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Hypothesis: Polymer architecture is known to have significant impact on its adsorption behaviour. Most studies have been concerned with the more concentrated, “close to surface saturation” regime of the isotherm, where complications such as lateral interactions and crowding also additionally affect the adsorption. We compare a variety of amphiphilic polymer architectures by determining their Henry's adsorption constant (kH), which, as with other surface active molecules, is the proportionality constant between surface coverage and bulk polymer concentration in a sufficiently dilute regime. It is speculated that not only the number of arms or branches, but also the position of adsorbing hydrophobes influence the adsorption, and that by controlling the latter the two can counteract each other. Methodology: The Self-consistent field calculation of Scheutjens and Fleer was implemented to calculate the adsorbed amount of polymer for many different polymer architectures including linear, star and dendritic. Using the adsorption isotherms at very low bulk concentrations, we determined the value of kH for these. Findings: It is found that the branched structures (star polymers and dendrimers) can be viewed as analogues of linear block polymers based on the location of their adsorbing units. Polymers containing consecutive trains of adsorbing hydrophobes in all cases showed higher level of adsorption compared to their counterparts, where the hydrophobes were more uniformly distributed on the chains. While increasing the number of branches (or arms for star polymers) also confirmed the known result that the adsorption decreased with the number of arms, this trend can be partially offset by the appropriate choice of the location of anchoring groups.

Polymer micelles represent one of the most attractive drug delivery systems due to their design flexibility based on a variety of macromolecular synthetic methods. The environmentally safe chemistry in which the use or generation of hazardous materials is minimized has an increasing impact on polymer-based drug delivery nanosystems. In this work, a solvent-free green synthetic procedure was applied for the preparation of an amphiphilic diblock copolymer consisting of biodegradable hydrophobic poly(acetylene-functional carbonate) and biocompatible hydrophilic polyethylene glycol (PEG) blocks. The cyclic functional carbonate monomer 5-methyl-5-propargyloxycarbonyl-1,3-dioxane-2-one (MPC) was polymerized in bulk using methoxy PEG-5K as a macroinitiator by applying the metal-free organocatalyzed controlled ring-opening polymerization at a relatively low temperature of 60 °C. The functional amphiphilic block copolymer self-associated in aqueous media into stable micelles with an average diameter of 44 nm. The copolymer micelles were physico-chemically characterized and loaded with the plant-derived anticancer drug curcumin. Preliminary in vitro evaluations indicate that the functional copolymer micelles are non-toxic and promising candidates for further investigation as nanocarriers for biomedical applications.

International audience; Block copolymers synthesized via Atom Transfer Radical Polymerization from alkyl acrylate and t-butyl acrylate and the subsequent hydrolysis of the t-butyl acrylate to acrylic acid were systematically varied with respect to their hydrophobic part by the variation in the alkyl chain length and the degree of polymerisation in this block. Depending on the architecture of the hydrophobic part, they had a more or less pronounced tendency to form copolymer micelles in an aqueous solution. They were employed for the preparation of IPECs by mixing the copolymer aggregates with the polycations polydiallyldimethylammonium chloride (PDADMAC) or q-chit. The IPEC structure as a function of the composition was investigated by Static Light and Small Angle Neutron Scattering. For weakly-associated block copolymers (short alkyl chain), complexation with polycation led to the formation of globular complexes, while already existing micelles (long alkyl chain) grew further in mass. In general, aggregates became larger upon the addition of further polycation, but this growth was much more pronounced for PDADMAC compared to q-chit, thereby leading to the formation of clusters of aggregates. Accordingly, the structure of such IPECs with a hydrophobic block depended largely on the type of complexing polyelectrolyte, which allowed for controlling the structural organisation via the molecular architecture of the two oppositely charged polyelectrolytes.

Water-soluble forms of α-tocopherol (TP) as an effective antioxidant were obtained by encapsulating it into nanoparticles (NPs) of amphiphilic copolymers of N-vinylpyrrolidone with triethylene glycol dimethacrylate (CPL1-TP) and N-vinylpyrrolidone with hexyl methacrylate and triethylene glycol dimethacrylate (CPL2-TP) synthesized by radical copolymerization in toluene. The hydrodynamic radii of NPs loaded with TP (3.7 wt% per copolymers) were typically ca. 50 or 80 nm depending on copolymer composition, media, and temperature. Characterization of NPs was accomplished by transmission electron microscopy (TEM), IR-, and 1H NMR spectroscopy. Quantum chemical modeling showed that TP molecules are capable to form hydrogen bonds with donor groups of the copolymer units. High antioxidant activity of both obtained forms of TP has been found by the thiobarbituric acid reactive species and chemiluminescence assays. CPL1-TP and CPL2-TP effectively inhibited the process of spontaneous lipid peroxidation as well as α-tocopherol itself. The IC50 values of luminol chemiluminescence inhibition were determined. Antiglycation activity against vesperlysine and pentosidine-like AGEs of TP water-soluble forms was shown. The developed NPs of TP are promising as materials with antioxidant and antiglycation activity and can be used in various biomedical applications.

The development of effective anti-cancer therapeutics remains one of the current pharmaceutical challenges. The joint delivery of chemotherapeutic agents and biopharmaceuticals is a cutting-edge approach to creating therapeutic agents of enhanced efficacy. In this study, amphiphilic polypeptide delivery systems capable of loading both hydrophobic drug and small interfering RNA (siRNA) were developed. The synthesis of amphiphilic polypeptides included two steps: (i) synthesis of poly-αl-lysine by ring-opening polymerization and (ii) its post-polymerization modification with hydrophobic l-amino acid and l-arginine/l-histidine. The obtained polymers were used for the preparation of single and dual delivery systems of PTX and short double-stranded nucleic acid. The obtained double component systems were quite compact and had a hydrodynamic diameter in the range of 90–200 nm depending on the polypeptide. The release of PTX from the formulations was studied, and the release profiles were approximated using a number of mathematical dissolution models to establish the most probable release mechanism. A determination of the cytotoxicity in normal (HEK 293T) and cancer (HeLa and A549) cells revealed the higher toxicity of the polypeptide particles to cancer cells. The separate evaluation of the biological activity of PTX and anti-GFP siRNA formulations testified the inhibitory efficiency of PTX formulations based on all polypeptides (IC50 4.5–6.2 ng/mL), while gene silencing was effective only for the Tyr-Arg-containing polypeptide (56–70% GFP knockdown).

Small hydrophilic drugs are widely used for systemic administration, but they suffer from poor absorption and fast clearance. Their nanoencapsulation can improve biodistribution, targeted delivery, and pharmaceutical efficacy. Hydrophilics are effectively encapsulated in compartmented particles, such as liposomes or extracellular vesicles, which are biocompatible but poorly customizable. Polymeric vectors can form compartmental structures, also being functionalizable. Here, we report a system composed of polymeric stabilized reversed micelles for hydrophilic drugs encapsulation. We optimized the preparation procedure, and calculated the critical micellar concentration. Then, we developed a strategy for stabilization that improves micelle stability upon dilution. We tested the drug loading and delivery capabilities with creatine as a drug molecule. Prepared stabilized reversed micelles had a size of around 130 nm and a negative z-potential around −16 mV, making them functional as a drug carrier. The creatine cargo increased micelle size and depended on the loading conditions. The higher amount of loaded creatine was around 60 μg/mg of particles. Delivery tests indicated full release within three days in micelles with the lower cargo, while higher loadings can provide a sustained release for longer times. Obtained results are interesting and encouraging to test the same system with different drug cargoes.

This research concerns the investigation of the preparation of polymeric nanocarriers containing a flavonoid—naringenin, xanthohumol or isoxanthohumol—based on Pluronics by the thin-film formation method. The size of the formed micelles and their stability upon dilution were evaluated using Dynamic light scattering (DLS) analysis; the high values of the drug loading and the encapsulation efficiency confirmed that the proposed systems of flavonoids delivery consisting of Pluronic P123 and F127 nanomicelles could effectively distribute the drug into tumour tissues, which makes these nanocarriers ideal candidates for passive targeting of cancer cells by the enhanced permeation and retention (EPR) effect. The in vitro cytotoxicity of proposed flavonoids in the Pluronic formulations was investigated by the SRB assay with human colon cancer cells. We designed mixed polymeric micelles, which was a successful drug delivery system for the case of naringenin not being able to enhance the bioavailability and cytotoxic activity of xanthohumol and isoxanthohumol. Furthermore, it was observed that the higher amount of polymer in the formulation achieved better cytotoxic activity.

