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Bioconjugate Chemistry

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 nonfouling. The use of highly efficient oxime chemistry allows the 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 22, 2017: Bioconjugate Chemistry
Sergey Deyev, Galina Proshkina, Anastasiya Ryabova, Francesco Tavanti, Maria Cristina Menziani, Gennady Eidelshtein, Gavriel Avishai, Alexander Kotlyar
We demonstrate that the designed ankyrin repeat protein (DARPin)_9-29, which specifically targets human epidermal growth factor receptor 2 (HER 2), binds tightly to gold nanoparticles (GNPs). Binding of the protein strongly increases the colloidal stability of the particles. The results of experimental analysis and molecular dynamics simulations show that approximately 35 DARPin_9-29 molecules are bound to the surface of a 5 nm GNP and that the binding does not involve the receptor-binding domain of the protein...
August 22, 2017: Bioconjugate Chemistry
Fangxia Guo, Yong Dong Liu, Chun Zhang, Qi Wang, Lianyan Wang, Yuhui Gao, Jingxiu Bi, Heng Wang, Zhiguo Su
As one of the pathogen-associated molecular patterns (PAMPs), flagellin is recently utilized as a potent adjuvant for many subunit vaccines. In this study, a truncated flagellin (tFL) with deletion of the hypervariable regions was adopted as a carrier-adjuvant by chemical conjugation with a chimeric malaria antigen M.RCAg-1 (M312) via a hetero-bifunctional PEG linker. After boosting immunization in mice without any extra adjuvants, the M312-PEG-tFL conjugates elicited 100-1,000 times higher M312-specific antibody titers than M312, and 10-100 times higher than the physical mixture of M312 and tFL...
August 10, 2017: Bioconjugate Chemistry
Zhuo Chen, Stefanie D Boyd, Jenifer S Calvo, Kyle W Murray, Galo L Mejia, Candace E Benjamin, Raymond P Welch, Duane D Winkler, Gabriele Meloni, Sheena D'Arcy, Jeremiah J Gassensmith
Proteinaceous nanomaterials and, in particular, virus-like particles (VLPs) have emerged as robust and uniform platforms that are seeing wider use in biomedical research. However, there are a limited number of bioconjugation reactions for functionalizing the capsids, and very few of those involve functionalization across the supramolecular quaternary structure of protein assemblies. In this work, we exploit the recently described dibromomaleimide moiety as part of a bioconjugation strategy on VLP Qβ to break and rebridge the exposed and structurally important disulfides in good yields...
August 22, 2017: Bioconjugate Chemistry
Amani A Hariri, Graham D Hamblin, Jack S Hardwick, Robert Godin, Jean-Francois Desjardins, Paul W Wiseman, Hanadi F Sleiman, Gonzalo Cosa
A wide variety of approaches have become available for the fabrication of nanomaterials with increasing degrees of complexity, precision, and speed while minimizing cost. Their quantitative characterization, however, remains a challenge. Analytical methods to better inspect and validate the structure and composition of large nanoscale objects are required to optimize their applications in diverse technologies. Here, we describe single-molecule fluorescence-based strategies relying on photobleaching and multiple-color co-localization features toward the characterization of supramolecular structures...
August 22, 2017: Bioconjugate Chemistry
Jared Spidel, Benjamin Vaessen, Earl Albone, Xin Cheng, Arielle Verdi, J Bradford Kline
The use of microbial transglutaminase (MTG) to produce site-specific antibody-drug conjugates (ADCs) has thus far focused on transamidation of engineered acyl donor glutamine residues in an antibody based on the hypothesis that the lower specificity of MTG for acyl acceptor lysines may result in transamidation of multiple native lysine residues, thereby yielding heterogeneous products. We investigated the utilization of native IgG lysines as acyl acceptor sites for glutamine-based acyl donor substrates. Of the approximately 80 lysines in multiple recombinant IgG monoclonal antibodies (mAbs), none were transamidated...
August 18, 2017: Bioconjugate Chemistry
Martin Schmidt, Livia K Bast, Franziska Lanfer, Lena Richter, Elisabeth Hennes, Rana Seymen, Christian Krumm, Joerg C Tiller
Conjugation of antibiotics with polymers is rarely done, but might be a promising alternative to low molecular weight derivatization. The two penicillins PenG and PenV were attached to the end groups of different water-soluble poly(2-oxazoline)s (POx) via their carboxylic acid function. This ester group was shown to be more stable against hydrolysis than the β-lactam ring of the penicillins. The conjugates are still antimicrobially active and up to 20 times more stable against penicillinase catalyzed hydrolysis...
August 17, 2017: Bioconjugate Chemistry
Wensi Zhang, Dongmei Lin, Haixia Wang, Jingfeng Li, Gerd Ulrich Nienhaus, Zhiqiang Su, Gang Wei, Li Shang
Metal nanoclusters (NCs) hold great potential as novel luminescent nanomaterials in many applications, while the synthesis of highly luminescent metal NCs still remains challenging. In this work, we report self-assembling peptides as a novel bioinspired scaffold capable of significantly enhancing the luminescence efficiency of gold nanoclusters (AuNCs). The resulting AuNCs capped with motif-designed peptides can self-assemble to form nanofiber structures, in which the luminescence of AuNCs is enhanced nearly 70-fold, with 21...
