Comparison of methods for the synthesis of silver nanoparticles stabilized in a solid polymethacrylate matrix.

Silver nanoparticles were synthesized inside the small plates of transparent polymer medium by reduction of silver cations. The difference in morphology and sizes of nanoparticles synthesized by chemical, photochemical and thermal reduction was revealed, which depends both on the component ratio of the mixture and on the reduction time for the specific component ratio The polymethacrylate matrix itself acts as the stabilizing agent. A colorimetric sensor based on polymethacrylate matrix and silver nanoparticles was developed for the detection of hydrogen peroxide. The optical properties of the sensor were characterized by spectrophotometer using the surface plasmon resonance. A colorimetric sensor with nanoparticles undergoing to thermal reduction showed a quick result for the determination of hydrogen peroxide in the range 0.2-4.4 mM with a detection limit 0.1 mM.

Silk Fibroin-Based Coatings for Pancreatin-Dependent Drug Delivery.

Triggerable coatings, such as pH-responsive polymethacrylate copolymers, can be used to protect the active pharmaceutical ingredients contained within oral solid dosage forms from the acidic gastric environment and to facilitate drug delivery directly to the intestine. However, gastrointestinal pH can be highly variable, which can reduce delivery efficiency when using pH-responsive drug delivery technologies. We hypothesized that biomaterials susceptible to proteolysis could be used in combination with other triggerable polymers to develop novel enteric coatings. Bioinformatic analysis suggested that silk fibroin is selectively degradable by enzymes in the small intestine, including chymotrypsin, but resilient to gastric pepsin. Based on the analysis, we developed a silk fibroin-polymethacrylate copolymer coating for oral dosage forms. In vitro and in vivo studies demonstrated that capsules coated with this novel silk fibroin formulation enable pancreatin-dependent drug release. We believe that this novel formulation and extensions thereof have the potential to produce more effective and personalized oral drug delivery systems for vulnerable populations including patients that have impaired and highly variable intestinal physiology.

Electrically Induced Structural Transformations of a Chiral Nematic under Tangential-Conical Boundary Conditions.

In this study, structural transformations induced by an electric field in the chiral nematic under tangential-conical boundary conditions have been considered. The composition influence of the orienting polymer films on the director tilt angles, the formation of orientational structures in the LC layer, as well as the electro-optical response and relaxation processes have been studied. It has been shown that the poly(tert-butyl methacrylate) concentration change in the orienting polymer mixture allows for smoothly controlling the director tilt angle without fixing its azimuthal orientation rigidly.

Effects of Digestion, Cell Culture Media, and Mucous on the Physical Properties, Cellular Effects, and Translocation of Polystyrene and Polymethacrylate Nanoparticles.

The discovery of plastic and metal nanoparticles in organisms, foods, and beverages has generated numerous studies on the effects of these particles on the barrier cells and their subsequent absorption into the body. Following ingestion, nanoparticles travel down the gastrointestinal tract (GIT), and their physicochemical characteristics change in response to the change in proteins and pH during their digestion. We measured the translocation of digested nanoparticles across a co-culture monolayer of Caco-2 and various combinations (1:9, 5:5, and 9:1) of HT29-MTX-E12. The in vitro model of the intestine was used to determine the translocation of digested 20 nm polymethacrylate (PMA) particles and the accompanying monolayer barrier effects after a 72 h exposure. The in vitro digestion increased the agglomeration and hydrodynamic diameters and decreased the surface charge of the nanoparticles. For NH2-functionalized polymethacrylate nanoparticles (PMA-NH2), the diameters increased from 57 nm (water) to 3800 nm (media), or 2660 nm (chyme). These nanoparticles compromised the integrity of the monolayer (trans-epithelial electrical resistance, Lucifer yellow translocation) and translocated across all the cell ratio configurations. Digestion can have a large effect on nanoparticle agglomeration and surface charge. Excess mucous was not seen as a barrier to the translocation of PMA-NH2.

Montmorillonite-based polymethacrylate composite monoliths as stationary phase materials for food and pharmaceutical analysis in capillary liquid and gas chromatography.

