Co-methacrylic Acid Research Articles

Emulsion Stabilized by Biocompatible and Stimuli-Responsive Poly(N-vinylcaprolactam)-Based Microgels: Effects of Electrostatic Repulsion and Deformability on Emulsion Stability.

Microgels have been widely used for stabilizing emulsions due to their softness and stimulus responsiveness. Although ultrastable emulsions have been prepared by microgel nanoparticles, the role of electrostatic interactions on emulsion stability is still a controversial topic and further investigation of the effect of microgel deformability is required. In the present study, neutral poly(N-vinylcaprolactam) (PVCL) and charged poly(N-vinylcaprolactam)-co-methacrylic acid (P(VCL-co-MAA)) microgels were synthesized and further used as emulsifiers to stabilizing emulsion. The P(VCL-co-MAA) microgel has a swelling ratio larger than that of the PVCL microgel in water. The nanomechanical properties of the microgels in water were characterized by atomic force microscopy with using the tip of different radii. The result reveals that the P(VCL-co-MAA) microgel is more deformable than the PVCL counterpart. Stability tests of the emulsions showed that below the volume phase transition temperature (VPTT) of the microgels, both microgel types can stabilize the emulsions under various conditions. Unexpectedly, most of the emulsions still remain stable above the VPTT. Further increasing the temperature to 60 °C, P(VCL-co-MAA) microgel emulsions remained stable at a pH value above the pKa of MAA while the emulsion was unstable below the pKa. However, phase separation occurs in PVCL microgel-stabilized emulsions at 60 °C. These results demonstrate that electrostatic repulsion and deformability of the microgels can enhance the emulsion stability, providing insights into the rational design and preparation of ultrastable Pickering emulsions.

Fabrication of pH-responsive poly(vinyl alcohol)-based microfibers crosslinked with copolymers containing benzoxaborole and carboxy groups

Water-insoluble pH-responsive poly (vinyl alcohol) (PVA)-based microfibers were prepared using terpolymer of poly ([2-(methacryloyloxy)ethyl]trimethylammonium chloride (METAC)-co-methacrylic acid (MAAc)-co-5-methacrylamido-1,2-benzoxaborole (MAAmBO)) (TP) containing a quaternary ammonium cation, as well as carboxy and benzoxaborole groups. The surface of the microfibers could be positively charged by the permanent positive charge of the METAC units owing to the presence of the quaternary ammonium cation. The MAAc units formed a covalent bond with the hydroxy group of the vinyl alcohol unit by thermal treatment at 135 °C for 24 h, and the MAAmBO units formed a dynamic covalent bond with the diol group in PVA. After thermal crosslinking for 24 h, the PVA/TP microfibers exhibited almost 100% of the residual weight after immersion in water at 80 °C for 30 min. The diameters of the dried PVA/TP_25 wt% fibers were 21.4 ± 3.9 μm, and the swelling ratio was 1.65 ± 0.16 after immersing in water for 24 h. All microfibers showed a low degree of hemolysis (<5%). The PVA/TP_25 wt% fibers were strongly dyed with anionic acid red 1 (AR1) molecules at pH 3 and with cationic methylene blue (MB) molecules at pH 12, since the balance of the surface charge depend on the solution pH. These microfibers could be bundled and twisted to improve their mechanical properties; the required fracture energy after twisting was 2.30 ± 0.91 times higher than that before twisting.

