Glycol Dimethacrylate Cross-linker Research Articles

Fabrication of amphiphilic porous PDVB-PAA Janus nanoparticles: Formation mechanism, simultaneous loading and regulated release of hydrophobic and hydrophilic cargos

In this work, we reported the amphiphilic porous polydivinylbenzene-poly(acrylic acid) (PDVB-PAA) Janus nanoparticles (NPs) with a cross-linked hydrophobic porous PDVB framework and a cross-linked hydrophilic porous PAA bulge, which were converted from polystyrene/polydivinylbenzene-poly(tert-butyl acrylate) (PS/PDVB-PtBA) Janus NPs via hydrolysis in dichloromethane. Cl,Br-labeled PS/PDVB-PtBA Janus NPs were designed and synthesized to experimentally verify the formation mechanism of PS/PDVB-PtBA Janus NPs and PDVB-PAA Janus NPs for the first time by combined techniques of TEM, SEM with element mapping and FTIR measurements. By simply varying the feeding amount of crosslinking agent ethylene glycol dimethacrylate (EGDMA) during the polymerization step of tBA, the morphologies of resultant PS/PDVB-PtBA Janus NPs and corresponding PDVB-PAA Janus NPs could be well controlled. It was demonstrated that the obtained amphiphilic porous PDVB-PAA Janus NPs could be applied as carrier materials for simultaneously loading hydrophobic coumarin 153 and hydrophilic rhodamine 6G.

Elucidating doxycycline loading and release performance of imprinted hydrogels with different cross-linker concentrations: a computational and experimental study

Effective non-covalent molecular imprinting on a polymer depends on the extent of non-bonded interactions between the template and other molecules before polymerization. Here, we first determine functional monomers that can yield a doxycycline-imprinted hydrogel based on the hydrogen bond interactions at the prepolymerization step, revealed by molecular dynamics (MD) simulations, molecular docking, and simulated annealing methods. Then, acrylic acid (AA)-based doxycycline (DOX) imprinted (MIP) and non-imprinted (NIP) hydrogels are synthesized in cross-linker ethylene glycol dimethacrylate (EGDMA) ratios of 1.0, 1.5, 2.0, and 3.0 mol%. Here, molecularly imprinted polymer with 3.0 mol% EGDMA has the highest imprinting factor (1.58) and best controlled drug release performance. At this point, full-atom MD simulations of DOX–AA solutions at different EGDMA concentrations reveal that AA and EGDMA compete to interact with DOX. However, at 3.0 mol% EGDMA, AA attains numerous stable hydrogen bond interactions with the drug. This study demonstrates that the concentration of the cross-linker and functional monomer can be adjusted to increase the success of imprinting, where the interplay between these two parameters can be successfully revealed by MD simulations.Supplementary informationThe online version contains supplementary material available at 10.1007/s10965-021-02740-6.

Preparation and properties of aflatoxins imprinted polymer grafted onto the surface of mesoporous silica SBA-15 functionalized with double bonds.

Mesoporous silica Santa Barbara-15 was functionalized by methacryloxypropyl trimethoxysilane. Taking this as the carrier material, a new mesoporous silica surface imprinted polymer was synthesized by using the C=C bond, functional monomer α-methacrylic acid, and crosslinker ethylene glycol dimethacrylate, which was used to extract aflatoxin from grain efficiently. It is different from the preparation of surface imprinted polymers which is physically wrapping carrier materials with polymer layers. The chemical grafting method makes the coating of the polymer layer more controllable. A new method for selective separation, enrichment, and determination of trace aflatoxin in grain was established by using the polymers as the filter of the solid-phase extraction column and high-performance liquid chromatography. The linear range of the method was 0.5-100 μg/kg, R2 =0.9990-0.9993. The recovery of aflatoxin G2, G1, B2, and B1 was 98.9-119.7% and the relative standard deviation was 3.07-5.76%. By comparing the self-made column with the immunoaffinity column, it was found that the self-made column had better extraction performance for aflatoxins than the immunoaffinity column. It can be used for the analysis and detection of aflatoxins in cereal.