August 16, 2017: Bioconjugate Chemistry
Li Lin, Xiaolong Liang, Yunxue Xu, Yongbo Yang, Xiaoda Li, Zhifei Dai
Hybrid bicelles have been demonstrated to have great potential for hydrophobic drug delivery. Herein, we report a near-infrared light-driven, temperature-sensitive hybrid bicelles co-encapsulating hydrophobic doxorubicin (DOX) and indocyanine green (ICG) (DOX/ICG@HBs). Encapsulation of ICG into the lipid bilayer membrane of DOX/ICG@HBs results in higher photostability than free ICG. DOX/ICG@HBs exhibited temperature-regulated drug release behavior and significant photothermal cytotoxicity. After tail vein injection, such discotic nanoparticles of DOX/ICG@HBs were found to accumulate selectively at the tumor site and act as an efficient probe to enhance fluorescence imaging greatly...
August 15, 2017: Bioconjugate Chemistry
Yifat Elharar, Ananda R Podilapu, Ziqiang Guan, Suvarn S Kulkarni, Jerry Eichler
N-glycosylation, the covalent attachment of glycans to select protein target Asn residues, is a post-translational modification performed by all three domains of life. In the halophilic archaea Haloferax volcanii, where understanding of this universal protein-processing event is relatively well-advanced, genes encoding the components of the Agl (archaeal glycosylation) pathway responsible for the assembly and attachment of an N-linked pentasaccharide have been identified. As elsewhere, the N-linked glycan is assembled on phosphodolichol carriers before transfer to target Asn residues...
August 15, 2017: Bioconjugate Chemistry
Emmi Pohjolainen, Sami Malola, Gerrit Groenhof, Hannu Häkkinen
Bio-compatible gold nanoclusters can be utilized as contrast agents in virus imaging. The labeling of viruses can be achieved non-covalently but site-specifically by linking the cluster to the hydrophobic pocket of a virus via a lipid-like pocket factor. We have estimated the binding affinities of three different pocket factors of echovirus 1 (EV1) in molecular dynamics simulations combined with non-equilibrium free energy calculations. We have also studied the effects on binding affinities with a pocket factor linked to the Au102pMBA44 nanocluster in different protonation states...
August 14, 2017: Bioconjugate Chemistry
Su Jeong Song, Seulgi Lee, Kyoung-Seok Ryu, Joon Sig Choi
Peptide nanostructure has been widely explored for drug-delivery systems in recent studies. Peptides possess comparatively lower cytotoxicity and are more efficient than polymeric carriers. Here, we propose a peptide nanorod system, composed of an amphiphilic oligo-peptide RH3F8 (Arg-His3-Phe8), as a drug-delivery carrier. Arginine is an essential amino acid in typical cell-penetration peptides, and histidine induces endo- and lysosomal escape because of its proton sponge effect. Phenylalanine is introduced to provide rich hydrophobicity for stable self-assembly and drug encapsulation...
August 11, 2017: Bioconjugate Chemistry
Haruthai Pansuwan, Boonsong Ditmangklo, Chotima Vilaivan, Banphot Jiangchareon, Porntip Pan-In, Supason Wanichwecharungruang, Tanapat Palaga, Thanesuan Nuanyai, Chaturong Suparpprom, Tirayut Vilaivan
Peptide nucleic acid (PNA) is a nucleic acid mimic in which the deoxyribose-phosphate was replaced by a peptide-like backbone. The absence of negative charge in the PNA backbone leads to several unique behaviors including a stronger binding and salt independency of the PNA-DNA duplex stability. However, PNA possesses poor aqueous solubility and cannot directly penetrate cell membranes. These are major obstacles that limit in vivo applications of PNA. In previous strategies, the PNA can be conjugated to macromolecular carriers or modified with positively charged side chains such as guanidinium groups to improve the aqueous solubility and cell permeability...
August 11, 2017: Bioconjugate Chemistry
Chloe Kim, Peter C Searson
To overcome the limitations associated with antibody-based sensors, we describe a proof-of-concept of an aptamer-based sandwich assay for detection of lactate dehydrogenase, an antigen associated with malaria. We show a detection limit of Plasmodium falciparum lactate dehydrogenase and Plasmodium vivax lactate dehydrogenase of 0.5 fmole in buffer, comparable to an antibody-based assay, using a magnetic particle - aptamer construct for capture, and a quantum dot - aptamer construct for detection. We then demonstrate a detection limit of 10 amole (50-fold amplification) using oligonucleotide-functionalized gold nanoparticles to allow conjugation of multiple quantum dots for each target antigen...
