Showing papers on "Methacrylic acid published in 2022"

Adsorption ability evaluation of the poly(methacrylic acid-co-acrylamide)/cloisite 30B nanocomposite hydrogel as a new adsorbent for cationic dye removal.

Abstract: The performance of poly(methacrylic acid-co-acrylamide)/Cloisite 30B nanocomposite (poly(MAA-co-AAm)/Cl30B) hydrogel to adsorb methylene blue (MB) dye from aqueous solutions was investigated and the adsorption efficiency was improved by incorporating Cloisite 30B nanoclays in the adsorbent structure. The hydrogels were analyzed using FTIR, XRD, TGA, and SEM analysis. The effect of adsorbent dose, temperature, initial dye concentration, contact time, and pH on the efficiency of the adsorption process was investigated. Adsorption efficiencies of 98.57 and 97.65% were obtained for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels, respectively. Kinetic study revealed that the adsorption process followed pseudo-first-order kinetic model and α-parameter values of 6.558 and 1.113 mg/g.min were obtained for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels, respectively indicating a higher ability of nanocomposite hydrogel in adsorbing MB-dye. In addition, the results of the intra-particle diffusion model showed that various mechanisms such as intra-particle diffusion and liquid film penetration are important in the adsorption. The Gibbs free energy parameter of adsorption process showed negative values of −256.52 and −84.071 J/mol.K for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels indicating spontaneous nature of the adsorption. The results of enthalpy and entropy showed that the adsorption process was exothermic and random collisions were reduced during the adsorption. The equilibrium data for the adsorption process using poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels followed Freundlich and Langmuir isotherm models, respectively. The maximum adsorption capacity values of 32.83 and 21.92 mg/g were obtained for poly(MAA-co-AAm)/Cl30B nanocomposite and poly(MAA-co-AAm) hydrogels, respectively. Higher adsorption capacity of nanocomposite hydrogel was attributed to the presence of Cloisite 30B clay nanoparticles in its structure. In addition, results of RL, n, and E parameters showed that the adsorption process was performed optimally and physically.

Self-Cascade Nanoenzyme of Cupric Oxide Nanoparticles (CuO NPs) Induced in Situ Catalysis Formation of Polyelectrolyte as Template for the Synthesis of Near-Infrared Fluorescent Silver Nanoclusters and the Application in Glutathione Detection and Bioimaging.

Abstract: In this work, near-infrared fluorescent silver nanoclusters (Ag NCs) were prepared based on the in situ formed poly methacrylic acid (PMAA) as the template and stabilizer, which is synthesized by methacrylic acid (MAA) and hydroxyl radical (·OH) that is generated by the cascade nanoenzyme reaction of cupric oxide nanoparticles (CuO NPs). CuO NPs possess the intrinsic glutathione-like (GPx-like) and peroxidase-like (POD-like) activities, which can catalyze glutathione (GSH) and O2 to produce hydrogen peroxide (H2O2), and then transform into ·OH. The fluorescence intensity of Ag NCs decreases with the addition of GSH, because the -SH can easily anchor on the surface, resulting in the PMAA leaving the Ag NCs, and the coeffect of GSH and PMAA results in the aggregation to form larger Ag NPs. A good linear relationship between the fluorescence quenching rate and the GSH concentration was found in the range 0.01-40 μM with the detection limit 8.0 nM. The Ag NCs can be applied in the detection of GSH in the serum, as well as bioimaging of endogenous and exogenous GSH in cells with high sensitivity. Moreover, the normal and cancer cells can be distinguished through bioimaging because of the different GSH levels. The new method for the preparation of biocompatible nanoprobe based on the nanozyme tandem catalysis and the in situ formed template can avoid the direct usage of polymers or protein templates that hinder preparation and separation, providing a reliable approach for the synthesis, biosensing, and bioimaging of nanoclusters.

Three-Dimensional Ordered Macroporous Magnetic Inverse Photonic Crystal Microsphere-Based Molecularly Imprinted Polymer for Selective Capture of Aflatoxin B1.