This work relates to the preparation of novel and promising stationary phases containing inorganic-organic composites for capillary liquid and gas chromatography. A naturally occurring montmorillonite was introduced to polymethacrylate monoliths, then used under different conditions of GC and HPLC at the same time. The performance of the columns was evaluated for the separation of alkane and alkylbenzene series in GC and capillary HPLC, respectively. While the bare monoliths failed to separate the model analytes, montmorillonite-based polymethacrylate allowed a full separation of the mixtures with Rs≥1.42. The columns were applied for the determination of myrcene and limonene isomers in the peel extracts of some fruits using GC, and for the analysis of active ingredients including aspirin, vitamin-C, caffeine, and ibuprofen extracted from common drugs using capillary HPLC. In GC, fast separation was achieved in 1.0 min with Rs of 6.53. The columns exhibited the best efficiency for myrcene with 20,900 plates/m. Using the capillary HPLC columns, the active ingredients were resolved in 10 min with Rs≥5.72. The efficiency values located between 12,800-21,700 plates/m in all cases. The developed methods were found to be linear in the range of 0.10-10.0 and 0.20-180 µg/mL for GC and HPLC, respectively. In comparison with commercial columns, the results in GC methods reveal that, despite their much shorter length, the prepared columns proved a faster separation with higher efficiency and comparable detection limits and chromatographic resolution. The prepared HPLC capillaries exposed lower run times and detection limits with comparable efficiency and resolution, and consume fewer samples and mobile phase solvents. The results demonstrate that the montmorillonite-based polymethacrylate composites are applicable as stationary phases for routine analysis and quality control of important fields such as food and pharmaceutical samples.

Visible-Light-Mediated Controlled Radical Branching Polymerization in Water.

Hyperbranched polymethacrylates were synthesized by green-light-induced atom transfer radical polymerization (ATRP) under biologically relevant conditions in the open air. Sodium 2-bromoacrylate (SBA) was prepared in situ from commercially available 2-bromoacrylic acid and used as a water-soluble inibramer to induce branching during the copolymerization of methacrylate monomers. As a result, well-defined branched polymethacrylates were obtained in less than 30 min with predetermined molecular weights (36 000

Enhancing stability and activity of β-galactosidase from Kluyveromyces lactis through immobilization on polymethacrylate monolith and optimisation using response surface methodology

Aims@#This study investigates the potential of porous polymethacrylate monoliths as enzyme support materials for large-scale enzyme commercialization. @*Methodology and results@#It focuses on their preparation and various immobilization techniques, such as adsorption, covalent-binding and cross-linking, specifically applied to β-galactosidase for bioprocess applications. The research assesses immobilization performance, operational stability, reusability and optimization using response surface methodology (RSM). The results reveal that covalent-binding exhibited the highest enzyme activity recovery, while cross-linking showed superior performance at lower enzyme concentrations but decreased at higher concentrations. Covalent-bound enzymes demonstrated reusability for up to four cycles, with optimal pH ranging between 7 and 8 and optimal temperature ranging between 30 °C and 40 °C. Furthermore, RSM optimization highlighted the significant influence of substrate concentration on enzyme activity, with a reliable model (R2 = 0.9163) and adequate precision (S/N = 13.1409).@*Conclusion, significance and impact of study@#Overall, this study provides valuable guidelines for effectively employing porous monoliths in large-scale industrial bioprocessing, offering potential cost-saving benefits and enhanced efficiency in enzyme commercialization.

Sodium Alginate-Quaternary Polymethacrylate Composites: Characterization of Dispersions and Calcium Ion Cross-Linked Gel Beads.

The objective of this work was to examine the effect of quaternary polymethacrylate (QPM), a water-insoluble polymer with a positive charge, on the characteristics of the sodium alginate (SA) dispersions and the calcium alginate (CA) gel beads containing propranolol HCl (PPN). The SA-QPM composite dispersions presented the formation of flocculates with a negative charge due to the electrostatic interaction of both substances. The QPM addition did not affect the SA dispersions' Newtonian flow, but the composite dispersions' viscosity enhancement was found. The PPN-loaded CA-QPM gel beads had more spherical than the PPN-loaded CA gel beads. The incorporation of QPM caused a bigger particle size, higher drug entrapment efficiency, and greater particle strength of the gel beads. Despite the similar water uptake property, the PPN-loaded CA-QPM gel beads displayed lower burst release and slower drug release rate than the PPN-loaded CA gel beads. However, the drug release from the PPN-loaded CA-QPM gel beads involved drug diffusion and matrix swelling mechanisms. This study demonstrated that adding QPM into the SA dispersions leads to a viscosity synergism. The CA-QPM gel beads display a good potential for use as a bioactive compound delivery system.

Influence of Surface Modification of Titanium and Its Alloys for Medical Implants on Their Corrosion Behavior.

