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Bioconjugate Chemistry | Page 2

Myagmarsuren Sengee, J Johannes Eksteen, Silje Lillemark Nergård, Terje Vasskog, Leiv K Sydnes
A series of self-immolative linkers containing a thiol-reactive group at one end and a hydroxyl- or amine-reactive group at the other have been prepared. The utility of these reagents for preparations of bioconjugates has been explored by reacting the linkers with appropriately functionalized model drugs and peptides. Degradation studies of a series of conjugates with different linkers reveal that the structure of the linkers has a significant impact on their stability.
April 29, 2019: Bioconjugate Chemistry
Xiaofen Ma, Mengzhe Wang, Hui Wang, Tao Zhang, Zhanhong Wu, Mariia Sutton, Vladimir V Popik, Guihua Jiang, Zi-Bo Li
Prostate cancer is a heterogeneous disease with poor survival rate at late stage. In this report, a dual targeting PET agent was developed to partially address tumor heterogeneity issue. The heterodimer F-BCN-PSMA-NT was designed to target PSMA and neurotensin receptor1 (NTR1), both of which have demonstrated the great potential in prostate cancer management. The heterodimer was synthesized through the conjugation of Glu-urea-lys(Ahx) (PSMA targeting motif) and NT20.3 (NTR1 targeting motif) to a symmetric trifunctional linker, bearing an azide group for further modification...
April 29, 2019: Bioconjugate Chemistry
Tak Ian Chio, Han Gu, Kamalika Mukherjee, Nathan Tumey, Susan L Bane
Precise control of covalent bond formation in the presence of multiple functional groups is pertinent in the development of many next-generation bioconjugates and materials. Strategies derived from bioorthogonal chemistries are contributing greatly in that regard; however, the gain of chemoselectivity is often compromised by the slow rates of many of these existing chemistries. Recent work on a variation of the classical aldehyde/ketone condensation based on ortho-carbonylphenylboronic acids has uncovered markedly accelerated rates compared to the simple carbonyl counterparts...
April 26, 2019: Bioconjugate Chemistry
Xiangdong Xue, Aaron Lindstrom, Yuanpei Li
As unique molecules with both therapeutic and diagnostic properties, porphyrin derivatives have been extensively employed for cancer treatment. Porphyrins not only show powerful phototherapeutic effects (photodynamic and photothermal therapies), but also exhibit excellent imaging capacities, such as near-infrared fluorescent imaging (NIRFI), magnetic resonance imaging (MRI), photoacoustic imaging (PAI), positron emission tomography (PET), and single-photon emission computed tomography (SPECT), etc. Taking advantage of their robust phototherapeutic effects and excellent imaging capacities, porphyrins can be used to create nanomedicines with effective therapeutic and precise diagnostic properties for cancer treatment...
April 26, 2019: Bioconjugate Chemistry
Yakov A Lomakin, Alena N Kaminskaya, Alexey V Stepanov, Anna A Shmidt, Alexander Gabibov, Alexey A Belogurov
Specific recognition of ligands by surface receptors of eukaryotic cells is a fundamental process in sensing of the exogenous environment, including cell-to-cell communication. These interactions are therefore widely probed in both basic studies and drug development to enhance or interrupt them. Here, we designed a high-throughput publicly available platform for visualization and selection of eukaryotic cells according to the specificity of surface-exposed receptors by consolidation of phage display and flow cytometry techniques...
April 25, 2019: Bioconjugate Chemistry
Heesung Jung, Hyo-Eun Jang, Yoon Young Kang, Jihyun Song, Hyejung Mok
Microspheres (MS; 1-3 μm) with different degree of surface roughness were prepared to assess the effects of surface topology on internalization into antigen-presenting cells (APCs; macrophages and dendritic cells). In this study, we demonstrated that the intracellular uptake of MS is readily enhanced by surface modification with nanoparticles or cancer cell-derived vesicles (VE) to modulate their surface topology. MS coated with nano-vesicles (MS-VE) with high surface roughness was more successfully and efficiently engulfed by APCs, compared with bare MS and those with low surface roughness...
April 25, 2019: Bioconjugate Chemistry
Debiprasad Roy, Chandrani Fouzder, Alpana Mukhuty, Sumana Pal, Maloy Kr Mondal, Rakesh Kundu, Pranesh Chowdhury
The innocent silicon quantum dots (SQDs) having dual emissive property (blue in VIS and red in NIR), high photo stability and free from auto fluorescence are designed and synthesized for the first time using ethylene glycol. A new attempt has been made for direct labeling of Alpha 2-HS-Glycoprotein (Fetuin A) through functionalizing of the synthesized dots by EDC coupling. The SQDs were characterized by FTIR, TEM, AFM, XRD, EDX, DLS and TGA. The chemistry involves in the synthesis and functionalization of dots is elucidated in details...