Abstract: Development of an efficient detection method to monitor residual mycotoxins in food is very important to ensure food safety, but the complex food matrix seriously affects the detection sensitivity and accuracy. Here, using a three-dimensional ordered macroporous magnetic inverse photonic crystal microsphere (MPCM) as the supporting material, a molecularly imprinted polymer (MIP) that can selectively recognize aflatoxin B1 (AFB1) was synthesized through the dummy template imprinting strategy. The MPCM@MIP prepared by employing 5,7-dimethoxycoumarin as the template and methacrylic acid as the functional monomer displayed selectivity toward AFB1 (imprinting factor of 1.5) and could be used as a solid-phase extraction material. By coupling with high-performance liquid chromatography, an analytical method targeting AFB1 was established and displayed a wide linear range of 5-1000 ng/mL with a low detection limit of 0.4 ng/mL. The method showed a good recovery rate of 73-92% in AFB1-spiked soy sauce and vinegar samples. Moreover, the MPCM@MIP could be separated from the sample solution easily because of its magnetic performance, displaying a promising future not only in the enrichment of AFB1 to improve the detection sensitivity and accuracy but also in the removal of AFB1 from food and environmental samples.

pH Sensitive Pluronic Acid/Agarose-Hydrogels as Controlled Drug Delivery Carriers: Design, Characterization and Toxicity Evaluation

Abstract: The objective of this study was to fabricate and evaluate a pH sensitive cross-linked polymeric network through the free radical polymerization technique for the model drug, cyclophosphamide, used in the treatment of non-Hodgkin’s lymphoma. The Hydrogels were prepared using a polymeric blend of agarose, Pluronic acid, glutaraldehyde, and methacrylic acid. The prepared hydrogels were characterized for drug loading (%), swelling pattern, release behavior, the ingredient’s compatibility, structural evaluation, thermal integrity, and toxicity evaluation in rabbits. The new polymer formation was evident from FTIR findings. The percentage loaded into the hydrogels was in the range of 58.65–75.32%. The developed hydrogels showed significant differences in swelling dynamics and drug release behavior in simulated intestinal fluid (SIF) when compared with simulated gastric fluid (SGF). The drug release was persistent and performed in a controlled manner for up to 24 h. A toxicity study was conducted on white albino rabbits. The developed hydrogels did not show any signs of ocular, skin, or oral toxicity; therefore, these hydrogels can be regarded as safe and potential carriers for controlled drug delivery in biomedical applications.

Selective Removal of the Emerging Dye Basic Blue 3 via Molecularly Imprinting Technique

Abstract: A molecularly imprinting polymer (MIP) was synthesized for Basic Blue 3 dye and applied to wastewater for the adsorption of a target template. The MIPs were synthesized by bulk polymerization using methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA). Basic Blue 3 dye (BB-3), 2,2′-azobisisobutyronitrile (AIBN) and methanol were used as a functional monomer, cross linker, template, initiator and porogenic solvent, respectively, while non-imprinting polymers (NIP) were synthesized by the same procedure but without template molecules. The contact time was 25 min for the adsorption of BB-3 dye from 10 mL of spiked solution using 25 mg polymer. The adsorption of dye (BB-3) on the MIP followed the pseudo-second order kinetic (k2 = 0.0079 mg·g−1·min−1), and it was according to the Langmuir isotherm, with maximum adsorption capacities of 78.13, 85.4 and 99.0 mg·g−1 of the MIP at 283 K, 298 K and 313 K, respectively and 7 mg·g−1 for the NIP. The negative values of ΔG° indicate that the removal of dye by the molecularly imprinting polymer and non-imprinting polymer is spontaneous, and the positive values of ΔH° and ΔS° indicate that the process is endothermic and occurred with the increase of randomness. The selectivity of the MIP for BB-3 dye was investigated in the presence of structurally similar as well as different dyes, but the MIP showed higher selectivity than the NIP. The imprinted polymer showed 96% rebinding capacity at 313 K towards the template, and the calculated imprinted factor and Kd value were 10.73 and 2.62, respectively. In this work, the MIP showed a greater potential of selectivity for the template from wastewater relative to the closely similar compounds.

Design and application of molecularly imprinted polymers for adsorption and environmental assessment of anti-inflammatory drugs in wastewater samples

