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Polyacrylic acid

Zhengze Yu, Yegang Ge, Qiaoqiao Sun, Wei Pan, Xiuyan Wan, Na Li, Bo Tang
Tumor-specific targeting based on folic acid (FA) is one of the most common and significant approaches in cancer therapy. However, the expression of folate receptors (FRs) in normal tissues will lead to unexpected targeting and unsatisfactory therapeutic effect. To address this issue, we develop a pre-protective strategy for precise tumor targeting and efficient photodynamic therapy (PDT) using a switchable DNA/upconversion nanocomposite, which can be triggered in the acidic tumor microenvironment. The DNA/upconversion nanocomposite is composed of polyacrylic acid (PAA) coated upconversion nanoparticles (UCNPs), the surface of which is modified using FA and chlorin e6 (Ce6) functionalized DNA sequences with different lengths...
April 14, 2018: Chemical Science
Mohamed S Abdel Aziz, Hend E Salama
This work aims to study the effect of a vinyl-modified montmorillonite (VMT) on the physical and antimicrobial properties of chitosan-graft-polyacrylic acid superabsorbent (Ch-g-PA). Ch-g-PA was first optimized using Box-Behnken Design to obtain the maximum equilibrium swelling, and the model was efficient to express the experimental swelling data (R2  = 0.999). VMT was further added to the optimized Ch-g-PA in different contents 0, 4, 7 and 10 wt%. FTIR confirmed the successful synthesis of the copolymers and their nanocomposites...
May 16, 2018: International Journal of Biological Macromolecules
T Brooijmans, R Okhuijsen, I Oerlemans, P J Schoenmakers, R Peters
Pyrolysis - gas chromatography - (PyGC) is a common method to analyse the composition of natural and synthetic resins. The analysis of acid functionality in, for example, waterborne polyacrylates and polyurethanes polymers has proven to be difficult due to solubility issues, inter- and intramolecular interaction effects, lack of detectability in chromatographic analysis, and lack of thermal stability. Conventional analytical techniques, such as PyGC, cannot be used for the direct detection and identification of acidic monomers, due to thermal rearrangements that take place during pyrolysis...
May 14, 2018: Journal of Chromatography. A
Jing Zhang, Victoria Boyes, Frederic Festy, Richard J M Lynch, Timothy F Watson, Avijit Banerjee
OBJECTIVE: To test the null hypothesis that chitosan application has no impact on the remineralisation of artificial incipient enamel white spot lesions (WSLs). METHODS: 66 artificial enamel WSLs were assigned to 6 experimental groups (n=11): (1) bioactive glass slurry, (2) bioactive glass containing polyacrylic acid (BG+PAA) slurry, (3) chitosan pre-treated WSLs with BG slurry (CS-BG), (4) chitosan pre-treated WSLs with BG+PAA slurry (CS-BG+PAA), (5) remineralisation solution (RS) and (6) de-ionised water (negative control, NC)...
May 8, 2018: Dental Materials: Official Publication of the Academy of Dental Materials
Diva Lugassy, Pnina Segal, Sigalit Blumer, Michal Eger, Asaf Shely, Shlomo Matalon
OBJECTIVES: A lack of appropriate adhesiveness is one of the biggest problems in restorative dentistry today and the main cause of microleakage. This is especially true in pediatric dentistry where moisture control is more difficult to achieve. Glass ionomer restorative materials increase adhesion and decrease microleakage given their chemical adhesion to the remaining tooth substance. Pretreatment improves the adhesion quality. The aim of this study was to assess the microleakage of Glass ionomer restorative materials following application of 20% polyacrylic acid, 10% polyacrylic acid or 2% chlorhexidine digluconate in Class V cavities...
May 11, 2018: Journal of Clinical Pediatric Dentistry
Jeng-An Wang, Yi-Ting Lu, Sheng-Chi Lin, Yu-Sheng Wang, Chen-Chi Martin Ma, Chi-Chang Hu
A novel copolymer, polyurethane-polyacrylic acid, is successfully synthesized from polyacrylic acid (PAA) backbone cross-linked with waterborne polyurethane (WPU). This sticky polymer neutralized with 1 M KOH and then soaked with 1 M KOH (denoted as WPU-PAAK-K) provides an ionic conductivity greater than 10-2 S cm-1 and acts as a gel electrolyte perfectly improving the electrode/electrolyte interfaces in a flexible all solid-state electrical double-layer capacitor (EDLC). The PAA backbone chains in the copolymer increase the amount of carboxyl groups and promote the segmental motion...
May 10, 2018: ACS Applied Materials & Interfaces
Chunyan Yong, Xiaoqin Chen, Qian Xiang, Qiang Li, Xiaodong Xing
There is a significant need for magnetite-silver nanocomposites that exhibit durable and recyclable antimicrobial activity. In this study, magnetic iron oxide nanoparticles (Fe3 O4 NPs) coated with ethylenediamine-modified chitosan/polyacrylic acid copolymeric layer (Fe3 O4 @ECS/PAA) were fabricated. Subsequently, directly deposited silver (Ag) NPs procedure was carried out to form the antibacterial heterodimers of Fe3 O4 @ECS/PAA-Ag NPs. The composition and morphology of the resultant nanostructures were confirmed by FT-IR, XRD, TEM and TGA...