In this study, reversible addition-fragmentation chain transfer (RAFT) polymerization is utilized in order to synthesize novel hyperbranched poly(oligoethylene glycol) methyl ether methacrylate-co-tert-butyl methacrylate-co-methacrylic acid) (H-[P(OEGMA-co-tBMA-co-MAA)]) copolymers in combination with selective hydrolysis reactions. The copolymers showing amphiphilicity induced by the polar OEGMA and hydrophobic tBMA monomeric units, and polyelectrolyte character due to MAA units, combined with unique macromolecular architecture were characterized by physicochemical techniques, such as size exclusion chromatography (SEC) and 1H-NMR spectroscopy. The hyperbranched copolymers were investigated in terms of their ability to self-assemble into nanostructures when dissolved in aqueous media. Dynamic light scattering and fluorescence spectroscopy revealed multimolecular aggregates of nanoscale dimensions with low critical aggregation concentration, the size and mass of which depend on copolymer composition and solution conditions, whereas zeta potential measurements indicated pH sensitive features. In addition, aiming to evaluate their potential use as nanocarriers, the copolymers were studied in terms of their drug encapsulation and protein complexation ability utilizing curcumin and lysozyme, as a model hydrophobic drug and a model cationic protein, respectively.

By combining oppositely charged polydiallyldimethylammonium chloride (PDADMAC) and sodium polyacrylate (NaPA), interpolyelectrolyte complexes (IPECs) can be formed in aqueous solution. Such IPECs are studied for rather short NaPA and under variation of the Mw of PDADMAC. The focus is on elucidating the effect of having a hydrophobic modification of the NaPA, which is introduced by having 10 mol% of the monomeric units substituted by ones carrying a dodecyl alkyl chain. This modification renders the complexes more hydrophobic, which is seen in the fact that precipitation of the complexes occurs at a lower mixing ratio and the biphasic region is also wider. The structures of the soluble IPECs are studied by a combination of light and neutron scattering (SANS). It is observed that the complexes formed possess typical radii of gyration of ≈30–40 nm, which become somewhat smaller with increasing length of the PDADMAC chain. The SANS data can be described well with the Beaucage model for complexes, where locally small hydrophobic domains of cylindrical shape are formed, whose persistence length decreases with increasing content of NaPA in the complexes. In contrast no such structures are seen for NaPA without the hydrophobic modification. The cylindrical domains are then arranged within larger-sized clusters of 30–40 nm, which become more compact with reduced length of the PDAMAC chains. The structure of the IPECs is largely determined by the presence of the hydrophobic modification of the NaPA and is further controlled by the length of the hydrophobic modification. Such IPECs of controlled structure, relatively small size, and containing hydrophobic domains are potentially interesting as delivery systems due to having domains of variable polarity.

This paper provides a review of the literature on the use of Pluronic (R) triblock copolymers for drug encapsulation over the last 10 years. A special focus is given to the progress of drug delivery systems (e.g., micelles, liposomes, micro/nanoemulsions, hydrogels and nanogels, and polymersomes and niosomes); the beneficial aspects of Pluronic (R) triblock copolymers as biological response modifiers and as pharmaceutical additives, adjuvants, and stabilizers, are also discussed. The advantages and limitations encountered in developing site-specific targeting approaches based on Pluronic-based nanostructures in cancer treatment are highlighted, in addition to inno-vative examples for improving tumor cytotoxicity while reducing side effects. info:eu-repo/semantics/publishedVersion

International audience; Hydrogels are deployed widely in all areas of regenerative medicine, including bioprinting. The transport and mechanical properties exhibited by hydrogel assemblies are controlled by their organization and hierarchical assembly. This paper points out the role of the nanoscale size and ordering of hydrophobic cross-linked domains on the mechanical and degradation properties of three-dimensional (3D) printed amphiphilic hydrogels. A series of six poly(propylene fumarate)-block-poly(ethylene glycol)-block-poly(propylene fumarate) (PPF-b-PEG-b-PPF) ABA triblock copolymers were synthesized by varying both the water-soluble PEG block and the cross-linkable hydrophobic terminal PPF block lengths. Self-assembled hydrogels were formed by dissolving these amphiphilic PPF-b-PEG-b-PPF copolymers in water and covalently cross-linking the PPF units via digital light processing (DLP) additive manufacturing. Differential scanning calorimetry (DSC), in situ diffuse reflectance infrared spectroscopy (DRIFTS-IR) measurements, small-angle neutron scattering (SANS), and compressive measurements highlight how structural properties correlate with mechanical properties within this hydrogel system. Finally, swelling and in vitro degradation tests showed the influence of the nanoscale ordering on the degradation timescale.

Amphiphilic copolymers with poly (alkyl acrylate) as hydrophobic and poly (acrylic acid) (AA) as hydrophilic block have been synthesised. The alkyl chain was varied from butyl to dodecyl, thereby varying systematically the polarity of the hydrophobic block whose length was between 35 and 70, while the PAA block had ~ 100 units. Such relatively short amphiphiles should equilibrate quickly in aqueous solution, and their corresponding self-assembly properties were characterised by means of critical micelle concentration (cmc) determination. Detailed information regarding the aggregate structures was obtained by static light scattering (SLS) and small angle neutron scattering (SANS). This could be correlated with the molecular architecture of the copolymers and the degree of ionisation of the PAA block. Generally, it is found that the aggregation numbers become smaller upon fully charging the PAA head group and only for dodecyl acrylate really well-defined micellar aggregates are formed. This means that the extent of hydrophobicity of the alkyl acrylate block and its length determine in a clear fashion the propensity for micelle formation and the mass and aggregation number of the formed micelles.

Poly(dimethylsiloxane) (PDMS) elastomer coatings containing an amphiphilic hydrolyzable diblock copolymer additive were prepared and their potential as marine antifouling and antiadhesion materials was tested. The block copolymer additive consisted of a PDMS first block and a random poly(trialkylsilyl methacrylate (TRSiMA, R = butyl, isopropyl)-co-poly(ethyleneglycol) methacrylate (PEGMA) copolymer second block. PDMS-b-TRSiMA block copolymer additives without PEGMA units were also used as additives. The amphiphilic character of the coating surface was assessed in water using the captive air bubble technique for measurements of static and dynamic contact angles. The attachment of macro- and microorganisms on the coatings was evaluated by field tests and by performing adhesion tests to the barnacle Amphibalanus amphitrite and the green alga Ulva rigida. All the additive-based PDMS coatings showed better antiadhesion properties to A. amphitrite larvae than to U. rigida spores. Field tests provided meaningful information on the antifouling and fouling release activity of coatings over an immersion period of 23 months.

In this research, the development and investigation of novel nanoobjects based on biodegradable random polypeptides and synthetic non-degradable glycopolymer poly(2-deoxy-2-methacrylamido-d-glucose) were proposed as drug delivery systems. Two different approaches have been applied for preparation of such nanomaterials. The first one includes the synthesis of block-random copolymers consisting of polypeptide and glycopolymer and capable of self-assembly into polymer particles. The synthesis of copolymers was performed using sequential reversible addition-fragmentation chain transfer (RAFT) and ring-opening polymerization (ROP) techniques. Amphiphilic poly(2-deoxy-2-methacrylamido-d-glucose)-b-poly(l-lysine-co-l-phenylalanine) (PMAG-b-P(Lys-co-Phe)) copolymers were then used for preparation of self-assembled nanoparticles. Another approach for the formation of polypeptide-glycopolymer particles was based on the post-modification of preformed polypeptide particles with an oxidized glycopolymer. The conjugation of the polysaccharide on the surface of the particles was achieved by the interaction of the aldehyde groups of the oxidized glycopolymer with the amino groups of the polymer on particle surface, followed by the reduction of the formed Schiff base with sodium borohydride. A comparative study of polymer nanoparticles developed with its cationic analogues based on random P(Lys-co-d-Phe), as well as an anionic one—P(Lys-co-d-Phe) covered with heparin––was carried out. In vitro antitumor activity of novel paclitaxel-loaded PMAG-b-P(Lys-co-Phe)-based particles towards A549 (human lung carcinoma) and MCF-7 (human breast adenocarcinoma) cells was comparable to the commercially available Paclitaxel-LANS.

The use of p,α-dimethylstyrene, potentially obtainable from renewable sources, as a substitute for styrene in the synthesis of amphiphilic copolymers is reported in this work. A series of novel poly(p,α-dimethylstyrene-co-maleic anhydride) (SMA) copolymers was synthesized, characterized, and studied as potential polymeric surfactants. After hydrolysis, the copolymers solution properties were compared to the similar and very well-known styrene-maleic acid copolymers. Both series of copolymers were synthesized using reversible addition-fragmentation chain transfer-mediated polymerization (RAFT), and a sample of poly(p,α-dimethylstyrene-co-maleic anhydride) was synthesized via classical free radical polymerization. The synthesized copolymers were studied from the point of view of their solution properties, with particular attention to the influence of the macromolecular and chemical structure on the surface tension of their aqueous solutions. Our results suggest that p,α-dimethylstyrene can be employed in copolymers with maleic anhydride, the resulting material being a valid alternative to SMA copolymers for various applications, such as emulsifiers and dispersants. Furthermore, the DMSMA series seems to be slightly more surface active than SMA.