Abstract: In this study, a series of molecularly imprinted polymers (MIPs) have been synthesized using separately diclofenac, naproxen, and ibuprofen as templates with three different polymerization approaches. Two functional monomers, methacrylic acid (MAA) and 2-vinylpyridine (2-VP), were tested and ethylene glycol dimethacrylate (EGDMA) was used as crosslinker; also, template-free polymers (NIPs) were synthesized. It was found that the MIP with the highest retention percentage for diclofenac was the one prepared by the emulsion approach and with MAA (98.3%); for naproxen, the one prepared by the bulk polymerization with MAA (99%); and for ibuprofen, the one synthesized by bulk with 2-VP (97.7%). These three MIPs were characterized by scanning electron microscopy, thermogravimetric test, Fourier transform infrared, specific area measurements, and surface charge. It was found that the emulsion method allowed particle size control, while the bulk method gave heterogeneous particles. The three evaluated MIPs exhibited thermal stability up to 300 °C, and it was observed that 2-VP confers greater stability to the material. From the BET analysis, it was demonstrated that the MIPs and NIPs evaluated are mesoporous materials with a pore size between 10 and 20 nm. In addition, the monomer influenced the surface charge of the material, since the MAA conferred an acidic point of zero charge (PZC), while the 2-VP conferred a PZC of basic character. Through adsorption isotherms, it was determined that there is a higher adsorption capacity of the MIPs at acidic pH following a pseudo-second-order kinetic model. Finally, the MIPs were used to determine the non-steroidal anti-inflammatory drugs (NSAIDs) understudy in San Luis Potosí, México, wastewater, finding concentrations of 0.642, 0.985, and 0.403 mg L-1 for DCF, NPX, and IBP, respectively.

Modification of cotton gauzes with poly(acrylic acid) and poly(methacrylic acid) using gamma radiation for drug loading studies

Abstract: Cotton gauzes are highly versatile medical devices for treating wounds due to their excellent absorption capacity and because they avoid contact between the wound and the environment. As materials of priority use, it is possible to take advantage of their ubiquity and use them as delivery systems for antimicrobial drugs that effectively treat skin wound infections. For this reason, this study proposes the modification of cotton gauzes through the grafting of pH-sensitive polymers, such as poly (acrylic acid) and poly (methacrylic acid), as a means of achieving drug delivery. The grafting process was carried out using gamma radiation, and the successful modification of the devices was verified with analytical techniques such as SEM, FTIR-ATR, TGA, and DSC, finding the novel properties of these modified materials. The grafted gauzes show a critical pH close to 4.7, which would allow for its application to some acidic skin wounds. In addition to the pH-buffering properties of the material, it was possible to load vancomycin onto the grafted materials as a pathway for the development of antimicrobial materials.

Testosterone Imprinted poly(HEMA‐MAA) Nanoparticles Based Surface Plasmon Resonance Sensor for Detection of Testosterone

Abstract: The selective, sensitive, and real-time detection of testosterone was performed from both testosterone aqueous solution and artificial urine samples by using the advantages of surface plasmon resonance sensor (SPR) with molecular imprinting technique. The testosterone imprinted (MIP) and non-imprinted (NIP) nanoparticle based poly(2-hydroxyethyl methacrylate-methacrylic acid (poly(HEMA-MAA)) SPR sensors were prepared for detection of testosterone. After characterization of MIP and NIP nanoparticles, nanoparticles were attached on the SPR chip surfaces. The characterization of SPR sensor surfaces was carried out with characterization methods such as atomic force microscopy, ellipsometer and contact angle measurements. The real-time measurements for detection of testosterone were performed with testosterone imprinted SPR sensor in the linear range of 0.5-20 ng/mL concentration in testosterone aqueous solution. The imprinting factor and the limit of detection was found 4.16 and 0.049 ng/mL, respectively. The validation studies were performed with both SPR sensor and enzyme-linked immunosorbent assay using testosterone samples prepared in artificial urine samples for the detection of testosterone.

Magnetic Surface Molecularly Imprinted Polymer for Selective Adsorption of 4-Hydroxycoumarin

Abstract: 4-hydroxyl coumarin (HC), an important intermediate during the synthesis procedure of rodenticide and anti-cardiovascular drug, shows highly medicinal value and economic value. To achieve the efficient adsorption of HC from natural biological samples, a novel magnetic surface molecularly imprinted polymer (HC/SMIPs) was constructed by employing methacrylic acid (MAA) as functional monomer, organic silane modified magnetic particles as matrix carrier and HC as template molecule. Due to the numerous specific imprinted cavities on the HC/SMIPs, the maximum adsorption capacity of HC/SMIPs for 4-hydroxycoumarin could reach to 22.78 mg g−1 within 20 min. In addition, HC/SMIPs exhibited highly selective adsorption for 4-hydroxycoumarin compared with other active drug molecules (osthole and rutin) and showed excellent regeneration performance. After 8 cycles of adsorption-desorption tests, the adsorption capacity of HC/SMIPs just slightly decreased by 6.64%. The efficient selective removal and easy recycle of 4-hydroxycoumarin from biological samples by HC/SMIPs made a highly promising to advance the application of imprinting polymers in complex practical environments.

