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Sahan C B Herath, Soheila Sharghi-Namini, Yue Du, Dongan Wang, Ruowen Ge, Qing-Guo Wang, Harry Asada, Peter C Y Chen
Advances in mechanobiology have suggested that physiological and pathological angiogenesis may be differentiated based on the ways in which the cells interact with the extracellular matrix (ECM) that exhibits partially different mechanical properties. This warrants investigating the regulation of ECM stiffness on cell behavior using angiogenesis assays. In this article, we report the application of the technique of active manipulation of ECM stiffness to study in vitro angiogenic sprouting of human microvascular endothelial cells (HMVECs) in a microfluidic device...
November 29, 2016: Journal of Laboratory Automation
Mojtaba Shamsipur, Afshin Pashabadi, Fatemeh Molaabasi, Saman Hosseinkhani
It is well known that cytochrome c (Cyt c) is a crucial death regulator that triggers programmed cell death, apoptosis. Here, we report on the successful application of an aptamer bioconjugated nanoclusters for the detection of apoptosis based on release of cytochrome c from mitochondria in lysates human embryonic kidney cells HEK293T. The aptamer-conjugated silver nanoclusters (Apt@AgNCs) were synthesized and immobilized on gold electrode for impedimetric detection of Cyt c over the range of 0.15-375nM. It was found that the presence of Ag(I) ions shell at the surface of prepared NCs could increase their affinity to the donor groups (COO(-) and some amine groups in its deprotonated form, NH2) of cysteine attached on the gold electrode surface...
November 23, 2016: Biosensors & Bioelectronics
Johnathan C Maza, Christina A Howard, Megha A Vipani, Christopher R Travis, Douglas D Young
The ability to introduce or modify protein function has widespread application to multiple scientific disciplines. The introduction of unique unnatural amino acids represents an excellent mechanism to incorporate new functionality; however, this approach is limited by ability of the translational machinery to recognize and incorporate the chemical moiety. To overcome this potential limitation, we aimed to exploit the functionality of existing unnatural amino acids to perform bioorthogonal reactions to introduce the desired protein modification, altering its function...
November 16, 2016: Bioorganic & Medicinal Chemistry Letters
Katrin Quester, Karla Juarez-Moreno, Isamel Secundino, Yvonne Roseinstein, Karla P Alejo, Alejandro Huerta-Saquero, Rafael Vazquez-Duhalt
Cancer is still a growing public health problem, especially breast cancer that is one of the most important cancers in women. Chemotherapy, even though a successful treatment, is accompanied by severe side effects. Moreover, most of the drugs used for chemotherapy are administered as prodrugs and need to be transformed to the active form by cytochromes P450 (CYPs). In addition, increasing numbers of cancer tissues show lower CYP activity than the surrounding healthy tissues in which prodrugs are preferentially activated causing cytotoxicity...
November 28, 2016: Macromolecular Bioscience
R Dondi, E Yaghini, K M Tewari, L Wang, F Giuntini, M Loizidou, A J MacRobert, I M Eggleston
Efficient syntheses of cell-penetrating peptide-porphyrin conjugates are described using a variety of bioconjugation chemistries. This provides a flexible means to convert essentially hydrophobic tetrapyrolle photosensitisers into amphiphilic derivatives which are well-suited for use in light-triggered drug delivery by photochemical internalisation (PCI) and targeted photodynamic therapy (PDT).
November 25, 2016: Organic & Biomolecular Chemistry
Indu Barwal, Rajiv Kumar, Suneel Kateriya, Amit Kumar Dinda, Subhash Chandra Yadav
Targeted nano-delivery vehicles were developed from genetically modified Cowpea chlorotic mottle virus (CCMV) capsid by ligands bioconjugation for efficient drug delivery in cancer cells. RNA binding (N 1-25aa) and β-hexamer forming (N 27-41aa) domain of capsid was selectively deleted by genetic engineering to achieve the efficient in vitro assembly without natural cargo. Two variants of capsids were generated by truncating 41 and 26 amino acid from N terminus (NΔ41 and NΔ26) designated as F1 and F2 respectively...
November 22, 2016: Scientific Reports
Jyoti Yellol, Sergio A Pérez, Gorakh Yellol, Juraj Zajac, Antonio Donaire, Gloria Vigueras, Vojtech Novohradsky, Christoph Janiak, Viktor Brabec, José Ruiz
A series of 6 substitutionally inert and luminescent iridium(iii) antitumor agents of the type [Ir(C(∧)N)2(N(∧)N)][PF6] containing a benzimidazole N(∧)N ligand with an ester group as a handle for further functionalization has been prepared. They exhibit IC50 values in the high nanomolar range in some ovarian and breast cancer cell lines (approximately 100× more cytotoxic than cisplatin (CDDP) in MDA-MB-231) and are located in the actin cortex predominantly as shown by confocal luminescence microscopy...