Orientador: Maria Isabel Felisbert Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química Resumo: Copolímeros em bloco de 2-etil-2-oxazolina (EtOx), 4-vinilpiridina (4VP) e ácido 4-vinilbenzoico (4VBA) foram sintetizados e estudados com respeito a auto-organização em meio aquoso e responsividade a pH. Poli(2-etil-2-oxazolinas), PEtOx, com graus de polimerização pré-definidos e dispersidade (?) ? 1,1, preparadas por polimerização catiônica por abertura de anel (CROP) da EtOx e funcionalizadas com 2-bromo-2-metilpropionato, foram utilizadas como macroiniciadores para polimerização radicalar por transferência de átomos (ATRP) de 4VP ou 4VBA. Duas séries de copolímeros com dispersidade de massas molares inferior a 1,3 foram sintetizadas: copolímeros P(EtOx-b-4VP) com fração molar de 4VP entre 0,40 e 0,71 e copolímeros P(EtOx-b-4VBA) com fração molar de 4VBA entre 0,42 a 0,82. A concentração micelar crítica dos copolímeros P(EtOx-b-4VP) e P(EtOx-b-4VBA) em meio aquoso variou de 5 x 10-4 a 1,7 x 10-3 mg mL-1 e 4,0 x 10-3 a 5 x 10-3 mg mL-1, respectivamente. Agregados de P(EtOx-b-4VP) foram preparados por titulação de soluções em DMF com água, ou por variação do pH de soluções dos polímeros. Os copolímeros desta série se auto-organizaram em estruturas como micelas, micelas alongadas e vesículas, dependendo da composição e método de preparo dos agregados. O procedimento análogo de troca de solventes utilizando água/DMF foi adotado para a série de P(EtOx-b-4VBA) e resultou em agregados heterogêneos com superfície rica em PEtOx, sendo a formação dos agregados governada pela taxa de adição de não-solvente. Não foi possível obter agregados de P(EtOx-b-4VBA) de ajuste de pH. Os agregados de P(EtOx-b-4VP) e P(EtOx-b-4VBA) foram capazes de encapsular o corante hidrofóbico vermelho do Nilo em ampla faixa de pH, inclusive a pH = 2 e 12, no caso das séries P(EtOx-b-4VP) e P(EtOx-b-4VBA), respectivamente, condições nas quais os blocos de P4VP e P4VBA estão ionizados e os copolímeros são solúveis em água. Vesículas e misturas de vesículas e micelas de P(EtOx-b-4VP) foram reticuladas utilizando-se 1,4-dibromobutano (DBB) e Cu2+ como reticulantes. A estabilidade hidrolítica, o comportamento pH-responsivo e a redispersabilidade após liofilização dos agregados reticulados foram afetadas pela natureza do reticulante e densidade de reticulação. Os agregados reticulados puderam ser carregados com o corante de Reichardt em meio aquoso a pH = 7, e com vermelho do Nilo a pH = 7 e 2, sendo que a pH = 2 ambos os blocos estão intumescidos. Dextrana (massa molar = 10 kDa), encapsulada no interior dos agregados no processo de auto-organização, seguido de reticulação, foi liberada a pH = 2, devido à protonação do bloco de P4VP, indicando o potencial de aplicação dos copolímeros e seus agregados no encapsulamento e liberação de moléculas hidrofóbicas e hidrofílicas Abstract: Block copolymers based on 2-ethyl-2-oxazoline (EtOx), 4-vinylpyridine (4VP) and 4-vinylbenzoic acid (4VBA) were synthesized and studied regarding the self-assembly in aqueous medium and the pH-responsiveness. Poly(2-ethyl-2-oxazolines), PEtOx, with pre-determined degrees of polymerization and molar mass dispersity (?) ? 1.1, prepared by the cationic ring-opening polymerization of EtOx and functionalized with 2-bromo-2-methylpropionate, were used as macroinitiators for the atom radical transfer polymerization of 4VP or 4VBA. Two series of copolymers were produced: P(EtOx-b-4VP) and P(EtOx-b-4VBA) copolymers with 4VP and 4VBA molar fractions in the range of 0.40 – 0.71 and 0.42 and 0.82, respectively. The critical micellar concentration of the P(EtOx-b-4VP) and P(EtOx-b-4VBA) copolymers in aqueous medium varied between de 5 x 10-4 to 3,75 x 10-3 mg mL-1 and 1,7 x 10-3 to 5 x 10-3, respectively. Aggregates of P(EtOx-b-4VP) were prepared by titration of a DMF solution with water and by adjusting the pH of the solution. The copolymers of this series self-assembled in micelles, worm-like micelles and vesicles, depending on the composition and method of preparation. The solvent switch procedure was adopted for the P(EtOx-b-4VBA) series and resulted in heterogeneous aggregates with a PEtOx-rich surface, their formation being dependent on the non-solvent addition rate. P(EtOx-b-4VBA) were not obtained by the pH adjustment method. P(EtOx-b-4VP) and P(EtOx-b-4VBA) aggregates could be loaded with Nile red. Even in conditions which P4VP and P4VBA block are ionized and water soluble, at pH = 2 and pH = 12 for P(EtOx-b-4VP) and P(EtOx-b-4VBA), respectively, the loading was observed. Vesicles and a mixture of vesicles and micelles of P(EtOx-b-4VP) were crosslinked with 1,4-dibromobutane and Cu2+. The hydrolytic stability, the pH-responsiveness and the redispersibility of freeze-dried aggregates were affected by the nature of the crosslinked and the crosslinking density. The crosslinked aggregates could be loaded with Reichardt’s dye in aqueous medium at pH = 7, and with Nile red at pH = 7 and 2; at pH = 2 both blocks are swollen with water. Dextran (molar mass = 10 kDa), encapsulated in the aggregates during the self-assembly followed by crosslinking, was released at pH = 2, due to the protonation of the P4VP block. These results indicate the potential application of the block copolymers and their aggregates on the loading and further release of hydrophobic and hydrophilic substances Doutorado Físico-Química Doutor em Ciências FAPESP 2017/16615-5 CAPES 001

A series of anionic homopolymers, poly(sodium 2-(acrylamido)-2-methyl-1-propanesulfonate) (PAMPS) and amphiphilic copolymers of AMPS and sodium 11-(acrylamido)undecanoate (AaU), both block (PAMPS75-b-PAaUn), and random (P(AMPSm-co-AaUn)), were synthesized and their antiviral activity against Zika virus (ZIKV) was evaluated. Interestingly, while the homopolymers showed limited antiviral activity, the copolymers are very efficient antivirals. This observation was explained considering that under the conditions relevant to the biological experiments (pH 7.4 PBS buffer) the macromolecules of these copolymers exist as negatively charged (zeta potential about −25 mV) nanoparticles (4–12 nm) due to their self-organization. They inhibit the ZIKV replication cycle by binding to the cell surface and thereby blocking virus attachment to host cells. Considering good solubility in aqueous media, low toxicity, and high selectivity index (SI) of the PAMPS-b-PAaU copolymers, they can be considered promising agents against ZIKV infections.

A series of nanoparticles (NPs) with a hydrodynamic radius from 20 to 100 nm in PBS was developed over the solubilization of hydrophobic dye methyl pheophorbide a (chlorin e6 derivative) by amphiphilic copolymers of N-vinylpyrrolidone with (di)methacrylates. Photophysical properties and biological activity of the NPs aqueous solution were studied. It was found that the dye encapsulated in the copolymers is in an aggregated state. However, its aggregation degree decreases sharply, and singlet oxygen quantum yield and the fluorescence signal increase upon the interaction of these NPs with model biological membranes—liposomes or components of a tissue homogenate. The phototoxic effect of NPs in HeLa cells exceeds by 1.5–2 times that of the reference dye chlorin e6 trisodium salt—one of the most effective photosensitizers used in clinical practice. It could be explained by the effective release of the hydrophobic photosensitizer from the NPs into biological structures. The demonstrated approach can be used not only for the encapsulation of hydrophobic photosensitizers for PDT but also for other drugs, and N-vinylpyrrolidone amphiphilic copolymers show promising potential as a modern platform for the design of targeted delivery vehicles.

The self-assembly of amphiphilic block-copolymers is a convenient way to obtain soft nanomaterials of different morphology and scale. In turn, the use of a biomimetic approach makes it possible to synthesize polymers with fragments similar to natural macromolecules but more resistant to biodegradation. In this study, we synthesized the novel bio-inspired amphiphilic block-copolymers consisting of poly(N-methacrylamido-d-glucose) or poly(N-vinyl succinamic acid) as a hydrophilic fragment and poly(O-cholesteryl methacrylate) as a hydrophobic fragment. Block-copolymers were synthesized by radical addition–fragmentation chain-transfer (RAFT) polymerization using dithiobenzoate or trithiocarbonate chain-transfer agent depending on the first monomer, further forming the hydrophilic block. Both homopolymers and copolymers were characterized by 1H NMR and Fourier transform infrared spectroscopy, as well as thermogravimetric analysis. The obtained copolymers had low dispersity (1.05–1.37) and molecular weights in the range of ~13,000–32,000. The amphiphilic copolymers demonstrated enhanced thermal stability in comparison with hydrophilic precursors. According to dynamic light scattering and nanoparticle tracking analysis, the obtained amphiphilic copolymers were able to self-assemble in aqueous media into nanoparticles with a hydrodynamic diameter of approximately 200 nm. An investigation of nanoparticles by transmission electron microscopy revealed their spherical shape. The obtained nanoparticles did not demonstrate cytotoxicity against human embryonic kidney (HEK293) and bronchial epithelial (BEAS-2B) cells, and they were characterized by a low uptake by macrophages in vitro. Paclitaxel loaded into the developed polymer nanoparticles retained biological activity against lung adenocarcinoma epithelial cells (A549).