Structure-Activity-Relationship Studies to Elucidate Sources of Antibacterial Activity of Modular Polyacrylate Microgels.

Emerging infections of unknown origin and increasing bacterial resistance against available antibiotics necessitate the development of different antimicrobial agents with unconventional mechanisms of action. A promising strategy to meet this need may be found by combining polymeric scaffolds with transition metals, e.g., by decorating polyacrylate-based microgels with Cu(II) complexes. A series of structure-activity relationship studies using broth microdilution assays with such materials and Staphylococcus aureus concluded that the antimicrobial activity of microgels can be tailored during their synthesis by choice of co-monomers, by design of the binding strength between Cu(II) ions and backbone ligands, and by selection of the counter ions for coordination to the metal complexes. A microgel Cu2LP(EG) (L = VBbsdpo) with an optimized minimal inhibitory concentration of 0.39 ± 0.03 μg/mL is thereby derived and synthesized from 60 mol % of cross-linking ethylene glycol dimethacrylate, 40 mol % butyl acrylate, 0.5 mol % VBbsdpo ligand with 1 mol % Cu(II) ions, and 5 mol % ethylene glycol as counter ions. The antimicrobial activity of the microgel has a lifetime of over 18 months at ambient temperature. Bactericidal activity of the same microgel is observed by replating assays in less than 15 min when exposing S. aureus to microgel concentrations of 1.5-fold of its minimum inhibitory concentration (MIC) value or higher. Furthermore, spectrophotometric evaluations at 260 nm revealed time- and concentration-dependent release of intracellular bacterial components after interactions with the microgel indicating irreversible damage to the bacterial cell membrane as a possible mechanism of activity. Preliminary results indicate that the selected microgels are not cytotoxic toward human dermal fibroblasts at MIC value concentrations for over 20 h.

Antifouling and Mechanical Properties of Photografted Zwitterionic Hydrogel Thin-Film Coatings Depend on the Cross-Link Density.

Zwitterionic polymer networks have shown promise in reducing the short- and long-term inflammatory foreign body response to implanted biomaterials by combining the antifouling properties of zwitterionic polymers with the mechanical stability provided by cross-linking. Cross-link density directly modulates mechanical properties (i.e., swelling behavior, resistance to stress and strain, and lubricity) but theoretically could reduce desirable biological properties (i.e., antifouling) of zwitterionic materials. This work examined the effect of varying poly(ethylene glycol) dimethacrylate cross-linker concentration on protein adsorption, cell adhesion, equilibrium swelling, compressive modulus, and lubricity of zwitterionic thin films. Furthermore, this work aimed to determine the appropriate balance among each of these mechanical and biologic properties to produce thin films that are strong, durable, and lubricious, yet also able to resist biofouling. The results demonstrated nearly a 20-fold reduction in fibrinogen adsorption on zwitterionic thin films photografted on polydimethylsiloxane (PDMS) across a wide range of cross-link densities. Interestingly, either at high or low cross-link densities, increased levels of protein adsorption were observed. In addition to fibrinogen, macrophage and fibroblast cell adhesion was reduced significantly on zwitterionic thin films, with a large range of cross-link densities, resulting in low cell counts. The macrophage count was reduced by 30-fold, while the fibroblast count was reduced nearly 10-fold on grafted zwitterionic films relative to uncoated films. Increasing degrees of cell adhesion were noted as the cross-linker concentration exceeded 50%. As expected, increased cross-link density resulted in a reduced swelling but greater compressive modulus. Notably, the coefficient of friction was dramatically reduced for zwitterionic thin films compared to uncoated PDMS across a broad range of cross-link densities, an attractive property for insertional implants. This work identified a broad range of cross-link densities that provide desirable antifouling effects while also maintaining the mechanical functionality of the thin films.

Preparation and In Vitro Evaluation of Aspartic/Alginic Acid Based Semi-Interpenetrating Network Hydrogels for Controlled Release of Ibuprofen.

