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Star-shaped glycopolymers due to the attractive combination of the physicochemical, morphological, self-assembly properties along with biological activity have gained increased attention as innovative agents in novel cancer therapies. Unfortunately, the production of these highly desirable biomaterials remains a challenge in modern macromolecular chemistry. The main reason for that is the low polymerizability of ionic glycomonomers originated from their steric congestion and the occurrence of ionic interactions that generally negatively influence the polymerization progress and hinder controllable reaction pathway. In this work, the new ionic sugar monomer was (co)polymerized for the first time via Activator Generated by Electron Transfer Atom Transfer Radical Polymerization (AGET ATRP) using a three-arm resveratrol-based core to obtain star-like (co)polymers. The obtained products were examined in terms of their physicochemical properties and morphology. Aside from the synthesis of these new glycopolymers, also a thorough description of their thermal properties, ability to self-assembly, the formation of stable superstructures was studied in detail. It was found that examined (co)polymers did not show any heterogeneities and phase separation, while their variation of glass transition temperature (Tg) was strictly related to the change in the number of glycomonomer. Also, the stability and shapes of formed superstructures strictly depend on their composition and topology. Finally, we have shown that synthesized carbohydrate-based polymers revealed high antiproliferative activity against several cancer cell lines (i.e., breast, colon, glioma, and lung cancer). The cytotoxic activity was particularly observed for star-shaped polymers that were systematically enhanced with the growing concentration of amine moieties and molecular weight. The results presented herein suggest that synthesized star-shaped glyco(co)polymers are promising as drug or gene carriers in anticancer therapies or anti-tumor agents, depending on their cytotoxicity. Graphical abstract

This work highlights the development of a robust and universal route towards gaining control over macromolecule molecular weight, molecular weight distribution and, more importantly, morphology through the implementation of photoiniferter-mediated RAFT (photo-RAFT) carried out using mesoporous materials varying in the composition, pore arrangement, and pore diameters (metal–organic framework SBA-15 powder d = 5–15 nm, silica SiO2 templates d = 4 nm, alumina oxide AAO templates d = 10 nm). In fact, the application of these matrices that can act as nanoreactors for in situ UV-irradiated photo-RAFT of both commercial methyl methacrylate (more-activated monomer) and the synthesized N-vinyl-1,2,4-triazolium-based ionic liquid (less-activated monomer) is a key aspect of our approach. The collected data allowed us to probe the influence of the structural features of nanoreactors (i.e., transparency, porosity, roughness, and acidity) as well as confinement-related effects connected to variation in free volume and surface interactions on the polymerization path and properties of the produced ionic and non-ionic polymers. It was found that the application of all tested nanoreactors ensures greater control over photo-RAFT than analogous batch systems (macroscale photo-RAFT). However, running the reaction in mesoporous AAO templates offered by far the best control over the course of photo-RAFT of both the less-activated monomer (LAM) and the more-activated monomer (MAM) irrespective of the type of selected RAFT agent (switchable) (carbamodithioate vs. trithiocarbonate), their properties and, more importantly, the yield of the recovered polymers.

Nanoparticles have attracted a great interest in scientific world because of the new applications they offer. They are commonly used in medical procedures such as hyperthermia and thermal ablation. Here, we propose, using magnetic and non-magnetic nanoparticles, as sonosensitizers which are the materials that improve the efficiency of heating induced by ultrasound. A comparison between various types of nanomaterials, such as magnetite, silicon dioxide, and Laponite nanoparticles, was done. The results show that both magnetic and non-magnetic nanomaterials can be utilized in ultrasonic heating. However, magnetite nanoparticles without surface modification can strongly interact with each other and are prone to agglomeration that can deteriorate thermal effect in tissuemimicking phantoms.

