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Keywords = double-hydrophilic block copolymers

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14 pages, 1220 KiB  
Article
Viscoelastic Response of Double Hydrophilic Block Copolymers for Drug Delivery Applications
by Achilleas Pipertzis, Angeliki Chroni, Stergios Pispas and Jan Swenson
Polymers 2025, 17(13), 1857; https://doi.org/10.3390/polym17131857 - 2 Jul 2025
Viewed by 348
Abstract
This study investigates the mechanical properties of double hydrophilic block copolymers (DHBCs) based on poly[oligo(ethylene glycol) methacrylate] (POEGMA) and poly(vinyl benzyl trimethylammonium chloride) (PVBTMAC) blocks by employing small amplitude oscillatory shear (SAOS) rheological measurements. We report that the mechanical properties of DHBCs are [...] Read more.
This study investigates the mechanical properties of double hydrophilic block copolymers (DHBCs) based on poly[oligo(ethylene glycol) methacrylate] (POEGMA) and poly(vinyl benzyl trimethylammonium chloride) (PVBTMAC) blocks by employing small amplitude oscillatory shear (SAOS) rheological measurements. We report that the mechanical properties of DHBCs are governed by the interfacial glass transition temperature (Tginter), verifying the disordered state of these copolymers. An increase in zero shear viscosity can be observed by increasing the VBTMAC content, yielding a transition from liquid-like to gel-like and finally to an elastic-like response for the PVBTMAC homopolymer. By changing the block arrangement along the backbone from statistical to sequential, a distinct change in the viscoelastic response is obvious, indicating the presence/absence of bulk-like regions. The tunable viscosity values and shear-thinning behavior achieved through alteration of the copolymer composition and block arrangement along the backbone render the studied DHBCs promising candidates for drug delivery applications. In the second part, the rheological data are analyzed within the framework of the classical free volume theories of glass formation. Specifically, the copolymers exhibit reduced fractional free volume and similar fragility values compared to the PVBTMAC homopolymer. On the contrary, the activation energy increases by increasing the VBTMAC content, reflecting the required higher energy for the relaxation of the glassy VBTMAC segments. Overall, this study provides information about the viscoelastic properties of DHBCs with densely grafted macromolecular architecture and shows how the mechanical and dynamical properties can be tailored for different drug delivery applications by simply altering the ratio between the two homopolymers. Full article
(This article belongs to the Special Issue Advances and Applications of Block Copolymers II)
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14 pages, 4803 KiB  
Article
Ion and Water Transports in Double Gyroid Nanochannels Formed by Block Copolymer Anion Exchange Membranes
by Karim Aissou, Maximilien Coronas, Jason Richard, Erwan Ponsin, Sambhav Vishwakarma, Eddy Petit, Bertrand Rebiere, Camille Bakkali-Hassani, Stéphanie Roualdes and Damien Quemener
Batteries 2025, 11(4), 126; https://doi.org/10.3390/batteries11040126 - 26 Mar 2025
Viewed by 604
Abstract
Mechanically improved polymeric membranes with high ionic conductivity (IC) and good permeability are highly desired for next-generation anion exchange membranes (AEMs) in order to reduce Ohmic losses and enhance water management in alkaline membrane fuel cells. To move towards the fabrication of such [...] Read more.