Different combinations of polymers, aspartic acid (ASP), alginic acid (AL), and monomer acrylic acid (AA) were crosslinked in the presence of an initiator ammonium peroxodisulfate (APS) and cross-linker ethylene glycol dimethacrylate (EGDMA) to develop aspartic acid/alginic acid-co-poly(acrylic acid) (ASP/ALPAA) (semi-interpenetrating polymer network (SIPN)) hydrogels by the free radical polymerization technique for the controlled delivery of ibuprofen (IBP). Various studies such as dynamic swelling studies, drug loading, in vitro drug release and sol−gel analysis were carried out for the hydrogels. Higher swelling was observed at higher pH 7.4 as compared to lower pH 1.2, due to the presence of carboxylic groups of polymers and the monomer. Hence, pH-dependent swelling was exhibited by the developed hydrogels which led to a pH-dependent drug release and vice versa. The structural properties of the hydrogels were assessed by FTIR, PXRD, TGA, DSC, and SEM which confirmed the fabrication and stability of the developed structure. FTIR analysis revealed the reaction of both polymers with the monomer during the polymerization process and confirmed the overlapping of the monomer on the backbone of the both polymers. The disappearance of high intense crystalline peaks and the encapsulation of the drug by the hydrogel network was confirmed by PXRD. TGA and DSC showed that the developed hydrogels were thermally more stable than their basic ingredients. Similarly, the surface morphology of the hydrogels was analyzed by SEM and showed a smooth surface with few pores. Conclusively, ASP/ALPAA hydrogels have the potential to deliver IBP for a long period of time in a controlled way.

NanoMIPs Design for Fucose and Mannose Recognition: A Molecular Dynamics Approach.

Nanoscale molecularly imprinted polymers (nanoMIPs) are powerful molecular recognition tools with broad applications in the diagnosis, prognosis, and treatment of complex diseases. In this work, fully atomistic molecular dynamics (MD) simulations are used to assist the design of nanoMIPs with recognition capacity toward l-fucose and d-mannose as prototype disease biomarkers. MD simulations were conducted on prepolymerization mixtures containing different molar ratios of the monomers N-isopropylacrylamide (NIPAM), methacrylamide (MAM), and (4-acrylamidophenyl)(amino)methaniminium acetate (AB) and fixed molar ratios of the cross-linker ethylene glycol dimethacrylate (EGDMA) in explicit acetonitrile as the porogenic solvent. Prepolymerization mixtures containing ternary mixtures of NIPAM (50%), MAM (25%), and AB (25%) exhibit the best imprinting potential for both l-fucose and d-mannose, as they maximize (i) the stability of template-monomer plus template-cross-linker interactions, (ii) the number of functional monomers plus cross-linkers organized around the template, and (iii) the number of hydrogen bonds participating in template recognition. The studied prepolymerization mixtures exhibit an overall increased recognition capacity toward d-mannose over l-fucose, which is attributed to the higher hydrogen-bonding capacity of the former template. Our results are valuable to guide the synthesis of efficient nanoMIPs for sugar recognition and provide a computational framework extensible to any other template, monomer, or cross-linker combination, thus constituting a promising strategy for the rational design of molecularly imprinted materials.

A polymer hybrid film based on poly(vinyl cinnamate) and poly(2-hydroxy ethyl methacrylate) for controlled flurbiprofen release