August 10, 2017: Bioconjugate Chemistry
Anne C Conibear, Sonja Hager, Josef Mayr, Matthias H M Klose, Bernhard K Keppler, Christian R Kowol, Petra Heffeter, Christian F W Becker
Increasing the specificity of cancer therapy, and thereby decreasing damage to normal cells, requires targeting to cancer-cell specific features. The αvβ6 integrin is a receptor involved in cell adhesion and is frequently up-regulated in cancer cells compared to normal cells. We have selected a peptide ligand reported to bind specifically to the β6 integrin and have synthesized a suite of multispecific molecules to explore the potential for targeting of cancer cells. A combination of solid-phase peptide synthesis and chemoselective ligations was used to synthesize multifunctional molecules composed of integrin-targeting peptides, cytotoxic platinum(IV) prodrugs, and fluorescent or affinity probes joined with flexible linkers...
August 10, 2017: Bioconjugate Chemistry
Bingbing Shi, Yuqing Deng, Peng Zhao, Xiaoyu Li
DNA-encoded chemical libraries (DELs) have recently emerged and become an important technology platform in biomedical research and drug discovery. DELs containing large numbers of compounds can be prepared and selected against biological targets to discover novel ligands and inhibitors. In practice, DELs are usually selected against purified and immobilized proteins using the typical "bind-wash-elute" protocol; however, selection methods compatible with non-immobilized proteins would be able to greatly expand the target scope of DELs beyond purified proteins to more-complex and biologically relevant targets...
August 10, 2017: Bioconjugate Chemistry
Ann-Christin Baranski, Martin Schaefer, Ulrike Bauder-Wüst, Anja Wacker, Jana Schmidt, Christos C Liolios, Walter Mier, Uwe Haberkorn, Michael Eisenhut, Klaus Kopka, Matthias Eder
(68)Ga-Glu-urea-Lys-(Ahx)-HBED-CC ((68)Ga-PSMA-11) represents a successful radiopharmaceutical for PET/CT imaging of prostate cancer. Further optimization of the tumor-to-background contrast might significantly enhance the sensitivity of PET/CT imaging and the probability of detecting recurrent prostate cancer at low PSA-values. This study describes the advantage of histidine (H)/glutamic acid (E) and tryptophan (W)/glutamic acid (E) containing linkers on the pharmacokinetic properties of (68)Ga-PSMA-11. The tracers were obtained by a combination of standard Fmoc-based solid phase synthesis and copper(I)-catalyzed azide-alkyne cycloaddition...
August 8, 2017: Bioconjugate Chemistry
Dian-Jang Lee, Eva Kessel, Taavi Lehto, Xueying Liu, Naoto Yoshinaga, Kärt Padari, Ying-Chen Chen, Susanne Kempter, Satoshi Uchida, Joachim O Rädler, Margus Pooga, Ming-Thau Sheu, Kazunori Kataoka, Ernst Wagner
Protection of small interfering RNA (siRNA) against degradation and targeted delivery across the plasma and endosomal membranes to the final site of RNA interference are major aims for the development of siRNA therapeutics. Targeting for folate receptor (FR)-expressing tumors, we optimized siRNA polyplexes by co-formulating a folate-PEG-oligoaminoamide (for surface shielding and targeting) with one of three lipo-oligoaminoamides (optionally tyrosine-modified, for optimizing stability and size) to generate ~ 100 nm targeted lipopolyplexes (TLPs), which self-stabilize by cysteine disulfide crosslinks...
August 3, 2017: Bioconjugate Chemistry
Handan Acar, Ravand Samaeekia, Matthew R Schnorenberg, Dibyendu K Sasmal, Jun Huang, Matthew V Tirrell, James L LaBelle
Peptides synthesized in the likeness of their native interaction domain(s) are natural choices to target protein-protein interactions (PPIs) due to their fidelity of orthostatic contact points between binding partners. Despite therapeutic promise, intracellular delivery of biofunctional peptides at concentrations necessary for efficacy remains a formidable challenge. Peptide Amphiphiles (PAs) provide a facile method of intracellular delivery and stabilization of bioactive peptides. PAs consisting of biofunctional peptide headgroups linked to hydrophobic alkyl lipid-like tails prevent peptide hydrolysis and proteolysis in circulation and PA monomers are internalized via endocytosis...
August 3, 2017: Bioconjugate Chemistry
Damien Duret, Adrien Grassin, Maxime Henry, Thibault Jacquet, Fabien Thoreau, Sandrine Denis-Quanquin, Jean-Luc Coll, Didier Boturyn, Arnaud Favier, Marie-Thérèse Charreyre
A new class of "polymultivalent" ligands combining several ligand-clusters and a water-soluble biocompatible polymer is introduced. These original conjugates bear two levels of multivalency. They are prepared by covalent coupling of a controlled number of tetrameric cRGD peptide-clusters along a well-defined copolymer synthesized by RAFT polymerization. The presence of multiple copies of peptide-clusters on the same polymer backbone resulted in a much higher relative potency than the free cluster reference...
August 2, 2017: Bioconjugate Chemistry
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