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Hongmei Yang, Yan Zhang, Lina Zhang, Kang Cui, Shenguang Ge, Jiadong Huang, Jinghua Yu
Highly conductive, robust, and multifunctional integrated paper-supported electrodes are requisite to fulfill the promise of paper-based analytical application. Herein, an all-in-one Au electrode comprising of detection zone, waterproof electronic bridge, and signal output contactor was engineered via combining the double-sided growth method with the secondary wax-printing. Benefiting from the strongly omnidirectional conductivity and desirably mechanical robustness of the as-prepared electrode, a stackable lab-on-paper cyto-device integrated with high-efficiency photoelectrochemical strategy was developed for the MCF-7 cells assay...
May 21, 2018: Analytical Chemistry
Naoko Ichiishi, John P Caldwell, Melissa Lin, Wendy Zhong, Xiaohong Zhu, Eric Streckfuss, Hai-Young Kim, Craig A Parish, Shane W Krska
Two radical-based approaches have been developed to effect the trifluoromethylation of aryl C-H bonds in native peptides either using stoichiometric oxidant or visible light photoredox catalysis. The reported methods are able to derivatize tyrosine and tryptophan sidechains under biocompatible conditions, and a number of examples are reported involving fully unprotected peptides with up to 51 amino acids. The development of this chemistry adds to the growing array of chemical methods for selectively modifying amino acid residues in the context of complex peptides...
May 7, 2018: Chemical Science
Ulla König, Evmorfia Psarra, Olga Guskova, Eva Bittrich, Klaus-Jochen Eichhorn, Martin Müller, Petra B Welzel, Manfred Stamm, Petra Uhlmann
The development of bioengineered surface coatings with stimuli-responsive properties is beneficial for a number of biomedical applications. Environmentally responsive and switchable polymer brush systems have a great potential to create such smart biointerfaces. This study focuses on the bioconjugation of cell-instructive peptides, containing the arginine-glycine-aspartic acid tripeptide sequence (RGD motif), onto well-defined polymer brush films. Herein, the highly tailored end-grafted homo polymer brushes are either composed of the polyelectrolyte poly(acrylic) acid (PAA), providing the reactive carboxyl functionalities, or of the temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm)...
May 18, 2018: Biointerphases
Kevin M Burridge, Thaiesha A Wright, Richard C Page, Dominik Konkolewicz
This review article highlights recent developments in the field of photochemistry and photochemical reversible deactivation radical polymerization applied to aqueous polymerizations. Photochemistry is a topic of significant interest in the fields of organic, polymer, and materials chemistry because it allows challenging reactions to be performed under mild conditions. Aqueous polymerization is of significant interest because water is an environmentally benign solvent, and the use of water enables complex polymer self-assembly and bioconjugation processes to occur...
May 17, 2018: Macromolecular Rapid Communications
Michelle W Lee, Ernest Y Lee, Gerard C L Wong
A common bioengineering strategy to add function to a given molecule is by conjugation of a new moiety onto that molecule. Adding multiple functions in this way becomes increasingly challenging and leads to composite molecules with larger molecular weights. In this review, we attempt to gain a new perspective by looking at this problem in reverse, by examining nature's strategies of multiplexing different functions into the same pleiotropic molecule using emerging analysis techniques such as machine learning...
May 17, 2018: Bioconjugate Chemistry
Samantha G L Keyser, Ashley Utz, Carolyn R Bertozzi
Site-selective protein modification based on covalent reactions of peptide tags and small molecules is a key capability for basic research as well as for the development of new therapeutic bioconjugates. Here we describe the computation-guided rational design of a cysteine- and lysine-containing 11-residue peptide sequence that reacts with 2-cyanobenzothiazole (CBT) derivatives. Our data show that the cysteine residue reversibly reacts with the nitrile group on the CBT moiety to form an intermediate thioimidate, which undergoes irreversible SN transfer to the lysine residue, yielding an amidine-linked product...
May 17, 2018: Journal of Organic Chemistry
Jaleh Varshosaz, Negin Anvari
Acute lymphoblastic leukemia (ALL) is the white blood cell cancer in children. L-asparaginase (L-ASNase) is one of the first drugs used in ALL treatment. Anti-tumor activity of L-ASNase is not specific and indicates limited stability in different biological environments, in addition to its quick clearance from blood. The purpose of the present study was to achieve a new L-ASNase polymer bioconjugate to improve pharmacokinetic, increase half-life and stability of the enzyme. The conjugations were achieved by the cross-linking agent of 1-ethyl-3-(3- dimethylaminopropyl) carbodiimide (EDC) which activates the carboxylic acid groups of polymeric nanoparticles to create amide bond...