A step towards RoHS compliance for perovskite devices by using a novel lead-capturing encapsulant

Despite the significant progress made in perovskite solar cells, device degradation under ambient conditions and the potentially hazardous release of toxic lead into the environment is a major concern. Packaging and encapsulation of solar cells and modules will address these issues to an extent. However, during leaching mobile lead ions can diffuse through most commercially used edge seal adhesives, making even standard encapsulation systems not appropriate for packaging perovskite solar cells. In this work, an ionomer of polyethylene co-methacrylic acid polymer film (Surlyn) modified with functional groups that interact with mobile lead ions is used to encapsulate perovskite films. The functionalization of the encapsulant was tailored by modifying the matrix polymer with Zeolitic imidazolium framework- 67 (ZIF-67) through polydopamine as the anchoring platform. This modified encapsulant exhibited a reduced lead leaching by more than ∼8 orders. The design of experiments was carried out to evaluate the modified encapsulant efficacy in preventing lead leaching through it. In addition, new experimental techniques were designed for understanding the characteristics and reliability for an extended period.

Effect of comb polymer dispersants with different molecular structures on the performance of LiFePO4 suspensions

A series of comb polymers poly(2-(dimethylamino)ethyl methacrylate (DMAEMA)-co-methacrylic acid (MAA)-co-methoxy polyethylene glycol methacrylate (MPEGMA)) (poly(DMAEMA-MAA-MPEGMA, DMM) were synthesized and used as N-methyl-2-pyrolidinone (NMP)-based lithium iron phosphate (LFP) suspension dispersants. The effects of the grafting density of the carboxyl group as the anchoring group and the chain length of the side chain of PEG, which plays the role of spatial site resistance, on the rheological properties and suspension stability of the slurry were systematically investigated. By investigating the adsorption amount and thickness of DMM on the LFP surface, combined with calculations based on the scalar law and Flory theory, the molecular structure of the comb polymer dispersant was revealed to influence the adsorption and dispersion performance. The dispersion of LiFePO4 was due to the synergistic effects of adsorption and steric hindrance effect, which resulted that dispersants with medium carboxyl density and PEG side chain length can improve the dispersion performance and stability.

Development of a water-based functional additive by using isobornyl acrylate copolymer to improve ink-adhesion on untreated polypropylene surfaces: A comparative approach

The good barrier and hot-fill properties of polypropylene (PP) films and sheets make packaging industries advantageous. However, printing over a PP substrate is a major issue encountered in the packaging industry. The present study intends to prepare, characterise, and compare isobornyl acrylate (IBOA)-co-acrylic acid (AA) and isobornyl acrylate (IBOA)-co-methacrylic acid (MAA) based non-halogenated functional additives by using oil in water emulsion processes. The bornyl group of IBOA helps in enhancing molecular bonding with the polypropylene (PP) surface. The various properties of these synthesised functional additives were characterised using dynamic light scattering-particle size and zeta potential analysis, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), and gel permeation chromatography (GPC). The adhesion of these functional additive incorporated ink samples on different untreated PP surfaces was compared using the cross-cut adhesion test. The methacrylic acid based functional additive shows better adhesion properties as compared to acrylic acid.

Fabrication of Cationic Poly(vinyl alcohol) Films Cross-Linked Using Copolymers Containing Quaternary Ammonium Cations, Benzoxaborole, and Carboxy Groups.