A crosslinked polymer hybrid film, ipn-poly(vinyl cinnamate-graft-2-hydroxy ethyl methacrylate)-v-poly(ethylene glycol dimethacrylate) was synthesized by UV initiation using poly(vinyl cinnamate) (polyVCi), 2-hydroxy ethyl methacrylate (HEMA) monomer and ethylene glycol dimethacrylate (EGDMA) crosslinker. Benzophenone (Ph2CO), was used as the photoinitiator. The synthesis was optimized by changing the concentration of HEMA, Ph2CO, EGDMA, and UV irradiation time. PolyVCi undergoes photocrosslinking by 2 + 2 photocylo addition while the monomer/crosslinker couple, HEMA/EGDMA, undergoes free radical polymerization and crosslinking to form EGDMA crosslinked polyHEMA. Hence, simultaneous interpenetrating polymer network (IPN) formation occurs. The IPN consists of dual network of photocrosslinked polyVCi and EGDMA crosslinked polyHEMA chains. Grafting of HEMA/EGDMA chains on the polyVCi backbone also occur during network formation. The chemical functionalities present in the polyVCi/polyHEMA/polyEGDMA IPN films obtained were characterized by FTIR and SEM analysis. The contact angle measurements show enhanced wettability of the IPN film compared to polyVCi surface. TGA analysis confirms thermal stability of the films. Swelling behavior of the films examined in water and in ethanol reveals the effects of the chemical natures of polyVCi and polyHEMA as well as that of crosslinking on the hydrophilicity of the film. The films were tested as drug release matrices using flurbiprofen. The drug was loaded into the film matrix during IPN formation under UV irradiation. PolyVCi/polyHEMA/polyEGDMA IPN proved to be a suitable release matrix for flurbiprofen demonstrating controlled release behavior and zero-order release kinetics. The release mechanism was confirmed by its Ritger-Peppas “n” value (1.00 to 1.42), which indicates super case II release.

Removal of sunset yellow FCF from aqueous solutions using a highly cross-linked PDMA star polymer

The highly cross-linked PDMA star polymer (PDMA-b-PEGDMA) was successfully synthesized by group transfer polymerization (GTP) using 2-(N,N-dimethylamino)ethyl methacrylate (DMA) and cross-linking agent ethylene glycol dimethacrylate (EGDMA) monomers. Highly cross-linked polymer as a huge molecule has many functional groups. Thanks to these properties, dye adsorption performance of this kind of polymer was investigated. Sunset yellow FCF (SY) dye was used to determine whether the polymer showed adsorption properties. The effect of solution pH, dye concentration change and adsorbent amount on adsorption were investigated and the most effective adsorption conditions were determined for polymer. According to these parameters, the reaction rate constants in the dye adsorption of highly cross-linked polymer and the thermodynamic parameters (ΔH°, ΔG° and ΔS°) of the adsorption were calculated. The reaction was spontaneous (ΔG° < 0) at all temperatures (20 °C, 35 °C, and 50 °C). Kinetic of adsorption of SY dye onto polymer was studied, as well as its adsorption isotherm. At the last stage of the study, recovery of the polymer was carried out. The polymer was recovered using the dissolution–precipitation method. Adsorption studies were performed using UV–Vis spectrophotometer. The characterizations of the synthesized highly cross-linked star polymer and the recovered polymer were carried out using proton NMR (1H NMR) spectroscopy and gel permeation chromatography (GPC).

An unusually stable solid state Ag|AgCl reference electrode for long term continuous measurements based on a crosslinked poly(vinyl acetate)/KCl composite

Electrochemical measurements are attractive for continuous or long-term monitoring of chemical species in a range of analytical applications including health, environmental and agricultural monitoring, as well as food analysis and industrial process control. A significant barrier to long-term electrochemical measurements in continuous online monitoring applications is the requirement for stable and durable reference electrodes. Most reference electrodes require regular maintenance in such situations to maintain the concentration of the internal electrolyte reservoir and prevent fouling of the electrode. Solid state reference electrodes (SSREs) are well suited to these long-term monitoring applications, but most only have their short-term performance reported or are designed for disposable applications. Additionally, polymer crosslinking has been demonstrated as an effective way to slow leakage of suspended solutes, improve chemical resistance, and control a polymer's physical properties; but application of this technique in SSRE materials is yet to be reported. This work describes the construction and performance of a novel SSRE with exceptional long-term stability, using an ethylene glycol dimethacrylate (EGDMA) crosslinked PVAc/KCl composite material. Open circuit potentiometry and electrochemical impedance spectroscopy were used to study the electrochemical performance. Conductivity measurements and micro X-ray fluorescence mapping were used to examine the effect of EGDMA crosslinking on electrolyte leakage and electrode lifetime. A SSRE with a 1% molar ratio of EGDMA/vinyl acetate proved to be exceptionally stable and provided a reliable reference potential for at least 175 days in a 1 M Na2SO4 solution. PVAc/KCl composites without crosslinker were found to leak electrolyte ca. 30% faster than those with 1% EGDMA. EGDMA crosslinking also was shown to improve electrochemical performance and SSRE lifetime in both highly acidic and strongly alkaline solutions, suggesting a broad range of applications. Additionally, a 1% crosslinked SSRE demonstrated comparable performance to a commercial reference electrode in potentiometric and voltammetric measurements. The results demonstrate that crosslinked polymer-electrolyte composites provide a promising new approach for improving reference electrode performance in electrochemical measurements, particularly in continuous long-term online monitoring applications.

