Search Results (35)

Stimuli-responsive polymeric nanostructures are compelling vectors for a wide range of application opportunities. The objective we sought was to broaden the array of self-assembling amphiphilic copolymers with stimuli-responsive characteristics by introducing a hydrophilic tunable monomer, (2-dimethylamino)ethyl methacrylate (DMAEMA), together with a hydrophilic one, lauryl methacrylate (LMA), within linear and branched copolymer topologies. Size exclusion chromatography was used to evaluate the resultant linear and hyperbranched copolymers’ molecular weight and dispersity, and FT-IR and ¹H-NMR spectroscopy techniques were used to delineate their chemical structure. The structural changes in the obtained self-organized supramolecular structures were thoroughly investigated using aqueous media with varying pH and salinity by dynamic light scattering (DLS), fluorescence spectroscopy (FS), and transmission electron microscopy (TEM). The nanoscale assemblies formed by the amphiphiles indicate significant potential for applications within the field of nanotechnology. Full article

The study investigates the development and characterization of dual-loaded niosomes incorporated into ion-sensitive in situ gel as a potential drug delivery platform for ophthalmic application. Cannabidiol (CBD) and epigallocatechin-3-gallate (EGCG) simultaneously loaded niosomes were prepared via the thin film hydration (TFH) method followed by pulsatile sonication and were subjected to comprehensive physicochemical evaluation. The optimal composition was included in a gellan gum-based in situ gel, and the antimicrobial activity, in vitro toxicity in a suitable corneal epithelial model (HaCaT cell line), and antioxidant potential of the hybrid system were further assessed. Dual-loaded niosomes based on Span 60, Tween 60, and cholesterol (3.5:3.5:3 mol/mol) were characterized by appropriate size (250 nm), high entrapment efficiency values for both compounds (85% for CBD and 50% for EGCG) and sustained release profiles. The developed hybrid in situ gel exhibited suitable rheological characteristics to enhance the residence time on the ocular surface. The conducted microbiological studies reveal superior inhibition of methicillin-resistant Staphylococcus aureus (MRSA) adhesion by means of the niosomal in situ gel compared to the blank gel and untreated control. Regarding the antioxidant potential, the dual loading of CBD and EGCG in niosomes enhances their protective properties, and the inclusion of niosomes in gel form preserves these effects. The obtained outcomes indicate the developed niosomal in situ gel as a promising drug delivery platform in ophthalmology. Full article

Liquid-core nanocapsules (NCs) coated with amphiphilic hyaluronic acid (AmHA) have been proposed for the preparation of drug and food formulations. Herein, we focused on the use of ultrasound techniques to (i) optimize the polysaccharide chain length with respect to the properties of NCs stabilized with AmHAs and (ii) form oil-core nanocapsules with a coating composed of AmHAs. The results indicate that sonication is a convenient and effective method that allows for a controlled reduction in HA molecular weight. The initial (H-HA) and degraded (L-HA) polysaccharides were then reacted with dodecylamine to obtain hydrophobic HA derivatives (HA-C12s). Then, NCs were prepared based on HA-C12s using ultrasound-assisted emulsification of glyceryl triacetate oil. The nanocapsules coated with L-HA-C12 showed greater stability compared to the longer-chain polysaccharide. Molecular dynamics (MD) simulations revealed that HA-C12 readily adsorbs at the water–oil interphase, adopting a more compact conformation compared to that in the aqueous phase. The dodecyl groups are immersed in the oil droplet, while the main polysaccharide chain remaining in the aqueous phase forms hydrogen bonds or water bridges with the polar part of the triglycerides, thus increasing the stability of the NC. Our research underscores the usefulness of ultrasound technology in preparing suitable formulations of bioactive substances. Full article

Despite the appealing properties of random copolymers, the use of these biomaterials in association with phospholipids is still limited, as several aspects of their performance have not been investigated. The aim of this work is the formulation of lipid/random copolymer platforms and the comprehensive study of their features by multiple advanced characterization techniques. Both biomaterials are amphiphilic, including two phospholipids (1,2-dioctadecanoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)) and a statistical copolymer of oligo (ethylene glycol) methyl ether methacrylate (OEGMA) and 2-(diisopropylamino) ethyl methacrylate (DIPAEMA). We examined the design parameters, including the lipid composition, the % comonomer ratio, and the lipid-to-polymer ratio that could be critical for their behavior. The structures were also probed in different conditions. To the best of the authors’ knowledge, this is the first time that P(OEGMA-co-DIPAEMA)/lipid hybrid colloidal dispersions have been investigated from a membrane mechanics, biophysical, and morphological perspective. Among other parameters, the copolymer architecture and the hydrophilic to hydrophobic balance are deemed fundamental parameters for the biomaterial co-assembly, having an impact on the membrane’s fluidity, morphology, and thermodynamics. Exploiting their unique characteristics, the most promising candidates were utilized for methotrexate (MTX) loading to explore their encapsulation capability and potential antitumor efficacy in vitro in various cell lines. Full article