Mechanically improved polymeric membranes with high ionic conductivity (IC) and good permeability are highly desired for next-generation anion exchange membranes (AEMs) in order to reduce Ohmic losses and enhance water management in alkaline membrane fuel cells. To move towards the fabrication of such high-performance membranes, the creation of hydrophilic ion-conducting double gyroid (DG) nanochannels within block copolymer (BCP) AEMs is a promising approach. However, this attractive solution remains difficult to implement due to the complexity of constructing a well-developed ion-conducting DG morphology across the entire membrane thickness. To deal with this issue, water permeable polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) membranes with ion-conducting DG nanochannels were produced by combining a solvent vapor annealing (SVA) treatment with a methylation process. Here, the SVA treatment enabled the manufacture of DG-forming BCP AEMs while the methylation process allowed for the conversion of pyridine sites to N-methylpyridinium (NMP+) cations via a Menshutkin reaction. Following this SVA-methylation method, the IC value of water-permeable (~384 L h−1 m−2 bar−1) DG-structured BCP AEMs in their OHcounter anion form was measured to be of ~2.8 mS.cm−1 at 20 °C while a lower IC value was probed, under the same experimental conditions, from as-cast NMP+-containing analogs with a non-permeable disordered phase (~1.2 mS.cm−1). Full article
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19 pages, 5132 KiB  
Article
Double Hydrophilic Hyperbranched Copolymer-Based Lipomer Nanoparticles: Copolymer Synthesis and Co-Assembly Studies
by Angelica Maria Gerardos and Stergios Pispas
Polymers 2024, 16(22), 3129; https://doi.org/10.3390/polym16223129 - 9 Nov 2024
Cited by 2 | Viewed by 1540
Abstract
Double hydrophilic, random, hyperbranched copolymers were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization of oligo(ethylene glycol) methyl ether methacrylate (OEGMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) utilizing ethylene glycol dimethacrylate (EGDMA) as the branching agent. The resulting copolymers were characterized in terms of their [...] Read more.
Double hydrophilic, random, hyperbranched copolymers were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization of oligo(ethylene glycol) methyl ether methacrylate (OEGMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) utilizing ethylene glycol dimethacrylate (EGDMA) as the branching agent. The resulting copolymers were characterized in terms of their molecular weight and dispersity using size exclusion chromatography (SEC), and their chemical structure was confirmed using FT-IR and 1H-NMR spectroscopy techniques. The choice of the two hydrophilic blocks and the design of the macromolecular structure allowed the formation of self-assembled nanoparticles, partially due to the pH-responsive character of the DMAEMA segments and their interaction with -COOH end groups remaining from the chain transfer agent. The copolymers showed pH-responsive properties, mainly due to the protonation–deprotonation equilibria of the DMAEMA segments. Subsequently, a nanoscopic polymer–lipid (lipomer) mixed system was formulated by complexing the synthesized copolymers with cosmetic amphiphilic emulsifiers, specifically glyceryl stearate (GS) and glyceryl stearate citrate (GSC). This study aims to show that developing lipid–polymer hybrid nanoparticles can effectively address the limitations of both liposomes and polymeric nanoparticles. The effects of varying the ionic strength and pH on stimuli-sensitive polymeric and mixed polymer–lipid nanostructures were thoroughly investigated. To achieve this, the structural properties of the hybrid nanoparticles were comprehensively characterized using physicochemical techniques providing insights into their size distribution and stability. Full article
(This article belongs to the Special Issue Block Copolymers: Self-Assembly and Applications, 2nd Edition)
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16 pages, 4867 KiB  
Article
Responsive Microgels through RAFT-HDA Dynamic Covalent Bonding Chemistry
by Jingkai Nie, Hang Yin, Ruyue Cao, Changyuan Huang, Xiang Luo and Jun Ji
Molecules 2024, 29(6), 1217; https://doi.org/10.3390/molecules29061217 - 8 Mar 2024
Cited by 1 | Viewed by 1601
Abstract
This paper developed a method for preparing ultrasound-responsive microgels based on reversible addition fragmentation chain transfer-hetero Diels–Alder (RAFT-HAD) dynamic covalent bonding. First, a styrene cross-linked network was successfully prepared by a Diels–Alder (DA) reaction between phosphoryl dithioester and furan using double-ended diethoxyphosphoryl dithiocarbonate [...] Read more.