Molecularly imprinted poly(methacrylic acid) based QCM biosensor for selective determination of L-tryptophan

In the present work, molecularly imprinted polymer (MIP) for L-tryptophan was synthesized using bulk polymerization method. A highly selective and sensitive biosensing method for the amino acid was developed using quartz crystal microbalance (QCM) biosensor. The molecular imprints were synthesized through in-situ method using poly(methacrylic acid) (PMAA) macromolecular network. Successful imprinting was confirmed through Fourier infrared spectroscopy (FTIR). The dynamic adsorption and Scatchard analysis were used to understand the effect of various imprinting parameters on the final structures. The molecularly imprinted polymer sample with 10 mmol of ethylene glycol dimethacrylate (EGDMA) crosslinker exhibited a high adsorption about 12 mg/g towards L-tryptophan. The morphological analysis of imprinted structures was studied using scanning electron and atomic force microscope techniques as well. Further, the optimized MIP pre-polymer solution has coated on QCM electrode surface and sensing studies was conducted using different concentrations of L-tryptophan. The limit of detection was determined as 0.73 ng/mL. The biosensor found highly selective and not responded to the presence of structural analogous of L-tryptophan such as D-tryptophan and ascorbic acid. The MIP modified QCM biosensor exhibited high selectivity coefficients towards L-tryptophan about 7.3 and 12 with respect to the analogous. Further, the proposed MIP-QCM sensor was successfully applied to the determination of Tryptophan in real sample analysis such as food and urine samples with excellent recoveries ranging (97–104 %).

Different Strategies for the Preparation of Galactose-Functionalized Thermo-Responsive Nanogels with Potential as Smart Drug Delivery Systems.

Different synthetic strategies were tested for the incorporation of galactose molecules on thermoresponsive nanogels owing to their affinity for receptors expressed in cancer cells. Three families of galactose-functionalized poly(N-vinylcaprolactam) nanogels were prepared with the aim to control the introduction of galactose-moieties into the core, the core-shell interface and the shell. First and second of the above mentioned, were prepared via surfactant free emulsion polymerization (SFEP) by a free-radical mechanism and the third one, via SFEP/reversible addition-fragmentation chain transfer (RAFT) polymerization. Synthetic recipes for the SFEP/free radical method included besides N-vinylcaprolactam (NVCL), a shell forming poly(ethylene glycol) methyl ether methacrylate (PEGMA), while the galactose (GAL) moiety was introduced via 6-O-acryloyl-1,2,:3,4-bis-O-(1-methyl-ethylidene)-α-D-galactopiranose (6-ABG, protected GAL-monomer): nanogels I, or 2-lactobionamidoethyl methacrylate (LAMA, GAL-monomer): nanogels II. For the SFEP/RAFT methodology poly(2-lactobionamidoethyl methacrylate) as GAL macro-chain transfer agent (PLAMA macro-CTA) was first prepared and on a following stage, the macro-CTA was copolymerized with PEGMA and NVCL, nanogels III. The crosslinker ethylene glycol dimethacrylate (EGDMA) was added in both methodologies for the polymer network construction. Nanogel’s sizes obtained resulted between 90 and 370 nm. With higher content of PLAMA macro-CTA or GAL monomer in nanogels, a higher the phase-transition temperature (TVPT) was observed with values ranging from 28 to 46 °C. The ρ-parameter, calculated by the ratio of gyration and hydrodynamic radii from static (SLS) and dynamic (DLS) light scattering measurements, and transmission electron microscopy (TEM) micrographs suggest that core-shell nanogels of flexible chains were obtained; in either spherical (nanogels II and III) or hyperbranched (nanogels I) form.

