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https://www.readbyqxmd.com/read/28815272/gold-nanoparticle-based-localized-surface-plasmon-immunosensor-for-staphylococcal-enterotoxin-a-sea-detection
#1
Maroua Ben Haddada, David Hu, Michèle Salmain, Lu Zhang, Chen Peng, Yi Wang, Bo Liedberg, Souhir Boujday
We describe the engineering of stable gold nanoparticle (AuNP) bioconjugates for the detection of staphylococcal enterotoxin A (SEA) using localized surface plasmon resonance (LSPR). Two types of AuNP bioconjugates were prepared by covalently attaching anti-SEA antibody (Ab) or SEA to AuNPs. This was achieved by reacting Traut's reagent with lysine residues of both proteins to generate thiol groups that bind to gold atoms on the AuNP surface. These bioconjugates were characterized in-depth by absorption spectroscopy, cryo-transmission electron microscopy, dynamic light scattering, and zeta potential measurements...
August 16, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28809078/profiling-protein-s-sulfination-with-maleimide-linked-probes
#2
Yu-Hsuan Kuo, Aaron M Konopko, Nicholas B Borotto, Jaimeen D Majmudar, Sarah E Haynes, Brent R Martin
Cysteine residues are susceptible to oxidation to form S-sulfinyl (R-SO2H) and S-sulfonyl (R-SO3H) post-translational modifications. Here we present a simple bioconjugation strategy to label S-sulfinated proteins using reporter-linked maleimides. After alkylation of free thiols with iodoacetamide, S-sulfinated cysteines react with maleimide to form a sulfone Michael adduct that remains stable under acidic conditions. Using this sequential alkylation strategy, we demonstrate differential S-sulfination across mouse tissue homogenates, as well as enhanced S-sulfination following pharmacological induction of ER stress, lipopolysaccharide stimulation, and inhibitors of the electron transport chain...
August 14, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28789897/functionalization-of-peptide-nucleolipid-bioconjugates-and-their-structure-anti-cancer-activity-relationship-studies
#3
Niki Rana, Christopher Cultrara, Mariana Phillips, David Sabatino
In the search for more potent peptide-based anti-cancer conjugates the generation of new, functionally diverse nucleolipid derived D-(KLAKLAK)2-AK sequences has enabled a structure and anti-cancer activity relationship study. A reductive amination approach was key for the synthesis of alkylamine, diamine and polyamine derived nucleolipids as well as those incorporating heterocyclic functionality. The carboxy-derived nucleolipids were then coupled to the C-terminus of the D-(KLAKLAK)2-AK killer peptide sequence and produced with and without the FITC fluorophore for investigating biological activity in cancer cells...
July 26, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28789584/monoclonal-antibodies-technologies-for-early-discovery-and-engineering
#4
Patrick J Kennedy, Carla Oliveira, Pedro L Granja, Bruno Sarmento
Antibodies are essential in modern life sciences biotechnology. Their architecture and diversity allow for high specificity and affinity to a wide array of biochemicals. Combining monoclonal antibody (mAb) technology with recombinant DNA and protein expression links antibody genotype with phenotype. Yet, the ability to select and screen for high affinity binders from recombinantly-displayed, combinatorial libraries unleashes the true power of mAbs and a flood of clinical applications. The identification of novel antibodies can be accomplished by a myriad of in vitro display technologies from the proven (e...
August 8, 2017: Critical Reviews in Biotechnology
https://www.readbyqxmd.com/read/28765875/quantum-dot-pmhc-multimers-vs-phycoerythrin-pmhc-tetramers-for-identification-of-hla-a-0201-restricted-phbv-core-antigen18-27-specific-t-cells
#5
Jianmeng Zhu, Yong Huang, Jing Su, Jian He, Yating Yu, Yongxiang Zhao, Xiaoling Lu
Detection of human leukocyte antigens-A2-restricted p-hepatitis B virus (HBV) core antigen‑specific cytotoxic T lymphocytes (CTLs) is important in the study of HBV immunopathogenesis and vaccine design. Currently, major histocompatibility complex (MHC) class I/peptide‑(p) MHCI tetramers are considered the optimal tools to detect antigen‑specific CTLs. However, the MHC‑tetramer technique also has certain drawbacks and is under continuous development. The quantum dot (QD) bioconjugates nanotechnology with its unique inorganic‑biological properties has been developing fast...
