Antibody conjugated PLGA nanocarriers and superparmagnetic nanoparticles for targeted delivery of oxaliplatin to cells from colorectal carcinoma

Anti-CD133 monoclonal antibody (Ab)-conjugated poly(lactide-co-glycolide) (PLGA) nanocarriers, for the targeted delivery of oxaliplatin (OXA) and superparamagnetic nanoparticles (IO-OA) to colorectal cancer cells (CaCo-2), were designed, synthesized, characterized, and evaluated in this study. The co-encapsulation of OXA and IO-OA was achieved in two types of polymeric carriers, namely, PLGA and poly(lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) by double emulsion. PLGA_IO-OA_OXA and PEGylated PLGA_IO-OA_OXA nanoparticles displayed a comparable mean diameter of 207 ± 70 nm and 185 ± 119 nm, respectively. The concentration of the released OXA from the PEGylated PLGA_IO-OA_OXA increased very rapidly, reaching ~100% release after only 2 h, while the PLGA_IO-OA_OXA displayed a slower and sustained drug release. Therefore, for a controlled OXA release, non-PEGylated PLGA nanoparticles were more convenient. Interestingly, preservation of the superparamagnetic behavior of the IO-OA, without magnetic hysteresis all along the dissolution process, was observed. The non-PEGylated nanoparticles (PLGA_OXA, PLGA_IO-OA_OXA) were selected for the anti-CD133 Ab conjugation. The affinity of Ab-coated nanoparticles for CD133-positive cells was examined using fluorescence microscopy in CaCo-2 cells, which was followed by a viability assay. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Grantová Agentura České Republiky, GA ČR: 19-02889S, A2_FCHI_2021_01

One-dimensional nanostructures of polypyrrole for shielding of electromagnetic interference in the microwave region

Polypyrrole one-dimensional nanostructures (nanotubes, nanobelts and nanofibers) were prepared using three various dyes (Methyl Orange, Methylene Blue and Eriochrome Black T). Their high electrical conductivity (from 17.1 to 60.9 S cm−1), good thermal stability (in the range from 25 to 150◦ C) and resistivity against ageing (half-time of electrical conductivity around 80 days and better) were used in preparation of lightweight and flexible composites with silicone for electromagnetic interference shielding in the C-band region (5.85–8.2 GHz). The nanostructures’ morphology and chemical structure were characterized by scanning electron microscopy, Brunauer–Emmett–Teller specific surface measurement and attenuated total reflection Fourier-transform infrared spectroscopy. DC electrical conductivity was measured using the Van der Pauw method. Complex permittivity and AC electrical conductivity of respective silicone composites were calculated from the measured scattering parameters. The relationships between structure, electrical properties and shielding efficiency were studied. It was found that 2 mm-thick silicone composites of polypyrrole nanotubes and nanobelts shield almost 80% of incident radiation in the C-band at very low loading of conductive filler in the silicone (5% w/w). Resulting lightweight and flexible polypyrrole composites exhibit promising properties for shielding of electromagnetic interference in sensitive biological and electronic systems. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Ministry of Education, Youth and Sports of the Czech Republicproject DKRVO [RP/CPS/2020/006]; [A2_FCHI_2020_030

Etude des mécanismes de phototransformation de polymères hydrosolubles en milieux aqueux