Matrix-assisted laser/desorption ionization (MALDI) has become a very popular ionization technique for mass spectrometry of synthetic polymers because it allows high throughput analysis of low amounts of sample while avoiding the complexity introduced by extensive multiple charging of electrospray ionization. Yet, fundamental mechanisms underlying this ionization process are not fully understood, so development of sample preparation methods remains empirical. Reliable prediction for the optimal matrix/analyte/salt system is indeed still not possible for homopolymers and it becomes even more challenging in the case of amphiphilic block copolymers where conditions dictated by one block are not compatible with MALDI requirements of the second block. In order to perform MALDI of copolymers composed of poly (ethylene oxide) (PEO) and polystyrene (PS) blocks, it was postulated here that experimental conditions suitable for both species would also be successful for PEO-b-PS. Accordingly, designs of experiments based on Quantitative Structure Activity Relationship (QSAR) analysis were first implemented, studying the influence of 19 matrices and 26 salts on the laser fluence requested for successful MALDI. This analysis first permitted to highlight correlations between the investigated 10 descriptors of matrices and salts and the analytical response, and then to construct models that permits reliable predictions of matrix/salt couples to be used for one or the other homopolymer. Selected couples were then used for MALDI of a PEO-b-PS copolymer but no general trend was observed: experimental conditions expected to work often failed whereas ionic adducts of the copolymer were clearly detected with some matrix/salt systems that were shown to badly perform for constituting homopolymers. Overall, this rules out the working assumption stating that the MALDI behavior of chains composed of PEO and PS segments should combine the behavior of the two polymeric species. Yet, although requiring a dedicated design of experiments, MALDI of the amphiphilic PEO-b-PS copolymer was achieved for the first time.

Nanosized systems of DOX with antitumor activity on the base of micelle-like particles of amphiphilic thermosensitive copolymers of N-vinylpyrrolidone (VP) with triethylene glycol dimethacrylate (TEGDM), and N-vinylpyrrolidone and methacrylic acid (MAA) with TEGDM were explored. They were investigated in aqueous solutions by electron absorption spectroscopy, dynamic light scattering and cyclic voltammetry. Experimental data and quantum-chemical modeling indicated the formation of a hydrogen bond between oxygen-containing groups of monomer units of the copolymers and H-atoms of OH and NH2 groups of DOX; the energies and H-bond lengths in the considered structures were calculated. A simulation of TDDFT spectra of DOX and its complexes with the VP and TEGDM units was carried out. Electrochemical studies in PBS have demonstrated that the oxidation of encapsulated DOX appeared to be easier than that of the free one, and its reduction was somewhat more difficult. The cytotoxicity of VP-TEGDM copolymer compositions containing 1, 5 and 15 wt% DOX was studied in vitro on HeLa cells, and the values of IC50 doses were determined at 24 and 72 h of exposure. The copolymer compositions containing 5 and 15 wt% DOX accumulated actively in cell nuclei and did not cause visual changes in cell morphology.

This paper deals with the development of polymeric nanocarriers based on amphiphilic copolymers of N-vinyl-2-pyrrolidone and acrylic acid of various molecular weights synthesized through the AIBN-initiated radical copolymerization of N-vinyl-2-pyrrolidone and acrylic acid in the presence of n-octadecyl mercaptan. The structure of the copolymers is characterized by 1Н NMR, 13С NMR, IR and MALDI-TOF MS spectroscopy. It is shown that the length of the hydrophilic block defines the size of the nanoaggregates while impacting the steric stabilization efficiency and the probability of the interchain hydrogen bond formation. The hydrogen bonds formation between the residues of N-vinyl-2-pyrrolidone and acrylic acid is in agreement with the reduction of the ζ-potential of the nanoaggregates and the critical aggregation concentrations upon increasing the molecular weight. The presence of acrylic acid residues in the amphiphilic macromolecules leads to a higher affinity for doxorubicin and slow partial release of doxorubicin bonded with the aggregates’ corona, which is helpful for reducing its cardiac toxicity. Nanoaggregates with a paclitaxel-loaded hydrophobic core are obtained, showing the possibility of dual loading. The amphiphilic copolymers of N-vinyl-2-pyrrolidone and acrylic acid containing an n-octadecyl thio end group are thus promising candidates for combination cancer therapy with immobilized anti-cancer drugs, paclitaxel, and doxorubicin.

This article presents the evaluation of diblock and triblock poly(ethylene glycol)-b-poly(1,3-trimethylene carbonate) amphiphilic copolymers (PEG-PTMCs) as excipients for the formulation of long-acting injectables (LAIs). Copolymers were successfully synthesised through bulk ring-opening polymerisation. The concomitant formation of PTMC homopolymer could not be avoided irrespective of the catalyst amount, but the by-product could easily be removed by gel chromatography. Pure PEG-PTMCs undergo faster erosion in vivo than their corresponding homopolymer. Furthermore, these copolymers show outstanding stability compared to their polyester analogues when formulated with amine-containing reactive drugs, which makes them particularly suitable as LAIs for the sustained release of drugs susceptible to acylation.

A family of amphiphilic copolymers containing hydrophobic cholate pendants has been prepared by copolymerization of cholic acid-based monomer 2-(methacryloxy)-ethyl cholate (MAECA) with polyethylene glycol methyl ether methacrylate (PEGMA). The polymers differ for the content of MAECA that increases from 0 to 35%. The copolymers partition within liposomes and display potent ionophoric activity forming large pores in the membrane and allowing the leakage of small inorganic ions (H+, Na+) and of large polar organic molecules (calcein). Their activity is strictly correlated to the content of cholic acid subunits, increasing as the fraction of cholate moiety increases.