June 2018: IET Nanobiotechnology
Younong Yu, Li-Kang Zhang, Alexei V Buevich, Guoqing Li, Haiqun Tang, Petr Vachal, Steven L Colletti, Zhi-Cai Shi
Targeting tryptophan is a promising strategy to achieve high levels of selectivity for peptide or protein modification. A chemoselective peptide modification method via photocatalytic tryptophan β-position conjugation has been discovered. This transformation has good substrate scope for both peptide and Michael acceptor, and has good chemoselectivity versus other amino acid residues. The endogenous peptides, glucagon and GLP-1 amide, were both successfully conjugated at the tryptophan β-position. Insulin was studied as a non-tryptophan control molecule, resulting in exclusive B-chain C-terminal-selective decarboxylative conjugation...
May 15, 2018: Journal of the American Chemical Society
Parasmani Pageni, Peng Yang, Marpe Bam, Tianyu Zhu, Yung Pin Chen, Alan W Decho, Mitzi Nagarkatti, Chuanbing Tang
Over-prescription and improper use of antibiotics has led to the emergence of bacterial resistance, posing a major threat to public health. There has been significant interest in the development of alternative therapies and agents to combat antibiotic resistance. We report the preparation of recyclable magnetic iron oxide nanoparticles grafted with charged cobaltocenium-containing metallopolymers by surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization. β-Lactam antibiotics were then conjugated with metallopolymers to enhance their vitality against both Gram-positive and Gram-negative bacteria...
May 3, 2018: Biomaterials
Tilman Läppchen, Jason P Holland, Yvonne Kiefer, Mark D Bartholomä
Background: We recently developed a chelating platform based on the macrocycle 1,4,7-triazacyclononane with up to three, five-membered azaheterocyclic arms for the development of 68 Ga- and 64 Cu-based radiopharmaceuticals. Here, a 68 Ga-labelled conjugate comprising the bifunctional chelator NODIA-Me in combination with the αv ß3 -targeting peptide c(RGDfK) has been synthesized and characterized. The primary aim was to evaluate further the potential of our NODIA-Me chelating system for the development of 68 Ga-labelled radiotracers...
2018: EJNMMI radiopharmacy and chemistry
Baker Syed, M N Nagendra Prasad, K Mohan Kumar, S Satish
The present study emphasizes the need for novel antimicrobial agents to combat the global drug resistant crisis. The development of novel nanomaterials is reported to be of the alternative tool to combat drug resistant pathogens. In present investigation, bioconjugated nano-complex was developed from secondary metabolite secreted from endosymbiont. The endosymbiont capable of secreting antimicrobial metabolite was subjected to fermentation and the culture supernatant was assessed for purification of antimicrobial metabolite via bio-assay guided fraction techniques such as thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and column chromatography...
May 9, 2018: Science of the Total Environment
Kalline L Ribeiro, Isaac A M Frías, Octavio L Franco, Simoni C Dias, Ailton A Sousa-Junior, Osmar N Silva, Andris F Bakuzis, Maria D L Oliveira, Cesar A S Andrade
The use of central venous catheters (CVC) is highly associated with nosocomial blood infections and its use largely requires a systematic assessment of benefits and risks. Bacterial contamination of these tubes is frequent and may result in development of microbial consortia also known as biofilm. The woven nature of biofilm provides a practical defense against antimicrobial agents, facilitating bacterial dissemination through the patient's body and development of antimicrobial resistance. In this work, the authors describe the modification of CVC tubing by immobilizing Fe3 O4 -aminosilane core-shell nanoparticles functionalized with antimicrobial peptide clavanin A (clavA) as an antimicrobial prophylactic towards Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae...
April 27, 2018: Colloids and Surfaces. B, Biointerfaces
Johannes Winkler
Although recent clinical successes of antisense, splice-switching, and siRNA oligonucleotides have established the therapeutic utility of this novel class of medicines, the efficient systemic application for non-liver targets remains elusive. Exploitation of active receptor-mediated targeting followed by efficient and productive cellular uptake is required for enabling the therapy of extrahepatic diseases on the expressional level. Evasion of liver accumulation and organ-specific targeting and also efficient cytosolic delivery after endosomal internalization are currently insufficiently solved issues...
May 7, 2018: Nucleic Acid Therapeutics
Yuanzi Wu, Zhen Cai, Shuigen Wu, Wenli Xiong, Shanyun Ma
A recoverable and thermoresponsive polymer-protein bioconjugate is synthesized and employed in the purification of protein with free sulfhydryl groups. Initiator with disulphide was modified on the cysteine residue of the target protein. Poly(N-isopropylacrylamide) exhibiting a lower critical solution temperature was grown from the protein. The resulting protein-polymer conjugate was successfully thermoprecipitated and separated from other proteins. The approach was demonstrated with bovine serum albumin with the recycling yield of 76...