August 1, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28765846/enhanced-enzymatic-activity-from-phosphotriesterase-trimer-gold-nanoparticle-bioconjugates-for-pesticide-detection
#6
John A Hondred, Joyce C Breger, Nate T Garland, Eunkeu Oh, Kimihiro Susumu, Scott A Walper, Igor L Medintz, Jonathan C Claussen
The rapid detection of organophosphates (OPs), a class of strong neurotoxins, is critically important for monitoring acute insecticide exposure and potential chemical warfare agent use. Herein, we improve the enzymatic activity of a phosphotriesterase trimer (PTE3), an enzyme that selectively recognizes OPs directly, by conjugation with distinctly sized (i.e., 5, 10, and 20 nm diameter) gold nanoparticles (AuNPs). The number of enzymes immobilized on the AuNP was controlled by conjugating increasing molar ratios of PTE3 onto the AuNP surface via metal affinity coordination...
August 2, 2017: Analyst
https://www.readbyqxmd.com/read/28764073/an-improved-process-for-the-production-of-highly-purified-recombinant-thaumatin-tagged-variants
#7
Robert D Healey, Helene Lebhar, Simon Hornung, Pall Thordarson, Christopher P Marquis
The sweetest tasting molecule known is the protein thaumatin, first isolated from the katemfe fruit, Thaumatococcus daniellii. Thaumatin is used in the food and beverage industry as a low-calorie sugar substitute. Thaumatin interacts with taste receptors in the oral cavity eliciting a persistent sweet taste and a bitter, liquorice flavor. Recombinant thaumatin was expressed in Pichia pastoris and through a co-expression strategy with a molecular chaperone, yields of one engineered thaumatin variant increased by greater than two-fold...
December 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28755608/fully-disposable-microfluidic-electrochemical-device-for-detection-of-estrogen-receptor-alpha-breast-cancer-biomarker
#8
Carolina V Uliana, Camila R Peverari, André S Afonso, Marcia R Cominetti, Ronaldo C Faria
A novel fully disposable microfluidic electrochemical array device (µFED) was developed and successfully applied for detection of the biomarker estrogen receptor alpha (ERα). The µFED was constructed using low-cost materials and an inexpensive home cutter printer enabled the manufacture of dozens of µFEDs in less than 2h, at a cost of less than US$ 0.20 in material per device. The µFED incorporates counter and reference electrodes and eight carbon-based working electrodes, which were modified with DNA sequences known as estrogen response elements (DNA-ERE), where ERα binds specifically...
July 20, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28754291/mechanistic-applications-of-click-chemistry-for-pharmaceutical-drug-discovery-and-drug-delivery
#9
REVIEW
Nilesh M Meghani, Hardik H Amin, Beom-Jin Lee
The concept of click chemistry (CC), first introduced by K.B. Sharpless, has been widely adopted for use in drug discovery, novel drug delivery systems (DDS), polymer chemistry, and material sciences. In this review, we outline novel aspects of CC related to drug discovery and drug delivery, with a brief overview of molecular mechanisms underlying each click reaction commonly used by researchers, and the main patents that paved the way for further diverse medicinal applications. We also describe recent progress in drug discovery and polymeric and carbon material-based drug delivery for potential pharmaceutical applications and advancements based on the CC approach, and discuss some intrinsic limitations of this popular conjugation reaction...
July 25, 2017: Drug Discovery Today
https://www.readbyqxmd.com/read/28752889/computationally-guided-discovery-of-a-reactive-hydrophilic-trans-5-oxocene-dienophile-for-bioorthogonal-labeling
#10
William D Lambert, Samuel L Scinto, Olga Dmitrenko, Samantha J Boyd, Ronald Magboo, Ryan A Mehl, Jason W Chin, Joseph M Fox, Stephen Wallace
The use of organic chemistry principles and prediction techniques has enabled the development of new bioorthogonal reactions. As this "toolbox" expands to include new reaction manifolds and orthogonal reaction pairings, the continued development of existing reactions remains an important objective. This is particularly important in cellular imaging, where non-specific background fluorescence has been linked to the hydrophobicity of the bioorthogonal moiety. Here we report that trans-5-oxocene (oxoTCO) displays enhanced reactivity and hydrophilicity compared to trans-cyclooctene (TCO) in the tetrazine ligation reaction...