Titanium and its alloys are often used for long-term implants after their surface treatment. Such surface modification is usually performed to improve biological properties but seldom to increase corrosion resistance. This paper presents research results performed on such metallic materials modified by a variety of techniques: direct voltage anodic oxidation in the presence of fluorides, micro-arc oxidation (MAO), pulse laser treatment, deposition of chitosan, biodegradable Eudragit 100 and poly(4-vinylpyridine (P4VP), carbon nanotubes, nanoparticles of TiO2, and chitosan with Pt (nano Pt) and polymeric dispersant. The open circuit potential, corrosion current density, and potential values were determined by potentiodynamic technique, and microstructures of the surface layers and coatings were characterized by scanning electron microscopy. The results show that despite the applied modifications, the corrosion current density still appears in the region of very low values of some nA/cm2. However, almost all surface modifications, designed principally for the improvement of biological properties, negatively influence corrosion resistance. The reasons for observed effects can vary, such as imperfections and permeability of some coatings or accelerated degradation of biodegradable deposits in simulated body fluids during electrochemical testing. Despite that, all coatings can be accepted for biological applications, and such corrosion testing results are presumed not to be of major importance for their applications in medicine.

Poly(methacrylate citric acid) as a Dual Functional Carrier for Tumor Therapy.

Owing to its pH-sensitive property and chelating Cu2+ effect, poly(methacrylate citric acid) (PCA) can be utilized as a dual functional nanocarrier to construct a nanodelivery system. Negatively charged carboxyl groups can interact with positively charged antineoplastic drugs through electrostatic interaction to form stable drug nanoparticles (NPs). Through drug experimental screening, doxorubicin (DOX) was selected as the model drug, PCA/DOX NPs with a diameter of 84 nm were prepared, and the drug-loading content was 68.3%. PCA/DOX NPs maintained good stability and a sustained release profile. Cell experiments presented that PCA/DOX NPs could inhibit effectively the growth of 4T1 cells; the IC50 value was decreased by approximately 15-fold after incubation for 72 h. The cytotoxicity toward H9C2 was decreased significantly. Moreover, based on its ability to efficiently adsorb copper ions, PCA showed good vascular growth inhibition effect in vitro. Furthermore, animal experiments showed that PCA/DOX NPs presented stronger anticancer effects than DOX; the tumor inhibition rate was increased by 1.5-fold. Myocardial toxicity experiments also confirmed that PCA reduced the cardiotoxicity of DOX. In summary, PCA/DOX NPs show good antitumor efficacy and low toxicity, and have good potential for clinical application.

Coupling AFM, DSC and FT-IR towards Elucidation of Film-Forming Systems Transformation to Dermal Films: A Betamethasone Dipropionate Case Study.

Polymeric film-forming systems have emerged as an esthetically acceptable option for targeted, less frequent and controlled dermal drug delivery. However, their dynamic nature (rapid evaporation of solvents leading to the formation of thin films) presents a true characterization challenge. In this study, we tested a tiered characterization approach, leading to more efficient definition of the quality target product profiles of film-forming systems. After assessing a number of physico-chemico-mechanical properties, thermal, spectroscopic and microscopic techniques were introduced. Final confirmation of betamethasone dipropionate-loaded FFS biopharmaceutical properties was sought via an in vitro skin permeation study. A number of applied characterization methods showed complementarity. The sample based on a combination of hydrophobic Eudragit® RS PO and hydroxypropyl cellulose showed higher viscosity (47.17 ± 3.06 mPa·s) and film thickness, resulting in sustained skin permeation (permeation rate of 0.348 ± 0.157 ng/cm2 h), and even the pH of the sample with Eudragit® NE 30D, along with higher surface roughness and thermal analysis, implied its immediate delivery through the epidermal membrane. Therefore, this study revealed the utility of several methods able to refine the number of needed tests within the final product profile.

Simultaneous Physico-Mechanical and In Vivo Assessment towards Factual Skin Performance Profile of Topical Polymeric Film-Forming Systems.