The development of easy and direct real-time monitoring of welded joint quality instead of surface damage analysis is crucial to improve the quality of industrial products. This work presents the results of high-density polyethylene (HDPE)-based composites with various carbon black (CB) content (from 20 to 30 vol.%) for use as a heating element and strain sensor in electrofusion-welded polymer joints. The pyroresistive heating process was used to determine the effect of generated Joule heat during welding on the structure and sensor properties of polymer–carbon composites. It is shown that the generation of Joule heat depends on the nanocarbon content and affects the crystallinity of the polymer matrix. The partial disruption of the conductive path of carbon black particles was observed and, as a result, a decrease in electrical conductivity for composites with lower CB content after welding was found. For the highest CB amount, conductivity increased, which is caused by smaller particle-to-particle distance for filler paths. Therefore, the best balance between pyroresistive and sensor properties was found. Full article

Nanomedicine is a discipline of medicine that applies all aspects of nanotechnology strategies and concepts for treatment and screening possibilities. Synthetic polymer nanostructures are among the many nanomedicine formulations frequently studied for their potential as vectors. Bioimaging is a valuable diagnostic tool, thus, there is always a demand for new excipients/nanocarriers. In this study, hydrophobic hyperbranched poly(lauryl methacrylate) (PLMA) homopolymers comprised of highly hydrophobic LMA moieties with –COOH polar end groups were synthesized by employing reversible addition-fragmentation chain transfer (RAFT) polymerization. Ethylene glycol dimethacrylate (EGDMA) was utilized as the branching agent. End groups are incorporated through the RAFT agent utilized. The resulting amphiphilic hyperbranched polymer was molecularly characterized by size exclusion chromatography (SEC), Fourier transformation infrared spectroscopy (FT–IR), and ¹H–NMR spectroscopy. Pyrene, curcumin, and IR-1048 dye were hydrophobic payload molecules successfully encapsulated to show how adaptable these homopolymer nanoparticles (prepared by nanoprecipitation in water) are as dye nanocarriers. This study demonstrates a simple way of producing excipients by generating polymeric nanoparticles from an amphiphilic, hyperbranched, hydrophobic homopolymer, with a low fraction of polar end groups, for bioimaging purposes. Full article

Oil-core nanocapsules (NCs, also known as nanoemulsions) are of great interest due to their application as efficient carriers of various lipophilic bioactives, such as drugs. Here, we reported for the first time the preparation and characterization of NCs consisting of chondroitin sulfate (CS)-based shells and liquid oil cores. For this purpose, two amphiphilic CS derivatives (AmCSs) were obtained by grafting the polysaccharide chain with octadecyl or oleyl groups. AmCS-based NCs were prepared by an ultrasound-assisted emulsification of an oil phase consisting of a mixture of triglyceride oil and vitamin E in a dispersion of AmCSs. Dynamic light scattering and cryo-transmission electron microscopy showed that the as-prepared core–shell NCs have typical diameters in the range of 30–250 nm and spherical morphology. Since CS is a strong polyanion, these particles have a very low surface potential, which promotes their stabilization. The cytotoxicity of the CS derivatives and CS-based NCs and their impact on cell proliferation were analyzed using human keratinocytes (HaCaTs) and primary human skin fibroblasts (HSFs). In vitro studies showed that AmCSs dispersed in an aqueous medium, exhibiting mild cytotoxicity against HaCaTs, while for HSFs, the harmful effect was observed only for the CS derivative with octadecyl side groups. However, the nanocapsules coated with AmCSs, especially those filled with vitamin E, show high biocompatibility with human skin cells. Due to their stability under physiological conditions, the high encapsulation efficiency of their hydrophobic compounds, and biocompatibility, AmCS-based NCs are promising carriers for the topical delivery of lipophilic bioactive compounds. Full article