Adjusting Some Properties of Poly(methacrylic acid) (Nano)Composite Hydrogels by Means of Silicon-Containing Inorganic Fillers

Abstract: The present work aims to show how the main properties of poly(methacrylic acid) (PMAA) hydrogels can be engineered by means of several silicon-based fillers (Laponite XLS/XLG, montmorillonite (Mt), pyrogenic silica (PS)) employed at 10 wt% concentration based on MAA. Various techniques (FT-IR, XRD, TGA, SEM, TEM, DLS, rheological measurements, UV-VIS) were used to comparatively study the effect of these fillers, in correlation with their characteristics, upon the structure and swelling, viscoelastic, and water decontamination properties of (nano)composite hydrogels. The experiments demonstrated that the nanocomposite hydrogel morphology was dictated by the way the filler particles dispersed in water. The equilibrium swelling degree (SDe) depended on both the pH of the environment and the filler nature. At pH 1.2, a slight crosslinking effect of the fillers was evidenced, increasing in the order Mt < Laponite < PS. At pH > pKaMAA (pH 5.4; 7.4; 9.5), the Laponite/Mt-containing hydrogels displayed a higher SDe as compared to the neat one, while at pH 7.4/9.5 the PS-filled hydrogels surprisingly displayed the highest SDe. Rheological measurements on as-prepared hydrogels showed that the filler addition improved the mechanical properties. After equilibrium swelling at pH 5.4, G’ and G” depended on the filler, the Laponite-reinforced hydrogels proving to be the strongest. The (nano)composite hydrogels synthesized displayed filler-dependent absorption properties of two cationic dyes used as model water pollutants, Laponite XLS-reinforced hydrogel demonstrating both the highest absorption rate and absorption capacity. Besides wastewater purification, the (nano)composite hydrogels described here may also find applications in the pharmaceutical field as devices for the controlled release of drugs.

Orally Administered, Biodegradable and Biocompatible Hydroxypropyl–β–Cyclodextrin Grafted Poly(methacrylic acid) Hydrogel for pH Sensitive Sustained Anticancer Drug Delivery

Abstract: In the current study, a pH sensitive intelligent hydroxypropyl–β–cyclodextrin-based polymeric network (HP-β-CD-g-MAA) was developed through a solution polymerization technique for site specific delivery of cytarabine in the colonic region. Prepared hydrogel formulations were characterized through cytarabine loading (%), ingredient’s compatibility, structural evaluation, thermal integrity, swelling pattern, release behavior and toxicological profiling in rabbits. Moreover, the pharmacokinetic profile of cytarabine was also determined in rabbits. New polymer formation was evident from FTIR findings. The percentage loaded into the hydrogels was in the range of 37.17–79.3%. Optimum swelling ratio of 44.56 was obtained at pH 7.4. Cytarabine release was persistent and in a controlled manner up to 24 h. In vitro degradation of hydrogels was more pronounced at intestinal pH as compared to acidic pH. Toxicity studies proved absence of any ocular, skin and oral toxicity, thus proving biocompatibility of the fabricated network. Hydrogels exhibited longer plasma half-life (8.75 h) and AUC (45.35 μg.h/mL) with respect to oral cytarabine solution. Thus, the developed hydrogel networks proved to be excellent and biocompatible cargo for prolonged and site-specific delivery of cytarabine in the management of colon cancer.

EGDMA- and TRIM-Based Microparticles Imprinted with 5-Fluorouracil for Prolonged Drug Delivery

Abstract: Imprinted materials possess designed cavities capable of forming selective interactions with molecules used in the imprinting process. In this work, we report the synthesis of 5-fluorouracil (5-FU)-imprinted microparticles and their application in prolonged drug delivery. The materials were synthesized using either ethylene glycol dimethacrylate (EGDMA) or trimethylolpropane trimethacrylate (TRIM) cross-linkers. For both types of polymers, methacrylic acid was used as a functional monomer, whereas 2-hydroxyethyl methacrylate was applied to increase the final materials’ hydrophilicity. Adsorption isotherms and adsorption kinetics were investigated to characterize the interactions that occur between the materials and 5-FU. The microparticles synthesized using the TRIM cross-linker showed higher adsorption properties towards 5-FU than those with EGDMA. The release kinetics was highly dependent upon the cross-linker and pH of the release medium. The highest cumulative release was obtained for TRIM-based microparticles at pH 7.4. The IC50 values proved that 5-FU-loaded TRIM-based microparticles possess cytotoxic activity against HeLa cell lines similar to pure 5-FU, whereas their toxicity towards normal HDF cell lines was ca. three times lower than for 5-FU.