May 6, 2018: Biopolymers
María Jesús Cabrera-Afonso, Zhi-Peng Lu, Christopher B Kelly, Simon B Lang, Ryan Dykstra, Osvaldo Gutierrez, Gary A Molander
This report details the development and implementation of a strategy to construct aryl- and heteroaryl sulfones via Ni/photoredox dual catalysis. Using aryl sulfinate salts, the C-S bond can be forged at room temperature under base-free conditions. An array of aryl- and heteroaryl halides are compatible with this approach. The broad tolerance and mild nature of the described reaction could potentially be employed to prepare sulfones with biological relevance ( e.g. , in bioconjugation, drug substance synthesis, etc...
March 28, 2018: Chemical Science
Xinyu Liu, Jiawei Sun, Weiping Gao
Protein modification with polymers has led to intriguing and new types of bioconjugates. They combine the tunable physicochemical properties of the polymers with the specific biological activity of the proteins. These unique attributes of protein-polymer conjugates render them interesting and useful in biomedicine. However, the application potential of protein-polymer conjugates is limited by the mostly non-selective protein modification with polymers due to the lack of site-selective protein modification technology...
April 25, 2018: Biomaterials
Maria Matos, Carlos Labão-Almeida, Claire Sayers, Oyinlola Dada, Matthias Tacke, Gonçalo J L Bernardes
Selective targeting and accumulation of potent cytotoxic drugs to cancer cells minimize systemic toxicity and several side effects. NHC*-Au-Cl is already proven to be a potent anticancer agent. In this study, we explore a strategy based on chemoselective cysteine conjugation of NHC*-Au-Cl to albumin and trastuzumab (Thiomab LC-V205C) to potentiate drug-ligand ratio, pharmacokinetics, and drug efficacy and safety. This strategy is a step forward towards the use of gold-based anticancer agents as targeted therapies...
May 5, 2018: Chemistry: a European Journal
Lijia Yu, Duanwei Liang, Changmai Chen, XinJing Tang
RNA interference (RNAi) mediated gene silencing holds significant promise in gene therapy. It is very important to manually regulate the activity of small interference RNAs (siRNAs) in the controllable mode. Here, we designed and synthesized a series of caged siRNAs through bioconjugation of cyclo(Arg-Gly-Asp-DPhe-Lys) (cRGD) peptide to the 5' end of siRNA through a photolabile linker. These cRGD modified caged siRNAs allowed for precise light-regulation of gene expression of two exogenous reporter genes (firefly luciferase and green fluorescent protein, GFP) and an endogenous gene (the mitosis motor protein, Eg5) in the integrin αvβ3 positive cells...
May 4, 2018: Biomacromolecules
Liliane Massaad-Massade, Suzan Boutary, Marie Caillaud, Céline Gracia, Beatrice Parola, Soukaina Bel Gnaouiya, Barbara Stella, Silvia Arpicco, Eric Buchy, Didier Desmaêle, Patrick Couvreur, Giorgia Urbinati
The aim of the present study is to take advantage of the unique property of polyisoprenoid chains to adopt a compact molecular conformation and to use these natural and biocompatible lipids as nanocarriers of drugs to deliver siRNA. A new chemical strategy is here applied to conjugate squalene (SQ) and solanesol (SOLA) to siRNA consisting in an activated variant of the azide-alkyne Huisgen cycloaddition also known as copper-free (Cu-free) click chemistry. We conjugated siRNA against TMPRSS2-ERG, a fusion oncogene found in more than 50% of prostate cancers to SQ or SOLA...
May 4, 2018: Bioconjugate Chemistry
Nannan Liu, Huan Yi, Yanyu Lin, Hongli Zheng, Xiangqing Zheng, Danmei Lin, Hong Dai
A dual-responsive sandwich-type immunosensor is described for the detection of interleukin 6 (IL-6) by combining electrochemiluminescent (ECL) and electrochemical (EC) detection based on the use of two kinds of TiO2 mesocrystal nanoarchitectures. A composite was prepared from TiO2 (anatase) mesocages (AMCs) and a carboxy-terminated ionic liquid (CTIL) and then placed on a glassy carbon electrode (GCE). In the next step, the ECL probe Ru(bpy)3 (II) and antibody against IL-6 (Ab1 ) were immobilized on the GCE...
May 2, 2018: Mikrochimica Acta
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