December 1, 2016: Chemical Communications: Chem Comm
Nuria Tort, J-Pablo Salvador, M-Pilar Marco
Biofunctional multimodal plasmonic nanostructures suitable for multiplexed localized surface plasmon resonance (LSPR) biosensing have been created by DNA-directed immobilization (DDI) of two distinct multifunctional biohybrid gold nanoparticles. Gold nanoparticles (AuNP) of distinct sizes, and therefore showing distinct plasmon resonant peaks (RP), have been biofunctionalized and codified with two different single stranded-DNA (ssDNA) chains. One of these oligonucleotide chains has been specifically designed to direct each AuNP to a distinct location of the surface of a DNA microarray chip through specific hybridization with complementary oligonucleotide strands...
November 11, 2016: Biosensors & Bioelectronics
Jessica Clavadetscher, Scott Hoffmann, Annamaria Lilienkampf, Logan Mackay, Rahimi M Yusop, Sebastien A Rider, John J Mullins, Mark Bradley
The copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction has proven to be a pivotal advance in chemical ligation strategies with applications ranging from polymer fabrication to bioconjugation. However, application in vivo has been limited by the inherent toxicity of the copper catalyst. Herein, we report the application of heterogeneous copper catalysts in azide-alkyne cycloaddition processes in biological systems ranging from cells to zebrafish, with reactions spanning from fluorophore activation to the first reported in situ generation of a triazole-containing anticancer agent from two benign components, opening up many new avenues of exploration for CuAAC chemistry...
November 15, 2016: Angewandte Chemie
Maria Vittoria Spanedda, Marcella De Giorgi, Fatouma Saïd Hassane, Francis Schuber, Line Bourel-Bonnet, Benoît Frisch
Click chemistry represents a new bioconjugation strategy that can be used to conveniently attach various ligands to the surface of preformed liposomes. This efficient and chemoselective reaction involves a Cu(I)-catalyzed azide-alkyne cycloaddition which can be performed under mild experimental conditions in aqueous media. Here we describe the application of a model click reaction to the conjugation, in a single step, of unprotected α-1-thiomannosyl ligands, functionalized with an azide group, to liposomes containing a terminal alkyne-functionalized lipid anchor...
2017: Methods in Molecular Biology
Hong Dai, Sihong Chen, Yilin Li, Baoshan Zeng, Shupei Zhang, Zhengsheng Hong, Yanyu Lin
Herein, a delicate photoelectrochemical biosensor for quantitative detection of trypsin was successfully established by virtue of polyethylenimine-sensitized TiO2 mesocrystal as the photoactive matrix integrated with Boron-doped carbon quantum dots labeled peptide as the signal amplification tags. Specifically, polyethylenimine with fine photo-stability was introduced here as the electron transporting layer to reduce the energy barrier of TiO2 mesocrystal, thereby facilitating the carriers transfer and improving the photocurrent response...
October 15, 2016: Biosensors & Bioelectronics
Takuya Genjo, Shingo Sotoma, Ryotaro Tanabe, Ryuji Igarashi, Masahiro Shirakawa
Recently, the importance of conformational changes in actin filaments induced by mechanical stimulation of a cell has been increasingly recognized, especially in terms of mechanobiology. Despite its fundamental importance, however, long-term observation of a single actin filament by fluorescent microscopy has been difficult because of the low photostability of traditional fluorescent molecules. This paper reports a novel molecular labeling system for actin filaments using fluorescent nanodiamond (ND) particles harboring nitrogen-vacancy centers; ND has flexible chemical modifiability, extremely high photostability and biocompatibility, and provides a variety of physical information quantitatively via optically detected magnetic resonance (ODMR) measurements...
2016: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Gangbing Zhu, Hye Jin Lee
A novel sandwich-type biosensor was developed for the electrochemical detection of α-1 antitrypsin (AAT, a recognized biomarker for Alzheimer's disease). The biosensor was composed of 3, 4, 9, 10-perylene tetracarboxylic acid/carbon nanotubes (PTCA-CNTs) as a sensing platform and alkaline phosphatase-labeled AAT antibody functionalized silver nanoparticles (ALP-AAT Ab-Ag NPs) as a signal enhancer. CNTs offer high surface area and good electrical conductivity. Importantly, Ag NPs could increase the amount of ALP on the sensing surface and the ALP could dephosphorylate 4-amino phenyl phosphate (APP) enzymatically to produce electroactive species 4-aminophenol (AP)...
September 25, 2016: Biosensors & Bioelectronics
Dongsook Chang, Aaron Huang, Bradley D Olsen
The self-assembly of nanostructured globular protein arrays in thin films is demonstrated using protein-polymer block copolymers based on a model protein mCherry and the polymer poly(oligoethylene glycol acrylate) (POEGA). Conjugates are flow coated into thin films on a poly(ethylene oxide) grafted Si surface, forming self-assembled cylindrical nanostructures with POEGA domains selectively segregating to the air-film interface. Long-range order and preferential arrangement of parallel cylinders templated by selective surfaces are demonstrated by controlling relative humidity...