Water-insoluble cationic poly(vinyl alcohol) (PVA) films were fabricated using a mixed aqueous solution of PVA and poly([2-(methacryloyloxy)ethyl]trimethylammonium chloride (METAC)-co-methacrylic acid (MAAc)-co-5-methacrylamido-1,2-benzoxaborole (MAAmBO)) copolymer (3D). The surface of the PVA film is typically negatively charged, and simple fabrication methods for water-insoluble PVA films with cationic surface charges are required to expand their application fields. METAC, which has a permanent positive charge owing to the presence of a quaternary ammonium cation, was selected as the cationic unit. The MAAc and MAAmBO units were used as two types of cross-linking structures for the thermal cross-linking of the hydroxy and carboxy groups of the MAAc unit (covalent bonding) as well as the diol and benzoxaborole groups of the MAAmBO unit (dynamic covalent bonding). The films were thermally cross-linked at 135 °C for 4 h without the addition of materials. After immersion in surplus water at 80 °C for 3 h, the cross-linked PVA/3D films retained almost 100% of their weights. The ζ-potential of the water-insoluble PVA/3D film was 9.4 ± 0.8 mV. The PVA/3D film was strongly dyed using anionic acid red 1 (AR1) because of its positively charged surface. Interestingly, it could also be slightly dyed using cationic methylene blue (MB) and became transparent (original state) after immersion in water for 2 days. These results suggested that positive and negative charges coexisted in the PVA/3D film, and the surface properties were positively inclined. Moreover, the degree of hemolysis of the PVA/3D films was similar to that of the negative control, which showed high blood compatibility. To our knowledge, this is the first report on the fabrication of water-insoluble cationic PVA films using two types of cross-linking structures containing carboxy and benzoxaborole groups. The cross-linked PVA films were analyzed using Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and contact angle (CA) and ζ-potential measurement, as well as by determining the mechanical properties, adsorption of charged molecules, and biocompatibility. These readily fabricated water-insoluble PVA films with positive charges can show potential applications in sensors, adsorption systems, and antimicrobial materials.

Development of dynamic pH and temperature-responsive smart membranes via immobilization of chitosan-graft-poly(N-isopropylacrylamide-co-methacrylic acid) hydrogels on microfiltration membrane-support

Ultrafiltration is a pressure-driven membrane process which is widely used for water treatment and separations in biotechnology, chemical, pharmaceutical and food industries. The study deals with the development of novel smart membranes for ultrafiltration which reversibly change flux and human serum albumin (HSA) rejection as a response to the change of the pH and temperature of the feed solution. Smart membranes were prepared via immobilization of cross-linked dual-responsive chitosan-graft-poly(N-isopropylacrylamide (NIPAM)-co-methacrylic acid) hydrogels on the surface of the microfiltration membrane via filtration in dead-end mode. It was shown that pure water flux (PWF) increases by 1.8–4.7 times upon the temperature increase from 25 °C to 50 °C due to the conformational changes of poly(NIPAM) chains grafted to chitosan at temperature higher than lower critical solution temperature. It was shown that PWF increases by 8.7 times at T = 25 °C and 16.5 times at T = 50 °C when pH of the feed water decreases from 10 to 3. The developed smart membranes demonstrate extremely high cleaning efficiency and can be simply washed by distilled water at T = 50 °C after ultrafiltration of HSA solution (pH = 3). It was shown that PWF of smart membrane is restored by 1154% compared to 67% for reference microfiltration membrane.

Synthesis and optical properties investigation of TiO2 ‎nanotubes for use in polymer gel-state dye sensitized solar cells

In this paper highly ordered TiO2 nanotube (TNT) arrays were synthesized using potentiostatic anodization of Ti foil for 12 h at voltage of 60 V and used in polymer gel-state dye senisitized solar cells (DSSCs) . To investigate the morphology and optical properties of the TNTs, scanning electron microscopy (SEM), Raman spectroscopy and X-ray diffraction techniques (XRD) have been used. The average diameter and length of the TNTs were 100 nm and 30 µm, respectively. XRD and Raman measurements indicated the pure anatase phase of TNTs. A polymer poly(methyl metacrylate- co-methacrylic acid) (PMMA-MA) was mixed with a 3-methoxypropionitrile (MPN) based liquid electrolyte to prepare a gel-state polymer electrolyte. The prepared electrolytes containing varied concentrations of PMMA-MA were characterized by electrochemical impedance spectroscopy (EIS). Power conversion efficiency of NT based DSSCs using a polymer gel electrolyte containing PMMA-MA was comparable with that of the corresponding liquid counterpart.

