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Surface chemistry

Jiabin Cui, Rui Jiang, Chang Guo, Xilin Bai, Suying Xu, Leyu Wang
We report the multifunctional nanocomposites (NCs) consisting of 19F-moieties grafted Cu7S4-Au nanoparticles (NPs) through click chemistry for sensitive and negligible background 19F-magnetic resonance imaging (19F-MRI) and computed tomography (CT) imaging guided photothermal therapy. The localized surface plasmon resonance (LSPR) peak can be reasonably tuned to the in vivo transparent window (800-900 nm) by coupling Au NPs (<10 nm, LSPR 530 nm) with Cu7S4 NPs (<15 nm, LSPR 1500 nm) into the Cu7S4-Au heterodimers...
April 20, 2018: Journal of the American Chemical Society
Laura Ina Selby, Luigi Aurelio, Daniel Yuen, Bim Graham, Angus P R Johnston
The ability to determine the amount of material endocytosed by a cell is important for our understanding of cell biology and in the de-sign of effective carriers for drug delivery. To quantify internalization by fluorescence, the signal from material remaining on the cell sur-face must be differentiated from endocytosed material. Sensors for internalization offer advantages over traditional methods for achiev-ing this as they exhibit improved sensitivity, allow for multiple fluorescent markers to be used simultaneously, and are amenable to high throughput analysis...
April 20, 2018: ACS Sensors
Ana Beloqui, Andrei Yu Kobitski, Gerd Ulrich Nienhaus, Guillaume Delaittre
We have established a simple one-step synthesis of single-enzyme nanogels (SENs), i.e. , nanobiocatalysts consisting of an enzyme molecule embedded in a hydrophilic, polymeric crosslinked nanostructure, as a most attractive approach to enhance the stability of enzymes. In contrast to earlier protocols, we demonstrate here that the addition of a small amount of sucrose makes the nanogel formation equally effective as earlier two-step protocols requiring enzyme pre-modification. This provides the dual advantage of skipping a synthetic step and preserving the surface chemistry of the enzymes, hence their native structure...
January 28, 2018: Chemical Science
Jacob Witten, Tahoura Samad, Katharina Ribbeck
Mucus is a hydrogel that exhibits complex selective permeability, permitting the passage of some particles while restricting the passage of other particles including important therapeutics. In this review, we discuss biochemical mechanisms underlying mucus penetration and mucus binding, emphasizing the importance of steric, electrostatic, and hydrophobic interactions. We discuss emerging techniques for engineering nanoparticle surface chemistries for mucus penetration as well as recent advances in tuning mucus interactions with small molecule, peptide, or protein therapeutics...
April 16, 2018: Current Opinion in Biotechnology
Hana Buchtelova, Vladislav Strmiska, Zuzana Skubalova, Simona Dostalova, Petr Michalek, Sona Krizkova, David Hynek, Lukas Kalina, Lukas Richtera, Amitava Moulick, Vojtech Adam, Zbynek Heger
BACKGROUND: Suitable fluorophores are the core of fluorescence imaging. Among the most exciting, yet controversial, labels are quantum dots (QDs) with their unique optical and chemical properties, but also considerable toxicity. This hinders QDs applicability in living systems. Surface chemistry has a profound impact on biological behavior of QDs. This study describes a two-step synthesis of QDs formed by CdTe core doped with Schiff base ligand for lanthanides [Ln (Yb3+ , Tb3+ and Gd3+ )] as novel cytocompatible fluorophores...
April 19, 2018: Journal of Nanobiotechnology
Jacek K Wychowaniec, Maria Iliut, Mi Zhou, Jonathan Moffat, Mohamed A Elsawy, Wagner A Pinheiro, Judith A Hoyland, Aline F Miller, Aravind Vijayaraghavan, Alberto Saiani
A recent strategy that has emerged for the design of increasingly functional hydrogels is the incorporation of nanofillers in order to exploit their specific properties to either modify the performance of the hydrogel or add functionality. The emergence of carbon nanomaterials in particular has provided great opportunity for the use of graphene derivatives (GDs) in biomedical applications. The key challenge when designing hybrid materials is the understanding of the molecular interactions between the matrix (peptide nanofibers) and the nanofiller (here GDs) and how these affect the final properties of the bulk material...
April 19, 2018: Biomacromolecules
Taisiia Berestok, Pablo Guardia, Ruifeng Du, Javier Blanco Portals, Massimo Colombo, Sonia Estrade, Francesca Peiró, Stephanie L Brock, Andreu Cabot
We present a novel method to produce crystalline oxide aerogels based on the cross linking of preformed colloidal nanocrystals (NCs) triggered by propylene oxide (PO). Ceria and titania are the oxides used to illustrate this new approach. Colloidal metal oxide NCs with tuned geometry and crystal facets were produced in solution from the decomposition of a suitable salt in the presence of oleylamine (OAm). The native surface ligands were replaced by amino acids, rendering the NCs colloidally stable in polar solvents...
