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Bioconjugate Chemistry

Krishan Kumar, Arijit Ghosh
The clinical applications of PET imaging pharmaceuticals have increased tremendously over the last several years since the approval of 18F-FDG (18fluorine-fluorodeoxyglucose) by the Food and Drug Administration (FDA). Numerous 18F-labeled target-specific potential imaging pharmaceuticals, based on small and large molecules, have been evaluated in preclinical and clinical settings. 18F-labeling of organic moieties involves the introduction of the radioisotope by C-18F bond formation via a nucleophilic or an electrophilic substitution reaction...
February 21, 2018: Bioconjugate Chemistry
Indranath Chakraborty, Neus Feliu, Sathi Roy, Kenneth A Dawson, Wolfgang J Parak
Silver nanoparticles were grown in aqueous solution, without the presence of typical surfactant molecules, but under the presence of different proteins. The shape of the resulting silver nanoparticles could be tuned by the selection of the types of proteins. The amount of accessible lysine groups was found to be mainly responsible for the anisotropy in nanoparticle formation. Viability measurements of cells exposed to protein capped spherical or prism-shaped NPs did not reveal differences between both geometries...
February 20, 2018: Bioconjugate Chemistry
Marcelina Cardoso Dos Santos, Joan Goetz, Hortense Bartenlian, Ka-Leung Wong, Loïc Joanny Charbonniere, Niko Hildebrandt
Fluorescent nanoparticles (NPs) have become irreplaceable tools for advanced cellular and sub-cellular imaging. While very bright NPs require excitation with UV or visible light, which can create strong autofluorescence of biological components, NIR-excitable NPs without autofluorescence issues exhibit much lower brightness. Here, we show the application of a new type of surface-photosensitized terbium NPs (Tb-NPs) for autofluorescence-free intracellular imaging in live HeLa cells. Combination of exceptionally high brightness, high photostability, and long photoluminecence (PL) lifetimes for highly efficient suppression of the short-lived autofluorescence, allowed for time-gated PL imaging of intracellular vesicles over 72 h without toxicity and at extremely low Tb-NP concentrations down to 12 pM...
February 20, 2018: Bioconjugate Chemistry
Praful Nair, Cory Alvey, Xiaoling Jin, Jerome Irianto, Irena Ivanovska, Dennis E Discher
Drug resistance and relapse is common in cancer treatments with chemotherapeutics, and while drug combinations with naturally occurring, differentiation-inducing retinoic acid (RA) are highly successful against one type of liquid tumor, solid tumors present major problems for delivery. Here, inspired by filoviruses that can be microns in length, flexible filomicelles that self-assemble from an amphiphilic block copolymer (PEG-PCL) are shown to effectively deliver RA and paclitaxel (TAX) to several solid tumor models, particularly in liver...
February 16, 2018: Bioconjugate Chemistry
Eunseon Oh, Yuhong Liu, Mahesh V Sonar, Diane Merry, Eric Wickstrom
Huntington's disease (HD) is an autosomal-dominant neurodegenerative genetic disorder caused by CAG repeat expansion in exon 1 of the HTT gene. Expression of the mutant gene results in the production of a neurotoxic polyglutamine (polyQ)-expanded huntingtin (Htt) protein. Clinical trials of knockdown therapy of mutant polyglutamine-encoding HTT mRNA in Huntington's disease (HD) have begun. To measure HTT mRNA knockdown effectiveness in human cells, we utilized a fluorescent hybridization imaging agent specific to the region encompassing the human HTT mRNA initiation codon...
February 16, 2018: Bioconjugate Chemistry
Jian Yu, Da Shen, Hanjie Zhang, Zheng Yin
A site-specific modification of aldehyde-containing proteins using a tandem Knoevenagel-intra Michael addition reaction was developed. The reaction featured fast kinetics (50 M-1s-1) and favorable stoichiometry. Various functionalities could be introduced into the protein with little impact on its function and conformation. The reaction was successfully applied in the labeling of living cells.
February 15, 2018: Bioconjugate Chemistry
Loganathan Rangasamy, Venkatesh Chelvam, Ananda Kumar Kanduluru, Madduri Srinivasarao, Achini N Bandara, Fei You, Esteban Orellana, Andrea L Kasinski, Philip S Low
Although peptides, antibodies/antibody fragments, siRNAs, antisense DNAs, enzymes and aptamers are all under development as possible therapeutic agents, the breadth of their applications has been severely compromised by their inability to reach intracellular targets. Thus, while macromolecules can often enter cells by receptor-mediated endocytosis, their missions frequently fail due to an inability to escape their entrapping endosomes. In this paper, we describe a general method for promoting release of any biologic material from any entrapping endosome...