Photooxidation (lambda> 300 nm) and thermooxidation poly (ethylene oxide) (PEO) and poly (N-vinylpyrrolidone) (PVP) were studied in the solid state and in aqueous solution, using different technical analysis (FTIR, UV-visible, SEC and TOC). The effect of the medium, pH and Fe (III) was examined. PEO degradation in aqueous solution leads to the formation of three products: formate, ester and formic acid from the hydrolysis formates. The dégrdation of PVP is done in two ways. Water guides the oxidation mechanism of PVP but not the PEO. Moreover, the presence of iron accelerates the degradation of PEO chains by cuttings through its effect photoinitiator by * OH radical production, whereas in the case of PVP, iron can direct the degradation mechanism of PVP based its concentration, with a cross-linking mechanism or switching mechanism of channelsLa photooxydation (lamda>300 nm) et la thermooxydation du poly(oxyde d'éthylène) (PEO) et de la poly(N-vinylpyrrolidone) (PVP) ont été étudiés à l'état solide et en solution aqueuse, en utilisant différentes techniques analytique (IRTF, UV-visible, SEC et TOC). L'effet du milieu, du pH et du Fe(III) a été examiné. La dégradation du PEO en solution aqueuse conduit à la formation de trois produits : formiate, ester et de l'acide formique provenant de l'hydrolyse des formiates. La dégrdation de la PVP se fait suivant deux voies. L'eau oriente le mécanisme d'oxydation de la PVP mais pas celui du PEO. De plus, la présence de fer accélère la dégradation du PEO par coupures de chaînes grâce à son effet photoinducteur par production de radicaux *OH, alors que dans le cas de la PVP, le fer peut orienter le mécanisme de dégradation de la PVP en fonction de sa concentration, avec un mécanisme de réticulation ou un mécanisme de coupure de chaîne

Etude des mécanismes de phototransformation de polymères hydrosolubles en milieux aqueux

La photooxydation (lamda>300 nm) et la thermooxydation du poly(oxyde d'éthylène) (PEO) et de la poly(N-vinylpyrrolidone) (PVP) ont été étudiés à l'état solide et en solution aqueuse, en utilisant différentes techniques analytique (IRTF, UV-visible, SEC et TOC). L'effet du milieu, du pH et du Fe(III) a été examiné. La dégradation du PEO en solution aqueuse conduit à la formation de trois produits : formiate, ester et de l'acide formique provenant de l'hydrolyse des formiates. La dégrdation de la PVP se fait suivant deux voies. L'eau oriente le mécanisme d'oxydation de la PVP mais pas celui du PEO. De plus, la présence de fer accélère la dégradation du PEO par coupures de chaînes grâce à son effet photoinducteur par production de radicaux *OH, alors que dans le cas de la PVP, le fer peut orienter le mécanisme de dégradation de la PVP en fonction de sa concentration, avec un mécanisme de réticulation ou un mécanisme de coupure de chaînesCLERMONT FD-BCIU Sci.et Tech. (630142101) / SudocSudocFranceF

Effect of Copolymer Properties on the Phase Behavior of Ibuprofen–PLA/PLGA Mixtures

Prediction of compatibility of the active pharmaceutical ingredient (API) with the polymeric carrier plays an essential role in designing drug delivery systems and estimating their long-term physical stability. A key element in deducing API–polymer compatibility is knowledge of a complete phase diagram, i.e., the solubility of crystalline API in polymer and mutual miscibility of API and polymer. In this work, the phase behavior of ibuprofen (IBU) with different grades of poly(D,L-lactide-co-glycolide) (PLGA) and polylactide (PLA), varying in composition of PLGA and molecular weight of PLGA and PLA, was investigated experimentally using calorimetry and computationally by the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EOS). The phase diagrams constructed based on a PC-SAFT EOS modeling optimized using the solubility data demonstrated low solubility at typical storage temperature (25 °C) and limited miscibility (i.e., presence of the amorphous–amorphous phase separation region) of IBU with all polymers studied. The ability of PC-SAFT EOS to capture the experimentally observed trends in the phase behavior of IBU–PLA/PLGA systems with respect to copolymer composition and molecular weight was thoroughly investigated and evaluated

Influence of water on the photodegradation of poly(ethylene oxide)