Orientador: Maria Isabel Felisberti Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química Resumo: Copolímeros tribloco baseados em poli(metacrilato de oligo(etileno glicol) metil éter) (POEGMA), um polímero termoresponsivo, e poli(4-vinil piridina) (P4VP), um polímero pH-responsivo, ou poli(metacrilato de dimetilaminoetila) (PDMAEMA), um polímero termo- e pH-responsivo foram sintetizados empregando-se a técnica de polimerização por transferência reversível de cadeia por adição-fragmentação (RAFT). POEGMA com grau de polimerização (DP) similar, porém com cadeia lateral OEG com diferentes DP, foram sintetizados, usando S,S-Bis(?,?’ dimetil-?’’ácido acético) (CMP) como agente de transferência de cadeia (CTA) bifuncional simétrico, e usados como macro-CTA para a copolimerização com 4VP ou DMAEMA. Os copolímeros se auto-organizaram em soluções aquosas, formando estruturas que podem ser afetadas pelo método de preparo, concentração, pH e temperatura. O método de preparo teve um efeito mais pronunciado nas estruturas auto-organizadas do copolímero POEGMA-b-P4VP-b-POEGMA com o maior bloco de P4VP. Partículas esféricas foram observadas a pH > pKa da P4VP, enquanto micelas interconectadas foram observadas a pH 3 e T > Tcp (temperatura crítica) do POEGMA, devido às pontes de P4VP entre os blocos de POEGMA presentes em núcleos adjacentes. A concentração micelar crítica a pH 3 e T > Tcp foi de 0,022 mg mL-1. A auto-organização resultou em estruturas capazes de encapsular o vermelho do Nilo a pH ? 7. Além disso, a coordenação de blocos de P4VP com Cu2+ resultou em um nanogel responsivo à temperatura e ao pH. A copolimerização do POEGMA com o DMAEMA foi mais eficaz para a produção de copolímeros com uma variação de composição mais ampla, do que o observado para a série POEGMA-b-P4VP-b-POEGMA, devido à estabilidade similar entre radicais do CTA e dos monômeros. Ambos os blocos POEGMA e PDMAEMA são hidrofílicos, dependendo da temperatura e pH. As imagens de cryo-EM mostraram que os copolímeros POEGxMAy-b-PDMAEMAz-b-POEGxMAy se auto-organizam como micelas esféricas ou alongadas, dependendo da concentração e da temperatura do meio. O comportamento de fases foi investigado por espectroscopia 1H RMN a pH 9 e a diferentes temperaturas. A pH 9, os blocos de PDMAEMA estão desprotonados e o aumento da temperatura resultou na desidratação de ambos os blocos PDMAEMA e POEG5MA e na formação de agregados. A baixas concentrações (0,125 mg mL-1), estes agregados mantiveram-se estáveis em toda a faixa de temperatura. Entretanto, a altas concentrações (5 mg mL-1) ocorreu a precipitação acima de 70 °C. O aumento da massa molar do bloco PDMAEMA causou a diminuição do raio hidrodinâmico (RH) de agregados a pH 7 e 9, a 25 °C. Este efeito foi gradativamente atenuado pelo aumento da cadeia lateral do OEG e, portanto, aumento da hidrofilicidade, que resultou no aumento da Tcp dos copolímeros. A incorporação do corante de Reichardt mostrou que os copolímeros POEGMA-b-PDMAEMA-b-POEGMA são capazes de incorporar moléculas hidrofóbicas e que o aumento da temperatura das soluções não altera o microambiente em que o corante se encontra Abstract: Triblock copolymers based on poly(oligo(ethylene glycol) methyl ether) methacrylate (POEGMA), a thermoresponsive polymer, and poly(4-vinyl pyridine) (P4VP), a pH-responsive polymer, or poly(dimethylaminoethyl methacrylate) (PDMAEMA), a thermo- and pH-responsive polymer were synthesized using the addition-fragmentation reversible chain transfer polymerization (RAFT). POEGMA with a similar degree of polymerization (DP) but with OEG side chain with different DP were synthesized using S,S-Bis(?,?' dimethyl-?''acetic acid) (CMP) as a symmetric bifunctional chain transfer agent (CTA), and used as macro-CTA for copolymerization with 4VP or DMAEMA. The copolymers self-assemble in aqueous solutions, forming structures that can be affected by the preparation method, concentration, pH, and temperature. The preparation method had a more pronounced effect on the self-assembled structures of the POEGMA-b-P4VP-b-POEGMA copolymer with a longer P4VP block. Spherical particles were observed at pH > pKa of P4VP, while interconnected micelles were observed at pH 3 and T > Tcp (critical temperature) of POEGMA, due to the P4VP-bridging between the POEGMA block in adjacent cores. The critical micellar concentration at pH 3 and T > Tcp was 0.022 mg mL-1. The self-assembly resulted in structures capable of encapsulating Nile red at pH ? 7. Furthermore, the coordination of P4VP blocks with Cu2+ resulted in a nanogel responsive to temperature and pH. The copolymerization of POEGMA with DMAEMA was more effective to produce copolymers with a wider composition range than that observed for the POEGMA-b-P4VP-b-POEGMA series, due to the similar stability between the radicals from the CTA and the monomers. Both POEGMA and PDMAEMA blocks are hydrophilic depending on temperature and pH. Cryo-EM images showed that the POEGxMAy-b-PDMAEMAz-b-POEGxMAy copolymers self-assemble as spherical and elongated micelles depending on their concentration and temperature. The phase behavior was investigated by 1H NMR spectroscopy at pH 9 and different temperatures. At pH 9, the PDMAEMA blocks are deprotonated and the increase in temperature resulted in a dehydration of both PDMAEMA and POEG5MA blocks and the formation of aggregates. At low concentrations (0.125 mg mL-1), these aggregates remained stable over the entire temperature range. However, at high concentrations (5 mg mL-1) precipitation occurred above 70 °C. The increase in the molar mass of the PDMAEMA block caused a decrease in the hydrodynamic radius (RH) of aggregates at pH 7 and 9, at 25 °C. This effect was gradually attenuated by the increase in the OEG side chain and, therefore, increased hydrophilicity, which increased the Tcp of the copolymers. Reichardt dye incorporation showed that POEGMA-b-PDMAEMA-b-POEGMA copolymers can incorporate hydrophobic molecules and that increasing the temperature of the solutions does not change the microenvironment in which the dye was incorporated Doutorado Físico-Química Doutora em Ciências FAPESP 2017/24938-9 CAPES 1733550

Hydrated copolymers of N-vinylpyrrolidone (VP) with triethylene glycol dimethacrylate as a promising platform for biologically active compounds (BAC) were investigated by different physical chemical methods (dynamic light scattering, infrared spectroscopy, thermal gravimetric analysis , and differential scanning calorimetry) and the quantum chemical modeling of water coordination by the copolymers in a solution. According to the quantum chemical simulation, one to two water molecules can coordinate on one O-atom of the lactam ring of VP units in the copolymer. Besides the usual terminal coordination, the water molecule can form bridges to bind two adjacent C=O groups of the lactam rings of VP units. In addition to the first hydration shell, the formation of a second one is also possible due to the chain addition of water molecules, and its structure depends on a mutual orientation of C=O groups. We showed that N,N-dimethylbiguanidine hydrochloride (metformin) as a frontline drug for the treatment of type 2 diabetes mellitus can be associated in aqueous solutions with free and hydrated C=O groups of the lactam rings of VP units in studied copolymers. Based on the characteristics of the H-bonds, we believe that the level of the copolymer hydration does not affect the behavior and biological activity of this drug, but the binding of metformin with the amphiphilic copolymer will delight in the penetration of a hydrophilic drug across a cell membrane to increase its bioavailability.

Over the past decade, the polymerization-induced self-assembly (PISA) has become an efficient tool for the preparation of block-copolymer nanoparticles at high solid contents, in both organic solvents and water. Nonetheless, most of the studied systems are currently based on simple AB diblock copolymers (where A = solvophilic, stabilizer block and B = solvophobic block). Another interesting class of block copolymers are associative BAB triblocks. To the best of our knowledge, very few studies report their synthesis by PISA and the polymerizations are performed in mixtures of alcohol and water. In this work, for the first time, a straightforward strategy to synthesize, in pure water, BAB triblock copolymers through the use of reversible deactivation radical polymerization is developed and studied in details. To this end, an hydrophilic, bifunctional macroRAFT agent of poly(N,N-dimethylacrylamide) with a central benzoic acid group was used in the aqueous dispersion polymerization of diacetone acrylamide. Various morphologies (spheres, fibers and vesicles) could be obtained with good polymerization controls. Moreover, we showed that the particle morphology and colloidal stability strongly depend on the degree of ionization of the central charge in the stabilizer loop. Then, the mechanism of formation of these triblock copolymers during PISA was investigated. Finally, we showed the possibility to form dynamic networks of BAB copolymers – using a one-pot process entirely in water – leading to the formation of thermoresponsive copolymer networks with tunable viscosity.; Depuis une dizaine d’années, l’auto-assemblage induit par polymérisation (PISA) s’est révélé être un outil efficace pour la préparation de nanoparticules à base de copolymères amphiphiles à des taux de solide élevés, aussi bien dans des solvants organiques que dans l’eau. Jusqu’à présent, la plupart des systèmes étudiés concernaient les copolymères diblocs AB (dans lesquels A = bloc solvophile stabilisant, et B = bloc solvophobe). Un autre type de copolymères à blocs intéressant est le tribloc associatif BAB. Peu d’études décrivent leur synthèse par PISA et les polymérisations sont réalisées dans des mélanges alcool/eau. Dans ce travail de thèse, et pour la première fois, la synthèse par voie radicalaire contrôlée de copolymères triblocs BAB par PISA a été réalisée dans l’eau pure et une étude approfondie du système a été menée. Un macro-agent RAFT hydrophile symétrique à base de poly(acrylamide de N,N-diméthyle) possédant une unité acide benzoïque au centre, et le diacétone acrylamide (blocs B) ont été sélectionnés pour étudier ce système. Des particules de différentes morphologies (sphères, fibres et vésicules) ont pu être obtenues avec de bons contrôles des polymérisations. Nous avons montré que le degré d’ionisation de l’unité centrale acide benzoïque du bloc stabilisant jouait un rôle crucial dans la stabilité du système et la morphologie obtenue. Le mécanisme de formation de ces copolymères triblocs au cours de la PISA a également été étudié. Enfin, nous avons montré qu’il était possible de former des réseaux dynamiques de copolymères BAB – via un procédé one-pot entièrement dans l’eau – menant à la formation de systèmes thermosensibles avec une viscosité modulable.

International audience; It is reported that low concentration of amphiphilic triblock copolymers of pMeOx‐b‐pTHF‐b‐pMeOx structure (TBCPs) improves gene expression in skeletal muscle upon intramuscular co‐injection with plasmid DNA. Physicochemical studies carried out to understand the involved mechanism show that a phase transition of TBCPs under their unimer state is induced when the temperature is elevated from 25 to 37 °C, the body temperature. Several lines of evidences suggest that TBCP insertion in a lipid bilayer causes enough lipid bilayer destabilization and even pore formation, a phenomenon heightened during the phase transition of TBCPs. Interestingly, this property allows DNA translocation across the lipid bilayer model. Overall, the results indicate that TBCPs exhibiting a phase transition at the body temperature is promising to favor in vivo pDNA translocation in skeletal muscle cells for gene therapy applications.