This paper developed a method for preparing ultrasound-responsive microgels based on reversible addition fragmentation chain transfer-hetero Diels–Alder (RAFT-HAD) dynamic covalent bonding. First, a styrene cross-linked network was successfully prepared by a Diels–Alder (DA) reaction between phosphoryl dithioester and furan using double-ended diethoxyphosphoryl dithiocarbonate (BDEPDF) for RAFT reagent-mediated styrene (St) polymerization, with a double-ended dienophile linker and copolymer of furfuryl methacrylate (FMA) and St as the dienophile. Subsequently, the microgel system was constructed by the HDA reaction between phosphoryl disulfide and furan groups using the copolymer of polyethylene glycol monomethyl ether acrylate (OEGMA) and FMA as the dienophore building block and hydrophilic segment and the polystyrene pro-dienophile linker as the cross-linker and hydrophobic segment. The number of furans in the dienophile chain and the length of the dienophile linker were regulated by RAFT polymerization to investigate the effects of the single-molecule chain functional group degree, furan/dithioester ratio, and hydrophobic cross-linker length on the microgel system. The prepared microgels can achieve the reversible transformation of materials under force responsiveness, and their preparation steps are simple and adaptive to various potential applications in biomedical materials and adaptive electrical materials. Full article
(This article belongs to the Special Issue Application of Synthetic and Natural Polymers in Medicine)
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19 pages, 4562 KiB  
Article
The Effect of Block Ratio and Structure on the Thermosensitivity of Double and Triple Betaine Block Copolymers
by Jongmin Lim, Hideki Matsuoka, Yusuke Kinoshita, Shin-ichi Yusa and Yoshiyuki Saruwatari
Molecules 2024, 29(2), 390; https://doi.org/10.3390/molecules29020390 - 12 Jan 2024
Cited by 1 | Viewed by 1610
Abstract
AB-type and BAB-type betaine block copolymers composed of a carboxybetaine methacrylate and a sulfobetaine methacrylate, PGLBT-b-PSPE and PSPE-b-PGLBT-b-PSPE, respectively, were synthesized by one-pot RAFT polymerization. By optimizing the concentration of the monomer, initiator, and chain transfer agent, [...] Read more.
AB-type and BAB-type betaine block copolymers composed of a carboxybetaine methacrylate and a sulfobetaine methacrylate, PGLBT-b-PSPE and PSPE-b-PGLBT-b-PSPE, respectively, were synthesized by one-pot RAFT polymerization. By optimizing the concentration of the monomer, initiator, and chain transfer agent, block extension with precise ratio control was enabled and a full conversion (~99%) of betaine monomers was achieved at each step. Two sets (total degree of polymerization: ~300 and ~600) of diblock copolymers having four different PGLBT:PSPE ratios were prepared to compare the influence of block ratio and molecular weight on the temperature-responsive behavior in aqueous solution. A turbidimetry and dynamic light scattering study revealed a shift to higher temperatures of the cloud point and micelle formation by increasing the ratio of PSPE, which exhibit upper critical solution temperature (UCST) behavior. PSPE-dominant diblocks created spherical micelles stabilized by PGLBT motifs, and the transition behavior diminished by decreasing the PSPE ratio. No particular change was found in the diblocks that had an identical AB ratio. This trend reappeared in the other set whose entire molecular weight approximately doubled, and each transition point was not recognizably impacted by the total molecular weight. For triblocks, the PSPE double ends provided a higher probability of interchain attractions and resulted in a more turbid solution at higher temperatures, compared to the diblocks which had similar block ratios and molecular weights. The intermediates assumed as network-like soft aggregates eventually rearranged to monodisperse flowerlike micelles. It is expected that the method for obtaining well-defined betaine block copolymers, as well as the relationship of the block ratio and the chain conformation to the temperature-responsive behavior, will be helpful for designing betaine-based polymeric applications. Full article
(This article belongs to the Special Issue Themed Issue Dedicated to Prof. Bernard Boutevin)
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36 pages, 2816 KiB  
Review
Polymersomes as the Next Attractive Generation of Drug Delivery Systems: Definition, Synthesis and Applications
by Mariana Fonseca, Ivana Jarak, Francis Victor, Cátia Domingues, Francisco Veiga and Ana Figueiras
Materials 2024, 17(2), 319; https://doi.org/10.3390/ma17020319 - 8 Jan 2024
Cited by 32 | Viewed by 6004
Abstract
Polymersomes are artificial nanoparticles formed by the self-assembly process of amphiphilic block copolymers composed of hydrophobic and hydrophilic blocks. They can encapsulate hydrophilic molecules in the aqueous core and hydrophobic molecules within the membrane. The composition of block copolymers can be tuned, enabling [...] Read more.