PENGARUH MILLING TERHADAP KARAKTERISTIK MOLECULARLY IMPRINTED POLYMER KARBARIL (C12H11NO2)

Molecularly Imprinted Polymer (MIP) has been synthesized with carbaryl used as a template and forms complex bonds with Methacrylic Acid (MAA)through hydrogen bonds, followed by a cross-linking process using Ethylene Glycol Dimethacrylate (EGDMA) cross-linkers. The polymerization process begins with the thermal decomposition of Benzoyl Peroxide (BPO) as an initiator. Non-Imprinted Polymer (NIP) as a control polymer has also been synthesized using a similar procedure without using carbaryl templates. In this study, two variations of carbaryl are used, which are not milled carbamates, and carbaryl has been milled using High Energy Milling (HEM). The FTIR study was carried out to investigate the presence of carbaryl in polymers, MIP, and NIP. The spectrum shows that the concentration of carbaryl compound decreases after the extraction process. This result was also confirmed by the increase in the value of the percentage of transmittance in the MIP, especially the nano carbaryl MIP. This result is supported by the X-RD results, which showed a decrease in the size of the crystals in the carbaryl MIP from 10.07 Å while the nano carbaryl MIP was 9.16 Å.

Synthesis of a Novel Molecularly Imprinted Polymer for the Sensitive and Selective Determination of Artemisinin in Urine Samples Based on Solid-Phase Extraction (SPE) and Determination with High-Performance Liquid Chromatography (HPLC)

A novel molecularly imprinted solid-phase extraction method coupled with high-performance liquid chromatography (HPLC) is reported for the sensitive and selective determination of artemisinin in urine samples. Molecularly imprinted polymers were synthesized by free-radical polymerization through a noncovalent imprinting method using artemisinin (template), methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross-linker), azobisisobutyronitrile (initiator), and acetonitrile (porogen). The adsorption properties of the artemisinin-imprinted polymers obeyed the Langmuir isotherm with 23.9 mg/g maximum adsorption capacity and pseudo-second-order kinetics with an equilibrium adsorption time of 60 min. The prepared artemisinin-imprinted polymers showed high selectivity toward artemisinin and could be used multiple times, at least five, without changes to adsorption capacity. Furthermore, the imprinted and nonimprinted particles were placed into cartridges through dry packing, and eluates collected from cartridges were subjected to high-performance liquid chromatography. The limit of quantification and limit of detection values were 4.5 µg/L and 1.3 µg/L, respectively. The recovery of artemisinin from urine samples varied between 95.7% and 100.0%, and the relative standard deviation was less than 4.0%. The results indicated the prepared sorbent can be used for simple, selective, and sensitive detection of artemisinin from urine by a combination of solid-phase extraction and high-performance liquid chromatography.