New type of carriers based on grafted poly(ionic liquid)s was designed for delivery of ionically attached salicylates (Sal). Choline derived ionic liquid monomeric units were successfully introduced with various content in the side chains by the controlled radical polymerization. Properly high amounts of ionic pharmaceutics in the polymer systems were achieved by the well-fitted length and grafting degree of the side chains. In aqueous solution the graft copolymers were self-assembled into the spherical superstructures with sizes up to 73 nm. Delivery studies showed “burst” release within 4 h, after that it was slower yielding ~70% of released drug within 80 h. Proposed nanocarriers supported low toxicity against human cells (NHDF and BEAS-2B), anti-inflammation activity evaluated with the use of pro-inflammatory interleukins (IL-6 and IL-8) and antibacterial activities towards E. coli. Adjustment of ionic drug content by structural parameters of graft copolymers, including grafting degree and graft length, are advantageous to tailor nanocarriers with self-assembly properties in aqueous media. Effective release process by ionic exchange and biological activity with low toxicity are promising for further development of this type of drug delivery (DDS).

Anionic drugs, i.e. salicylate (Sal−) and sulfacetamide (Sfc−) were chosen as counterions in trimethylammonium based poly(meth)acrylates. These ionic systems with amphiphilic properties were used to form polymeric systems for dual drug delivery by loading of nonionic pharmaceutics like immunosuppressant quercetin (QUE), anti-inflammatory indomethacin (IMC) and antibiotic erythromycin (ERY). The latter one was loaded with high efficiency (>60%), whereas poorer loading efficiency was obtained for aromatic compounds (

A rhodamine B (RhB)-based initiator for atom transfer radical polymerization (ATRP) was synthesized and applied for preparation of poly(2-trimethylammoniumethyl methacrylate) (PChMA), poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(2-trimethylsilyloxyethyl methacrylate) (PHEMATMS). Polymer fluorescence was confirmed by determination of quantum yield by comparative method with piroxicam as the standard exhibiting dependency of emission intensity on the polymer chain hydrophilicity and the kind of solvent. The RhB functionalized polymers were used for biological tests in plant materials except for RhB-PHEMATMS because of weak fluorescence. These two polymers slightly differed in cellular localization. RhB-PChMA was mostly observed in cell walls of root tissues and cotyledon epidermis. It was also observed in cytoplasm and cell organelles of root cap cells and rhizodermis, in contrast with cytoplasm of cotyledon epidermis. RhB-PHEMA was also present in apoplast. A strong signal in protoxylem cell walls and a weak signal in cell walls of rhizodermis and cortex were visible. Moreover, it was also present in cell walls of cotyledon epidermis. However, RhB-PHEMA was mostly observed in cytoplasm and cell organelles of all root tissues and epidermis of cotyledons. Both RhB-polymers did not cause cell death which means that they can be used in living plant material.

Ultrasound attenuation spectroscopy has found wide application in the study of colloidal dispersions such as emulsions or suspensions. The main advantage of this technique is that it can be applied to relatively high concentration systems without sample preparation. In particular, the use of Epstein-Carhart-Allegra-Hawley’s (ECAH) ultrasound scattering theory, along with experimental data of ultrasound velocity or attenuation, provide the method of estimation for the particle or droplet size from nanometers to millimeters. In this study, suspensions of magnetite and silica nanoparticles in high viscous media (i.e., castor oil) were characterized by ultrasound spectroscopy. Both theoretical and experimental results showed a significant difference in ultrasound attenuation coefficients between the suspensions of magnetite and silica nanoparticles. The fitting of theoretical model to experimental ultrasound spectra was used to determine the real size of objects suspended in a high viscous medium that differed from the size distributions provided by electron microscopy imaging. The ultrasound spectroscopy technique demonstrated a greater tendency of magnetic particles toward agglomeration when compared with silica particles whose sizes were obtained from the combination of experimental and theoretical ultrasonic data and were more consistent with the electron microscopy images.