March 2018: Bioactive Materials
Ratna S Katiyar, Prateek K Jha
We have performed two sets of all atom Molecular Dynamics (MD) simulations of polyacrylic acid (PAA) oligomers, considered as a model pH-responsive drug carrier. In the first set, multiple oligomers of PAA are simulated in model gastric and intestinal fluids, where the degree of deprotonation of PAA oligomers vary with the medium pH. Since the gastric fluid has a pH substantially lower than intestinal fluid, PAA is relatively lesser ionized in gastric fluid and forms aggregates. In the second set, we simulated multiple oligomers of PAA with multiple molecules of a cationic anticancer drug, Doxorubicin (DOX), for a range of pH values representative of various physiological conditions...
May 8, 2018: Molecular Pharmaceutics
Weiqiao Qian, Qin Zhu, Bing Duan, Weijun Tang, Yuan Yuan, Aiguo Hu
Magnetic resonance imaging (MRI) is one of the most important medical imaging techniques for clinical diagnosis. Contrast agents (CAs) are commonly necessarily used to enhance the imaging quality of MRI and differentiate diseased tissues from normal ones. Herein, we introduced a macromolecular carrier, spherical polyelectrolyte brushes (SPBs), which consists of a solid polystyrene (PS) core and polyacrylic acid (PAA) chains as a brush layer to host Gd(iii) complexes. The cationic Gd(iii) complex Gd-DTPA-NO-C4 was synthesized through a 6-step approach and then formed electrostatic self-assemblies with SPBs to afford magnetic assemblies...
May 8, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
L García-Aparicio, E Blázquez-Gómez, O Martin, S Pérez-Bertólez, J Arboleda, A Soria, X Tarrado
OBJECTIVE: To compare the radiological and clinical outcomes of endoscopic treatment of primary VUR using polyacrylate-polyalcohol copolymer (PPC-Vantris® ) or dextranomer-hyaluronic acid copolymer (Dx/HA-Deflux® ). MATERIALS AND METHODS: From October 2014 to April 2017, patients with primary VUR grade III to V that needed endoscopic treatment (ET) were eligible for this randomized clinical trial. We excluded toilet-trained patients with lower urinary tract symptoms...
May 3, 2018: World Journal of Urology
Nadja A Farshad-Amacker, Daniel Nanz, Arjun Thanbanbalasingam, Gustav Andreisek, Mathias Nittka, Roger Luechinger
We aimed to investigate whether different transmission settings of the dual-transmit technology may influence the amount of heat induction around an implant material dependent on its location within the magnetic field. Metallic hip implants were positioned in the magnet of a 3-T scanner at various lateral offset positions in relation to the magnetic axis in a body-phantom tank filled with polyacrylic acid gel. The temperature increase close to the implants was measured during turbo spin-echo scanning using dual-channel parallel radiofrequency (RF) transmission with circular in comparison to elliptic RF polarization...
2018: European radiology experimental
Mandy L Wallace, Gary W Ellison, Robson F Giglio, Christopher D Batich, Clifford R Berry, J Brad Case, Stanley E Kim
OBJECTIVE: To determine the ability of a polyacrylic acid-silicone radiolucent self-retaining gradual occlusion device (PAS-OD) to attenuate congenital extrahepatic portosystemic shunts (EHPSS) in dogs. STUDY DESIGN: Prospective clinical trial. ANIMALS: Six client-owned dogs with single, congenital EHPSS. METHODS: Serum bile acids (SBA), abdominal ultrasonography, and computed tomographic angiography (CTA) were performed preoperatively and at 4 and 8 weeks postoperatively...
April 26, 2018: Veterinary Surgery: VS
Zhenluan Xue, Songjun Zeng, Jianhua Hao
Optical bioimaging by using the new short-wavelength infrared window (SWIR, also named as NIR-II, 1000-1700 nm) is emerged as a next generation imaging technique for disease diagnosis owing to the unprecedented improvements in imaging sensitivity and spatial resolution. However, it is challenging to search new imaging agents with highly biocompatible and bright narrow-band emission located in the 1500-1700 nm (referred as NIR-IIb) region. Here we developed high quality polyacrylic acid (PAA) modified NaYF4 :Gd/Yb/Er nanorods (PAA-NRs) with remarkably enhanced NIR-IIb emission and decent bio-compatibility for in vivo cerebral vascular bioimaging and small tumor visualization...
April 17, 2018: Biomaterials
Jean-Paul Douliez, Nicolas Martin, Thomas Beneyton, Jean-Charles Eloi, J-Paul Chapel, Laurence Navailles, Jean-Christophe Baret, Stephen Mann, Laure Béven
We describe the fabrication of stable colloidosomes derived from water-in-water Pickering-like emulsions produced by addition of fluorescent amine-modified polystyrene latex beads to an aqueous two-phase system consisting of dextran-enriched droplets dispersed in a PEG-enriched continuous phase. Addition of polyacrylic acid followed by carbodiimide-induced crosslinking with dextran produces hydrogelled droplets capable of reversible swelling and selective molecular uptake and exclusion. Colloidosomes produced specifically in all-water systems could offer new opportunities in microencapsulation and the bottom-up construction of synthetic protocells...