Topical film-forming systems (FFS) change drastically after solvent displacement, therefore indicating their skin metamorphosis/transformation as a property of special regulatory and research interest. This paper deals with the lack of suitable characterization techniques, suggesting a set of methods able to provide a comprehensive notion of FFS skin performance. After screening the physico-chemical, mechanical and sensory properties of FFS and resulting films, an elaborate three-phase in vivo study was performed, covering skin irritation, friction and substantivity. Upon removal of 24-hour occlusion, no significant change in erythema index was observed, while the film-former type (cellulose ether, acrylate and/or vinyl polymer) affected transepidermal water loss (TEWL); hydrophobic methacrylate copolymer-based samples decreased TEWL by 40-50%, suggesting a semi-occlusive effect. Although both the tribological parameters related to the friction coefficient and the friction curve's plateau provided valuable data, their analysis indicated the importance of the moment the plateau is reached as the onset of the secondary formulation, while the tertiary state is still best described by the completion of the film's drying time. The final part of the in vivo study proved the high in-use substantivity of all samples but confirmed the optimal 4:1 ratio of hydrophobic cationic and hydrophilic polymers, as indicated during early physico-mechanical screening.

An Antimicrobial Peptide-Mimetic Methacrylate Random Copolymer Induces Domain Formation in a Model Bacterial Membrane.

To address the emerging issue of drug-resistant bacteria, membrane-active synthetic polymers have been designed and developed to mimic host-defense antimicrobial peptides (AMPs) as antibiotic alternatives. In this study, we investigated the domain formation induced by synthetic polymer mimics of AMPs using model membranes to elucidate the biophysical principles that govern their membrane-active mechanisms. To that end, lipid vesicles mimicking Escherichia coli (E. coli) membrane were prepared using an 8:2 (molar ratio) mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol), sodium salt (POPG). Our studies using differential scanning calorimetry (DSC) and fluorescence microscopy indicated that cationic amphiphilic methacrylate random copolymers induced the phase separation to form POPE- or POPG-rich domains. A rhodamine-labeled polymer also showed the binding to separated domains in the membrane. Based on these results, we propose the mechanism that the copolymers induce domain formation by clustering of anionic POPG lipids similar to natural AMPs. In addition, the time-course of polymer binding to the GUV membrane was sigmoidal, suggesting the positive feedback loop in the membrane binding. We also hypothesize that this cooperative binding of the polymer is driven by the domain formation. This study demonstrates the potential of the amphiphilic copolymers to modulate the lipid organization of cell membranes, which may provide a new strategy to design membrane-active antimicrobial agents.

Surface Characteristics of Poly(alkyl methacrylate)s from Molecular Dynamics Simulations Using All-Atom Force Field.

Molecular dynamics (MD) simulations of melt films of poly(alkyl methacrylate)s (PAMAs) with methyl, ethyl, and n-butyl substituents, respectively, have been performed using an all-atom model to investigate their surface and thin film properties. The applied all-atom force fields predict the bulk densities of PAMAs in good agreement with experiments. Moreover, predictions of the surface tensions of PMMA, PEMA, and Pn-BMA melts are in reasonably good agreement with experiments. The density profiles and orientational-order parameters of chain segments show atomic-scale characteristics in the air/polymer interfacial region. In the surface region, the backbone segments of PAMAs form a well-defined layer structure with the chain vectors oriented parallel to the surface, while the ester side-chains strongly segregate to the surface region and show perpendicular orientation to the surface, with the most pronounced surface segregation noted for Pn-BMA. Such surface segregations of chain segments make it difficult to apply a simple relationship between the cohesive energy density and the surface tension of polymers, for example, and should be taken into account in relating the surface/thin film characteristics to the bulk properties of polymers in general.

Eudragit®: A Versatile Family of Polymers for Hot Melt Extrusion and 3D Printing Processes in Pharmaceutics.

Eudragit® polymers are polymethacrylates highly used in pharmaceutics for the development of modified drug delivery systems. They are widely known due to their versatility with regards to chemical composition, solubility, and swelling properties. Moreover, Eudragit polymers are thermoplastic, and their use has been boosted in some production processes, such as hot melt extrusion (HME) and fused deposition modelling 3D printing, among other 3D printing techniques. Therefore, this review covers the studies using Eudragit polymers in the development of drug delivery systems produced by HME and 3D printing techniques over the last 10 years. Eudragit E has been the most used among them, mostly to formulate immediate release systems or as a taste-masker agent. On the other hand, Eudragit RS and Eudragit L100-55 have mainly been used to produce controlled and delayed release systems, respectively. The use of Eudragit polymers in these processes has frequently been devoted to producing solid dispersions and/or to prepare filaments to be 3D printed in different dosage forms. In this review, we highlight the countless possibilities offered by Eudragit polymers in HME and 3D printing, whether alone or in blends, discussing their prominence in the development of innovative modified drug release systems.

Nematic Structures under Conical Anchoring at Various Director Tilt Angles Specified by Polymethacrylate Compositions.