Loading of doxorubicin on poly(methyl methacrylate-co-methacrylic acid) nanoparticles and release study

Nanoparticles (NP) of 12.7 nm in diameter of the poly(methyl methacrylate (MMA)-co-methacrylic acid (MAA)) copolymer were prepared. 13C-NMR results showed a MMA:MAA molar ratio of 0.64:0.36 in the copolymer, which is similar to the poly(MMA-co-MAA) commercially known as the FDA approved Eudragit S100 (0.67:0.33). The NP prepared in this study were loaded at pH 5 with varying amounts (from 0.54 to 6.91%) of doxorubicin (DOX), an antineoplastic drug. 1H-NMR results indicated the electrostatic interactions between the ionized carboxylic groups of the MAA units in the copolymer and the proton of the glycosidic amine in DOX. Measurements by QLS and TEM indicated that the loading destabilizes the NP, and that for increase stability, they aggregate in a reversible way, forming aggregates with a diameter up to 99.5 nm at a DOX load of 6.91%. The analysis of drug release data at pH 7.4 showed that loaded NP with at least 4.38% DOX release the drug very slowly and follows the Higuchi model; the former suggests that they could remain for long periods in the bloodstream to reach and destroy cancer cells.

New property-performance optimization of scalable alginate-g-terpolymer for Ce(IV), Mo(VI), and W(VI) exclusions

New property-performance optimization approach of purely-aliphatic scalable-and-reusable multifunctional terpolymer hydrogels envisaging the excellent performance potential has been reported. Accordingly, the optimum potassium alginate (KA)-g-[2-hydroxyethylmethacrylate (HEMA)-co-3-(2-(isobutyryloxy)ethoxy)-2-methylpropanoic acid (IBEMPA)-co-methacrylic acid (MAA)/ 1], i.e., 2, among twelve KA-grafted terpolymer hydrogels has been designed and synthesized via OH functionalized OC/ CC coupled in situ protrusion of third monomer, i.e., IBEMPA, and grafting of KA into 1 in polymerization of two monomers employing variable monomer ratio; pH; amounts of KA, crosslinker, and initiators; and temperatures. The structures of 1/ 2, in situ IBEMPA, grafted-KA, thermal stabilities, surface properties, superadsorption mechanism, and reusability have been explored via 1H/ 13C NMR, FTIR, XPS, TGA, XRD, SEM, DLS, network parameters, pHPZC, %graft-ratio, %gel-content, and thermodynamic-parameters. The maximum adsorption capacities of Ce(IV), Mo(VI), and W(VI) are 1575.57, 1581.32, and 1990.11 mg g–1, respectively, within 500–1000 ppm at 308 K for 0.02 g adsorbent.

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.

Development of an HKUST-1 Nanofiller-Templated Poly(ether sulfone) Mixed Matrix Membrane for a Highly Efficient Ultrafiltration Process.

Mixed-matrix membranes (MMMs) have been drawing increasing attention due to the high permeability and high rejection capabilities for highly efficient wastewater treatment applications. Nonetheless, improving the water permeance while maintaining the high rejection capability is still an ongoing challenge for the practically state-of-the-art MMMs. Herein, a new class of poly(ether sulfone) (PES) based MMM containing metal-organic framework (MOF) nanofillers of HKUST-1 and blending with poly(methyl methacrylate- co-methacrylic acid) (PMMA- co-MAA) copolymer, designated as HKUST-1@mPES MMM, were developed for the highly efficient ultrafiltration (UF) process. In this study, the nanosized HKUST-1 nanofillers were removed by water dissolution as sacrificial templating materials, so that the additional nanovoids were deliberately generated throughout the dense polymer matrix. The introduction of PMMA- co-MAA copolymer facilitated the even dispersion of HKUST-1 nanofillers in a polymer matrix, by constructing the bridge connection between inorganic nanofillers and organic matrix. The resultant HKUST-1@mPES MMM exhibited a high pure water permeability (PWP) up to 490 L·m-2·h-1·bar-1, substantially reaching nearly 3 times higher than that of the mPES membrane without HKUST-1 nanofillers loading and maintaining a relatively high BSA rejection rate of 96% without obvious deterioration. The newly developed HKUST-1@mPES MMM thereby exhibited a comparable separation efficiency compared to the cutting-edge UF membranes reported so far. Overall, the nanovoid-generated approach provides new insight into developing advanced MMMs used for highly efficient water treatment applications.