Efficient ROP polymerization of e-caprolactone, resulting in products characterized by high molecular weight of low dispersities, remains a challenging task and is currently an important matter of ongoing research, mostly due to the accompanying side reactions, i.e., hydrolysis and transesterification. Herein, we studied in detail the impact of 2D hard confinement on the progress and product of ring-opening polymerization (ROP) of e-caprolactone with and without water acting as initiator in comparison to the macroscale conditions, where various forms (powder, sheet) of alumina were used. It turned out that applied aluminum oxide nanotemplates act as both catalyst and initiator (INICAT) of ROP nanopolymerization and seem to operate accordingly to the pseudoliving coordination–insertion mechanism, resulting in nanowires of PCL characterized by Mn up to 53.5 kg/mol. Additionally, due to the applied confinement, the side reactions were successfully suppressed, resulting in macromolecules of moderate molecular...

Droplets covered by adsorbed particles are used in a wide range of research studies and applications, including stabilising emulsions used in the food or cosmetic industries, and fabricating new materials, such as microcapsules or multi-cavity structures. Pickering emulsions are commonly prepared by bulk emulsification techniques, for instance, by ultrasonic homogenisation or mechanical stirring, by membrane emulsification, or with the use of microfluidics. The latter two methods typically allow for more precise control of the droplet size distribution, whereas the bulk techniques guarantee high throughput. Here we propose a new bulk approach to fabricating Pickering emulsions by utilising electric fields. We prepare oil-in-oil emulsions stabilised by microparticles and control the mean size of the Pickering droplets. In our approach we take advantage of total surface area reduction of emulsion droplets by electrocoalescence. This leads to an increase in particle coverage, and eventually to formation of densely packed particle shells on Pickering droplets. First, we prepare an unstable pre-emulsion with droplets having small sizes and low particle coverages, from which the final Pickering emulsion is formed via consecutive coalescence events speeded up by application of electric fields. We monitor the development of the emulsions with optical microscopy imaging. The results demonstrate that the utilisation of electric fields goes beyond the mere role of enhancing coalescence; it plays an important role in surface particle manipulation and droplet rotation that further promote formation of stable particle-covered drops.

Hyperthermia treatment is the heating of tumor tissue up to temperatures between 41 ºC and 45 ºC, which trigger several physiological reactions in the body. Hyperthermia within tissue can be applied through various mechanisms. One of them is magnetic hyperthermia which uses superparamagnetic iron oxide nanoparticles (SPIONs) heated by an externally applied magnetic field. SPIONs can also be used as sonosensitizers in ultrasound hyperthermian increasing acoustic wave attenuation. The impact of SPION concentration on thermal effect during ultrasonic and magnetic hyperthermia was investigated in agar-gel phantom with added magnetite nanoparticles. The presence of nanoparticles in the tissue-mimicking phantom increases the thermal losses of ultrasound energy and temperature of the phantom.

Magnetic heating of colloidal systems is becoming a more and more common route for inducing temperature rise, especially in applications where very local temperature elevation is desired. Although the calorimetric properties of magnetic colloids are extensively investigated, the influence of the alternating magnetic field on their structure has rarely been reported. Meanwhile, potential permanent structural changes such as the formation of agglomerates can affect the stability of magnetic dispersions or magnetic Pickering emulsions. In the present work, we propose to use ultrasound as a technique to determine if such changes occur during magnetic heating. Oil-in-oil emulsions with magnetite particle shells around the droplets and oil-based magnetic fluids were exposed to alternating magnetic fields, and the changes in ultrasonic attenuation and the speed of ultrasound were determined. Finally, changes in acoustic properties were investigated in dispersions of magnetic and polystyrene particles after heating to the melting temperature of the soft particles.