Dependence of the director tilt angle of nematic liquid crystal (LC) under conical anchoring from the two-component polymer mixture composition has been studied. We varied the ratio of poly(isobutyl methacrylate) (PiBMA), which specifies a conical anchoring for the nematic liquid crystal LN-396, and poly(methylmethacrylate) (PMMA) assigning a tangential alignment for the same nematic. An oblique incidence light technique to determine a tilt angle has been used. It has been shown that the tilt angle increases from 0∘ to 47.7∘ when PiBMA:PMMA ratio changes in the range 30:70 to 100:0. The specific optical textures viewed under the polarizing microscope and proper orientational structures have been considered for various compositions of the polymer films. An electric field action on the formed orientational structures has been investigated. The obtained results are promising for the application in various electro-optical LC devices with a conical anchoring in which the director tilt angle is a crucial parameter: a controlled diffraction gratings, an electrically operated achromatic rotators of linear light polarization, etc.

Smartphone-based colorimetric determination of fluoride anions using polymethacrylate optode.

We developed a new transparent polymer optode based on polymethacrylate with Zr(IV) and alizarin red complex immobilized into it for digital colorimetric and solid-phase spectrophotometric determination of fluoride anions. The matrix changes its colour from purple to yellow after it contacts fluoride anion. We developed a processing algorithm for coloured images which helps calculate mean value for the RGB colour-coordinate system in a selected optode image and translates it into a fluoride concentration value. The analytical signal of the suggested method has a linearity range of 0.1-30 mg⋅L-1 with the detection limit 0.03 mg⋅L-1. Compared to other methods, the modified polymethacrylate matrix is actually a ready-to-use colorimetric system offering rapid results for drinking water quality control.

Determination of antioxidant capacity of medicinal tinctures using cuprac method involving Cu(II) neocuproine immobilized into polymethacrylate matrix.

This work suggests using Cu(II) - neocuproine redox system immobilized into transparent polymethacrylate matrix for assessment of antioxidant capacity using CUPRAC method. The method we developed makes it possible to quantify the content of the antioxidants in the concentration range of 5.9 × 10-8-9.1 × 10-5 M. The sensor was tolerant to pH variations and painting, and used for the antioxidant capacity determination values of some commercial medicinal tinctures without pretreatment.

Filling of Nanometric Pores with Polymer by Initiated Chemical Vapor Deposition.

The integration of porous thin films using microelectronic compatible processes sometimes requires the protection of the interior of the pores during the critical integration steps. In this paper, the polymerization of neo-pentyl methacrylate (npMA) is performed via initiated chemical vapor deposition (iCVD) on a porous organosilicate (SiOCH) and on a dense SiOCH. The characterizations by Fourier-transform infrared spectroscopy, spectroscopic ellipsometry, and time-of-flight secondary ion mass spectrometry of the different stacks show that iCVD is a powerful technique to polymerize npMA in the nanometric pores and thus totally fill them with a polymer. The study of the pore filling for very short iCVD durations shows that the polymerization in the pores is complete in less than ten seconds and is uniform in depth. Then, the poly(npMA) film growth continues on top of the filled SiOCH layer. These characteristics make iCVD a straightforward and very promising alternative to other infiltration techniques in order to fill the porosity of microporous thin films.

Nanoadsorbents preparing from oligoethylene glycol dendron and citric acid: Enhanced adsorption effect for the removal of heavy metal ions.

Poly(methacrylate oligoethylene glycol dendron-co-citric acid) (PGCA) that is based on citric acid and oligoethylene glycol (OEG) dendrons is utilized as a nanomaterial for the removal of heavy metal ions from aqueous solution. PGCA shows excellent solubility in aqueous solution and realizes satisfactory removal efficacy for Pb2+ ions; the removal rate exceeds 95 %. In addition, PGCA can be utilized in Chinese herbal decoctions; the removal rate of Pb2+ ions in the ligusticum wallichii decoction exceeds 90 %, meanwhile the concentration of the active ingredient, namely, ferulic acid, is maintained. In this nanoadsorbent, citric acid provides the active site for the chelation of heavy metal ions, and OEG dendron serves as a protective layer that reduces the opportunity for carboxyl groups to be occupied by other ingredients. In summary, nanomaterial PGCA is designed and synthesized successfully that can be applied as a nanoadsorbent for the removal of Pb2+ ions from aqueous solution, especially in Chinese herbal decoctions that have acidic compounds as active ingredients.