Polymersomes are artificial nanoparticles formed by the self-assembly process of amphiphilic block copolymers composed of hydrophobic and hydrophilic blocks. They can encapsulate hydrophilic molecules in the aqueous core and hydrophobic molecules within the membrane. The composition of block copolymers can be tuned, enabling control of characteristics and properties of formed polymersomes and, thus, their application in areas such as drug delivery, diagnostics, or bioimaging. The preparation methods of polymersomes can also impact their characteristics and the preservation of the encapsulated drugs. Many methods have been described, including direct hydration, thin film hydration, electroporation, the pH-switch method, solvent shift method, single and double emulsion method, flash nanoprecipitation, and microfluidic synthesis. Considering polymersome structure and composition, there are several types of polymersomes including theranostic polymersomes, polymersomes decorated with targeting ligands for selective delivery, stimuli-responsive polymersomes, or porous polymersomes with multiple promising applications. Due to the shortcomings related to the stability, efficacy, and safety of some therapeutics in the human body, polymersomes as drug delivery systems have been good candidates to improve the quality of therapies against a wide range of diseases, including cancer. Chemotherapy and immunotherapy can be improved by using polymersomes to deliver the drugs, protecting and directing them to the exact site of action. Moreover, this approach is also promising for targeted delivery of biologics since they represent a class of drugs with poor stability and high susceptibility to in vivo clearance. However, the lack of a well-defined regulatory plan for polymersome formulations has hampered their follow-up to clinical trials and subsequent market entry. Full article
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25 pages, 3004 KiB  
Review
Nanoscale Self-Assemblies from Amphiphilic Block Copolymers as Proficient Templates in Drug Delivery
by Dhruvi Patel, Ketan Kuperkar, Shin-ichi Yusa and Pratap Bahadur
Drugs Drug Candidates 2023, 2(4), 898-922; https://doi.org/10.3390/ddc2040045 - 22 Nov 2023
Cited by 15 | Viewed by 3093
Abstract
This review article emphasizes the current enlargements in the formation and properties of the various nanostructured aggregates resulting from the self-assembly of a variety of block copolymers (BCPs) in an aqueous solution. The development of the different polymerization techniques which produce polymers with [...] Read more.
This review article emphasizes the current enlargements in the formation and properties of the various nanostructured aggregates resulting from the self-assembly of a variety of block copolymers (BCPs) in an aqueous solution. The development of the different polymerization techniques which produce polymers with a desired predetermined molecular weight and low polydispersity is investigated with regard to their technological and biomedical applications; in particular, their applications as vehicles for drug delivery systems are considered. The solution behavior of amphiphilic BCPs and double-hydrophilic block copolymers (DHBCs), with one or both blocks being responsive to any stimulus, is discussed. Polyion complex micelles (PICMs)/polymersomes obtained from the electrostatic interaction of a polyelectrolyte-neutral BCP with oppositely charged species are also detailed. Lastly, polymerization-induced self-assembly (PISA), which forms nanoscale micellar aggregates with controlled size/shape/surface functionality, and the crystallization-driven self-assembly of semicrystalline BCPs facilitated when one block of the BCP is crystallizable, are also revealed. The scalability of the copolymeric micelles in the drug delivery systems and pharmaceutical formations that are currently being used in clinical trials, research, or preclinical testing is emphasized as these micelles could be used in the future to create novel nanomedicines. The updated literature and the future perspectives of BCP self-assembly are considered. Full article
(This article belongs to the Section Preclinical Research)
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17 pages, 4193 KiB  
Article
Solvent-Free Synthesis of Multifunctional Block Copolymer and Formation of DNA and Drug Nanocarriers
by Radostina Kalinova, Kirilka Mladenova, Svetla Petrova, Jordan Doumanov and Ivaylo Dimitrov
Nanomaterials 2023, 13(22), 2936; https://doi.org/10.3390/nano13222936 - 13 Nov 2023
Cited by 1 | Viewed by 1702
Abstract
The synthesis of well-defined multifunctional polymers is of great importance for the development of complex materials for biomedical applications. In the current work, novel and multi-amino-functional diblock copolymer for potential gene and drug delivery applications was successfully synthesized. A highly efficient one-step and [...] Read more.