Preparation and application of molecularly imprinted polymers for chiral HPLC separation of biologically active substances

Chiral separations are one of the important analytical tasks, since there are increasing demands for production of enantiomerically pure compounds. The separation and determination of enantiomers find applications in pharmaceutical and food analysis, and it is necessary to pay attention to the development and improvement of chiral analytical methods. High performance liquid chromatography (HPLC) with chiral stationary phase (CSP) based on molecularly imprinted polymers (MIPs) is perspective way. One of the main advantage of these stationary phases is the possibility of predetermining the elution order of enantiomers. The presented work is focused on the methods of preparation and the applications of selective sorption materials (MIPs) in the field of HPLC separation of biologically active substances, amino acids. This review contains comprehensive informations about MIP-amino acid synthesis: compositions of polymerization mixture (monomer, template, cross-linker, porogen), type of polymerization and polymerization conditions, what can affect final efficiency of enantioseparation. The most used porogen was toluene, crosslinker ethylene glycol dimethacrylate (EDMA) and initiator azoisobutyronitrile (AIBN). MIP CSP prepared for derivatized amino acids show better results (higher resolution) than MIP prepared for underivatized amino acids. MIP are very promising material to be used as stationary phase in HPLC, although further developments and new approaches are necessary to fully exploit their potential.

Development of Neutral pH-Responsive Microgels by Tuning Cross-Linking Conditions.

Polymer microgels that respond in a range of neutral pH can be useful for the development of molecular imaging tools and drug-delivery carriers. Here, we describe a simple approach in developing microgels that undergo volume phase transitions and substantial nuclear magnetic resonance (NMR) relaxometric changes within a narrow pH range of 6.4 to 7.4. The pH-responsive microgels were synthesized using methacrylic acid and a series of ethylene glycol dimethacrylate cross-linkers with repeating units of ethylene glycol that range from one to four. NMR relaxometry demonstrated that the transverse relaxation time (T2) of a suspension containing microgels that were cross-linked with diethylene glycol dimethacrylate sharply decreases at the pH where volume phase transition occurs. The polymer microgels cross-linked with 40 and 45 mol% of diethylene glycol dimethacrylate caused about 50% T2 reduction with decreasing pH from 6.8 to 6.4. These results demonstrated that responses of microgels to a range of neutral pH can be easily tuned by using appropriate cross-linkers with certain cross-linking degree. This approach can be useful in developing highly sensitive molecular sensors for magnetic resonance imaging (MRI) of tissue pH values.

Degradable Poly(Methyl Methacrylate)-co-Methacrylic Acid Nanoparticles for Controlled Delivery of Growth Factors for Bone Regeneration.

Bone tissue engineering strategies have been developed to address the limitations of the current gold standard treatment options for bone-related disorders. These systems consist of an engineered scaffold that mimics the extracellular matrix and provides an architecture to guide the natural bone regeneration process, and incorporated growth factors that enhance cell recruitment and ingress into the scaffold and promote the osteogenic differentiation of stem cells and angiogenesis. In particular, the osteogenic growth factor bone morphogenetic protein 2 (BMP-2) has been widely studied as a potent agent to improve bone regeneration. A key challenge in growth factor delivery is that the growth factors must reach their target sites without losing bioactivity and remain in the location for an extended period to effectively aid in the formation of new bone. Protein incorporation into nanoparticles can both protect protein bioactivity and enable its sustained release. In this study, a poly(methyl methacrylate-co-methacrylic acid) nanoparticle-based system was synthesized incorporating a custom poly(ethylene glycol) dimethacrylate crosslinker. It was demonstrated that the nanoparticle degradation rate can be controlled by tuning the number of hydrolytically degradable ester units along the crosslinker. We also showed that the nanoparticles had high affinity for a model protein for BMP-2, and optimal conditions for maximum protein loading efficiency were elucidated. Ultimately, the proposed system and its high degree of tunability can be applied to a wide range of growth factors and tissue engineering applications. Impact Statement In this study, we developed a novel method of synthesizing nanoparticles with tunable degradation rates through the incorporation of a custom synthesized, hydrolytically degradable crosslinker. In addition, we demonstrated the affinity of the synthesized nanoparticles for a model protein for bone morphogenetic protein 2 (BMP-2). The tunability of these nanoparticles can be used to develop complex tissue engineering systems, for example, for the delivery of multiple growth factors involved at different stages of the bone regeneration process.