November 4, 2016: Macromolecular Rapid Communications
Huai-Xin Zhao, Cheng-Xiong Yang, Xiu-Ping Yan
Persistent luminescent nanoparticles (PLNPs) show great potential in realizing precision imaging due to the absence of in situ excitation and no background interference. However, the current PLNP-based tumour imaging is usually achieved by single targeting or passive targeting strategies, and thus it lacks high specificity and affinity for efficient persistent luminescence imaging in vivo. Herein we report the bioconjugation of multiple targeting ligands on the surface of PLNPs for dual-targeted bioimaging to improve the specificity and affinity of the PLNP nanoprobe for in vitro and in vivo bioimaging...
December 7, 2016: Nanoscale
Yong Il Park, Eunha Kim, Chen-Han Huang, Ki Soo Park, Cesar M Castro, Hakho Lee, Ralph Weissleder
The use of inorganic nanoparticles (NPs) for biosensing requires that they exhibit high colloidal stability under various physiological conditions. Here, we report on a general approach to render hydrophobic NPs into hydrophilic ones, ready for bioconjugation. The method uses peglyated polymers conjugated with multiple dopamines, which results in multidentate coordination. As proof-of-concept, we applied the coating to stabilize ferrite and lanthanide NPs synthesized by thermal decomposition. Both polymer-coated NPs showed excellent water solubility and were stable at high salt concentrations under physiological conditions...
October 28, 2016: Bioconjugate Chemistry
Jutta Pauli, Marieke Pochstein, Andrea Haase, Joanna Napp, Andreas Luch, Ute Resch-Genger
The design of bright and functional dye-protein conjugates requires hydrophilic and stable fluorophores with high molar absorption coefficients and high fluorescence quantum yields, which must not be prone to dimerization, as well as conservation of protein function and suppression of protein association. Although many synthetic dyes meet these needs, the influence of dye charge on bioconjugate performance is commonly neglected. This encouraged us to assess the spectroscopic properties, antibody functionality, binding behavior, folding, and association of conjugates of the therapeutic antibodies trastuzumab and cetuximab with the red cyanine dyes S0586, S2381, and 6SIDCC (bearing two, three, and six sulfonate groups, respectively)...
October 28, 2016: Chembiochem: a European Journal of Chemical Biology
Barbara Bernardim, Pedro M S D Cal, Maria J Matos, Bruno L Oliveira, Nuria Martínez-Sáez, Inês S Albuquerque, Elizabeth Perkins, Francisco Corzana, Antonio C B Burtoloso, Gonzalo Jiménez-Osés, Gonçalo J L Bernardes
Maleimides remain the reagents of choice for the preparation of therapeutic and imaging protein conjugates despite the known instability of the resulting products that undergo thiol-exchange reactions in vivo. Here we present the rational design of carbonylacrylic reagents for chemoselective cysteine bioconjugation. These reagents undergo rapid thiol Michael-addition under biocompatible conditions in stoichiometric amounts. When using carbonylacrylic reagents equipped with PEG or fluorophore moieties, this method enables access to protein and antibody conjugates precisely modified at pre-determined sites...
October 26, 2016: Nature Communications
Seah Ling Kuan, Tao Wang, Tanja Weil
The synthetic transformation of polypeptides with molecular accuracy holds great promise for providing functional and structural diversity beyond the proteome. Consequently, the last decade has seen an exponential growth of site-directed chemistry to install additional features into peptides and proteins even inside living cells. The disulfide rebridging strategy has emerged as a powerful tool for site-selective modifications since most proteins contain disulfide bonds. In this Review, we present the chemical design, advantages and limitations of the disulfide rebridging reagents, while summarizing their relevance for synthetic customization of functional protein bioconjugates, as well as the resultant impact and advancement for biomedical applications...
November 21, 2016: Chemistry: a European Journal
Jing Liu, Dujuan Zhao, Wenxiu He, Huiyuan Zhang, Zhonghao Li, Yuxia Luan
The anti-leukemia effect of cytarabine (Ara-C) is severely restricted by its high hydrophilic properties and rapid plasma degradation. Herein, a novel amphiphilic small molecular prodrug of Ara-C was developed by coupling a short aliphatic chain, hexanoic acid (HA) to 4-NH2 of the parent drug. Based on the amphiphilic nature, the resulting bioconjugate (HA-Ara) could spontaneously self-assemble into stable spherical nanoassemblies (NAs) with an extremely high drug loading (∼71wt%). Moreover, folate receptor (FR)-targeting NAs with high grafting efficient folic acid - bovine serum albumin (FA-BSA) conjugate immobilized on the surface (NAs/FA-BSA) was prepared...
October 19, 2016: Journal of Colloid and Interface Science
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