February 15, 2018: Bioconjugate Chemistry
Selma Eising, Nicole van der Linden, Fleur Kleinpenning, Kimberly M Bonger
Bioorthogonal chemistry can be used for the selective modification of biomolecules without interfering with any other functionality present in the cell. The tetrazine ligation is very suitable as bioorthogonal reaction because of its selectivity and high reaction rates with several alkenes and alkynes. Recently, we described vinylboronic acids (VBAs) as novel hydrophilic bioorthogonal moieties that react efficiently with dipyridyl-s-tetrazines and used them for protein modification in cell lysate. It is not clear, however, whether VBAs are suitable for labeling experiments in living cells because of the possible coordination with, for example, vicinal carbohydrate diols...
February 13, 2018: Bioconjugate Chemistry
Mads Østergaard, Niels Johan Christensen, Christian T Hjuler, Knud J Jensen, Mikkel B Thygesen
The reaction of unprotected carbohydrates with aminooxy reagents to provide oximes is a key method for the construction of glycoconjugates. Aniline and derivatives serve as organocatalysts for the formation of oximes from simple aldehydes, and we have previously reported that aniline also catalyzes the formation of oximes from the more complex aldehydes, carbohydrates. Here we present a comprehensive study of the effect of aniline analogs on formation of carbohydrate oximes and related glycoconjugates, depending on organocatalyst structure, pH, nucleophile, and carbohydrate, covering more than 150 different reaction conditions...
February 13, 2018: Bioconjugate Chemistry
Alexandra N Tsoras, Julie A Champion
Peptide subunit vaccines are desirable because they increase control over the immune response and safety of the vaccine by reducing the risk of off-target responses to molecules other than the target antigen. The immunogenicity of most peptides, however, is low. Peptide nanoclusters (PNC) are proposed as a subunit peptide vaccine delivery system made completely of cross-linked peptide antigen that could improve the immunogenicity of a peptide vaccine. Proof of concept is demonstrated with oncofetal antigen (OFA), an immature laminin receptor protein expressed by many hematologic cancer cells but not by healthy cells...
February 13, 2018: Bioconjugate Chemistry
Fernando Albericio, Ivan Tomillero, Gema Perez-Chacon, Beatriz Somovilla-Crespo, Francisco Sanchez-Madrid, Juan M Dominguez, Carmen Cuevas, Juan M Zapata, Hortensia Rodriguez
The design and generation of complex multifunctional macromolecular structures by bioconjugation is a hot topic due to increasing interest conjugates with therapeutic applications. In this regard, the development of efficient, selective, and safe conjugation methods is a major objective. In this report, we describe the use of the bis(bromomethyl)benzene scaffold as a linker for bioconjugation with special emphasis in antibody conjugation. We first performed the monothioalkylation of 1,3,5-tris(bromomethyl)benzene, which rendered the reactive dibromotrimethylbenzyl derivatives to be used in thiol bis-alkylation...
February 13, 2018: Bioconjugate Chemistry
Subhadip Maiti, Puja Saha, Tania Das, Irene Bessi, Harald Schwalbe, Jyotirmayee Dash
Small molecules that stabilize G-quadruplex structures in telomeres can prevent telomere lengthening by telomerase and subsequently lead to cell death. We herein report two fluoro-isoquinoline derivatives IQ1 and IQ2 as selective ligands for human telomeric G-quadruplex DNA. IQ1 and IQ2 containing different triazolyl side chains have been synthesized by Cu (I) catalyzed azide-alkyne cycloaddition. Fluorescence Resonance Energy Transfer (FRET) melting assay and fluorescence binding titrations indicate that both these ligands exhibit binding preference for telomeric G-quadruplex DNA (h-TELO) over other promoter DNA quadruplexes and duplex DNA...
February 13, 2018: Bioconjugate Chemistry
Michel Paquette, Simon Beaudoin, Mylene-Annie Tremblay, Steve Jean, Angel F Lopez, Roger Lecomte, Brigitte Guérin, M'hamed Bentourkia, Robert Sabbagh, Jeffrey V Leyton
Receptor-mediated internalization followed by trafficking and degradation of antibody-conjugates (ACs) via the endosomal-lysosomal pathway is the major mechanism for delivering molecular payloads inside target tumor cells. Although, a mainstay for delivering payloads with clinically approved ACs in cancer treatment and imaging, tumor cells are often able to decrease intracellular payload concentrations and thereby reduce the effectiveness of the desired application. Thus, increasing payload intracellular accumulation has become a focus of attention for designing next-generation ACs...
February 13, 2018: Bioconjugate Chemistry
Quang Huy Quach, Roxanne Li Xian Kong, James Chen Yong Kah
Gold nanoparticles (AuNPs) are widely used in biomedical applications, but much less is known about their immunological properties, particularly their interaction with the complement system, a key component of innate immunity serving as an indicator of their biocompatibility. Using a library of different-sized AuNPs (10, 20, 40, and 80 nm) passivated with polyethylene glycol (PEG) of different molecular weight (Mw = 1, 2, 5, and 10 kDa), we demonstrated that citrate-capped AuNPs activated the whole complement system in size-dependent manner, characterized by the formation of the end-point activation product, SC5b-9, in human serum...
