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https://www.readbyqxmd.com/read/28812329/acid-labile-acyclic-cucurbit-n-uril-molecular-containers-for-controlled-release
#1
Dake Mao, Yajun Liang, Yamin Liu, Xianhao Zhou, Jiaqi Ma, Jia Liu, Biao Jiang, Da Ma
Stimuli responsive molecular containers are of great importance for controlled drug delivery and other biomedical applications. Here, we report a new type of acid labile acyclic cucurbit[n]uril (CB[n]) molecular containers, which can degrade and release the encapsulated cargo with accelerated rates under mildly acidic conditions (pH 5.5-6.5). These containers retain the excellent recognition property of CB[n] type hosts. Cell culture study demonstrated that the cellular uptake of cargos could be fine-tuned by complexation with different containers...
August 15, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28812314/self-assembled-chiral-nanostructures-of-amphiphilic-peptide-from-single-molecule-to-aggregate
#2
Ting Zhou, Zhiqing Zhang, Xuemei Zhang, Chen Wang, Guiying Xu, Yanlian Yang
We report interesting hierarchical self-assembled architectures from a designed amphiphilic peptide. The bisignate cotton effects in circular dichroism spectra show typical peptide aggregation-induced. The observation of peptide assembly structures from initial particles and fibrils to ribbon structures is supported by microscopy (atomic force microscopy and transmission electron microscopy). The visualization of individual peptide at the single molecular level offered insights of the intermolecular interactions responsible for the formation of aggregates, which is investigated by scanning tunneling microscopy...
August 15, 2017: Journal of Peptide Science: An Official Publication of the European Peptide Society
https://www.readbyqxmd.com/read/28811100/is-supercritical-fluid-chromatography-hyphenated-to-mass-spectrometry-suitable-for-the-quality-control-of-vitamin-d3-oily-formulations
#3
B Andri, A Dispas, R Klinkenberg, B Streel, R D Marini, E Ziémons, Ph Hubert
Nowadays, many efforts are devoted to improve analytical methods regarding efficiency, analysis time and greenness. In this context, Supercritical Fluid Chromatography (SFC) is often regarded as a good alternative over Normal Phase Liquid Chromatography (NPLC). Indeed, modern SFC separations are fast, efficient with suitable quantitative performances. Moreover, the hyphenation of SFC to mass spectrometry (MS) provides additional gains in specificity and sensitivity. The present work aims at the determination of vitamin D3 by SFC-MS for routine Quality Control (QC) of medicines specifically...
July 27, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28810516/lectin-from-inflorescences-of-ornamental-crop-alpinia-purpurata-acts-on-immune-cells-to-promote-th1-and-th17-responses-nitric-oxide-release-and-lymphocyte-activation
#4
Jéssica de Santana Brito, Gustavo Ramos Salles Ferreira, Emeline Klimczak, Liliya Gryshuk, Nataly Diniz de Lima Santos, Leydianne Leite de Siqueira Patriota, Leyllane Rafael Moreira, Ana Karine Araújo Soares, Bruno Rafael Barboza, Patrícia Maria Guedes Paiva, Daniela Maria do Amaral Ferraz Navarro, Virgínia Maria Barros de Lorena, Cristiane Moutinho Lagos de Melo, Marília Cavalcanti Coriolano, Thiago Henrique Napoleão
Alpinia purpurata is an ornamental crop known as a source of bioactive molecules. This is the first study to report isolation of a lectin (carbohydrate-binding protein) from A. purpurata inflorescences (ApuL). The immunomodulatory potential of ApuL was evaluated by investigating its effects on the production of cytokines and release of nitric oxide by human peripheral blood mononuclear cells (PBMCs). In addition, the differentiation and activation of lymphocytes treated with ApuL was evaluated by immunophenotyping assays...
August 10, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28810054/dynamic-self-assembly-of-gold-polymer-nanocomposites-ph-encoded-switching-between-1d-nanowires-and-3d-nanosponges
#5
Da-Hui Qu, Qi Zhang, Tian-Yi Xu, Cai-Xin Zhao, Wei-Hang Jin, Qian Wang
The design of tunable dynamic self-assembly of nanoparticles with switchable assembled dimensions and morphologies is a challenging goal whose realization is vital for the evolution of smart nanomaterials. Herein we show the chitosan polymer as an effective supramolecular "glue" for aldehyde-modified Au nanoparticles to reversibly modulate the states of self-assembled nanocomposites. By simultaneous integration of dynamic covalent Schiff base interactions and noncovalent hydrogen bonds, the chitosan/Au nanocomposites could reversibly transform their assembled morphologies from one-dimensional nanowires to three-dimensional nanosponges in response to the variation of pH value...