Poly(1-vinyl-2-pyrrolidone) (Povidone, PVP) is one of the most interesting and versatile synthetic polymers utilised in the pharmaceutical and cosmetic industries. Its large-scale commercial production offers an assortment of products in a wide range of molecular weights but poorly-controlled (macro)structural parameters (i.e., dispersity, functionality) limiting the efficiency of PVP-based drug delivery systems (DDS). In this work, synthesised linear and star-shaped PVPs with a strictly defined structure and functionality were compared with the linear, commercially-supplied product and explored as potential vehicles for physical entrapment of metronidazole (MTZ). Here, a question is addressed how differences in their macromolecular properties affect the amorphisation of MTZ, drug encapsulation, the stability of drug-loaded micellar structures and their in vitro release from the carrier. The X-ray diffraction studies and calorimetric measurements revealed that MTZ crystallises in all investigated herein systems reducing the glass transition temperature of the binary mixture significantly. Transmission electron microscopy and dynamic light scattering analysis revealed that MTZ-loaded DDS are able to form ultrasmall regular nanocarriers with an increasing effect of regularity and sphericity from star-shaped DDS to linear-based ones. We founded that synthesised linear-based DDS is the most effective for MTZ entrapment (PVP:MTZ = 1:1 weight ratio) due to their smallest hydrodynamic radius dh = 14.7 nm, the highest stability of micellar structures −2.37 mV, and the highest values of loaded drug 76.5%. Moreover, all applied PVP-based DDS revealed an initial burst release effect of MTZ (pH = 7.4) reaching up to 60% of drug released within the first 5 h (the first-order release model fits). The marked efficiency of MTZ-loaded DDS of strictly defined structural parameters indicates the great importance of polymer preparation strategy in the targeted therapy.

Amphiphilic polymer carriers were designed for the delivery of ionically bonded drugs. The ionic liquid, trimethylammonium methacrylate monomer, containing biologically active salicylate anions was selected for the preparation of copolymers via atom transfer radical polymerization (ATRP) with methyl methacrylate (MMA) or methyl acrylate (MA). The resulting polymers varied in the content and arrangement of ionic units in the chain. The self-assembly of polymers in aqueous solution yielded particles at critical micelle concentration (CMC) values below 0.1 mg ml−1 and with hydrodynamic diameters in the range of 170–290 nm, which were also visualized by TEM. Drug release studies indicated the exchange of 42–52% of salicylate anions with phosphate anions using dialysis in PBS, which corresponded to 0.15–0.25 mg of salicylate released from 1 mg of polymeric carrier.

Emulsions stabilized with magnetic particles have been reported as useful for numerous applications, including thermal medical therapies where they can be used as heating materials. It is well-known that magnetic particles placed in the alternating magnetic field can act as heating agents. The generation of thermal energy is owing to magnetic energy dissipation caused by Neel and Brown relaxation, and hysteresis loss. These mechanisms depend on the properties of the applied magnetic field and the characterization of magnetic particles used as well. But, when residing on droplet surfaces e.g. as stabilizers in Pickering emulsions, magnetic particles somehow can be found trapped and their movement can be limited. Also, the change in Pickering droplet sizes and the increasing solidity of particle shell, e.g. through the coalescence events of droplets, can influence how magnetic energy is dissipated in such multi-phase system. In our work, we investigate the efficiency of magnetic heating of oil-in-oil emulsions stabilized with magnetite particles of various sizes. The results indicate that the temperature rise in such systems varied for different concentrations of particles used, but also for the different macroscopic appearance of emulsions, i.e. coarse emulsions, not fully-covered by particles and final emulsions with stable droplets demonstrated different heating efficiency when placed in the alternating magnetic field. The emulsion droplets with different particle coverage were obtained either by using only ultrasonic homogenization or using ultrasound and a subsequent coalescence under the electric field. The presented study can help in the development of applications of magnetite-stabilized droplets in heating, e.g. when magnetic Pickering droplets are used as thermal agents in hyperthermia treatment or as templates for colloidal capsules.

Ultrasonic heating has become an interesting topic among scientists because of its biomedical applications. One of them is using an ultrasound-induced temperature rise in the hyperthermia procedure. In most reports on ultrasonic hyperthermia measurements, the information of initial temperature was neglected or was not given due diligence. The current research aimed to check the influence of initial temperature on the efficiency of ultrasound hyperthermia in tissue-mimicking agar-based phantoms doped with silica nanoparticles that acted as sonosensitizers – they increased the attenuation of ultrasound and, as a consequence, the heating efficiency. The results indicated that temperature rise after sonication with a frequency of 1 MHz and intensity of 2.5 W/cm2 was indeed lower, with statistical significance, when experiments started at higher temperatures, while ultrasonic attenuation, the main factor influencing the ultrasonic heating efficiency, remained the same. These results suggest that the initial temperature should be regarded as an important factor when ultrasonic hyperthermia experiments are designed.