The synthesis of well-defined multifunctional polymers is of great importance for the development of complex materials for biomedical applications. In the current work, novel and multi-amino-functional diblock copolymer for potential gene and drug delivery applications was successfully synthesized. A highly efficient one-step and quantitative modification of an alkyne-functional polycarbonate-based precursor was performed, yielding double hydrophilic block copolymer with densely grafted primary amine side groups. The obtained positively charged block copolymer co-associated with DNA, forming stable and biocompatible nanosized polyplexes. Furthermore, polyion complex (PIC) micelles with tunable surface charge and decorated with cell targeting moieties were obtained as a result of direct mixing in aqueous media of the multi-amino-functional block copolymer and a previously synthesized oppositely charged block copolymer bearing disaccharide end-group. The obtained well-defined nanosized PIC–micelles were loaded with the hydrophobic drug curcumin. Both types of nanoaggregates (polyplexes and PIC–micelles) were physico-chemically characterized. Moreover, initial in vitro evaluations were performed to assess the nanocarriers’ potential for biomedical applications. Full article
(This article belongs to the Section Synthesis, Interfaces and Nanostructures)
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14 pages, 3415 KiB  
Article
A Star-Shaped Copolymer with Tetra-Hydroxy-Phenylporphyrin Core and Four PNIPAM-b-PMAGA Arms for Targeted Photodynamic Therapy
by Changling Liu, Yirong Wang, Siyu Wang, Pengcheng Xu, Renning Liu, Dandan Han and Yen Wei
Polymers 2023, 15(3), 509; https://doi.org/10.3390/polym15030509 - 18 Jan 2023
Cited by 3 | Viewed by 2540
Abstract
The novel thermosensitive star-shaped tetra-hydroxy-phenylporphyrin-cored (THPP) double hydrophilic poly(N-isopropylacrylamide)-b-poly(methylacrylamide glucose) block copolymers (THPP-(PNIPAM-b-PMAGA)4) were synthesized via the reversible addition-fragmentation chain transfer (RAFT) polymerization. Notably, the low critical solution temperatures (LCSTs) of THPP-(PNIPAM-b-PMAGA)4 were above normal body [...] Read more.
The novel thermosensitive star-shaped tetra-hydroxy-phenylporphyrin-cored (THPP) double hydrophilic poly(N-isopropylacrylamide)-b-poly(methylacrylamide glucose) block copolymers (THPP-(PNIPAM-b-PMAGA)4) were synthesized via the reversible addition-fragmentation chain transfer (RAFT) polymerization. Notably, the low critical solution temperatures (LCSTs) of THPP-(PNIPAM-b-PMAGA)4 were above normal body temperature (37 °C) which depended on the hydrophilic PMAGA contents of copolymers. When the temperature was higher than the LCST of the copolymer, the copolymer could be neutralized into micelles in aqueous and could be coated with antitumor drugs and released around tumor cells. The MTT study indicated that THPP-(PNIPAM-b-PMAGA)4 had a low toxicity to L929 and HeLa cells in the absence of light. However, THPP-(PNIPAM-b-PMAGA)4 showed a high toxicity with HeLa cells under light irradiation which could be used as a potential photosensitizer for photodynamic therapy (PDT). In addition, THPP-(PNIPAM-b-PMAGA)4 showed specific a recognition function with Concanavalin A (Con A) to achieve active targeted drug delivery. This work provides a new approach for the development of tumor targeting and chemotherapy/PDT. Full article
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19 pages, 28046 KiB  
Article
Development of Double Hydrophilic Block Copolymer/Porphyrin Polyion Complex Micelles towards Photofunctional Nanoparticles
by Maria Karayianni, Dimitra Koufi and Stergios Pispas
Polymers 2022, 14(23), 5186; https://doi.org/10.3390/polym14235186 - 29 Nov 2022
Cited by 6 | Viewed by 1909
Abstract
The electrostatic complexation between double hydrophilic block copolymers (DHBCs) and a model porphyrin was explored as a means for the development of polyion complex micelles (PICs) that can be utilized as photosensitive porphyrin-loaded nanoparticles. Specifically, we employed a poly(2-(dimethylamino) ethyl methacrylate)-b-poly[(oligo [...] Read more.