August 15, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28809977/correlation-between-collective-and-molecular-dynamics-in-ph-responsive-cyclodextrin-based-hydrogels
#6
C Bottari, L Comez, S Corezzi, F D'Amico, A Gessini, A Mele, C Punta, L Melone, A Pugliese, C Masciovecchio, B Rossi
UV Raman and Brillouin light scattering (BLS) experiments have been used in this study to explore the complex phase change behavior occurring in pH-responsive polysaccharide hydrogels as a function of temperature. Due to the different physical quantities measured by the two techniques, the joint analysis of Raman and BLS spectra has provided an unprecedented large-scale characterization of the molecular rearrangements and of the different kinds of hydrophilic and hydrophobic interactions that cooperate to determine the phase transformation observed in these hydrogels during the heating of the gel...
August 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28809970/ph-sensitive-metal-free-carbon-monoxide-prodrugs-with-tunable-and-predictable-release-rates
#7
Xingyue Ji, Ladie Kimberly C De La Cruz, Zhixiang Pan, Vayou Chittavong, Binghe Wang
Carbon monoxide prodrugs with triggered release profiles are highly desirable for targeted CO delivery to minimize their untoward side-effects. Herein, we describe a series of pH-sensitive metal-free CO prodrugs which are stable under acidic conditions and yet begin to release CO in response to increases in pH with tunable and predictable release rates.
August 15, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28809545/plasmonic-nanoprobe-of-gold-triangular-nanoprism-core-polyaniline-shell-for-real-time-three-dimensional-ph-imaging-of-anterior-chamber
#8
Peijun Tang, Xueqin Jiang, Yangyang Wang, Huanjun Chen, Yu Shrike Zhang, Panpan Gao, Hao Wang, Xuemeng Li, Jianhua Zhou
Three-dimensional (3D) molecular imaging enables the study of biological processes in both living and nonviable systems at the molecular level and has a high potential on early diagnosis. In conjunction with specific molecular probes, optical coherent tomography (OCT) is a promising imaging modality to provide 3D molecular features at the tissue level. In this study, we introduced (gold-triangular-nanoprism-core)/(polyaniline-shell nanoparticles) (GTNPs@PANI) as an OCT contrast agent and pH-responsive nanoprobe for 3D imaging of pH distribution...
August 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28809539/polymersomes-with-endosomal-ph-induced-vesicle-to-micelle-morphology-transition-and-a-potential-application-for-controlled-doxorubicin-delivery
#9
Turgay Yildirim, Anja Traeger, Pelin Sungur, Stephanie Hoeppener, Carolin Kellner, Ilknur Yildirim, David Pretzel, Stephanie Schubert, Ulrich S Schubert
A series of pH responsive block copolymers were synthesized via the reversible addition-fragmentation chain transfer (RAFT) polymerization of 3,4-dihydro-2H-pyran (DHP) protected 2-hydroxyethyl methacrylate (HEMA) (2-((tetrahydro-2H-pyran-2-yl)oxy)ethyl methacrylate (THP-HEMA)) and 2-(dimethylamino) ethyl methacrylate (DMAEMA) using p(THP-HEMA) as a macro chain transfer agent (mCTA). The degree of polymerization (DP) of the p(THP-HEMA) block was fixed to 35, whereas the DP of the p(DMAEMA) block was systematically varied from 21 to 50...
August 15, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28809538/dynamic-covalent-hydrogels-for-triggered-cell-capture-and-release
#10
Fatemeh Karimi, Joe Collins, Daniel E Heath, Luke A Connal
A dual-responsive, cell capture and release surface was prepared through the incorporation of phenylboronic acid (PBA) groups into an oxime-based polyethylene glycol (PEG) hydrogel. Owing to its PEG-like properties, the unfunctionalized hydrogel was non-fouling. The use of the highly efficient oxime-click chemistry allows for the facile incorporation of commercially available 3,5-diformylphenyl boronic acid into the hydrogel matrix. Thus, the surface properties of the hydrogel were modified to enable reversible cell capture and release...