The 4-armed star-shaped copolymers containing methyl (meth)acrylate (MMA, MA) and (meth)acrylic acid (MAA, AA) units were synthesized by ATRP with the use of pentaerythritol (PTL) derivatives as tetrafunctional initiators and by post-polymerization modification to deprotect acidic units. The resultant MMA/MAA, MMA/AA, and MA/MAA based stars were varied by composition of arms using various initial proportions of comonomer pairs. The amphiphilic copolymers were self-assembled by dialysis or solvent evaporation methods into particles, which were also loaded with indomethacin (IMC). The sizes of polymeric aggregates were in the range of 100–200 nm, whereas drug loading efficiency was 10–85%. The in vitro release of IMC in phosphate buffer solution (PBS) demonstrated a higher rate of drug release at pH 5.0 than at 7.4. Drug release profiles can be adjusted by the content of the hydrophilic fraction (15–98%) and distribution of acidic units among arm chains (statistical vs. gradient vs. reverse gradient) as indicated by the broad range of the maximum drug release (10–85%).

A new method for the chemo-enzymatic Baeyer–Villiger oxidation of cyclic ketones to lactones has been developed. The influence of reaction parameters and the structure of various ionic liquids were studied. Free Candida antarctica lipase B or Novozyme-435 suspended in an ionic liquid was used as the catalytic phase. The reaction was carried out under mild conditions at room temperature using 30% aq. H2O2 as the oxidation agent. 1-Butyl-3-methyl bistriflimide was the most effective ionic liquid and increased the reaction rate compared to toluene. Lipase exhibited good stability, and the ionic liquid could be easily reused. Therefore, a general chemo-enzymatic method for the oxidation of cyclohexanones and cyclobutanones to obtain adequate lactones in high yields (79–95%) has been proposed.

Particle-stabilised emulsions are of interest to many scientists in both academia and industry as they hold promise for numerous applications. There is a lot of research effort put into developing new methods for their fabrication. Often, different experimental techniques are used for monitoring the process of the emulsion formation. However, the control of the emulsion fabrication and its real-time characterisation is generally challenging. In this work, we propose a convenient method to control fabrication of Pickering emulsions using ultrasound. The benefit of acoustical measurements compared to other techniques is their ability to test the medium in a non-destructive way, without requiring special sample preparation (e.g., dilution like in the case of DLS or NMR) nor a usage of thin sample cells (e.g., in the case of optical microscopy). Here, ultrasonic measurements are able to follow droplets growth during the emulsion development using the limited coalescence approach. We found that ultrasonic attenuation increased with the droplet size within the time frame of droplet stabilisation. Following these changes in ultrasonic attenuation enabled the study of macroscopic behaviour – for example, estimation of a time when droplets achieve their final size and become fully covered by solid particles. These results are compared with the results obtained from the optical measurements. We also make an attempt to theoretically describe ultrasound propagation in particle-stabilised emulsions by comparing our experimental results with the scattering theory ECAH for emulsions.

A new fluorescent initiator based on pyranine was synthesized and applied for synthesis of the water-soluble polymers by controlled radical polymerization. The fluorophore based polymethacrylates were dependent on chain content providing small nanoparticles in the range of 0.6–3.4 nm. Fluorescent properties corresponding to green light emission were verified by quantum yield and fluorescence intensity showing the influence of polymer type and solvent. 7-day-old seedlings of Arabidopsis thaliana Col-0 were used in analysis of the penetration/movement of fluorescent nanoparticles (FNPs) in roots and cotyledons. Obtained results showed that: i) the best fluorescent nanoparticles for biological studies appeared to be choline methacrylate containing polymer (HPTS-ChMA); ii) cell membrane is a barrier for FNPs and iii) HPTS-ChMA is efficient fluorescent marker of plant cell walls independently of plant organ.