April 19, 2018: ACS Applied Materials & Interfaces
Giulio Tesei, Vidar Aspelin, Mikael Lund
The large and sparsely hydrated thiocyanate anion, SCN- , plays a prominent role in the study of specific ion effects in biological, colloid, and atmospheric chemistry due to its extreme position in the Hofmeister series. Using atomistic modeling of aqueous SCN- solutions, we provide novel insight at the molecular scale into the experimentally observed differences in ion pairing, clustering, reorientation dynamics, mutual diffusion, and solubility between the sodium, Na+ , and the potassium, K+ , salt. Compared to KSCN, NaSCN has a less pronounced tendency to ion pairing, nevertheless, at high salt concentrations, we observe a strong attraction between Na+ cations and the nitrogen end of SCN- , resulting in larger and more closely packed ion clusters...
April 19, 2018: Journal of Physical Chemistry. B
Ernesto Doncel-Pérez, Gary Ellis, Christophe Sandt, Peter S Shuttleworth, Agatha Bastida, Julia Revuelta, Eduardo García-Junceda, Alfonso Fernández-Mayoralas, Leoncio Garrido
Therapeutic options for spinal cord injuries are severely limited; current treatments only offer symptomatic relief and rehabilitation focused on educating the individual on how to adapt to their new situation to make best possible use of their remaining function. Thus, new approaches are needed, and interest in the development of effective strategies to promote the repair of neural tracts in the central nervous system inspired us to prepare functional and highly anisotropic polymer scaffolds. In this work, an initial assessment of the behavior of rat neural progenitor cells (NPCs) seeded on poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) fiber scaffolds using synchrotron-based infrared microspectroscopy (SIRMS) is described...
April 18, 2018: Analytical and Bioanalytical Chemistry
Imen Ghouma, Mejdi Jeguirim, Lionel Limousy, Najoua Bader, Abdelmottaleb Ouederni, Simona Bennici
The textural properties and surface chemistry of different activated carbons, prepared by the chemical activation of olive stones, have been investigated in order to gain insight on the NO₂ adsorption mechanism. The parent chemical activated carbon was prepared by the impregnation of olive stones in phosphoric acid followed by thermal carbonization. Then, the textural properties and surface chemistry were modified by chemical treatments including nitric acid, sodium hydroxide and/or a thermal treatment at 900 &deg;C...
April 18, 2018: Materials
Abhay Singh Chauhan
Dendrimers have come a long way in the last 25 years since their inception. Originally created as a wonder molecule of chemistry, dendrimer is now in the fourth class of polymers. Dr. Donald Tomalia first published his seminal work on Poly(amidoamine) (PAMAM) dendrimers in 1985. Application of dendrimers as a drug delivery system started in late 1990s. Dendrimers for drug delivery are employed using two approaches: (i) formulation and (ii) nanoconstruct. In the formulation approach, drugs are physically entrapped in a dendrimer using non-covalent interactions, whereas drugs are covalently coupled on dendrimers in the nanoconstruct approach...
April 18, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Xiaoming Zhang, Tianwei Gu, Shaodong Shi, Leyi Li, Shansheng Yu
Pt monolayer catalyst could greatly reduce the use of platinum. However, the core or subsurface transition metal could easily segregate to the surface and eventually selectively dissolve in the working conditions. In this work, a type of PtML /MML /WC multi-layer structure catalyst has been designed using DFT method. The results show that the stability of W-terminated core catalysts is lower than that of the corresponding C-terminated one. More importantly, C-terminated PtML/CoML/WC alloy could also maintain a stable platinum monolayer structure in various electrolyte solutions (eg, perchloric acid, phosphoric acid, alkaline solutions) and via different ORR pathways, in addition to the previously well-known precious alloy elements, such as Ru, Ir, etc...
April 18, 2018: ACS Applied Materials & Interfaces
Cheng Zou, Jingxia Wang, Meng Wang, Yuchen Wu, Kehua Gu, Zhihao Shen, Guirong Xiong, Huai Yang, Lei Jiang, Tomiki Ikeda
The large-area formation of functional micropatterns with liquid crystals is of great significance for diversified applications in interdisciplinary fields. Meanwhile, the control of molecular alignment in the patterns is fundamental and prerequisite for the adequate exploitation of their photoelectric properties. However, it would be extremely complicated and challenging for discotic liquid crystals (DLCs) to achieve the goal, because they are insensitive to external fields and surface chemistry. Herein, a simple method of patterning and aligning DLCs on flat substrates is disclosed through precise control of the formation and dewetting of the capillary liquid bridges, within which the DLC molecules are confined...