The electrostatic complexation between double hydrophilic block copolymers (DHBCs) and a model porphyrin was explored as a means for the development of polyion complex micelles (PICs) that can be utilized as photosensitive porphyrin-loaded nanoparticles. Specifically, we employed a poly(2-(dimethylamino) ethyl methacrylate)-b-poly[(oligo ethylene glycol) methyl ether methacrylate] (PDMAEMA-b-POEGMA) diblock copolymer, along with its quaternized polyelectrolyte copolymer counterpart (QPDMAEMA-b-POEGMA) and 5,10,15,20-tetraphenyl-21H,23H-porphine-p,p′,p″,p′′′-tetrasulfonic acid tetrasodium hydrate (TPPS) porphyrin. The (Q)PDMAEMA blocks enable electrostatic binding with TPPS, thus forming the micellar core, while the POEGMA blocks act as the corona of the micelles and impart solubility, biocompatibility, and stealth properties to the formed nanoparticles. Different mixing charge ratios were examined aiming to produce stable nanocarriers. The mass, size, size distribution and effective charge of the resulting nanoparticles, as well as their response to changes in their environment (i.e., pH and temperature) were investigated by dynamic and electrophoretic light scattering (DLS and ELS). Moreover, the photophysical properties of the complexed porphyrin along with further structural insight were obtained through UV-vis (200-800 nm) and fluorescence spectroscopy measurements. Full article
(This article belongs to the Special Issue Advances and Applications of Block Copolymers)
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21 pages, 5567 KiB  
Review
Amphiphilic Block Copolymers: Their Structures, and Self-Assembly to Polymeric Micelles and Polymersomes as Drug Delivery Vehicles
by Ketan Kuperkar, Dhruvi Patel, Leonard Ionut Atanase and Pratap Bahadur
Polymers 2022, 14(21), 4702; https://doi.org/10.3390/polym14214702 - 3 Nov 2022
Cited by 171 | Viewed by 18939
Abstract
Self-assembly of amphiphilic block copolymers display a multiplicity of nanoscale periodic patterns proposed as a dominant tool for the ‘bottom-up’ fabrication of nanomaterials with different levels of ordering. The present review article focuses on the recent updates to the self-association of amphiphilic block [...] Read more.
Self-assembly of amphiphilic block copolymers display a multiplicity of nanoscale periodic patterns proposed as a dominant tool for the ‘bottom-up’ fabrication of nanomaterials with different levels of ordering. The present review article focuses on the recent updates to the self-association of amphiphilic block copolymers in aqueous media into varied core-shell morphologies. We briefly describe the block copolymers, their types, microdomain formation in bulk and micellization in selective solvents. We also discuss the characteristic features of block copolymers nanoaggregates viz., polymer micelles (PMs) and polymersomes. Amphiphilic block copolymers (with a variety of hydrophobic blocks and hydrophilic blocks; often polyethylene oxide) self-assemble in water to micelles/niosomes similar to conventional nonionic surfactants with high drug loading capacity. Double hydrophilic block copolymers (DHBCs) made of neutral block-neutral block or neutral block-charged block can transform one block to become hydrophobic under the influence of a stimulus (physical/chemical/biological), and thus induced amphiphilicity and display self-assembly are discussed. Different kinds of polymer micelles (viz. shell and core-cross-linked, core-shell-corona, schizophrenic, crew cut, Janus) are presented in detail. Updates on polymerization-induced self-assembly (PISA) and crystallization-driven self-assembly (CDSA) are also provided. Polyion complexes (PICs) and polyion complex micelles (PICMs) are discussed. Applications of these block copolymeric micelles and polymersomes as nanocarriers in drug delivery systems are described. Full article
(This article belongs to the Special Issue Polymers and Drug Delivery Systems II)
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18 pages, 4142 KiB  
Article
Poly[oligo(ethylene glycol) methacrylate]-b-poly[(vinyl benzyl trimethylammonium chloride)] Based Multifunctional Hybrid Nanostructures Encapsulating Magnetic Nanoparticles and DNA
by Angeliki Chroni, Aleksander Forys, Barbara Trzebicka, Adam Alemayehu, Vaclav Tyrpekl and Stergios Pispas
Polymers 2020, 12(6), 1283; https://doi.org/10.3390/polym12061283 - 3 Jun 2020
Cited by 10 | Viewed by 3752
Abstract
We report on the preparation of novel and multifunctional hybrid spherical-shaped nanostructures involving a double-hydrophilic block copolymer, namely the neutral cationic poly[oligo(ethylene glycol) methacrylate]-b-poly[(vinyl benzyl trimethylammonium chloride)] (POEGMA-b-PVBTMAC) diblock copolymer, initially complexed with hydrophilic anionic magnetic nanoparticles (MNPs), and [...] Read more.