To create materials that interact effectively with electromagnetic (EM) radiation, new nanosized substituted ferrites (NiZn)_1−xMn_xFe₂O₄ (x = 0, 0.5, and 1) anchored on the surface of multi-walled carbon nanotubes (CNTs) have been synthesized. The concentration of CNTs in the (NiZn)_1−xMn_xFe₂O₄/CNT system was from 0.05 to 0.07 vol. fractions. The dielectric and magnetic characteristics of both pristine (NiZn)_1−xMn_xFe₂O₄ ferrites and (NiZn)_1−xMn_xFe₂O₄/CNT composite systems were studied. The introduction of (NiZn)_1−xMn_xFe₂O₄/CNT composites into the amorphous epoxy matrix allows to tailor absorbing properties at the high-frequency by effectively shifting the maximum peak values of the absorption and reflection coefficient to a region of lower frequencies (20–30 GHz). The microwave adsorption properties of (NiZn)_1−xMnxFe₂O₄/0.07CNT–ER (x = 0.5) systems showed that the maximum absorption bandwidth with reflection loss below −10 dB is about 11 GHz. Full article

The combination of phospholipids and block-copolymers yields advanced hybrid nanoparticles through the self-assembly process in an aqueous environment. The physicochemical features of the lipid/polymer components, like the lipid–polymer molar ratio, the macromolecular architecture of the block copolymer, the main transition temperature of the phospholipid, as well as the formulation and preparation protocol parameters, are some of the most crucial parameters for the formation of hybrid lipid/polymer vesicles and for the differentiation of their morphology. The morphology, along with other physicochemical nanoparticle characteristics are strictly correlated with the nanoparticle’s later biological behavior after being administered, affecting interactions with cells, biodistribution, uptake, toxicity, drug release, etc. In the present study, a structural evaluation of hybrid lipid–polymer nanoparticles based on cryo-TEM studies was undertaken. Different kinds of hybrid lipid–polymer nanoparticles were designed and developed using phospholipids and block copolymers with different preparation protocols. The structures obtained ranged from spherical vesicles to rod-shaped structures, worm-like micelles, and irregular morphologies. The obtained morphologies were correlated with the formulation and preparation parameters and especially the type of lipid, the polymeric guest, and their ratio. Full article

Ropinirole is a non-ergolinic dopamine agonist used to manage Parkinson’s disease and it is characterized by poor oral bioavailability. This study aimed to design and develop advanced drug delivery systems composed of poloxamer 407, a non-ionic surfactant (Tween 80), and cyclodextrins (methyl-β-CD or hydroxy-propyl-β-CD) for possible brain targeting of ropinirole after nasal administration for the treatment of Parkinson’s disease. The hybrid systems were formed by the thin-film hydration method, followed by an extensive physicochemical and morphological characterization. The in vitro cytotoxicity of the systems on HEK293 cell lines was also tested. In vitro release and ex vivo mucosal permeation of ropinirole were assessed using Franz cells at 34 °C and with phosphate buffer solution at pH 5.6 in the donor compartment, simulating the conditions of the nasal cavity. The results indicated that the diffusion-controlled drug release exhibited a progressive increase throughout the experiment, while a proof-of-concept experiment on ex vivo permeation through rabbit nasal mucosa revealed a better performance of the prepared hybrid systems in comparison to ropinirole solution. The encouraging results in drug release and mucosal permeation indicate that these hybrid systems can serve as attractive platforms for effective and targeted nose-to-brain delivery of ropinirole with a possible application in Parkinson’s disease. Further ex vivo and in vivo studies to support the results of the present work are ongoing. Full article

This manuscript presents the synthesis of hyperbranched amphiphilic poly (lauryl methacrylate-co-tert-butyl methacrylate-co-methacrylic acid), H-P(LMA-co-tBMA-co-MAA) copolymers via reversible addition fragmentation chain transfer (RAFT) copolymerization of tBMA and LMA, and their post-polymerization modification to anionic amphiphilic polyelectrolytes. The focus is on investigating whether the combination of the hydrophobic characters of LMA and tBMA segments, as well as the polyelectrolyte and hydrophilic properties of MAA segments, both distributed within a unique hyperbranched polymer chain topology, would result in intriguing, branched copolymers with the potential to be applied in nanomedicine. Therefore, we studied the self-assembly behavior of these copolymers in aqueous media, as well as their ability to form complexes with cationic proteins, namely lysozyme (LYZ) and polymyxin (PMX). Various physicochemical characterization techniques, including size exclusion chromatography (SEC) and proton nuclear magnetic resonance (¹H-NMR), verified the molecular characteristics of these well-defined copolymers, whereas light scattering and fluorescence spectroscopy techniques revealed promising nanoparticle (NP) self- and co-assembly properties of the copolymers in aqueous media. Full article