April 18, 2018: Small
Yupeng He, Shifeng Hou, Liqiong Yang, Fang Zhang, Guizheng Zou
Tunable optics and electronics of II-VI nanocrystals (NCs) is mainly achieved in the traditional size-dependent strategy. Herein, adjustable triggering energy, intensity, and even spectrum for reductive-oxidation electrochemiluminescence (ECL) from highly-passivated CdTe/CdS NCs of the same size are achieved via decorating NCs with counterions, which proves surface chemistry can bring out varied electrostatic interaction between surface vacancies and electrochemically injected carriers for adjustable electrochemical redox induced radiative charge-transfer...
April 17, 2018: Chemistry: a European Journal
Lorenzo Angiolini, Sabrina Valetti, Boiko Cohen, Adam Feiler, Abderrazzak Douhal
We report on the encapsulation of the antibiotic clofazimine (CLZ) within the pores of mesoporous silica particles having hydrophilic (CBET value of 137) and more hydrophobic (CBET value of 94 after calcination at 600 °C) surfaces. We studied the effect of pH on the released amount of CLZ in aqueous solutions and observed a maximum at pH 4.1 in correlation with the solubility of the drug. Less release of the drug was observed from the more hydrophobic particles which was attributed to a difference in the affinity of the drug to the carrier particles...
April 18, 2018: Physical Chemistry Chemical Physics: PCCP
Nadine Sobotzki, Michael A Schafroth, Alina Rudnicka, Anika Koetemann, Florian Marty, Sandra Goetze, Yohei Yamauchi, Erick M Carreira, Bernd Wollscheid
Cellular responses depend on the interactions of extracellular ligands, such as nutrients, growth factors, or drugs, with specific cell-surface receptors. The sensitivity of these interactions to non-physiological conditions, however, makes them challenging to study using in vitro assays. Here we present HATRIC-based ligand receptor capture (HATRIC-LRC), a chemoproteomic technology that successfully identifies target receptors for orphan ligands on living cells ranging from small molecules to intact viruses...
April 17, 2018: Nature Communications
Ling Tang, Guoliang Wang, Long Jiang, Panpan Chen, Wei Wang, Juan Chen, Luya Wang
OBJECTIVES: Familial hypercholesterolemia (FH) is an autosomal dominant disorder of cholesterol metabolism. Three recognized genes (LDLR, APOB and PCSK9) present in only 20-30% of patients with possible FH cases. Additional FH-causing genes need to be explored. The present study found an isolated gene change, sEH R287Q, in a core family of FH. In this study, we aimed to investigate the roles of R287Q on sEH expression and on LDLR expression, LDL binding to LDLR and LDL internalization...
April 14, 2018: Gene
Rui Xiong, Ho Shin Kim, Volodymyr F Korolovych, Shuaidi Zhang, Yaroslava Yingling, Vladimir V Tsukruk
Constructing advanced functional nanomaterials with pre-designed organized morphologies from low-dimension synthetic and biological components is extremely challenging because of complex inter-component interactions, high-aspect ratios, flexible shapes, crumpling instabilities and limited common wet-chemistry processing conditions. Herein, we report an efficient and universal amphiphilicity-driven assembly strategy to construct "hairy" flexible hybrid nanosheets with the net of 1D cellulose nanofibers (CNFs) conformally wrapped around 2D graphene oxide (GO) monolayers...
April 17, 2018: Angewandte Chemie
Johannes Schneider, Thomas Berger, Oliver Diwald
The surface functionalization of metal oxide nanoparticles with complex organic molecules can lead to optoelectronically very different materials' properties depending on whether adsorption occurs at the solid-gas or solid-liquid interface. Here, we report on two different approaches to decorate anatase TiO2 nanoparticle powders with 2H-tetraphenylporphyrin (2HTPP) molecules: i) porphyrin adsorption in dispersions of organic liquids and ii) gas phase functionalization where evaporated porphyrin molecules attach to dehydrated particle surfaces in the absence of solvent molecules...
April 17, 2018: ACS Applied Materials & Interfaces
Ezgi Antmen, Menekse Ermis, Utkan Demirci, Vasif Hasirci
Cell-substrate interactions involve constant probing of microenvironment by cells. One of the responses of cells to environmental cues is to change the conformation of their cytoplasm and nucleus. We hypothesized that surface chemistry and topography could be engineered to make these differences significant enough. When designing the substrates that would accentuate these differences, we prepared surfaces carrying cell adhesive biological cues arranged in specific patterns. Collagen type I and poly(lactic acid-co-glycolic acid) (PLGA) were used to represent substrates with biological cues and those without, and these materials were decorated with four square prism micropillars with different dimensions...
April 16, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
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