Adsorption of methyl violet dye from wastewater using poly(methacrylic acid-co-acrylamide)/bentonite nanocomposite hydrogels

Abstract: In this study, nanocomposite hydrogels of poly(methacrylic acid-co-acrylamide) (Poly(MAA-co-AAm)) containing different weight percent bentonite clay nanoparticles (0, 5, 10, and 15 wt. %) were used to remove methyl violet (MV) dye. FTIR, SEM, TGA, and XRD were used to analyze the properties of adsorbents. Results showed that bentonite nanoparticles were successfully distributed in the hydrogel system. Bentonite nanoparticles at 10 wt. % gave the maximum MV dye adsorption efficiency. The highest adsorption was obtained at a pH of 5, an adsorbent dosage of 1.5 g/L, a temperature of 25 °C, a contact time of 60 min, and a pollutant concentration of 10 mg/L. In thermodynamics studies, a negative values of Gibbs free energy (ΔG°) indicating that the adsorption process was spontaneous. In addition, Poly(MAA-co-AAm) hydrogels and Poly(MAA-co-AAm)/bentonite nanocomposite hydrogels gave the adsorption enthalpy (ΔH°) of –61.24 and –36.14 kJ/mol witch shows that the adsorption process is exothermic in the temperature range 25–45 °C using both adsorbents. Langmuir isotherm model was successfully applied in describing the equilibrium behavior of the adsorption process. The kinetic study showed that the pseudo-second-order model was more successful in describing the kinetic behavior of the adsorption process than pseudo-first-order and Elovich models. Poly(methacrylic acid-co-acrylamide) and poly(methacrylic acid-co-acrylamide)/bentonite adsorbents gave the α parameter values of 0.4276 and 22.15 mg.(g.min)−1, respectively indicating the high adsorption capacity of these adsorbents.

Negatively charged poly(N-isopropyl acrylamide-co-methacrylic acid)/polyacrylamide semi-IPN hydrogels: Correlation between swelling and compressive elasticity

Abstract: A series of thermoresponsive semi-interpenetrating polymer network (semi-IPN) based on linear polyacrylamide (PAAm), N-isopropylacrylamide (NIPA) and methacrylic acid (MA) were synthesized by varying linear polymer content via free radical polymerization. An interpenetrated network of P(NIPA-MA)/PAAm was designed to modulate elasticity by varying inner composition and to improve rate of swelling-deswelling phenomenon. Correlation between swelling and compression elasticity was demonstrated. Inclusion of linear PAAm chains with high molecular weight (Mw = 9.639 × 105 g/mol) into P(NIPA-MA) network induced physical entanglements, increased apparent crosslinking density νeand enlarged compressive elasticity. Dependence of νeon linear polymer content was expressed as a cubic polynomial function. Extent of swelling of semi-IPN P(NIPA-MA)/PAAm gels was sensitive to presence of linear PAAm chains. Existence of linear polymer decreased apparent ionic group density and increased crosslinking density compared to that of copolymer P(NIPA-MA) network which in turn decreased equilibrium swelling. A significant increase in swelling/shrinking rate was observed in the presence of linear PAAm. Due to ionization of carboxylic acid groups in P(NIPA-MA) network, semi-IPN P(NIPA-MA)/PAAm gels showed different degrees of swelling depending on linear PAAm content and temperature of swelling medium. Semi-IPNs exhibited phase transition temperatures shifted higher temperature, suggesting physical entanglements between P(NIPA-MA) network and linear PAAm. Increasing swelling temperature resulted in an increase in Flory-Huggins interaction parameter. Entropic contributionχSincreased and enthalpic contribution χH decreased with PAAm content. The results showed that the prepared semi-IPNs are a suitable adsorbent for adsorption of the cationic dye Methyl violet (MV). Adsorption kinetics followed a pseudo-second-order model and exhibited a two-stage intra-particle diffusion. A detailed understanding of physicochemical properties of negatively charged thermoresponsive semi-IPNs in relation to structural architecture is an important criterion in many biomedical and pharmaceutical applications.