April 22, 2019: Bioconjugate Chemistry
Lily Li, María de Guadalupe Jaraquemada-Peláez, Hsiou-Ting Kuo, Helen Merkens, Neha Choudhary, Katrin Gitschalter, Una Jermilova, Nadine Colpo, Carlos Uribe-Munoz, Valery Radchenko, Paul Schaffer, Kuo-Shyan Lin, Francois Benard, Chris Orvig
Here, we present the synthesis and characterization of a new potentially nonadentate chelator, H4pypa and its bifunctional analog tBu4pypa-C7-NHS conjugated to PSMA (prostate-specific membrane antigen) - targeting peptidomimetic (Glu-urea-Lys). H4pypa is very functionally versatile and biologically stable. Compared to the conventional chelators (e.g. DOTA, DTPA), H4pypa has outstanding affinities for both 111In (EC, t1/2 ~2.8 d) and 177Lu (-, t1/2~6.64 d). Its radiolabeled complexes were achieved at >98% radiochemical yield, RT within 10 minutes, at ligand concentration as low as 10-6 M, with excellent stability in human serum over at least 5-7 days (<1% transchelation)...
April 22, 2019: Bioconjugate Chemistry
Rebecca Gilson, Rui Tang, Krishna Gautam, Dorota Grabowska, Samuel Achilefu
Photodynamic therapy (PDT) is often used in preclinical and clinical treatment regimens. Reactive oxygen species (ROS) generated by photosensitizers (PSs) upon exposure to light induce cell death via diverse mechanisms. PSs can exert therapeutic effects in different cellular organelles, although the efficacy of organelle-specific PDT has yet to be determined as most previous studies use different PSs in different organelles. Here, we explored how a single PS, chlo-rin e6 (Ce6), targeted to different organelles altered the effectiveness of PDT...
April 22, 2019: Bioconjugate Chemistry
Emily B Ehlerding, Hye Jin Lee, Todd E Barnhart, Dawei Jiang, Lei Kang, Douglas G McNeel, Jonathan W Engle, Weibo Cai
Immune checkpoint expression is highly dynamic, and combination treatments including radiotherapy can particularly modulate this expression. PET imaging using 89 Zr-Df-atezolizumab can provide insight into the levels of PD-L1 variation following radiotherapy treatments. In vitro screening was used to monitor PD-L1 expression by lung cancer cells following radiotherapy. Mice bearing PD-L1+ (H460) or PD-L1- (A549) tumors were subjected to various external beam radiotherapy regimens and then imaged using 89 Zr-Df-atezolizumab PET...
April 19, 2019: Bioconjugate Chemistry
Hallie M Hintz, Aidan E Cowan, Mariya Shapovalova, Aaron M LeBeau
Here, we document the discovery of a monoclonal antibody that selectively binds to both human and murine fibroblast activation protein alpha (FAP), a serine protease that is overexpressed on cancer-associated fibroblasts (CAFs), making it an attractive therapeutic target for the aiding and abetting tumor microenvironment. The lead antibody, B12, was identified from a naïve murine single-chain variable fragment antibody phage display library screened against recombinant human FAP on magnetic beads. The heavy and light chains of B12 were cloned into full-length human immunoglobulin 1 (IgG) vectors and expressed as a chimeric monoclonal antibody (B12 IgG)...
April 18, 2019: Bioconjugate Chemistry
Shani Leviatan Ben-Arye, Christoph Schneider, Hai Yu, Salam Bashir, Xi Chen, Stephan von Gunten, Vered Padler-Karavani
Sialic acids (Sias) cover vertebrate cell surface glycans. N-acetylneuraminic acid (Neu5Ac) and its hydroxylated form N-glycolylneuraminic acid (Neu5Gc) are common Sia in mammals. Humans cannot synthesize Neu5Gc, but accumulate it on cells through red-meat rich diets, generating numerous immunogenic Neu5Gc-neoantigens. Consequently, humans have diverse anti-Neu5Gc antibodies affecting xenotransplantation, cancer, atherosclerosis and infertility. Anti-Neu5Gc antibodies circulate as IgG, IgM and IgA isotypes, however repertoires of the different isotypes in a large population had not been studied yet...
April 17, 2019: Bioconjugate Chemistry
Koushi Hidaka, Motoyasu Adachi, Yuko Tsuda
Protease inhibitors are used as both research tools and therapeutics. Many of these inhibitors consist of substrate amino acid sequence-derived structure with a transition state mimic to interact with the active site of the protease, suppressing enzymatic activity. However, once they bind, macrodilution or protein denaturation are required to remove them, limiting their usage. In this study, we describe a removable protease inhibitor, which is a directly biotinylated analogue to control the activities of HIV-1 protease and human cathepsin D...