August 9, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28750536/magnetite-quantum-dot-immunoarray-for-plasmon-coupled-fluorescence-imaging-of-blood-insulin-and-glycated-hemoglobin
#11
Vini Singh, Rajasekhara Nerimetla, Ming Yang, Sadagopan Krishnan
New microarray chip strategies that are sensitive and selective and that can measure low levels of important biomarkers directly in a blood sample are significant for improving human health by allowing timely diagnosis of an abnormal condition. Herein, we designed an antibody-aptamer immunoarray chip to demonstrate simultaneous measurement of blood insulin and glycated hemoglobin (HbA1c) levels relevant to diabetic and prediabetic disorders using a surface plasmon microarray with validation by fluorescence imaging...
July 28, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28745296/bbn-conjugated-gnps-a-new-targeting-contrast-agent-for-imaging-of-breast-cancer-in-radiology
#12
Mojtaba Salouti, Faranak Saghatchi
Using of targeted contrast agents in X-ray imaging of breast cancer can improve the accuracy of diagnosis, staging, and treatment planning by providing early detection and superior definition of tumour volume. This study demonstrates a new class of X-ray contrast agents based on gold nanoparticles (GNPs) and bombesin (BBN) for imaging of breast cancer in radiology. GNPs were synthesised in spherical shape in the size range of 15 ± 2 nm and conjugated with BBN followed by coating with polyethyleneglycol (PEG)...
August 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/28745291/biogenic-fabrication-of-cunps-cu-bioconjugates-and-in-vitro-assessment-of-antimicrobial-and-antioxidant-activity
#13
Raksha Pandit, Swapnil Gaikwad, Mahendra Rai
In the present study, the authors synthesised copper nanoparticles (CuNPs) by using extract of Zingiber officinale (ginger) and later the NPs were bioconjugated with nisin, which shows antimicrobial activity against food spoilage microorganisms. CuNPs and its bioconjugate were characterised by ultraviolet-vis spectroscopy, NP tracking analysis, Zetasizer, transmission electron microscopy analysis, X-ray diffraction and Fourier transform infra-red (FTIR) spectroscopy. Zeta potential of CuNPs and its bioconjugate were found to be very stable...
August 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/28742337/gallium-complexation-stability-and-bioconjugation-of-1-4-7-triazacyclononane-derived-chelators-with-azaheterocyclic-arms
#14
Alexander Schmidtke, Tilman Läppchen, Christian Weinmann, Lorenz Bier-Schorr, Manfred Keller, Yvonne Kiefer, Jason P Holland, Mark D Bartholomä
We have recently introduced a 1,4,7-triazacyclononane (TACN) based chelating system with additional five-membered azaheterocyclic substituents for complexation of radioactive Cu(2+) ions. In this work, we investigated the complexation properties of these novel chelators with Ga(3+). In labeling experiments, we could show that the penta- and hexadentate imidazole derivatives NODIA-Me 4 and NOTI-Me 1 can be labeled with (68)Ga in specific activities up to ∼30 MBq nmol(-1), while the corresponding thiazole derivative NOTThia 2 did not label satisfactorily under identical conditions...
August 7, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28742317/disposable-microfluidic-immunoarray-device-for-sensitive-breast-cancer-biomarker-detection
#15
Ricardo A G de Oliveira, Elsa María Materón, Matias Eliseo Melendez, Andre L Carvalho, Ronaldo C Faria
Breast cancer is the most common cancer in women worldwide. The detection of biomarkers has played a significant role in the early diagnosis and prognosis of breast cancer. Herein, we describe the construction of a disposable microfluidic immunoarray device (DµID) for rapid and low-cost detection of CA15-3 a protein biomarker for breast cancer. The DµID was constructed using a simple and rapid prototyping technique and was applied to detect CA15-3 in cancer patients. The DµID construction was based on a use of double-sided adhesive card with the microfluidic channel and a screen-printed array with 8 electrodes...