RESUMEN En años recientes hubo un auge del uso de terapias génicas para el tratamiento de enfermedades de gran incidencia, como el cáncer. Generalmente, estas se basan en la liberación de material genético como plásmidos, en el núcleo celular, con lo cual se corrige una función o se induce la producción de proteínas deficientes a nivel fisiológico. Para llevar a cabo la terapia génica se requiere de vectores capaces de encapsular el material genético y garantizar su entrega en el núcleo celular. Los polímeros catiónicos sintéticos han llamado la atención como vectores, debido a su capacidad de condensar ácidos nucleicos para formar partículas que los protegen de la degradación enzimática y facilitan su captación celular. La polietilenimina y el polimetacrilato de N, N-dimetilaminoetilo son los polímeros catiónicos más eficaces para la administración génica. Sin embargo, estos requieren modificaciones químicas específicas para eliminar o disminuir algunas limitaciones tales como su alta citotoxicidad y baja biodegradabilidad. En este artículo se analizan algunas de estas modificaciones, enfocándose en avances recientes en el desarrollo de copolímeros anfifílicos como precursores de nanopartículas usadas como vectores génicos. SUMMARY During recent years, the use of genetic therapies has taken relevance in the treatment of high-incidence diseases such as cancer. Usually, they are based on the release of genetic material, as plasmids, into the cell nucleus, which corrects a function or induces the production of a deficient protein at the physiological level. To carry out gene therapy, vectors capable of encapsulating the genetic material and guaranteeing its delivery in the target cell nucleus are required. Synthetic cationic polymers have attracted great attention as vectors due to their ability to condense nucleic acids to form particles that protect them from enzymatic degradation and facilitate their cellular uptake. Polyethylenimine and poly (N, N-dimethylaminoethyl methacrylate) are the most effective cationic polymers for gene delivery. However, these polymers require specific chemical modifications to either avoid or diminish their high cytotoxicity and low biodegradability. This review analyzes some of these modifications, focusing on recent advances in the development of amphiphilic copolymers as precursors of nanoparticles used as gene vectors.

Due to unique chelating and macrocyclic effects, crown ether compounds exhibit wide application prospects. They could be introduced into amphiphilic copolymers to provide new trigger mode for drug delivery. In this work, new amphiphilic random polymers of poly(lipoic acid-methacrylate-co-poly(ethylene glycol) methyl ether methacrylate-co-N-isopropylacrylamide-co-benzo-18-crown-6-methacrylamide (abbrev. PLENB) containing a crown ether ring and disulphide bond were synthesized via RAFT polymerization. Using the solvent evaporation method, the PLENB micelles were formed and then used to load substances, such as doxorubicin hydrochloride (DOX) and gold nanoparticles. The results showed that PLENB exhibited a variety of lowest critical solution temperature (LCST) in response to the presence of different ions, such as K+, Na+ and Mg2+. In particular, the addition of 150 mM K+ increased the LCST of PLENB from 31 to 37 °C and induced the release of DOX from the PLENB@DOX assemblies with a release rate of 99.84% within 12 h under 37 °C. However, Na+ and Mg2+ ions could not initiate the same response. Furthermore, K+ ions drove the disassembly of gold aggregates from the PLENB-SH@Au assemblies to achieve the transport of Au NPs, which is helpful to construct a K+-triggered carrier system.

In this publication the results are presented of an analysis of statistical properties of the distribution of monomer units in copolymer chains synthesized in silico based on vinylcaprolactam and vinylimidazole. Such polymer chains demonstrate one of the basic properties of protein molecules, and exactly, they are able under conditions of a «bad» solvent (for vinylcaprolactam blocks) to take a dense globular structure with a hydrophobic core surrounded by a hydrophilic «corona». Despite the external similarity of the morphology of globules with protein-like copolymers, the distribution of comonomers attached to the first hydrophobic block has a random character.

Summary Amphiphilic copolymers capable of extracting membrane proteins directly from lipid bilayers into “native nanodiscs” promise a simpler membrane protein sample preparation procedure for structural and functional studies. Unfortunately, the selection of nanodisc-forming copolymers is currently limited to molecules that are heterogeneous in terms of molecular weight and monomer sequence, limiting their efficacy in extracting membrane proteins. Here, we report the development of a highly alternating copolymer composed of acrylic acid and styrene by taking advantage of the fundamental reactivity ratios of these monomers. We show that these copolymers, which we term AASTY, are effective solubilizers of membrane proteins expressed in mammalian cells by virtue of their structured amphiphilicity. These AASTY copolymers are promising alternatives to styrene-maleic acid copolymers and provide a new chemical platform for structural and functional characterization of integral membrane proteins in native nanodiscs.

We present new results of computer simulations of synthesis of block A-AB copolymers. Our model shows that compact and water-soluble globules, which can be used as basis for sinzymes, can be obtained in narrow range of investigated parameters.

In this work we study the synthesis and properties of copolymers constituted of lauryl methacrylate and poly(ethylene glycol) methyl ether methacrylate monomers, prepared by atom transfer radical copolymerization in the entire composition range (with low and high monomer conversion). We propose a description of the copolymer microstructure, and evaluate the composition drift effect in the thermal and solution properties of the obtained copolymers. Nuclear magnetic resonance (NMR) was used to determine the chemical composition of the copolymers, while differential scanning calorimetry and themogravimetric analysis was employed to understand the thermal chracteristics. Rheological studies were conducted to obtain the viscosity and viscoelastic properties that were correlated with thermal transitions at different temperatures. Finally, dynamic light scattering (DLS) and surface tension measurements were used to evaluate the copolymer solution properties. The incorporation of an oil phase in the self-assembled aggregates was evaluated by DLS and characterized by atomic force microscopy, diffusion-ordered spectroscopy NMR and nuclear Overhauser effect NMR spectroscopy. Our results suggest a longer sequence of LMA units in the copolymer chain and a drift effect in the case of high monomer conversions. A clear dependence on copolymer composition and microstructure to disperse an oil phase in water was observed. We believe that these results bring valuable knowledge that advances the field of macrosurfactants as well as their potential applications in oil recovery and other industrial processes., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas

Orientadores: Maria Isabel Felisberti, Cesar Liberato Petzhold Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química Resumo: Copolímeros em bloco e anfifílicos, baseados nos metacrilato de sacarose (SMA) e metacrilato de metila (MMA) foram sintetizados via polimerização controlada por transferência reversível de cadeia adição/fragmentação (RAFT), em duas etapas sequenciais. Copolímeros dibloco foram sintetizados empregando-se o agente de transferência de cadeia (CTA) ditiobenzoato de 2-cianopropila (CPDB), enquanto os copolímeros tribloco foram sintetizados empregando-se o CTA S,S'-Bis(R,R¿ dimetil-R¿¿ ácido acético) -tritiocarbonato (CMP). Nos copolímeros anfifílicos, os blocos hidrofílico e hidrofóbico são o poli(metacrilato de sacarose) (PSMA) e poli(metacrilato de metila) (PMMA), respectivamente. Inicialmente, foram sintetizados homopolímeros, apresentando fragmentos do CTA nas terminações de cadeias, do tipo PMMA-CPDB, PMMA-CMP-PMMA e PSMA-CMP-PSMA, os quais foram empregados como macroCTA para a etapa de copolimerização com SMA ou MMA, dando origem aos copolímeros dibloco P(MMA-b-SMA) e tribloco P(MMA-b-SMA-b-MMA) e P(SMA-b-MMA-b-SMA), respectivamente. O emprego do CTA CMP permitiu a síntese de copolímeros tribloco simétricos em apenas duas etapas de síntese. Os macroCTA se mostraram capazes de promover a extensão da cadeia mesmo após um período de 36 meses de armazenamento a -4°C. MacroCTA e copolímeros foram caracterizados por ressonância magnética nuclear de prótons e carbono (1H e 13C RMN), cromatografia de permeação em gel (GPC), analise calorimétrica diferencial exploratória (DSC), analise termogravimétrica (TGA), difratometria de raios-X (DRX) e solubilidade em diferentes solventes. Os copolímeros apresentaram a capacidade de se organizarem em contato a um solvente seletivo, e também no estado sólido. As estruturas resultantes da organização dos copolímeros no estado sólido e em solução/dispersão foram investigadas por microscopia eletrônica de varredura (SEM), espalhamento dinâmico de luz (DLS), medidas de potencial zeta e espalhamento de raios-X a baixos ângulos (SAXS). Também se mostraram capazes de emulsionar água/óleo e, de encapsular e estabilizar moléculas hidrofóbicas em meio aquoso. Copolímeros contendo fração molar de ~10 mol% de SMA foram solúveis em dimetilformamida (DMF) e apresentaram solubilidade parcial em benzeno, tetrahidrofurano (THF) e água, sendo que nestes solventes os copolímeros se apresentaram na forma de estruturas organizadas dispersas do tipo core-shell vesiculares e com dimensões dependentes da massa molar e configuração dos copolímeros. O caráter anfifílico dos copolímeros foi comprovado por 1H RMN em benzeno e água. As estruturas vesiculares foram observadas por SEM e os diâmetros médios determinados por DLS e SEM. Resultados de SAXS indicaram que os copolímeros dibloco P(MMA-b-SMA) e tribloco P(MMA-b-SMA-b-MMA) e P(SMA-b-MMA-b-SMA) no estado sólido se organizam em estruturas lamelares, cujo período longo aumenta com a massa molar do polímero Abstract: Amphiphilic block copolymers based on sucrose methacrylate (SMA) and methyl methacrylate (MMA) were synthesized by a two sequential step of reversible addition/fragmentation chain transfer polymerization (RAFT). Diblock and triblock copolymers were synthesized using 2-cyano-2-propyl benzodithioate (CPDB) and S,S'-Bis(R,R'-dimethyl-R"-acetic acid)-trithiocarbonate (CMP) as chain transfer agents (CTA), respectively. The hydrophilic and the hydrophobic blocks of the amphiphilic copolymers are poly(sucrose methacrylate) (PSMA) and poly(methyl methacrylate) (PMMA), respectively. Initially, homopolymers containing fragments of CTA at the chain end PMMA-CPDB, PMMA-CMP-PMMA PSMA-CMP-PSMA, were synthesized and characterized and further used as macroCTA for copolymerization of SMA and MMA, resulting in diblock P(MMA-b-SMA) and triblock P(MMA-b-SMA-b-MMA) and P(SMA-b-MMA-b-SMA) copolymers, respectively. The CTA CMP allowed synthesizing symmetrical triblock copolymers just in two stages. MacroCTA were capable to promote chain extension even after a period of 36 months of storage at -4 ° C MacroCTA and copolymers were characterized by proton and carbon nuclear magnetic resonance (1H and 13C NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and the solubility of the copolymers in different solvents. The copolymers presented the self-assembly capability in contact with a selective solvent, and in solid state. The structures resulting from self-assembly of the copolymers were characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), zeta potential measurements, small angle X-ray scattering (SAXS) and Fourier transform infrared spectroscopy by attenuated total reflectance (FTIR-ATR). In addition, the copolymers were capable to stabilize nonpolar molecules such as benzene, dichloromethane and aromatic dyes in aqueous medium. Copolymers containing ~ 10 mol% of SMA were soluble in dimethylformamide (DMF) and exhibited partial solubility in benzene, tetrahydrofuran (THF) and water. In these solvents, the copolymers presented as dispersed self-assembled structures of the vesicular core-shell type with dimensions dependent on the molar mass and configuration of the copolymers. The amphiphilic feature of the copolymers were demonstrated by 1H NMR in benzene and water. The vesicular structures were observed by SEM and their mean diameters determined by DLS and SEM. SAXS experiments provided evidences of the self-assembly of the diblock copolymers P(MMA-b-SMA) and triblock P(MMA-b-SMA-b-MMA) and P(SMA-b-MMA-b-SMA) in the solid state in lamellar structures with long period dependent on the molar mass of the polymers determined by SAXS Doutorado Físico-Química Doutor em Ciências CAPES FAPESP 2015/25406-5 e 2016/03394-8 CNPEM CNPQ 444329/2014-9