February 12, 2018: Bioconjugate Chemistry
Gergely Knorr, Eszter Kozma, Judith Schaart, Krisztina Németh, György Török, Peter Kele
The synthesis, fluorogenic characterization and labeling application of four tetrazine-quenched cyanine probes with emission maxima in the red - far red range is reported. Fluorescence of the cyanine-cores is quenched via through-bond-energy-transfer (TBET) exerted by a bioorthogonal tetrazine unit. Upon bioorthogonal labeling reaction with cyclooctyne tagged proteins, the quenching effect ceases, thus the fluorescence reinstates, resulting in an increase in fluorescence intensity. As a rare example amongst indocyanines, one of our new probes was found suitable in STED-based super-resolution imaging...
February 12, 2018: Bioconjugate Chemistry
Makan Khoshnejad, Colin Fred Greineder, Katherine W Pulsipher, Carlos H Villa, Burcin Altun, Daniel C Pan, Andrew Tsourkas, Ivan J Dmochowski, Vladimir Muzykantov
Genetic incorporation of biologically orthogonal functional groups into macromolecules has the potential to yield efficient, controlled, reproducible, site-specific conjugation of affinity ligands, contrast agents, or therapeutic cargoes. Here, we applied this approach to ferritin, a ubiquitous iron-storage protein that self-assembles into multimeric nanocages with remarkable stability, size uniformity (12 nm), and endogenous capacity for loading and transport of a variety of inorganic and organic cargoes. The unnatural amino acid, 4-azidophenylalanine (4-AzF), was incorporated at different sites in the human ferritin light chain (hFTL) to allow site-specific conjugation of alkyne-containing small molecules or affinity ligands to the exterior surface of the nanocage...
February 10, 2018: Bioconjugate Chemistry
Yifei Guo, Shuang Zhao, Hanhong Qiu, Ting Wang, Yanna Zhao, Meihua Han, Zhengqi Dong, Xiangtao Wang
It was reported that the shape of nanocarriers played an important role in achieving better therapeutic effect. To optimize the morphology and enhance the antitumor efficacy, in this study based on the amphiphilic PAMAM-b-OEG codendrimer (POD), docetaxel-loaded spherical and flake-like nanoparticles (DTX nanospheres and nanosheets) were prepared via antisolvent precipitation method with the similar particle size, surface charge, stability, and release profiles. The feed weight ratio of DTX/POD and the branched structure of OEG dendron were suggested to influence on the shapes of the self-assembled nanostructures...
February 9, 2018: Bioconjugate Chemistry
Rachana Ohri, Sunil Bhakta, Aimee Fourie-O'Donohue, Josefa Dela Cruz-Chuh, Siao Ping Tsai, Ryan Cook, Binqing Wei, Carl Ng, Athena W Wong, Aaron B Bos, Farzam Farahi, Jiten Bhakta, Thomas H Pillow, Helga Raab, Richard Vandlen, Paul Polakis, Yichin Liu, Hans Erickson, Jagath R Junutula, Katherine R Kozak
THIOMAB antibody technology utilizes cysteine residues engineered onto an antibody to allow for site-specific conjugation. The technology has enabled the exploration of different attachment sites on the antibody in combination with small molecules, peptides, or proteins to yield antibody conjugates with unique properties. As reported previously ( Shen , B. Q. , et al. ( 2012 ) Nat. Biotechnol. 30 , 184 - 189 ; Pillow , T. H. , et al. ( 2017 ) Chem. Sci. 8 , 366 - 370 ), the specific location of the site of conjugation on an antibody can impact the stability of the linkage to the engineered cysteine for both thio-succinimide and disulfide bonds...
February 9, 2018: Bioconjugate Chemistry
Diana Gulei, Alexandra Iulia Irimie, Roxana Cojocneanu-Petric, Joachim L Schultze, Ioana Berindan-Neagoe
Incipiently named extracellular vesicles, exosomes are forming now a separate class of cellular mediators with important functions in physiological and pathological states. Their ability to transfer information between cells through encapsulation of proteins, nucleic acids and lipids for the preservation of the homeostatic equilibrium is translated also in pathological conditions. The recipient cells react to the reception of foreign molecules adjusting their molecular state according to the enclosed message...
February 9, 2018: Bioconjugate Chemistry
Mengyuan Wang, Yunchao Xiao, Lizhou Lin, Xiaoyue Zhu, Lianfang Du, Xiangyang Shi
Detection of circulating tumor cells (CTCs) in peripheral blood is of paramount significance for early-stage cancer diagnosis, estimation of cancer development, and individualized cancer therapy. Herein, we report the development of hyaluronic acid (HA)-functionalized electrospun chitosan nanofiber (CNF)-integrated microfludic platform for highly specific capture and nondestructive release of CTCs. First, electrospun CNFs were formed and modified with zwitterion of carboxyl betaine acrylamide (CBAA) via Michael addition reaction and then targeted ligand HA through a disulfide bond...
February 7, 2018: Bioconjugate Chemistry
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