April 23, 2018: Angewandte Chemie
P M Pires, T P Santos, A Fonseca-Gonçalves, M M Pithon, R T Lopes, A A Neves
AIM: To test the hypothesis that polyacrylic acid-based and calcium silicate materials are able to increase mineral density of artificially demineralized dentine produced by a microcosm model for caries formation. METHODOLOGY: Forty-five dentine cavities were prepared in 9 sound human third molars (5 in each tooth). Specimens received a bacterial inoculum and were incubated in BHI plus 5% of sucrose for 96h to allow biofilm formation. After that, the specimens were scanned in a high energy micro-CT (baseline stack) and then, each cavity was filled with different cements: zinc polycarboxylate (Poly Zinc™ , Prevest DenPro, Jammu, India), conventional glass ionomer (Ketac Molar, 3M ESPE, Seefeld, Germany) and two calcium silicate based materials (MTA, Angelus, Londrina, Brazil and Biodentine™ , Septodont, Saint Maur des Fosses, France) while the central cavity was filled with utility wax (negative control)...
April 22, 2018: International Endodontic Journal
Annah Farashishiko, Jacqueline R Slack, Mauro Botta, Mark Woods
Although paraCEST is a method with immense scope for generating image contrast in MRI, it suffers from the serious drawback of high detection limits. For a typical discrete paraCEST agent the detection limit is roughly an order of magnitude higher than that of a clinically used relaxation agent. One solution to this problem may be the incorporation of a large payload of paraCEST agents into a single macromolecular agent. Here we report a new synthetic method for accomplishing this goal: incorporating a large payload of the paraCEST agent DyDOTAM3+ into a Reverse Assembled nano-Capsule...
2018: Frontiers in Chemistry
Alexander I Wiechert, Wei-Po Liao, Eunice Hong, Candice E Halbert, Sotira Yiacoumi, Tomonori Saito, Costas Tsouris
This study focuses on the influence of hydrophilic groups and metal-ion loading on adsorbent polymer conformation, which controls access to adsorption sites and may limit adsorption capacity. Gaining a better understanding of the factors that influence conformation may yield higher-capacity adsorbents. Polyamidoxime (PAO), deuterated-PAO polyacrylic acid diblock copolymers (d-PAO-b-PAA), and randomly configured copolymers (PAO-co-PAA) were synthesized and characterized by neutron reflectometry in air and D2 O...
April 6, 2018: Journal of Colloid and Interface Science
Yong Fu, Yue Huang, Jianshe Hu
A novel functional hybrid mesoporous composite material (CMP) based on chitosan and MCM-41-PAA was reported and its application as an excellent adsorbent for Hg(II) ions was also investigated. Innovatively, MCM-41-PAA was prepared by using diatomite and polyacrylic acid (PAA) with integrated polymer-silica hybrid frameworks, and then CMP was fabricated by introducing MCM-41-PAA to chitosan using glutaraldehyde as a cross-linking agent. The structure and morphology of CMP were characterized by X-ray diffraction, Fourier transform infrared spectra, thermogravimetric analysis, scanning electron microscopy and Brunauer-Emmett-Teller measurements...
March 2018: Royal Society Open Science
Lei Xu, Yiran Shao, Chengkang Chang, Yingchun Zhu
Tumor hypoxia is known to result in radiotherapy resistance and traditional radiotherapy using super-hard X-ray irradiation can cause considerable damage to normal tissue. Therefore, formamide peroxide (FPO) with high reactive oxygen content was employed to enhance the oxygen concentration in tumor cells and increase the radio-sensitivity of low-energy soft-X-ray. To improve stability of FPO, FPO is encapsulated into polyacrylic acid (PAA)-coated hollow mesoporous silica nanoparticles (FPO@HMSNs-PAA). On account of the pH-responsiveness of PAA, FPO@HMSNs-PAA will release more FPO in simulated acidic tumor microenvironment (pH 6...
April 12, 2018: Materials
Esteban Piccinini, Jimena S Tuninetti, Joseba Irigoyen Otamendi, Sergio E Moya, Marcelo Ceolín, Fernando Battaglini, Omar Azzaroni
Interfacial supramolecular architectures displaying mesoscale organized components are of fundamental importance for developing materials with novel or optimized properties. Nevertheless, engineering the multilayer assembly of different building blocks onto a surface and exerting control over the internal mesostructure of the resulting film is still a challenging task in materials science. In the present work we demonstrate that the integration of surfactants (as mesogenic agents) into layer-by-layer (LbL) assembled polyelectrolyte multilayers offers a straightforward approach to control the internal film organization at the mesoscale level...
April 4, 2018: Physical Chemistry Chemical Physics: PCCP
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