Correlating the effect of co-monomer content with responsiveness and interfacial activity of soft particles with stability of corresponding smart emulsions

HypothesisThis study presents the synthesis and characterization of Poly(N-isopropylacrylamide)-co-methacrylic acid (PNIPAM-co-MAA) based multi-responsive soft microgel particles employed as “smart emulsifiers” for controlled stabilization and breakage of the decane-in-water Pickering emulsions. These soft microgel particles can act as reversible stabilizers, i.e. they can either stay at the oil-water interface by supporting emulsion formation or preventing aggregates; while triggering demulsification can be controlled by varying the temperature, pH or ionic strength of the microgel system. ExperimentsDynamic light scattering was applied to observe the variation in hydrodynamic radius of the particles as a function of temperature and pH of the multi-responsive microgel system. Microgel composition was varied in terms of MAA-content and influence of this variation on their thermo-sensitivity and pH responsiveness as well as on the stability of corresponding emulsions was evaluated. FindingsThe microgel particles with highest MAA content showed a significant impact on multi-responsive behaviour. Thermal sensitivity is pH dependent under acidic conditions but this dependence is gradually reduced as the pH increases above 7.5. On the other hand, pH-responsiveness is enhanced with the rise in temperature and stable emulsions were formed under highly alkaline conditions even the temperature was far above the volume phase transition temperature (VPTT). Understanding the correlation of stimuli responsiveness at interface with the emulsion stability would help to fabricate and design novel smart Pickering emulsions with better control over desired properties.

Avidin-Biotin Cross-Linked Microgel Multilayers as Carriers for Antimicrobial Peptides.

Herein, we report on the formation of cross-linked antimicrobial peptide-loaded microgel multilayers. Poly(ethyl acrylate- co-methacrylic acid) microgels were synthesized and functionalized with biotin to enable the formation of microgel multilayers cross-linked with avidin. Microgel functionalization and avidin cross-linking were verified with infrared spectroscopy, dynamic light scattering, and z-potential measurements, while multilayer formation (up to four layers) was studied with null ellipsometry and quartz crystal microbalance with dissipation (QCM-D). Incorporation of the antimicrobial peptide KYE28 (KYEITTIHNLFRKLTHRLFRRNFGYTLR) into the microgel multilayers was achieved either in one shot after multilayer formation or through addition after each microgel layer deposition. The latter was found to strongly promote peptide incorporation. Further, antimicrobial properties of the peptide-loaded microgel multilayers against Escherichia coli were investigated and compared to those of a peptide-loaded microgel monolayer. Results showed a more pronounced suppression in bacterial viability in suspension for the microgel multilayers. Correspondingly, LIVE/DEAD staining showed promoted disruption of adhered bacteria for the KYE28-loaded multilayers. Taken together, cross-linked microgel multilayers thus show promise as high load surface coatings for antimicrobial peptides.

Label-Free Detection of Tear Biomarkers Using Hydrogel-Coated Gold Nanoshells in a Localized Surface Plasmon Resonance-Based Biosensor.