International audienceThe UV-light degradation of polyethylene oxide (PEO) in aqueous solution was investigated operating under long wavelengths (λ > 300 nm) at 20 °C in different pH conditions varying from 2.3 to 12.0 and at two different concentrations. Thermo-oxidation experiments on PEO aqueous solution at 50 °C are also reported and compared to photo-oxidation results. The formation of oxidation products was followed by infrared analysis of deposits obtained by evaporation of aliquots of irradiated polymer solution. Photo-oxidation led to formates and esters but a third product was also identified, formic acid ions formed by partial hydrolysis of formates. The degradation of PEO in water led to the acidification of the aquatic medium. Size exclusion chromatography (SEC) was used to monitor the changes in molar weight and intrinsic viscosity with irradiation time. It was shown that the photo-oxidation produced a dramatic decrease of the average molar weights which is more important in acidic medium. Total organic carbon (TOC) measurements of the aged aqueous solutions showed that the mineralization of PEO could not be achieved in these photo-oxidative conditions

Polylactic acid modified by reactive extrusion technology

In recent years there has been an increase in interest in biodegradable polymers. Biopolymers are upcoming competitors for the synthetic polymers with their profound attributes like eco-friendliness and biodegradability. They can be classified as natural biopolymers, chemically synthesized biopolymers, and microbial biopolymers. One of the most widely used chemically synthesized biopolymers is aliphatic polyester polylactic acid (PLA). It is a thermoplastic derived from renewable, organic sources such as corn starch or sugar cane. Although PLA offers a number of advantages such as high strength and high modulus, excellent optical properties, moisture resistance and biocompatibility, this is a quite fragile material. Other disadvantages are poor impact strength and low elongation. One way to improve the unsuitable PLA mechanical properties is to modify the material with additives like plasticizers, fillers etc. In this research, attention is focused on modification of PLA by reactive extrusion technology. Obtained materials were tested by DSC to evaluate changes in transition temperatures of PLA (Tg, Tm) and mechanical properties were tested too. The significant changes in mechanical properties were noticed.Tomas Bata University in Zlín, TBU, (AKTION 95p5, IGA/FT/2022/003, IGA/FT/2023/008

Influence of iron salts on the photooxidation of poly(N-vinylpyrrolidone) in aqueous solution

International audienceThis article reports on the effect of UV-visible radiation (λ ≥ 300 nm) on the degradation of poly(N-vinylpyrrolidone) PVP photoinduced by Fe(III) in aqueous solution and in the presence of oxygen. The formation of oxidation products was followed by infrared analysis of deposits obtained after evaporation of water and by UV-visible analysis of the irradiated polymer solutions. Size exclusion chromatography (SEC) was used for monitoring the variations of molar weight and intrinsic viscosity with irradiation time. Total organic carbon (TOC) measurements were performed with the aim of checking the mineralisation of aqueous solutions. Depending on the concentration of Fe(III), the concentration of PVP and the pH of the solution, we were able to show that the photooxidation of PVP leads to a chain scission and to a cross-linking mechanism, contrary to photooxidation of PVP in the absence of Fe(III) which only involves a mechanism of chain scission. A mechanism of PVP photooxidation until its possible mineralisation is proposed, taking into account the concentration of Fe(III) in the solution

Nanocluster-Based Drug Delivery and Theranostic Systems: Towards Cancer Therapy

Over the last decades, the global life expectancy of the population has increased, and so, consequently, has the risk of cancer development. Despite the improvement in cancer therapies (e.g., drug delivery systems (DDS) and theranostics), in many cases recurrence continues to be a challenging issue. In this matter, the development of nanotechnology has led to an array of possibilities for cancer treatment. One of the most promising therapies focuses on the assembly of hierarchical structures in the form of nanoclusters, as this approach involves preparing individual building blocks while avoiding handling toxic chemicals in the presence of biomolecules. This review aims at presenting an overview of the major advances made in developing nanoclusters based on polymeric nanoparticles (PNPs) and/or inorganic NPs. The preparation methods and the features of the NPs used in the construction of the nanoclusters were described. Afterwards, the design, fabrication and properties of the two main classes of nanoclusters, namely noble-metal nanoclusters and hybrid (i.e., hetero) nanoclusters and their mode of action in cancer therapy, were summarized

Direct Synthesis of Benzoylpyridines from Chloropyridines via a Palladium-Carbene Catalyzed Carbonylative Suzuki Cross-Coupling Reaction

International audienc