The effect of UV irradiation on the cloud points (CP) of aqueous solutions of a random 1:1 copolymer of oligo(ethylene glycol) methyl ether methacrylate (OEGMA(500)) and a 2-(hydroxyimino)aldehyde (HIA) functionalized methacrylate is presented. CPs are determined by visible spectroscopy and dynamic light scattering (DLS). H-1 and C-13 NMR experiments are carried out in D2O and DMSO-d(6) on the polymer and on an HIA-functionalized model of the photoresponsive repeat unit. UV-irradiated solutions exhibit an unprecedented increase of the phase-separation temperature for an OEGMA photoresponsive copolymer (10-22 degrees C, depending on concentration and irradiation conditions). Phase separation is reversible with little hysteresis. With both pristine and irradiated polymer solutions, aggregate dimensions are 100 nm form at the CP and gradually grow as temperature increases, whereas the light-induced processes of the repeat unit model in DMSO-d(6) are well identified (e.g., oxime E/Z isomerization and Norrish-Yang cyclization of the aldehyde moiety), it is not straightforward to extrapolate such behavior to the polymeric solution in water. The remarkably large phototriggered thermal effect in the present work motivates further investigations on the solvent-dependent photochemistry of HIA as a promising functional group for the synthesis of multi-stimuli responsive materials.

Results of coarse grained simulations of synthesis of amphiphilic AB copolymers with the aim to obtain compact and stable core-shell nanostructures are presented. It is shown that the target nanostructures are formed at an optimal monomer ratio in the reaction mixture. These results can be used as the reference point in a laboratory synthesis.

International audience; In the development of subunit vaccines with purified or recombinant antigens for cancer and infectious diseases, the design of improved and safe adjuvants able to efficiently target the antigen presenting cells, such as dendritic cells, represents a crucial challenge. Nanoparticle-based antigen delivery systems have been identified as an innovative strategy to improve the efficacy of subunit vaccines. Among them, self-assembled micellar nanoparticles from amphiphilic (macro)molecules have recently emerged as promising candidates. In this short review, we report on the recent research findings highlighting the versatility and potential of such systems in vaccine delivery.

Microbial biofilms are known to support a number of human infections, including those related to medical devices. This work is focused on the development of novel dual-function amphiphilic random copolymers to be employed as coatings for medical devices. Particularly, copolymers were obtained by polymerization of an antimicrobial cationic monomer (bearing tertiary amine) and an antioxidant and antimicrobial hydrophobic monomer (containing hydroxytyrosol, HTy). To obtain copolymers with various amphiphilic balance, different molar ratios of the two monomers were used. 1H NMR and DSC analyses evidenced that HTy aromatic rings are able to interact with each other leading to a supra-macromolecular re-arrangement and decrease the copolymer size in water. All copolymers showed good antioxidant activity and Fe2+ chelating ability. Cytotoxicity and hemolytic tests evidenced that the amphiphilic balance, cationic charge density and polymer size in solution are key determinants for polymer biocompatibility. As for the antimicrobial properties, the lowest minimal inhibitory concentration (MIC = 40 μg/mL) against Staphylococcus epidermidis was shown by the water-soluble copolymer having the highest HTy molar content (0.3). This copolymer layered onto catheter surfaces was also able to prevent staphylococcal adhesion. This approach permits not only prevention of biofilm infections but also reduction of the risk of emergence of drug-resistant bacteria. Indeed, the combination of two active compounds in the same polymer can provide a synergistic action against biofilms and suppress reactive species oxygen (ROS), known to promote the occurrence of antibiotic resistance. © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Title: The study of the association behaviour of the amphiphilic copolymers in solutions containing low molar compounds by means of computer simulations. Author: Mgr. Karel Šindelka Department: Faculty of Science, Charles University Supervisor: Doc. Ing. Zuzana Limpouchová, Csc. Abstract This doctoral thesis focuses on the study of electrostatic self- and co-assembly in complex polymer solutions containing polyelectrolyte (PE) block copolymers together with surfactants, neutral homopolymers, or oppositely charged PEs using the dissipative particle dynamics (DPD). It was shown that the electro- static self-assembly depends not only on the cooperative interactions of oppo- sitely charged PE chains, but also on the amphiphilicity of PE species or on the polymer block compatibility, among other properties. PEs with incompatible blocks create well-defined core-shell structures, while large ill-defined crew-cut aggregates form from PEs with compatible blocks In non-stoichiometric mixtures of PEs with incompatible blocks, co-assembled nanoparticles are smaller than in stoichiometric mixtures and are charged. The destabilization of larger aggregates depends on how the PE charge surplus is introduced: the effect is strongest when the density of the surplus PE charge on the PE chains is increased and weakest when the...

Background Polyglycerol is an attractive hydrophilic building block of amphiphilic copolymers for biomedical and pharmaceutical applications due to its biocompatibility, facile chemical modification, and anti-fouling activity. Herein we introduce theranostic nanoemulsions incorporating anti-cancer therapeutic and contrast agents using linear polyglycerol-poly(ε-caprolactone) diblock copolymers (PG-b-PCL). Lipiodol is used as a core oil that dissolves paclitaxel and serves as a contrast agent for computer tomography (CT). Methods PG-b-PCL is synthesized by three-step processes: polymerization of ethoxyethyl glycerol ether; ring-opening polymerization of ε-caprolactone; and deprotection of the PEEGE block. In vitro cytotoxicity of the polyglycerolated lipiodol nanoemulsions is demonstrated using HeLa ovarian cancer cells. The applicability of the prepared nanoemulsions as a contrast agent for CT imaging is also evaluated using micro-CT. Results Three compositions of PG-b-PCL with different block lengths are synthesized to prepare nanoemulsions. The polyglycerolated lipiodol nanoemulsions exhibit excellent anti-cancer activities, while placebo nanoemulsions have no significant cytotoxicity under the same condition. Micro-CT imaging of the nanoemulsions confirms the ability of nanoemulsions as a contrast agent. Conclusions This study suggests that PG-b-PCL is a promising polymeric emulsifier for effective stabilization and surface functionalization of drug delivery nanocarriers for therapeutic and imaging agents. Electronic supplementary material The online version of this article (10.1186/s40824-017-0108-4) contains supplementary material, which is available to authorized users.