August 15, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28809425/ph-responsive-quencher-free-molecular-beacon-systems-containing-2-deoxyuridine-units-labeled-with-fluorene-derivatives
#11
Ji Won Lee, Ye-Seul Son, Jun Yeon Hwang, Yoojin Park, Gil Tae Hwang
Three fluorescent nucleosides-U(FL), U(AF), and U(DAF), containing fluorene, 2-aminofluorene, and 2-dimethylaminofluorene units, respectively, covalently attached to 2'-deoxyuridine-have been incorporated into the central positions of oligodeoxynucleotides (ODNs) to examine the effects of their flanking bases (FBs) and pH on the emission properties upon hybridization with fully matched and single-base-mismatched targets. The ODN containing U(FL) and cytosine-FBs in the pH range from 5.5 to 8.0 and the ODN containing U(DAF) and cytosine-FBs under slightly acidic conditions (pH 6...
August 15, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28809394/smad5-signaling-more-than-meets-the-nuclei
#12
John Orlowski
SMADs are essential transcriptional effectors of transforming growth factor-β (TGFβ)/TGFβ-related signaling that underlies embryonic development and adult homeostasis. A recent study by Fang et al. in Cell Research adds to this biological complexity by demonstrating an atypical cytoplasmic role for SMAD5 in modulating the bioenergetic homeostasis (i.e., glycolysis and mitochondrial respiration) of cells in response to fluctuations in intracellular pH that is independent of receptor signaling.
August 15, 2017: Cell Research
https://www.readbyqxmd.com/read/28809111/tumor-acidic-microenvironment-targeted-drug-delivery-based-on-phlip-modified-mesoporous-organosilica-nanoparticles
#13
Yunlei Zhang, Meng Dang, Ying Tian, Yefei Zhu, Wenfei Liu, Wei Tian, Yunyan Su, Qianqian Ni, Chaoli Xu, Nan Lu, Jun Tao, Yanjun Li, Shuang Zhao, Ying Zhao, Zhenlu Yang, Li Sun, Zhaogang Teng, Guangming Lu
Enhancing the tumor-targeting delivery of chemotherapeutic drugs is important yet challenging for improving therapeutic efficacy and reducing the side effects. Here, we firstly construct a drug delivery system for targeting tumor acidic microenvironment by modification of pH (low) insertion peptide (pHLIP) on mesoporous organosilica nanoparticles (MONs). The MONs has thioether-bridged framework, uniform diameter (60 nm), good biocompatibility and high doxorubicin (DOX) loading capacity (334 mg/g). The DOX loaded in the pHLIP modified MONs can be released responsive to glutathione and low pH circumstance, ensuring the chemotherapeutic drug exerts higher cytotoxic effects to cancer cells than normal cells because of high intracellular GSH of tumor cells and low pH of tumor microenvironment...
August 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28808908/a-new-smart-surface-enhanced-raman-scattering-sensor-based-on-ph-responsive-polyacryloyl-hydrazine-capped-ag-nanoparticles
#14
Shuai Yuan, Fengyan Ge, Man Zhou, Zaisheng Cai, Shanyi Guang
A novel pH-responsive Ag@polyacryloyl hydrazide (Ag@PAH) nanoparticle for the first time as a surface-enhanced Raman scattering (SERS) substrate was prepared without reducing agent and end-capping reagent. Ag@PAH nanoparticles exhibited an excellent tunable detecting performance in the range from pH = 4 to pH = 9. This is explained that the swelling-shrinking behavior of responsive PAH can control the distance between Ag NPs and the target molecules under external pH stimuli, resulting in the tunable LSPR and further controlled SERS...
August 14, 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28808714/a-complicated-biocomputing-system-based-on-multi-responsive-p-nipam-co-apba-copolymer-film-electrodes-and-electrocatalysis-of-nadh
#15
Jiying Liang, Xue Yu, Tiangang Yang, Menglu Li, Li Shen, Yue Jin, Hongyun Liu
In this paper, poly(N-isopropylacrylamide-co-3-aminophenylboronic acid) (P(NIPAM-co-APBA)) copolymer films were successfully electropolymerized on the Au electrode surface. The electroactive probe ferrocene carboxylic acid (FCA) in solution showed reversible thermal-, glucose- and pH-responsive on-off cyclic voltammetric (CV) behaviors at the film electrodes. The comparative experiments demonstrated that the thermo-responsive property of the film electrode was ascribed to the PNIPAM component of the films, whereas the glucose- and pH-sensitive behaviors came from the PAPBA constituent...
