropenyl-2-oxazoline) (PiPOx) is a functional polymer showing great potential for the development of smart biomaterials. The straightforward synthesis and post-polymerization functionalization of PiPOx offers many opportunities for tailoring the properties of the polymer towards biomaterials. In this study we report for the first time PiPOx-based cationic charged polymethacrylamides with amino acid side chains that can complex siRNA and promote transfection in vitro. Therefore, PiPOx was fully modified via ring opening addition reactions with the carboxylic acid groups of a series of N-Boc-L-amino acids and their reaction kinetics were investigated. Based on the determined kinetic constants, another series of PiPOx-based copolymers with balanced hydrophilic/hydrophobic content of N-Boc-L-amino acids were obtained via one-pot modification reaction with two different N-Boc-L-amino acids. The N-Boc protected homopolymers and related copolymers were deprotected to obtain (co)polymers with the targeted side chain cationic charged units. The (co)polymers' structures were fully investigated via FT-IR and 1H NMR spectroscopy, size exclusion chromatography (SEC), and TGA-DSC-MS analysis. The polarimetry measurements revealed that the homopolymers retain their chiroptical properties after post-modification, and a sign inversion is noticed from (L) N-Boc-protected analogues to (D) for the TFA cationic charged homopolymers. Generally, cationically charged homopolymers with hydrophilic amino acids on the side chain showed efficient complexation of siRNA, but poor transfection while cationic copolymers having both tryptophan and valine or proline side chains revealed moderate siRNA binding, high transfection efficiency (> 90% of the cells) and potent gene silencing with IC50 values down to 5.5 nM. Particularly, these cationic copolymers showed higher gene silencing potency as compared to the commercial JetPRIME® reference, without reducing cell viability in the concentration range used for transfection, making this a very interesting system for in vitro siRNA transfection.
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Detailed Understanding of Solvent Effects for the Cationic Ring-Opening Polymerization of 2-Ethyl-2-oxazoline. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c01930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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3
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Abstract
The synthesis of poly(N-allyl acrylamide) (PNAllAm) as a platform for the preparation of functional hydrogels is described. The PNAllAm was synthesized via organocatalyzed amidation of poly(methyl acrylate) (PMA) with allylamine and characterized by 1H NMR spectroscopy, size exclusion chromatography (SEC), and turbidimetry, which allowed an estimation of the lower critical solution temperature of ∼26 °C in water. The PNAllAm was then used to make functional hydrogels via photoinitiated thiol-ene chemistry, where dithiothreitol (DTT) was used to cross-link the polymer chains. In addition, mercaptoethanol (ME) was added as a functional thiol to modulate the hydrogel properties. A decrease of the volume-phase transition temperature of the resulting hydrogels was observed with increasing ME content. Altogether this work introduces a straightforward way for the preparation of PNAllAm from PMA and demonstrates its value as a reactive polymer platform for the generation of functional hydrogels.
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Self‐healing Hydrogels by Metal Complexation of 2,6‐bis(1,2,3‐triazol‐4yl)pyridine Functionalized Tetra‐arm Star Poly(ethylene glycol). MACROMOL CHEM PHYS 2022. [DOI: 10.1002/macp.202200330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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5
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In Vitro Assessment of the Hydrolytic Stability of Poly(2-isopropenyl-2-oxazoline). Biomacromolecules 2021; 22:5020-5032. [PMID: 34753285 DOI: 10.1021/acs.biomac.1c00994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Poly(2-isopropenyl-2-oxazoline) (PiPOx) is emerging as a promising, versatile polymer platform to design functional materials and particularly biomaterials that rely on the hydrophilic character of the 2-oxazoline side units. To be able to assess the applicability of PiPOx in a biomedical context, it is essential to understand its stability and degradation behavior in physiological conditions. In the present work, the hydrolytic stability of PiPOx was systematically investigated as a function of pH during incubation in various buffers. PiPOx was found to be stable in deionized water (pH 6.9), to have good stability in basic conditions (pH 8 and 9), to be satisfactorily stable in neutral conditions (pH 7.4), and to have moderate to low stability in acidic conditions (decreases drastically from pH 6 to pH 1.2). At pH 4, PiPOx formed a crosslinked network in a timeframe of hours, while at pH 1.2, PiPOx was transformed to a water-soluble poly(N-(2-hydroxyethyl)methacrylamide) type of structure over the course of 2 weeks. In vitro stability assays were performed in phosphate-buffered saline (pH 7.4), simulated body fluid (SBF) (pH 7.4), simulated saliva (pH 6.4), simulated intestinal fluid (pH 6.8), and plasma (pH 7.4) revealing that PiPOx is stable in these SBFs up to 1 week of incubation. When incubated in simulated gastric fluid (pH 1.2), PiPOx exhibited a similar degradation behavior to that observed in the buffer at pH 1.2, rendering a water-soluble structure. The presented results on the stability of PiPOx will be important for future use of PiPOx for the development of drug-delivery systems and biomedical applications, such as hydrogels.
