Nanosized colloidal particles from thermosensitive poly(methoxydiethyleneglycol methacrylate)s in aqueous media

Triple Hydrophilic Statistical Terpolymers via RAFT Polymerization: Synthesis and Properties in Aqueous Solutions

In this work, we report the synthesis of novel triple hydrophilic statistical terpolymers consisting of three different methacrylate monomers with varying degrees of responsivity to solution conditions. Terpolymers of the type poly(di(ethylene glycol) methyl ether methacrylate-co-2-(dimethylamino)ethylmethacrylate-co-oligoethylene glycol methyl ether methacrylate), P(DEGMA-co-DMAEMA-co-OEGMA), and of different compositions, were prepared by using the RAFT methodology. Their molecular characterization was carried out using size exclusion chromatography (SEC) and spectroscopic techniques, including ¹H-NMR and ATR-FTIR. Studies in dilute aqueous media by dynamic and electrophoretic light scattering (DLS and ELS) show their potential responsiveness regarding changes in temperature, pH, and kosmotropic salt concentration. Finally, the change in hydrophilic/hydrophobic balance of the formed terpolymer nanoparticles during heating and cooling was studied using fluorescence spectroscopy (FS) in conjunction with pyrene giving additional information on the responsiveness and internal structure of the self-assembled nanoaggregates.

The Role of Polymer Structure in Formation of Various Nano- and Microstructural Materials: 30 Years of Research in the Laboratory of Nano- and Microstructural Materials at the Centre of Polymer and Carbon Materials PAS

The review summarizes the research carried out in the Laboratory of Nano- and Microstructural Materials at the Centre of Polymer and Carbon Materials, Polish Academy of Sciences (CMPW PAS). Studies carried out for many years under the guidance of Professor Andrzej Dworak led to the development and exploration of the mechanisms of oxirane and cyclic imine polymerization and controlled radical polymerization of methacrylate monomers. Based on that knowledge, within the last three decades, macromolecules with the desired composition, molar mass and topology were obtained and investigated. The ability to control the structure of the synthesized polymers turned out to be important, as it provided a way to tailor the physiochemical properties of the materials to their specific uses. Many linear polymers and copolymers as well as macromolecules with branched, star, dendritic and hyperbranched architectures were synthesized. Thanks to the applied controlled polymerization techniques, it was possible to obtain hydrophilic, hydrophobic, amphiphilic and stimulus-sensitive polymers. These tailor-made polymers with controlled properties were used for the construction of various types of materials, primarily on the micro- and nanoscales, with a wide range of possible applications, mainly in biomedicine. The diverse topology of polymers, and thus their properties, made it possible to obtain various types of polymeric nanostructures and use them as nanocarriers by encapsulation of biologically active substances. Additionally, polymer layers were obtained with features useful in medicine, particularly regenerative medicine and tissue engineering.

Thermoresponsive Nanogels of Modified Poly((di(ethylene glycol) methyl ether methacrylate)-co-(2-aminoethyl methacrylate))s

A series of copolymers of di(ethylene glycol) methyl ether methacrylate (D) and 2-aminoethyl methacrylate (A) (P(D-co-A)) with variable ratios of comonomers were synthesized using atom transfer radical polymerization. Then, the amino groups of obtained copolymers were modified to clickable azide or prop-2-yn-1-yl carbamate groups. A thermoresponsive copolymers were obtained with the value of cloud point temperature (T_CP) dependent on the type and number of functional groups in the copolymer and on the concentration of solutions. For P(D-co-A) copolymers, the T_CP increased with increasing content of 2-aminoethyl methacrylate comonomer. The presence of azide and prop-2-yn-1-yl carbamate groups caused the changes of T_CP of modified copolymers. All studied copolymers in dilute aqueous solutions aggregated above T_CP to nanoparticles with sizes dependent on the solution concentration, heating procedures, and types and numbers of functional groups present in a copolymer chain. The presence of hydrophilic elements in the chain and the increase in the copolymer concentration led to the enlargement of the particle sizes. Aggregates were crosslinked using click reaction between an azide and prop-2-yn-1-yl carbamate groups that led to stable thermoresponsive nanogels. A systematic study of the behavior of copolymers allowed the determination of the chains useful for possible application in drug delivery.

Emerging Strategies in Stimuli-Responsive Nanocarriers as the Drug Delivery System for Enhanced Cancer Therapy

The conventional Drug Delivery System (DDS) has limitations such as leakage of the drug, toxicity to normal cells and loss of drug efficiency, while the stimuli-responsive DDS is non-toxic to cells, avoiding the leakage and degradation of the drug because of its targeted drug delivery to the pathological site. Thus nanomaterial chemistry enables - the development of smart stimuli-responsive DDS over the conventional DDS. Stimuliresponsive DDS ensures spatial or temporal, on-demand drug delivery to the targeted cancer cells. The DDS is engineered by using the organic (synthetic polymers, liposomes, peptides, aptamer, micelles, dendrimers) and inorganic (zinc oxide, gold, magnetic, quantum dots, metal oxides) materials. Principally, these nanocarriers release the drug at the targeted cells in response to external and internal stimuli such as temperature, light, ultrasound and magnetic field, pH value, redox potential (glutathione), and enzyme. The multi-stimuli responsive DDS is more promising than the single stimuli-responsive DDS in cancer therapy, and it extensively increases drug release and accumulation in the targeted cancer cells, resulting in better tumor cell ablation. In this regard, a handful of multi-stimuli responsive DDS is in clinical trials for further approval. A comprehensive review is crucial for addressing the existing knowledge about multi-stimuli responsive DDS, and hence, we summarized the emerging strategies in tailored ligand functionalized stimuli-responsive nanocarriers as the DDS for cancer therapies.

One-pot synthesis of oligonucleotide-grafted polymeric nanoparticles

A feasible one-pot approach for constructing oligonucleotide-grafted polymeric nanoparticles is reported. The approach involves formation of mesoglobules from a thermoresponsive polymer, coating of the mesoglobules with a cross-linked polymeric shell, and grafting the latter with oligonucleotide strands. Dynamic and static light scattering are used to parameterize the novel constructs. They are relatively large structures with hydrodynamic radii and molar masses reaching 200 nm and 150.0 × 10⁶ g mol^-1, respectively. The oligonucleotide-grafted polymeric nanoparticles are of spherical morphology and moderately negative (-12.4 to -19.1 mV) ζ potential as revealed by AFM, TEM, and electrophoretic light scattering. In accordance with their large size, they are found to carry thousands of oligonucleotide strands per particle. The novel constructs are thermoresponsive. They undergo reversible collapse upon heating and swelling upon cooling, which is associated with changes in the grafting density and, hence, the conformation of the oligonucleotide strands from unextended at room temperature to a more extended one at elevated temperatures. The versatility of the approach is demonstrated by varying the type of the cross-linked shell and content of the oligonucleotide strands and, hence, the grafting density. Appropriate diversification and modifications are suggested as well.