Amphiphilic copolymers were obtained by grafting azide-terminated polyglycidol, poly(ethylene oxide), or poly(2-hydroxyethyl acrylate) chain segments onto alkyne-functionalized arborescent poly(γ-benzyl l-glutamate) (PBG) cores of generations G1–G3 via copper(I)-catalyzed azide–alkyne Huisgen cycloaddition (CuAAC) coupling. The alkyne functional groups on the arborescent PBG substrates were either distributed randomly or located exclusively at the end of the chains added in the last grafting cycle of the core synthesis. The location of these coupling sites influenced the ability of the arborescent copolymers to form unimolecular micelles in aqueous environments: The chain end grafting approach provided enhanced dispersibility in aqueous media and favored the formation of unimolecular micelles in comparison to random grafting. This is attributed to a better defined core-shell morphology for the copolymers with end-grafted shell segments. Aqueous solubility also depended on the type of material used for the shell chains. Coupling by CuAAC opens up possibilities for grafting a broad range of polymers on the arborescent substrates under mild conditions.

The new polymeric systems for delivery in cosmetology applications were prepared using self-assembling amphiphilic graft copolymers. The synthesis based on &ldquo, click&rdquo, chemistry reaction included grafting of azide-functionalized polyethylene glycol (PEG-N3) onto multifunctional polymethacrylates containing alkyne units. The latter ones were obtained via atom transfer radical polymerization (ATRP) of alkyne-functionalized monomers, e.g., ester of hexynoic acid and 2-hydroxyethyl methacrylate (AlHEMA) with methyl methacrylate (MMA), using bromoester-modified retinol (RETBr) as the initiator. Varying the content of alkyne moieties adjusted by initial monomer ratios of AlHEMA/MMA was advantageous for the achievement of a well-defined grafting degree. The designed amphiphilic graft copolymers P((HEMA-graft-PEG)-co-MMA), showing tendency to micellization in aqueous solution at room temperature, were encapsulated with arbutin (ARB) or vitamin C (VitC) with high efficiencies (&gt, 50%). In vitro experiments carried out in the phosphate-buffered saline solution (PBS) at pH 7.4 indicated the maximum release of ARB after at least 20 min and VitC within 10 min. The fast release of the selected antioxidants and skin-lightening agents by these micellar systems is satisfactory for applications in cosmetology, where they can be used as the components of masks, creams, and wraps.

Novel amphiphilic copolymers have been synthesized based on a biocompatible poly(hydroxyethylaspartamide) (PHEA) backbone, bearing both anchoring groups for gold nanoparticles, such as thiols and disulfide, and conjugable moieties, such as amino groups, the latter as points suitable for appending further functional agents. The strategy was to functionalize α,β-poly[(N-2- hydroxyethyl)-d,l-aspartamide] (PHEA) with PEG2000-NH2 and with ethylenediamine (EDA) obtaining a partially pegylated copolymer with a large number of pendant primary amino groups. A fraction of the latter was conjugated with molecules bearing terminal thiol moieties such as 12-mercaptododecanoic acid (MDA) and disulfide groups such as lipoic acid (LA), obtaining the two amphiphilic derivatives PHEA-PEG2000-EDA-MDA (PPE-MDA) and PHEA-PEG2000-EDA-LA (PPE-LA), which also proved intrinsically able to self-assemble in polymeric micelles. The two copolymers efficiently coated gold nanostars (GNSs, size ∼40 nm), wrapping around the surface increasing only slightly the hydrodynamic diameter (reaching ∼45 nm), imparting them stability and a pH-switchable surface charge, due to the unreacted amino groups. Remarkably, the poor solvation and the huge steric hindrance experienced by the amino groups lowers the observed logarithmic protonation constants to 5.6-5.7. In vitro experiments demonstrated that PPE-MDA and PPE-LA copolymers have an intrinsic excellent biocompatibility in both the human brain neuroblastoma (SH-SY5Y) and human bronchial epithelial (16-HBE) cell lines. Interaction of the same cell lines with "nude" GNS and GNS coated with PPE-LA was also studied, disclosing a completely satisfactory biocompatibility of the latter. © 2013 American Chemical Society.

This PhD thesis is devoted to the study of the conformational behavior of branched polymers in confined volumes. This behavior depends not only on polymer architecture and composition but also on steric confinement and on interaction of polymer segments with the confining wall. Better understanding of complex entropy-to-enthalpy interplay can elucidate the mechanism of the chromatographic separation at the microscopic level. An unambiguous size-exclusion chromatography (SEC) analysis of mixtures containing different polymer architectures is difficult because the sizes of polymer coils, which determine the separation, depend not only on molar mass but also on the polymer architecture. Modern chromatographic methods combine the SEC with the interaction chromatography (IC). They exploit the fact that polymer interactions with pore walls, which are the prerequisite for efficient IC separation, depend strongly on polymer architecture. The knowledge of the conformational behavior of linear and branched polymers in confined volumes and of their interactions with confining medium enables to find optimum conditions either for enhancing or for suppressing the role of individual factors that influence the separation. We have shown that the complex entropy-to-enthalpy interplay in polymer solutions in confined...

Amphiphilic copolymers based on renewable resources were involved as emulsifiers to prepare transparent terpene-in-water nanoemulsions. The amphiphilic copolymers are composed of hydrophobically modified poly(acrylic acid) (HMPAA) grafted with different fractions of hydrophobic bio-based tetrahydrogeraniol (THG) side chains. The well-defined PAA were synthesized by reversible addition fragmentation transfer (RAFT) polymerization in order to tune the number-average molar mass of the initial PAA. The self-assembly in aqueous solution of the HMPAA copolymers was investigated through the measurement of their critical aggregation concentration by viscometry, tensiometry, dynamic light scattering and the determination of their aggregation number by static light scattering. Series of oil-in-water nanoemulsions using dihydromyrcenol (DHM) terpene as dispersed phase and PAA-THG as emulsifier were prepared with different PAA-THG/DHM weight ratios and DHM/water weight ratios. The level of transparency of the emulsions was monitored though the transmittance value measured at 600 nm and the measurements of the hydrodynamic diameter of droplets by dynamic light scattering. This study highlights that the structure of the PAAx-THGy is a key parameter to prepare terpene-in-water nanoemulsions with the required high level of transparency. The optimised structure of the emulsifier consists in a moderate degree of polymerization of PAA backbone ( DP ‾ n ,PAA ≤ 180 ) along with an intermediate average degree of substitution in hydrophobic THG side chains (13 ≤ DS ‾ ≤ 32).

Combination of antiangiogenic molecules with chemotherapeutics is considered a valuable strategy to increase cancer cell killing through decreased blood supply to the tumor. Our final aim is to develop biodegradable nanoparticles (NPs) which accumulate in cancer cells through folate receptor (FR) and bearing an antiangiogenic anti-FLT1 hexapeptide, which inhibits VEGF-induced endothelial cell migration and angiogenesis. Docetaxel (DTX) was selected as model of poorly water-soluble chemotherapeutics.

Nanoparticles (NPs) have attracted significant attention in the field of innovative anticancer therapies. The most common approach to improve selectively their accumulation in tumor tissues remains surface decoration with small targeting moieties recognizing specific receptors that are over-expressed in cancer cells. Surface-decorated NPs can be prepared by either post-modification of the surface, or by synthesizing tailored all-in-one amphiphilic copolymers. With this approach, the number and nature of molecules on the surface of the resulting NPs can be finely tuned, also avoiding the premature release of drug cargo. Furthermore, NPs made with a charged copolymer can be decorated on the surface with bioresponsive polymers through electrostatic interactions. Here we describe two different synthetic approaches: NPs made by self-assembling amphiphilic copolymers bearing the target unit covalently linked on the hydrophilic chain end, and cationic NPs, able to deeply penetrate inside tumors, decorated with hyaluronic acid (HA). In the first case, copolymers are made up of PEG as hydrophilic block and PCL as hydrophobic one; in this way, methods of synthesis aimed to asymmetrically modify PEG in order to introduce ethero end groups are largely explored in literature. Here, a simple route of synthesis to selectively obtain PCL-PEG-?Folate (Fol) copolymer, with high yield and purity is described. It is known from literature that only ?-folate conjugates retain affinity towards folate-receptor ?, that is overexpressed in the majority of cancer cells. Furthermore, we demonstrate that the extent of specific internalization of targeted nanoparticles can be improved by regulating the length of the PEG chains in PCL-PEG to attain stealth properties (1000 Da) and in PCL-PEG-?Fol to improve Fol exposition on NPs surface (1500 Da). Formulations of NPs using amphiphilic copolymers with different length of PEG blocks turned to be a good strategy to enhance exposition of Fol on their surface. In the second case, amino-terminated homopolymer PCL was synthesized to obtain PCL- or PEG-PCL-based NPs with cationic surface. Cationic NPs can be "covered" with anionic molecules, like HA, through non-covalent interaction. HA encourages NPs uptake in cell overexpressing CD44 receptors. We showed how modulation of surface charge density influences cell uptake.