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[2 × 2] metallo-supramolecular grids based on 4,6-bis((1 H-1,2,3-triazol-4-yl)-pyridin-2-yl)-2-phenylpyrimidine ligands: from discrete [2 × 2] grid structures to star-shaped supramolecular polymeric architectures. Dalton Trans 2021; 50:8746-8751. [PMID: 34079970 DOI: 10.1039/d1dt01373d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The self-assembly of bis-tridentate ligands leads to the spontaneous formation of [2 × 2] grid-like metal complexes. However, the synthesis of such ligands is rather cumbersome. In the work, we demonstrate a straightforward synthesis route to prepare bis-tridentate 4,6-bis((1H-1,2,3-triazol-4-yl)-pyridin-2-yl)-2-phenylpyrimidine ligands through double CuAAC click chemistry with 4,6-bis(6-ethynylpyridin-2-yl)-2-phenylpyrimidine as well as their self-assembly into [2 × 2] grid-like metal complexes. In addition, four macromolecular ligands were synthesized starting from azido-end-functionalized poly(2-ethyl-2-oxazoline) (PEtOx) or poly(ethylene glycol) (PEG). These macromolecular ligands were used in the construction of star-shaped supramolecular polymers through complexation with transition metal ions (e.g., Fe2+ or Zn2+). The successful fabrication of complexes and star-shaped polymers was confirmed by UV-vis titration measurements and MALDI-TOF mass spectrometry. However, the chemical structure of the polymer was found to have a strong influence on the [2 × 2] grid formation, which was successful with the PEG-ligands but not with the PEtOx-ligands, while the molecular weight of the PEG did not interfere with grid formation.
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Bioinspired double network hydrogels: from covalent double network hydrogels via hybrid double network hydrogels to physical double network hydrogels. MATERIALS HORIZONS 2021; 8:1173-1188. [PMID: 34821910 DOI: 10.1039/d0mh01514h] [Citation(s) in RCA: 125] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The design and synthesis of double network (DN) hydrogels that can mimic the properties and/or structure of natural tissue has flourished in recent years, overcoming the bottlenecks of mechanical performance of single network hydrogels and extending their potential applications in various fields. In recent years, such bioinspired DN hydrogels with extraordinary mechanical performance, excellent biocompatibility, and considerable strength have been demonstrated to be promising candidates for biomedical applications, such as tissue engineering and biomedicine. In this minireview, we provide an overview of the recent developments of bioinspired DN hydrogels defined as DN hydrogels that mimic the properties and/or structure of natural tissue, ranging from, e.g., anisotropically structured DN hydrogels, via ultratough energy dissipating DN hydrogels to dynamic, reshapable DN hydrogels. Furthermore, we discuss future perspectives of bioinspired DN hydrogels for biomedical applications.
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Self-Healing and Moldable Poly(2-isopropenyl-2-oxazoline) Supramolecular Hydrogels Based on a Transient Metal Coordination Network. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01242] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Reduction-Responsive Molecularly Imprinted Poly(2-isopropenyl-2-oxazoline) for Controlled Release of Anticancer Agents. Pharmaceutics 2020; 12:E506. [PMID: 32498326 PMCID: PMC7356239 DOI: 10.3390/pharmaceutics12060506] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/29/2020] [Accepted: 05/31/2020] [Indexed: 01/09/2023] Open
Abstract
Trigger-responsive materials are capable of controlled drug release in the presence of a specific trigger. Reduction induced drug release is especially interesting as the reductive stress is higher inside cells than in the bloodstream, providing a conceptual controlled release mechanism after cellular uptake. In this work, we report the synthesis of 5-fluorouracil (5-FU) molecularly imprinted polymers (MIPs) based on poly(2-isopropenyl-2-oxazoline) (PiPOx) using 3,3'-dithiodipropionic acid (DTDPA) as a reduction-responsive functional cross-linker. The disulfide bond of DTDPA can be cleaved by the addition of tris(2-carboxyethyl)phosphine (TCEP), leading to a reduction-induced 5-FU release. Adsorption isotherms and kinetics for 5-FU indicate that the adsorption kinetics process for imprinted and non-imprinted adsorbents follows two different kinetic models, thus suggesting that different mechanisms are responsible for adsorption. The release kinetics revealed that the addition of TCEP significantly influenced the release of 5-FU from PiPOx-MIP, whereas for non-imprinted PiPOx, no statistically relevant differences were observed. This work provides a conceptual basis for reduction-induced 5-FU release from molecularly imprinted PiPOx, which in future work may be further developed into MIP nanoparticles for the controlled release of therapeutic agents.