August 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28807690/synergistic-effect-of-quercetin-and-ph-responsive-deae-chitosan-carriers-as-drug-delivery-system-for-breast-cancer-treatment
#16
Rafael de Oliveira Pedro, Francisco M Goycoolea, Susana Pereira, Carla C Schmitt, Miguel G Neumann
Amphiphilic chitosans, which may self-assemble in aqueous solution to form nanoaggregates with different conformations depending to the environmental pH, can be used as drug transport and delivery agents, when the target pH differs from the delivery medium pH. In this study, quercetin, a bioactive flavonoid, was encapsulated in a pH-responsive system based on amphiphilic chitosan. The hydrophilic reagent 2-chloro-N,N-diethylethylamine hydrochloride (DEAE), also known to inhibit the proliferation of cancer cells, was used as a grafting agent...
August 11, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28807561/mass-spectrometry-analysis-of-intact-francisella-bacteria-identifies-lipid-a-structure-remodeling-in-response-to-acidic-ph-stress
#17
Camille B Robert, Michael Thomson, Alain Vercellone, Francesca Gardner, Robert K Ernst, Gérald Larrouy-Maumus, Jérôme Nigou
Structural modification of lipid A, the lipid anchor of LPS, is one of the strategies used by Gram-negative bacteria to evade host innate immunity. Francisella tularensis is a human pathogen that infects and replicates within phagocytic cells. It produces an atypical lipid A, whose structure precludes an efficient recognition by both innate immune players, TLR4 and cationic antimicrobial peptides. Interestingly, a recent report indicates that the lipid A of Francisella (LVS vaccinal strain) undergoes polar modifications when bacteria are grown in human macrophages as compared to in broth...
August 11, 2017: Biochimie
https://www.readbyqxmd.com/read/28806549/liming-impacts-on-soils-crops-and-biodiversity-in-the-uk-a-review
#18
REVIEW
J E Holland, A E Bennett, A C Newton, P J White, B M McKenzie, T S George, R J Pakeman, J S Bailey, D A Fornara, R C Hayes
Fertile soil is fundamental to our ability to achieve food security, but problems with soil degradation (such as acidification) are exacerbated by poor management. Consequently, there is a need to better understand management approaches that deliver multiple ecosystem services from agricultural land. There is global interest in sustainable soil management including the re-evaluation of existing management practices. Liming is a long established practice to ameliorate acidic soils and many liming-induced changes are well understood...
August 11, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28806528/surface-adaptive-gold-nanoparticles-with-effective-adherence-and-enhanced-photothermal-ablation-of-methicillin-resistant-staphylococcus-aureus-biofilm
#19
Dengfeng Hu, Huan Li, Bailiang Wang, Zi Ye, Wenxi Lei, Fan Jia, Qiao Jin, Ke-Feng Ren, Jian Ji
Biofilms which contribute to the persistent bacterial infections pose serious threats to global public health, mainly due to their resistance to antibiotics penetration and escaping innate immune attacks by phagocytes. Here, we report a kind of surface-adaptive gold nanoparticles (AuNPs) exhibiting (1) self-adaptive target to the acidic microenvironment of biofilm, (2) enhanced photothermal ablation of methicillin-resistant Staphylococcus aureus (MRSA) biofilm under near-infrared (NIR) light irradiation and (3) no damage to the healthy tissues around biofilm...
August 14, 2017: ACS Nano
https://www.readbyqxmd.com/read/28806055/selective-release-system-for-antioxidative-and-anti-inflammatory-activities-using-h2o2-responsive-therapeutic-nanoparticles
#20
A Young Kim, Ji Hoon Ha, Soo Nam Park
We developed nanoparticles that were degraded by H2O2, a reactive oxygen species (ROS), to study a drug delivery system that targets damaged skin cells with oxidative stress and inflammation. In this study, tyrosol-incorporated copolyoxalate (TPOX) was synthesized by using 1,4-cyclohexanedimethanol, 4-(2-hydroxyethyl)phenol (tyrosol) and oxalyl chloride (Mw ~8835 Da). In vitro drug release behavior was assessed by loading nile red, a lipophilic fluorescent material such as quercetin, into the TPOX nanoparticles...
August 14, 2017: Biomacromolecules
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