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bio chemistry

Jay K Bhattarai, Dharmendra Neupane, Bishal Nepal, Vasilii Mikhaylov, Alexei V Demchenko, Keith J Stine
Nanoporous gold (np-Au), because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au...
March 16, 2018: Nanomaterials
Han Zuilhof, Digvijay Gahtory, Rickdeb Sen, Andriy R Kuzmyn, Jorge Escorihuela
Novel click reactions are of continued interest in fields as diverse as bio-conjugation, polymer science and surface chemistry. Qualification as a proper 'click' reaction requires stringent criteria, including fast kinetics and high conversion, to be met. Herein, we report a novel strain-promoted cycloaddition between cyclopropenes and o-quinones in solution and on a surface. We demonstrate the 'click character' of the reaction in solution and on surfaces for both monolayer and polymer brush functionalization...
March 15, 2018: Angewandte Chemie
Hiang Kwee Lee, Charlynn Sher Lin Koh, Yih Hong Lee, Chong Liu, In Yee Phang, Xuemei Han, Chia-Kuang Tsung, Xing Yi Ling
Electrochemical nitrogen-to-ammonia fixation is emerging as a sustainable strategy to tackle the hydrogen- and energy-intensive operations by Haber-Bosch process for ammonia production. However, current electrochemical nitrogen reduction reaction (NRR) progress is impeded by overwhelming competition from the hydrogen evolution reaction (HER) across all traditional NRR catalysts and the requirement for elevated temperature/pressure. We achieve both excellent NRR selectivity (~90%) and a significant boost to Faradic efficiency by 10 percentage points even at ambient operations by coating a superhydrophobic metal-organic framework (MOF) layer over the NRR electrocatalyst...
March 2018: Science Advances
Zijian Guo, Jing Zhao
No abstract text is available yet for this article.
April 2018: Current Opinion in Chemical Biology
Ang Li, Yunfei Jia, Shengtong Sun, Yisheng Xu, Burcu Minsky, Martien Abraham Cohen Stuart, Helmut Cölfen, Regine von Klitzing, Xuhong Guo
Underwater adhesion is crucial to many marine life forms living a sedentary life style. Amongst them, mussel adhesion has been mostly studied, which inspires numerous investigations of 3,4-dihydroxyphenylalanine (DOPA)-based organic adhesives. In contrast, reef-buliding oysters represent another important "inorganic" strategy of marine molluscs for adhesion by generating biomineralized organic-inorganic adhesives, which is still rarely studied and no synthetic analogues have ever been reported so far...
March 8, 2018: ACS Applied Materials & Interfaces
Snehali Mali, Sachin Shinde, Shashikant Damte, Suresh Patil
Without using any toxic or hazardous reagent, ligand, acid, transition metal catalyst, additives/promoters and organic solvent, green Knoevenagel condensation and tandem Knoevenagel-Michael reactions have been successfully carried out by using chickpea leaf exudates as a naturally sourced Bronsted acid type bio-catalyst. The reaction proceeds in neat chickpea leaf exudates at room temperature in aqueous conditions in very short reaction times, and therefore, it is an evergreen and environmentally sound alternative to the existing protocols for benzopyran synthesis...
February 2018: Royal Society Open Science
Franco Tassi, Stefano Fazi, Simona Rossetti, Paolo Pratesi, Marco Ceccotti, Jacopo Cabassi, Francesco Capecchiacci, Stefania Venturi, Orlando Vaselli
Volcanic lakes are characterized by physicochemical favorable conditions for the development of reservoirs of C-bearing greenhouse gases that can be dispersed to air during occasional rollover events. By combining a microbiological and geochemical approach, we showed that the chemistry of the CO2- and CH4-rich gas reservoir hosted within the meromictic Lake Averno (Campi Flegrei, southern Italy) are related to the microbial niche differentiation along the vertical water column. The simultaneous occurrence of diverse functional groups of microbes operating under different conditions suggests that these habitats harbor complex microbial consortia that impact on the production and consumption of greenhouse gases...
2018: PloS One
Hang Zhang, Jinlong Chen, Chunsheng Xiao, Youhua Tao, Xianhong Wang
The growing application of quantum dots (QDs) in biomedical research necessitates, in turn, continuous development of surface functionalizing ligands to optimize their performance for ever more challenging and diverse biological applications. Here, we demonstrate the novel multifunctional polypeptide ligands for compact and biocompatible QDs. The target ligand preparation exploits the efficient, activating agent-free Ugi reaction of four functional components to incorporate lipoic acid, pyridine, zwitterion motifs, and reactive functionalities in a one-pot procedure under mild conditions...