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Cation−π Interactions Accelerate the Living Cationic Ring-Opening Polymerization of Unsaturated 2-Alkyl-2-oxazolines. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00865] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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12
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Structural Diversification of Pillar[
n
]arene Macrocycles. Angew Chem Int Ed Engl 2020; 59:6314-6316. [DOI: 10.1002/anie.202002467] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Indexed: 02/06/2023]
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Self‐Healing Metallo‐Supramolecular Hydrogel Based on Specific Ni
2+
Coordination Interactions of Poly(ethylene glycol) with Bistriazole Pyridine Ligands in the Main Chain. Macromol Rapid Commun 2020; 41:e1900457. [DOI: 10.1002/marc.201900457] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/08/2019] [Indexed: 12/19/2022]
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Abstract
Polyampholytes consist of alternating opposite charges were synthesized by alternating RAFT (co)polymerization of cationic and anionic monomers and their pH dependent thermoresponsive behavior in water and alcohol/water solvent mixtures is reported.
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Metal Ion Selective Self‐Assembly of a Ligand Functionalized Polymer into [1+1] Macrocyclic and Supramolecular Polymer Structures via Metal–Ligand Coordination. Macromol Rapid Commun 2019; 41:e1900305. [DOI: 10.1002/marc.201900305] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/30/2019] [Indexed: 11/06/2022]
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Well‐Defined Thermoresponsive Polymethacrylamide Copolymers with Ester Pendent Groups through One‐Pot Statistical Postpolymerization Modification of Poly(2‐Isopropenyl‐2‐Oxazoline) with Multiple Carboxylic Acids. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/pola.29188] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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18
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Photocontrol in Complex Polymeric Materials: Fact or Illusion? Angew Chem Int Ed Engl 2018; 57:7945-7947. [DOI: 10.1002/anie.201804027] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Indexed: 11/08/2022]
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20
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Poly(2-isopropenyl-2-oxazoline) as a versatile platform towards thermoresponsive copolymers. Polym Chem 2018. [DOI: 10.1039/c8py00612a] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Thermoresponsive (co)polymers with LCST behavior based on a well-defined PiPOx scaffold showing high versatility in tuning up the TCP as well as the interval of response.
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Abstract
The synthesis and properties of poly(2-oxazoline)s with cubane side chains are explored in this work.
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22
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New insights into the self-assembling of some hydrophobically modified polyacrylates in aqueous solution. Colloid Polym Sci 2016. [DOI: 10.1007/s00396-015-3825-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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23
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Poly(2-cycloalkyl-2-oxazoline)s: high melting temperature polymers solely based on Debye and Keesom van der Waals interactions. Polym Chem 2016. [DOI: 10.1039/c5py01755f] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The synthesis of new 2-cycloalkyl-2-oxazoline monomers, namely 2-cyclobutyl (cBuOx), 2-cyclopentyl (cPentOx) and 2-cyclohexyl-2-oxazoline (cHexOx) is described. Polymers thereof are semi-crystalline and reveal unexpectedly high melting transitions.
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2-Oxazoline based photo-responsive azo-polymers. Synthesis, characterization and isomerization kinetics. Eur Polym J 2013. [DOI: 10.1016/j.eurpolymj.2012.11.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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25
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Simultaneous two and three photon resonant enhancement of third-order NLO susceptibility in an azo-dye functionalized polymer film. Phys Chem Chem Phys 2013; 15:7060-3. [DOI: 10.1039/c3cp50547b] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Synthesis and characterization of side-chain oxazoline–methyl methacrylate copolymers bearing azo-dye. REACT FUNCT POLYM 2010. [DOI: 10.1016/j.reactfunctpolym.2010.07.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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30
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Synthesis and characterization of side-chain maleimide-styrene copolymers with new pendant azobenzene moieties. JOURNAL OF POLYMER RESEARCH 2010. [DOI: 10.1007/s10965-010-9501-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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31
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Synthesis and characterization of side-chain poly(methacrylate)s bearing new azo-moieties. Polym Bull (Berl) 2010. [DOI: 10.1007/s00289-010-0302-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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