The objective of this research was to develop highly effective conductive polymer composite (CPC) materials for flexible piezoresistive sensors, utilizing hollow three-dimensional graphitic shells as a highly conductive particulate component. Polystyrene (PS), a cost-effective and robust polymer widely used in various applications such as household appliances, electronics, automotive parts, packaging, and thermal insulation materials, was chosen as the polymer matrix. The hollow spherical three-dimensional graphitic shells (GS) were synthesized through chemical vapor deposition (CVD) with magnesium oxide (MgO) nanoparticles serving as a support, which was removed post-synthesis and employed as the conductive filler. Commercial multi-walled carbon nanotubes (CNTs) were used as a reference one-dimensional graphene material. The main focus of this study was to investigate the impact of the GS on the piezoresistive response of carbon/polymer composite thin films. The distribution and arrangement of GS and CNTs in the polymer matrix were analyzed using techniques such as X-ray diffraction and scanning electron microscopy, while the electrical, thermal, and mechanical properties of the composites were also evaluated. The results revealed that the PS composite films filled with GS exhibited a more pronounced piezoresistive response as compared to the CNT-based composites, despite their lower mechanical and thermal performance. Full article

Cannabidiol (CBD) is a promising drug candidate with pleiotropic pharmacological activity, whose low aqueous solubility and unfavorable pharmacokinetics have presented obstacles to its full clinical implementation. The rational design of nanocarriers, including niosomes for CBD encapsulation, can provide a plausible approach to overcoming these limitations. The present study is focused on exploring the feasibility of copolymer-modified niosomes as platforms for systemic delivery of CBD. To confer steric stabilization, the niosomal membranes were grafted with newly synthesized amphiphilic linear or star-shaped 3- and 4-arm star-shaped copolymers based on polyglycidol (PG) and poly(ε-caprolactone) (PCL) blocks. The niosomes were prepared by film hydration method and were characterized by DLS, cryo-TEM, encapsulation efficacy, and in vitro release. Free and formulated cannabidiol were further investigated for cytotoxicity and pro-apoptotic and anti-inflammatory activities in vitro in three human tumor cell lines. The optimal formulation, based on Tween 60:Span60:Chol (3.5:3.5:3 molar ration) modified with 2.5 mol% star-shaped 3-arm copolymer, is characterized by a size of 235 nm, high encapsulation of CBD (94%), and controlled release properties. Niosomal cannabidiol retained the antineoplastic activity of the free agent, but noteworthy superior apoptogenic and inflammatory biomarker-modulating effects were established at equieffective exposure vs. the free drug. Specific alterations in key signaling molecules, implicated in programmed cell death, cancer cell biology, and inflammation, were recorded with the niosomal formulations. Full article

The thermal behavior and aggregation process of the poly(N-isopropyl acrylamide), poly[oligo(ethylene glycol) methyl ether methacrylate], and poly[(2-hydroxyethyl methacrylate)-co-oligo(ethylene glycol) methyl ether methacrylate] thermoresponsive polymers were studied in a commonly used Dulbecco’s Modified Eagle Medium (DMEM) cell culture medium and solutions of its individual components in the same concentration as found in DMEM. All studied copolymers exhibited an unexpected transmittance profile in the DMEM. During heating above the cloud point temperature (T_CP), the polymers additionally aggregated, which led to the formation of their precipitates. The behavior of the polymers was further studied to evaluate how individual salts affected the transition temperature, size (D_h), and stability of the polymer particles. Organic additives, such as amino acids and glucose, had a significantly lesser impact on the thermoresponsive aggregation of the polymers than inorganic ones. Changes to the T_CP were small and the formation of precipitates was not observed. The presence of small amounts of amino acids caused a decrease in the polymer aggregate sizes. Obtained results are of utmost importance in thermoresponsive drug nanocarrier studies. Full article

Gel dressings, composed of polymers both natural and synthetic, are successfully used in the treatment of burn wounds. They protect the burn wound site against adverse external factors, ensure an adequate level of tissue hydration, have soothing and pain-relieving properties, and also support the healing process and reduce the risk of pathological scars. Another promising material that can be used in the wound-healing process is an amnion membrane. Due to its valuable properties such as protecting the body against bacterial infections and permeability to nutrition, it has found usage in different brands of medicine. In this work, we have combined the beneficial properties of hydrogels and amnion in order to make the laminar dressing that may serve for wound healing. For that purpose, the physically crosslinked cryogel of poly(vinyl alcohol) (PVA) was covered with an amnion membrane. Subsequently, gamma irradiation was performed, leading to the simultaneous internal crosslinking of the hydrogel, its permanent bonding with the amnion, and dressing sterilization. The physicochemical properties of the dressing including gel fraction, swelling, and hardness were studied. Biological tests such as the MTT assay, antimicrobial activity, and histopathological examination confirmed that the obtained material constituted a promising candidate for further, more in-depth studies aiming at wound dressing application. Full article