July 25, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28731116/liquid-exfoliation-of-2d-mos2-nanosheets-and-their-utilization-as-a-label-free-electrochemical-immunoassay-for-subclinical-ketosis
#16
Satish K Tuteja, Todd Duffield, Suresh Neethirajan
We report the step-by-step fabrication of a 2D MoS2 nanostructure-based disposable electrochemical immunosensor to detect β-hydroxybutyrate (βHBA), a novel subclinical ketosis biomarker. The MoS2 nanosheets were exfoliated in the liquid phase by ultrasonication, and then followed by deposition on gold colloid modified screen-printed electrodes (Au-SPE). The MoS2-modified electrodes were thoroughly characterized by physical, electrochemical as well as spectroscopic techniques, and the obtained results indicate the successful and irreversible electrodeposition of MoS2 nanosheets...
August 3, 2017: Nanoscale
https://www.readbyqxmd.com/read/28730957/design-preparation-and-characterization-of-modular-squalene-based-nanosystems-for-controlled-drug-release
#17
Jiao Feng, Sinda Lepetre-Mouelhi, Patrick Couvreur
This article reviews the innovative and original concept the "squalenoylation", a technology allowing the formulation of a wide range of drug molecules (both hydrophilic and lipophilic) as nanoparticles. The "squalenoylation" approach is based on the covalent linkage between the squalene, a natural and biocompatible lipid belonging to the terpenoid family, and a drug, in order to increase its pharmacological efficacy. Fundamentally, the dynamically folded conformation of squalene triggers the resulting squalene-drug bioconjugates to self-assemble as nanoparticles of 100-300 nm...
July 19, 2017: Current Topics in Medicinal Chemistry
https://www.readbyqxmd.com/read/28727913/alpha-l-fucosidase-immunoassay-for-early-detection-of-hepatocellular-carcinoma
#18
Eric Waidely, Abdulrahman Obaid Al-Youbi, Abdulaziz Saleh Omar Bashammakh, Mohammad Soror El-Shahawi, Roger M Leblanc
Detection of alpha-L-fucosidase has been shown to have relevance in diagnosing hepatocellular carcinoma. Few assays have been developed to measure this enzyme, with most relying on colorimetric techniques involving the enzyme's kinetics. While these assays are facile and quick, the sensitivity is not always sufficient for early tumor detection. To improve upon previous assays for alpha-L-fucosidase, a fluorescence based immunoassay was produced implementing an alpha-L-fucosidase specific antibody (FUCA2). The immobilization of the alpha-L-fucosidase-specific antibody onto a quartz slide was investigated with several bioconjugation approaches and an immunoassay for detection of alpha-L-fucosidase was produced...
July 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28727441/adsorption-induced-changes-of-human-hemoglobin-on-ferric-pyrophosphate-nanoparticle-surface-probed-by-isotope-exchange-mass-spectrometry-an-implication-on-structure-function-correlation
#19
Bindu Y Srinivasu, Beena Bose, Gopa Mitra, Anura V Kurpad, Amit K Mandal
In general, proteins in the biological system interact with nanoparticles (NPs) via adsorption on the particle surface. Understanding the adsorption at the molecular level is crucial to explore NP-protein interactions. The increasing concerns about the risk to human health on NP exposure have been explored through the discovery of a handful protein biomarkers and biochemical analysis. However, detailed information on structural perturbation and associated functional changes of proteins on interaction with NPs is limited...
August 2, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28724927/dual-functionality-nanobioconjugates-targeting-intracellular-bacteria-in-cancer-cells-with-enhanced-antimicrobial-activity
#20
Rohini Singh, Smita Patil, Neetu Singh, Shalini Gupta
Bacterial drug resistance has emerged as a serious global threat mandating the development of novel methodologies that allow facile modulation of antimicrobial action in a controlled fashion. Conjugating antibiotics to nanoparticles helps to meet this goal by increasing the drug's overall avidity, bioavailability and easier internalisation into mammalian cells, targeting bacteria that otherwise escape antibacterial action by host cell-localisation. We used polymyxin B sulfate (PMB) and sushi peptide as model drugs against Gram-negative bacteria and established their enhanced antimicrobial activity on Escherichia coli (E...
July 19, 2017: Scientific Reports
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