March 5, 2018: Bioconjugate Chemistry
Federica Valeriani, Silvia Crognale, Carmela Protano, Gianluca Gianfranceschi, Massimiliano Orsini, Matteo Vitali, Vincenzo Romano Spica
Several factors influence bacteria biodiversity in hot springs. The impact of biotic and abiotic pathways on travertine deposition plays a key role in microbial ecology and in the final composition of the waterborne microbiota. The metabolism of some bacterial groups such as photoautotrophs or lithoautotrophs influences water chemistry, favoring carbonate precipitation processes. The role of microbial mats in mineral precipitation processes is not fully clarified. For the first time, a comprehensive metagenomic analysis has been undertaken in the historical Bullicame hot spring...
March 2, 2018: New Microbiologica
Dhruva Katrekar, Ana M Moreno, Genghao Chen, Atharv Worlikar, Prashant Mali
Recombinant adeno-associated viruses (AAVs) are among the most commonly used vehicles for in vivo gene delivery. However, their tropism is limited, and additionally their efficacy can be negatively affected by prevalence of neutralizing antibodies in sera. Methodologies to systematically engineer AAV capsid properties would thus be of great relevance. In this regard, we develop here multi-functional AAVs by engineering precision tethering of oligonucleotides onto the AAV surface, and thereby enabling a spectrum of nucleic-acid programmable functionalities...
February 26, 2018: Scientific Reports
Luciana D Trino, Erika S Bronze-Uhle, Amsaveni Ramachandran, Paulo N Lisboa-Filho, Mathew T Mathew, Anne George
Titanium (Ti) is widely used in biomedical devices due to its recognized biocompatibility. However, implant failures and subsequent clinical side effects are still recurrent. In this context, improvements can be achieved by designing biomaterials where the bulk and the surface of Ti are independently tailored. The conjugation of biomolecules onto the Ti surface can improve its bioactivity, thus accelerating the osteointegration process. Ti was modified with TiO2 , two different spacers, 3-(4-aminophenyl) propionic acid (APPA) or 3-mercaptopropionic acid (MPA) and dentin matrix protein 1 (DMP1) peptides...
February 21, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Henrique S Fernandes, Maria J Ramos, Nuno M F S A Cerqueira
The notable advances obtained by computational (bio)chemistry provided its widespread use in many areas of science, in particular, in the study of reaction mechanisms. These studies involve a huge number of complex calculations, which are often carried out using the Gaussian suite of programs. The preparation of input files and the analysis of the output files are not easy tasks and often involve laborious and complex steps. Taking this into account, we developed molUP: a VMD plugin that offers a complete set of tools that enhance the preparation of QM and ONIOM (QM/MM, QM/QM, and QM/QM/MM) calculations...
February 21, 2018: Journal of Computational Chemistry
Sofia Raniolo, Giulia Vindigni, Alessio Ottaviani, Valeria Unida, Federico Iacovelli, Antonio Manetto, Mariangela Figini, Lorenzo Stella, Alessandro Desideri, Silvia Biocca
Selective targeting is a crucial property of nanocarriers used for drug delivery in cancer therapy. We generated biotinylated octahedral DNA nanocages functionalized with folic acid through bio-orthogonal conjugation chemistry. Molecular modelling indicated that a distance of about 2.5 nm between folic acid and DNA nanocage avoids steric hindrance with the folate receptor. HeLa cells, a folate receptor positive tumour cell line, internalize folate-DNA nanocages with efficiency greater than 40 times compared to cells not expressing the folate receptors...
February 16, 2018: Nanomedicine: Nanotechnology, Biology, and Medicine
Leonardo G Ferreira, Glaucius Oliva, Adriano D Andricopulo
Scientific and technological breakthroughs have compelled the current players in drug discovery to increasingly incorporate knowledge-based approaches. This evolving paradigm, which has its roots attached to the recent advances in medicinal chemistry, molecular and structural biology, has unprecedentedly demanded the development of up-to-date computational approaches, such as bio- and chemo-informatics. These tools have been pivotal to catalyzing the ever-increasing amount of data generated by the molecular sciences, and to converting the data into insightful guidelines for use in the research pipeline...