We report on the preparation of novel and multifunctional hybrid spherical-shaped nanostructures involving a double-hydrophilic block copolymer, namely the neutral cationic poly[oligo(ethylene glycol) methacrylate]-b-poly[(vinyl benzyl trimethylammonium chloride)] (POEGMA-b-PVBTMAC) diblock copolymer, initially complexed with hydrophilic anionic magnetic nanoparticles (MNPs), and subsequently, with short deoxyribonucleic acid (113 bases DNA). The POEGMA-b-PVBTMAC copolymer, the copolymer/MNPs and the copolymer/MNPs/DNA tricomponent hybrid electrostatic complexes were studied by dynamic/electrophoretic light scattering (DLS/ELS) and cryogenic transmission electron microscopy (cryo-TEM) techniques for the determination of their structure and solution properties. The MNPs were complexed efficiently with the oppositely charged diblock chains, leading to well-defined hybrid organic–inorganic spherical-shaped nanostructures. A significant aggregation tendency of the MNPs is noticed in cryo-TEM measurements after the electrostatic complexation of DNA, implying an accumulation of the DNA macromolecules on the surface of the hybrid tricomponent complexes. Magnetophoretic experiments verified that the MNPs maintain their magnetic properties after the complexation initially with the copolymer, and subsequently, within the block polyelectrolyte/MNPs/DNA nanostructures. Full article
(This article belongs to the Special Issue Polymer Hybrid Nanomaterials)
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14 pages, 3318 KiB  
Article
Optical Sensing of Humidity Using Polymer Top-Covered Bragg Stacks and Polymer/Metal Thin Film Structures
by Katerina Lazarova, Darinka Christova, Rosen Georgiev, Biliana Georgieva and Tsvetanka Babeva
Nanomaterials 2019, 9(6), 875; https://doi.org/10.3390/nano9060875 - 10 Jun 2019
Cited by 6 | Viewed by 3805
Abstract
Thin films with nanometer thicknesses in the range 100–400 nm are prepared from double hydrophilic copolymers of complex branched structures containing poly(N,N-dimethyl acrylamide) and poly(ethylene oxide) blocks and are used as humidity sensitive media. Instead of using glass or [...] Read more.
Thin films with nanometer thicknesses in the range 100–400 nm are prepared from double hydrophilic copolymers of complex branched structures containing poly(N,N-dimethyl acrylamide) and poly(ethylene oxide) blocks and are used as humidity sensitive media. Instead of using glass or opaque wafer for substrates, polymer thin films are deposited on Bragg stacks and thin (30 nm) sputtered Au–Pd films thus bringing color for the colorless polymer/glass system and enabling transmittance measurements for humidity sensing. All samples are characterized by transmittance measurements at different humidity levels in the range from 5% to 90% relative humidity. Additionally, the humidity induced color change is studied by calculating the color coordinates at different relative humidity using measured spectra of transmittance or reflectance. A special attention is paid to the selection of wavelength(s) of measurements and discriminating between different humidity levels when sensing is performed by measuring transmittance at fixed wavelengths. The influence of initial film thickness, sensor architecture, and measuring configuration on sensitivity is studied. The potential and advantages of using top covered Bragg stacks and polymer/metal thin film structures as humidity sensors with simple optical read-outs are demonstrated and discussed. Full article
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15 pages, 2118 KiB  
Article
Tannic Acid-Mediated Aggregate Stabilization of Poly(N-vinylpyrrolidone)-b-poly(oligo (ethylene glycol) methyl ether methacrylate) Double Hydrophilic Block Copolymers
by Noah Al Nakeeb, Ivo Nischang and Bernhard V.K.J. Schmidt
Nanomaterials 2019, 9(5), 662; https://doi.org/10.3390/nano9050662 - 26 Apr 2019
Cited by 11 | Viewed by 6150
Abstract
The self-assembly of block copolymers in aqueous solution is an important field in modern polymer science that has been extended to double hydrophilic block copolymers (DHBC) in recent years. In here, a significant improvement of the self-assembly process of DHBC in aqueous solution [...] Read more.