A NEW MIP EMBEDDED CRYOGEL FOR SELECTIVE PRE-CONCENTRATION AND REMOVAL OF PROPACHLOR

Propachlor is a pesticide commonly used in the chloroacetanilide herbicide group. Propachlor contamination occurs in groundwater resources and soil sources. Therefore removal and also the determination of trace amounts of propachlor is a very important issue. Molecularly imprinted polymers (MIPS) are preferred for their advantages such as high affinity, strength, and selectivity in pesticide removal and determination. In this study, MIP embedded cryogel was synthesized for selective adsorption and removal of propachlor. MIP synthesis was performed using the template molecule propachlor, functional monomer methacrylic acid, crosslinker ethylene glycol dimethacrylate (EDGMA), solvent hexadecane and 2,2-azo-bis-isobutyronitrile (AIBN) as the initiator. Cryogels are a good alternative for separation and purification because of their advantageous properties such as short diffusion, low pressure and adsorption and elution in a short time. The structure of MIP was determined using scanning electron microscopy (SEM), Elemental analyze and Fourier transform infrared spectroscopy (FT-IR), and the structure of MIP embedded cryogel was determined using scanning electron microscopy (SEM). The highest adsorption capacity for MIP was 5.58 mg g-1 at pH 5. The highest adsorption capacity for MIP embedded cryogel was found to be 14.38 mg g-1. MIP embedded cryogel were used for selective adsorption and desorption of propachlor in environmental samples. The concentration of propachlor in environmental samples was analyzed by high-performance liquid chromatography (HPLC).

A Neutron Scattering Study of the Structure of Poly(dimethylsiloxane)-Stabilized Poly(methyl methacrylate) (PDMS-PMMA) Latexes in Dodecane.

Hard-sphere particles in nonpolar solvents are an essential tool for colloid scientists. Sterically stabilized poly(methyl methacrylate) (PMMA) particles have long been used as the exemplary hard-sphere system. However, neither the particles themselves nor the poly(12-hydroxystearic acid) (PHSA) stabilizer necessary to prevent aggregation in nonpolar solvents are commercially available. To counter this, several alternatives have been proposed. In recent years, there has been an increased interest in poly(dimethylsiloxane) (PDMS) stabilizers as a commercially available alternative to PHSA, yet the structure of particles made in this way is not as well understood as those produced using PHSA. In this work, we employ small-angle neutron scattering to determine the internal structure of PDMS-stabilized PMMA particles, synthesized with and without an additional crosslinking agent. We report data consistent with a homogeneous PMMA core with a linearly decaying PDMS shell. The thickness of the shell was in excess of 50 nm, thicker than the PHSA layer typically used to stabilize PMMA but consistent with reports of the layer thickness for similar molecular weight PDMS at planar surfaces. We also show that the amount of the hydrogenous material in the particle core of the crosslinked particles notably exceeds the amount of added ethylene glycol dimethacrylate crosslinker, suggesting some entrapment of the PDMS stabilizer in the PMMA matrix.

Effect of Graphene Nanoparticles on the Physical Properties of Ophthalmic Polymer Containing Pyrrolidone Group.

In this study, the functional ophthalmic hydrogel lens containing graphen oxide nanoparticles, PVP (polyvinylpyrrolidone) were manufactured. For 2-hydroxyethyl methacrylate (HEMA), which is the main component of the ophthalmic hydrogel lens, and azobisisobutyronitrile (AIBN), an initiator for thermal polymerization. And for photopolymerization, 2-hydroxy-2-methylpropiophenone (2H2M). And used for cross linker ethylene glycol dimethacrylate (EGDMA). The prepared ophthalmic hydrogel lens samples were hydrated in a sterile physiological saline solution for 24 hours before evaluating their physical properties, such as optical transmittance, refractive index, and water content. The surface characteristics of the lenses were also evaluated by measuring the AFM and contact angle. The results of this study suggest that PVP and graphene oxide nanoparticles have high wettability as additives, and that the lens manufactured by using the photopolymerization method demonstrated an ultraviolet shielding effect, thereby prompting us to conclude its suitability as a highly functional ophthalmic lens.