April 16, 2019: Bioconjugate Chemistry
Changmai Chen, Zhongyu Wang, Jinhao Zhang, Xinli Fan, Luzheng Xu, XinJing Tang
RNA interference (RNAi)-based gene therapy is a precision therapeutic approach for highly efficient sequence-specific gene silencing in vivo or in vitro. Caged RNAs featuring dextran conjugation of antisense and sense RNA strands using photolabile linker were rationally designed and self-assembled to form caged siRNA nanoparticles (Dex-p-siRNA) for photoregulation of target gene expression. The dextran-conjugated caged siRNA nanoparticles showed significant se-rum nuclease-resistance due to the formation of dextran-siRNA nanoparticles...
April 16, 2019: Bioconjugate Chemistry
Jasmin Federizon, Yi-Pin Lin, Jonathan F Lovell
Increasing rates of Lyme disease necessitate preventive measures such as immunization to mitigate the risk of contracting the disease. At present, there is no human Lyme disease vaccine available on the market, although there was in the past. Since the withdrawal of the first and only licensed Lyme disease vaccine based on lipidated recombinant OspA, vaccine and antigen research has aimed to overcome its risks and shortcomings. Replacement of the putative cross-reactive T-cell epitope in OspA via mutation or chimerism addresses the potential risk of autoimmunity...
April 16, 2019: Bioconjugate Chemistry
Xiang Li, Zheng Ma, Haoran Wang, Li Ren, Dianwen Zhang, Weiguo Liang, Guangji Zhang, Jinrui Zhang, Dahai Yu, Xuexun Fang
Membrane type-1 matrix metalloproteinase (MT1-MMP) plays a crucial role in many physiological and pathological processes, especially in tumor invasion and metastasis. Bioimaging of this key molecule may find wide usage in various applications. MT-loop is a unique sequence of MT1-MMP and locates in the surface of the protein. In our previous studies, AF7p, an affinity peptide that targeting the MT-loop domain of MT1-MMP was identified by screening a phage display (Ph.D.) peptide library. However, the target of AF7p is a synthetic sequence which lacked native conformation of MT-loop region, thus the binding affinity and specificity in reality may not be optimal...
April 15, 2019: Bioconjugate Chemistry
Ying Xiong, Xiaodong Tian, Hui-Wang Ai
Reactive oxygen species (ROS) not only are by-products of aerobic respiration, but also play vital roles in metabolism regulation and signal transductions. It is important to understand the functions of ROS in biological systems. In addition, scientists have made use of ROS to kill bacteria and tumors through a process known as photodynamic therapy (PDT). This paper provides a concise review of current molecular tools that can generate ROS in biological systems via either non-genetic or genetically-encoded way...
April 15, 2019: Bioconjugate Chemistry
Sarthak Mandal, Xu Zhou, Su Lin, Hao Yan, Neal W Woodbury
Strongly coupled molecular dye aggregates have unique optoelectronic properties that often resemble those of light harvesting complexes found in nature. The exciton dynamics in coupled dye aggregates could enhance the long-range transfer of optical excitation energy with high efficiency. In principle, dye aggregates could serve as important components in molecular-scale photonic devices, however, rational design of these coupled dye aggregates with precise control over their organization, interactions and dynamics remains a challenge...
April 15, 2019: Bioconjugate Chemistry
Tewoderos Ayele, Steve D Knutson, Satheesh Ellipilli, Hyun Hwang, Jennifer M Heemstra
Genetically encoded fluorescent proteins or small-molecule probes that recognize specific protein binding partners can be used to label proteins to study their localization and function with fluorescence microscopy. However, these approaches are limited in signal-to-background resolution and the ability to temporally control labeling. Herein, we describe a covalent protein labeling technique using a fluorogenic malachite green probe functionalized with a photoreactive crosslinker. This enables a controlled covalent attachment to a genetically encodable fluorogen activating protein (FAP) with low background signal...
April 12, 2019: Bioconjugate Chemistry
Adam Shuhendler, Lina Cui, Zixin Chen, Bin Shen, Michelle L James, Timothy Witney, Sanjiv S Gambhir, Frederick T Chin, Magdalena Bazalova-Carter, Edward Graves, Jianghong Rao, Min Chen
Poly (ADP ribose) polymerase (PARP) enzymes generate poly (ADP ribose) post-translational modifications on target proteins for an array of functions centering on DNA and cell stress. PARP isoforms 1 and 2 are critically charged with the surveillance of DNA integrity, and are the first line guardians of the genome against DNA breaks. Here we present a novel probe ([18F]-SuPAR) for non-invasive imaging of PARP-1/2 activity using positron emission tomography (PET). [18F]-SuPAR is a radiofluorinated nicotinamide adenine dinucleotide (NAD) analog that can be recognized by PARP-1/2 and incorporated into the long branched polymers of poly(ADP ribose) (PAR)...
April 11, 2019: Bioconjugate Chemistry
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