The self-assembly of block copolymers in aqueous solution is an important field in modern polymer science that has been extended to double hydrophilic block copolymers (DHBC) in recent years. In here, a significant improvement of the self-assembly process of DHBC in aqueous solution by utilizing a linear-brush macromolecular architecture is presented. The improved self-assembly behavior of poly(N-vinylpyrrolidone)-b-poly(oligo(ethylene glycol) methyl ether methacrylate) (PVP-b-P(OEGMA)) and its concentration dependency is investigated via dynamic light scattering (DLS) (apparent hydrodynamic radii ≈ 100–120 nm). Moreover, the DHBC assemblies can be non-covalently crosslinked with tannic acid via hydrogen bonding, which leads to the formation of small aggregates as well (apparent hydrodynamic radius ≈ 15 nm). Non-covalent crosslinking improves the self-assembly and stabilizes the aggregates upon dilution, reducing the concentration dependency of aggregate self-assembly. Additionally, the non-covalent aggregates can be disassembled in basic media. The presence of aggregates was studied via cryogenic scanning electron microscopy (cryo-SEM) and DLS before and after non-covalent crosslinking. Furthermore, analytical ultracentrifugation of the formed aggregate structures was performed, clearly showing the existence of polymer assemblies, particularly after non-covalent crosslinking. In summary, we report on the completely hydrophilic self-assembled structures in solution formed from fully biocompatible building entities in water. Full article
(This article belongs to the Special Issue Nanoscale Self-Assembly: Nanopatterning and Metrology)
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18 pages, 2288 KiB  
Article
Magnetic Polyion Complex Micelles for Cell Toxicity Induced by Radiofrequency Magnetic Field Hyperthermia
by Vo Thu An Nguyen, Marie-Claire De Pauw-Gillet, Mario Gauthier and Olivier Sandre
Nanomaterials 2018, 8(12), 1014; https://doi.org/10.3390/nano8121014 - 6 Dec 2018
Cited by 13 | Viewed by 3577
Abstract
Magnetic nanoparticles (MNPs) of magnetite (Fe3O4) were prepared using a polystyrene-graft-poly(2-vinylpyridine) copolymer (denoted G0PS-g-P2VP or G1) as template. These MNPs were subjected to self-assembly with a poly(acrylic acid)-block-poly(2-hydroxyethyl acrylate) double-hydrophilic block copolymer (DHBC), [...] Read more.
Magnetic nanoparticles (MNPs) of magnetite (Fe3O4) were prepared using a polystyrene-graft-poly(2-vinylpyridine) copolymer (denoted G0PS-g-P2VP or G1) as template. These MNPs were subjected to self-assembly with a poly(acrylic acid)-block-poly(2-hydroxyethyl acrylate) double-hydrophilic block copolymer (DHBC), PAA-b-PHEA, to form water-dispersible magnetic polyion complex (MPIC) micelles. Large Fe3O4 crystallites were visualized by transmission electron microscopy (TEM) and magnetic suspensions of MPIC micelles exhibited improved colloidal stability in aqueous environments over a wide pH and ionic strength range. Biological cells incubated for 48 h with MPIC micelles at the highest concentration (1250 µg of Fe3O4 per mL) had a cell viability of 91%, as compared with 51% when incubated with bare (unprotected) MNPs. Cell internalization, visualized by confocal laser scanning microscopy (CLSM) and TEM, exhibited strong dependence on the MPIC micelle concentration and incubation time, as also evidenced by fluorescence-activated cell sorting (FACS). The usefulness of MPIC micelles for cellular radiofrequency magnetic field hyperthermia (MFH) was also confirmed, as the MPIC micelles showed a dual dose-dependent effect (concentration and duration of magnetic field exposure) on the viability of L929 mouse fibroblasts and U87 human glioblastoma epithelial cells. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles in Biological Applications)
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