The dependence of the localized surface plasmon resonance (LSPR) of noble-metal nanomaterials on refractive index makes LSPR a useful, label-free signal transduction strategy for biosensing. In particular, by decorating gold nanomaterials with molecular recognition agents, analytes of interest can be trapped near the surface, resulting in an increased refractive index surrounding the nanomaterial, and, consequently, a red shift in the LSPR wavelength. Ionic poly( N-isopropylacrylamide- co-methacrylic acid) (PNM) hydrogels were used as protein receptors because PNM nanogels exhibit a large increase in refractive index upon protein binding. Specifically, PNM hydrogels were synthesized on the surface of silica gold nanoshells (AuNSs). This composite material (AuNS@PNM) was used to detect changes in the concentration of two protein biomarkers of chronic dry eye: lysozyme and lactoferrin. Both of these proteins have high isoelectric points, resulting in electrostatic attraction between the negatively charged PNM hydrogels and positively charged proteins. Upon binding lysozyme or lactoferrin, AuNS@PNM exhibits large, concentration-dependent red shifts in LSPR wavelength, which enabled the detection of clinically relevant concentration changes of both biomarkers in human tears. The LSPR-based biosensor described herein has potential utility as an affordable screening tool for chronic dry eye and associated conditions.

DNA-Functionalized Dye-Loaded Polymeric Nanoparticles: Ultrabright FRET Platform for Amplified Detection of Nucleic Acids.

Going beyond the limits of optical biosensing motivates exploration of signal amplification strategies that convert a single molecular recognition event into a response equivalent to hundreds of fluorescent dyes. In this respect, Førster Resonance Energy Transfer (FRET) with bright fluorescent nanoparticles (NPs) is an attractive direction, but it is limited by poor efficiency of NPs as FRET donors, because their size is typically much larger than the Førster radius (∼5 nm). Here, we established FRET-based nanoparticle probes that overcome this fundamental limitation by exploiting a phenomenon of giant light harvesting with thousands of strongly coupled dyes in a polymer matrix. These nanoprobes are based on 40 nm dye-loaded poly(methyl methacrylate- co-methacrylic acid) (PMMA-MA) NPs, so-called light-harvesting nanoantennas, which are functionalized at their surface with oligonucleotides. To achieve this functionalization, we developed an original methodology: PMMA-MA was modified with azide/carboxylate bifunctional group that enabled assembly of small polymeric NPs and their further Cu-free click coupling with oligonucleotides. The obtained functionalized nanoantenna behaves as giant energy donor, where hybridization of target nucleic acid (encoding survivin cancer marker) with ∼23 grafted oligonucleotides/Cy5-acceptors switches on/off FRET from ∼3200 rhodamine-donors of the nanoantenna, leading to 75-fold signal amplification. In solution and on surfaces at single-particle level, the nanoprobe provides sequence-specific two-color ratiometric response to nucleic acids with limit of detection reaching 0.25 pM. It displays unprecedented brightness for a FRET biosensor: it outperforms analogous FRET-based molecular probe by >2000-fold and QDot-605 by ∼100-fold. The developed concept of amplified sensing will increase orders of magnitude sensitivity of fluorescent probes for biomolecular targets.

Peptide-Loaded Microgels as Antimicrobial and Anti-Inflammatory Surface Coatings.

Here we report on covalently immobilized poly(ethyl acrylate- co-methacrylic acid) microgels loaded with the host defense peptide KYE28 (KYEITTIHNLFRKLTHRLFRRNFGYTLR), which is derived from human heparin cofactor II, as well as its poly(ethylene glycol)-conjugated (PEGylated) version, KYE28PEG. Peptide loading and release, as well as the consequences of these processes on the microgel and peptide properties, were studied by in situ ellipsometry, confocal microscopy, zeta potential measurements, and circular dichroism spectroscopy. The results show that the microgel-peptide interactions are electrostatically dominated, thus promoted at higher microgel charge density, while PEGylation suppresses peptide binding. PEGylation also enhances the α-helix induction observed for KYE28 upon microgel incorporation. Additionally, peptide release is facilitated at physiological salt concentration, particularly so for KYE28PEG, which illustrates the importance of electrostatic interactions. In vitro studies on Escherichia coli show that the microgel-modified surfaces display potent antifouling properties in both the absence and presence of the incorporated peptide. While contact killing dominates at low ionic strength for the peptide-loaded microgels, released peptides also provide antimicrobial activity in bulk at a high ionic strength. Additionally, KYE28- and KYE28PEG-loaded microgels display anti-inflammatory effects on human monocytes. Taken together, these results not only show that surface-bound microgels offer an interesting approach for local drug delivery of host defense peptides but also illustrate the need to achieve high surface loads of peptides for efficient biological effects.