February 15, 2018: Anais da Academia Brasileira de Ciências
Ming Li, Yupeng Chen, Li-Bo Mao, Yuan Jiang, Mingfeng Liu, Qiaoling Huang, Zhiyang Yu, Shutao Wang, Shu-Hong Yu, Changjian Lin, Xiang Yang Liu, Helmut Cölfen
Like their biogenic counterparts, synthetic minerals with hierarchical architectures should exhibit (multiple) structural functions, which nicely bridge the boundaries between engineering and functional materials. Nevertheless, design of bio-inspired mineralization approaches to thin coatings with distinct micro-/nano-textures remains challenging in the realm of materials chemistry. Herein, a general morphosynthetic method based on seeded mineralization was extended to achieve prismatic-type thin CaCO3 coatings on fibrous substrates for oil/water separation applications...
February 13, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Yunxiang Gao
Magnetic resonance imaging (MRI) is the most powerful tool for deep penetration and high-quality 3D imaging of tissues with anatomical details. However, the sensitivity of the MRI technique is not as good as that of the radioactive or optical imaging methods. Carbon-based nanomaterials have attracted significant attention in biomaterial research in recent decades due to their unique physical properties, versatile functionalization chemistry, as well as excellent biological compatibility. Researchers have employed various carbon nano-allotropes to develop hybrid MRI contrast agents for improved sensitivity...
February 6, 2018: Journal of Functional Biomaterials
Zhinan Wang, Xianfeng Hou, Jin Sun, Meng Li, Zhiyong Chen, Zhenzhong Gao
Two ultrasound-assisted pretreatment technologies, ultrasound-assisted alkaline and ultrasound-assisted aqueous ionic liquid tetrabutylammonium hydroxide ([TBA][OH]), are compared systematically in regard to enzymatic saccharification. Pretreated Eucalyptus samples were characterized by powder X-ray diffraction, 13C cross polarization/magic-angle spinning solid state NMR spectroscopy, Fourier transform infrared spectroscopy, Scanning electron microscope (SEM) and chemistry composition analysis. These results not only explain the enzymatic saccharification difference between samples from the microstructure level, but also provide helpful information for relevant pretreatment research...
January 6, 2018: Bioresource Technology
Marie Hechelski, Alina Ghinet, Brice Louvel, Pierrick Dufrenoy, Benoît Rigo, Adam Daïch, Christophe Waterlot
The concept of green chemistry was appeared in the USA in the nineties. Since the publication of the 12 principles of this concept, many reactions in organic chemistry have been developed, chemical products have been synthesized under environmentally friendly conditions. Lewis acids-mediated synthetic transformations are by far the most numerous, best studied. However, the use of certain Lewis acids may cause environmental and human health hazards problems. The aim of this review is to point out the evolution of the Lewis acid catalyzed reactions from homogeneous liquid phase to solid phase in order to obtain the expected organic molecules under green, safe conditions...
February 6, 2018: ChemSusChem
R Sivakumarasamy, R Hartkamp, B Siboulet, J-F Dufrêche, K Nishiguchi, A Fujiwara, N Clément
Despite being ubiquitous in the fields of chemistry and biology, the ion-specific effects of electrolytes pose major challenges for researchers. A lack of understanding about ion-specific surface interactions has hampered the development and application of materials for (bio-)chemical sensor applications. Here, we show that scaling a silicon nanotransistor sensor down to ~25 nm provides a unique opportunity to understand and exploit ion-specific surface interactions, yielding a surface that is highly sensitive to cations and inert to pH...
February 5, 2018: Nature Materials
Pamela Torres-Salas, Vicente Bernal, Fernando López-Gallego, Javier Martínez-Crespo, Pedro Alejandro Sánchez-Murcia, Víctor Barrera, Rocío Morales-Jiménez, Ana García-Sánchez, Aurora Mañas-Fernández, José Miguel Seoane, Marta Sagrera Polo, Juande D Miranda, Javier Calvo, Sonia Huertas, José Luis Torres, Ana Alcalde-Bascones, Sergio González-Barrera, Federico Gago, Antonio Morreale, María Del Mar González-Barroso
Thiolases catalyze the condensation of acyl-CoA thioesters through the Claisen condensation reaction. The best described enzymes usually yield linear condensation products. Using a combined computational/experimental approach, and guided by structural information, we have studied the potential of thiolases to synthesize branched compounds. We have identified a bulky residue located at the active site that blocks proper accommodation of substrates longer than acetyl-CoA. Amino acid replacements at such position exert effects on the activity and product selectivity of the enzymes that are highly dependent on protein scaffold...
January 23, 2018: Biochemistry
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