Selective adsorption of oppositely charged PNIPAAM on halloysite surfaces: a route to thermo-responsive nanocarriers

Halloysite nanotubes were functionalized with stimuli-responsive macromolecules to generate smart nanohybrids. Poly(N-isopropylacrylamide)-co-methacrylic acid (PNIPAAM-co-MA) was selectively adsorbed into halloysite lumen by exploiting electrostatic interactions. Amine-terminated PNIPAAM polymer was also investigated that selectively interacts with the outer surface of the nanotubes. The adsorption site has a profound effect on the thermodynamic behavior and therefore temperature responsive features of the hybrid material. The drug release kinetics was investigated by using diclofenac as a non-steroidal anti-inflammatory drug model. The release kinetics depends on the nanoarchitecture of the PNIPAAM/halloysite based material. In particular, diclofenac release was slowed down above the LCST for PNIPAAM-co-MA/halloysite. Opposite trends occurred for halloysite functionalized with PNIPAAM at the outer surface. This work represents a further step toward the opportunity to extend and control the delivery conditions of active species, which represent a key point in technological applications.

Doxorubicin and chrysin combination chemotherapy with novel pH-responsive poly [(lactide-co-glycolic acid)-block-methacrylic acid] nanoparticle

A novel pH-responsive poly [(lactide-co-glycolic acid)-co-methacrylic acid] [(PLGA-co-PMAA)] copolymer was synthesized through the combination of radical telomerization and ring opening polymerization method (ROP). A novel strategy to stabilize polymeric nanoparticles interacted on the terminal groups of PLGA segments in (PLGA-co-PMAA) nanoparticles with chrysin (CHS) and it was inverted to (PLGA-co-PMAA)–CHS. The studied copolymers were fully characterized by FTIR and 1HNMR spectroscopy. Nanoparticles were characterized by TEM, dynamic light scattering (DLS) and zeta potential (ξ) measurements. These polymeric nanoparticles were developed with the aim of co-delivering two different anticancer drugs Doxorubicin hydrochloride (DOX) and chrysin. In vitro cytotoxicity and antitumor effect of DOX@CHS-loaded (PLGA-co-PMAA) and DOX-loaded (CHS-PLGA-co-PMAA) were also studied through assessing the survival rate of lung cancer cell line (A549) using MTT and DAPI staining assays. Nanoparticles with homogeneous spherical morphology and an average diameter of around 100 nm were successfully obtained. The viability of human lung epithelial cancer cell lines (A549) was significantly decreased upon interaction DOX@CHS-loaded (PLGA-co-PMAA) nano-formulation.As results, we envision that the novel developed pH-responsive nanoparticle can enhance the efficacy of DOX and Chrysin combination chemotherapy effect and could be applied as an anticancer drug delivery nanosystem for further in vivo uses.

Electronic Cortisol Detection Using an Antibody-Embedded Polymer Coupled to a Field-Effect Transistor.

A field-effect transistor-based cortisol sensor was demonstrated in physiological conditions. An antibody-embedded polymer on the remote gate was proposed to overcome the Debye length issue (λD). The sensing membrane was made by linking poly(styrene- co-methacrylic acid) (PSMA) with anticortisol before coating the modified polymer on the remote gate. The embedded receptor in the polymer showed sensitivity from 10 fg/mL to 10 ng/mL for cortisol and a limit of detection (LOD) of 1 pg/mL in 1× PBS where λD is 0.2 nm. A LOD of 1 ng/mL was shown in lightly buffered artificial sweat. Finally, a sandwich ELISA confirmed the antibody binding activity of antibody-embedded PSMA.