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Rahbek Niebuhr posted an update 6 months, 1 week ago
Accurate double-blind identification of unknown samples using the proposed sensor array was also demonstrated, indicating its reliability for practical practice. In this study, a facile one step solvo-thermal procedure has been employed in generating magnetite-silver core-shell nanocomposites (AgNPs@ Fe3O4) with superior peroxidase-like catalytic property than bare magnetic nanoparticles (Fe3O4). The composites were characterized using different techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and surface-enhanced infrared absorption spectroscopy (SEIRA). In the presence of hydrogen peroxide, the synthesized composites were able to oxidize the colorless o-phenylenediamine (OPD) to a yellow colour 2, 3-diaminophenazine (DAP) with a better peroxidase-like activity than Fe3O4 alone. The obtained Km value of AgNPs@ Fe3O4 with H2O2 and OPD substrates are 28.0 mM and 2.91 mM respectively. These are substantially lower than previously reported values and indicate the strong binding affinity of the substrates towards AgNPs@ Fe3O4 nanocomposites. Based on the obstruction activity of cysteine on the peroxidase-like catalytic property of the nanocomposites, a sensor was developed for detection of cystein with a limit of detection as low as 87 nM and a wider range of linearity. The sensor also exhibited excellent selectivity against potentially interfering molecules. Ascorbic acid (AA) as an essential biological molecule for proper performance of body can act as a biological metric for precise detection of various kinds of disease through measuring the level of oxidative stress; thus its precise/dividable detection is an urgent requirement for development of advanced biosensors. To address this requirement, we decorated well-exfoliated graphene oxide (GO) with Ag and hybrid Ag-Fe3O4 metallic nanoparticles toward precise, real-time and repeatable detection of AA within the blood plasma samples via electrochemical approaches that led to the development of a retrievable biosensor. Outcome of performed evaluations showed that modification of glassy carbon electrode (GCE) with selected additives significantly improved its sensitivity/selectivity. In this matter, the modified GCE with GO-Ag-Fe3O4 showed limit of detection and sensitivity of 74 nM and 1146.8 μA mM-1 cm-2, respectively, within the concentration range of 0.2-60 μM. Additionally, the modified electrode kept 91.23% of its total performance after 15 days of performance and detected the oxidation peak of AA even with present of 50 fold of annoying contents which highlighting its superior stability/selectivity. More importantly, the developed electrode showed recovery range between 96.0 and 104.4% within the human blood plasma samples that confirmed the ideal capability of developed platform for accurate detection of AA within biological fluids. Hydrogen sulfide and cysteine are momentous endogenous regulators of many physiological processes and maintain a dynamic balance of redox in living organisms. To investigate the inter-relationship of them in vivo, there is a pressing need to develop analytical molecular tools to identify related biomolecules. We construct a mitochondria-targeted single fluorescence probe (Mit-CM) for separately and continuously visualizing H2S, Cys and H2S/Cys with multi-response fluorescence signals. Mit-CM has the following advantages (Ⅰ) colorimetric and ratiometric two well-separated emission bands can ensure accurate detection of the analyte and significant color changes contribute to rapid identification of the analyte by the naked eye; (Ⅱ) mitochondrial localization study the physiological functions of H2S and Cys in mitochondria; (Ⅲ) separate and continuous detection of H2S and Cys reveal the inter-relationship and interconversion of them in biological system. Moreover, the desirable attributes of low cytotoxicity, better biocompatibility and excellent mitochondria enrichment ability indicate that Mit-CM can be employed to achieve detection and observe distribution of H2S, Cys and H2S/Cys in living organism. Weak and transient protein-protein interactions (PPIs) mediated by the post-translational modifications (PTMs) play key roles in biological systems. However, technical challenges to investigate the PTM-mediated PPIs have impeded many research advances. In this work, we develop a photo-affinity pull-down assay method to pull-down low-affinity binding proteins, thus for the screen of PTM-mediated PPIs. In this method, the PTM-mediated non-covalent interactions can be converted to the covalent interactions by the photo-activated linkage, so as to freeze frame the low-affinity binding interactions. read more The fabricated photo-affinity magnetic beads (PAMBs) ensure high specificity and resolution to capture the interacted proteins. Besides, the introduction of PEG passivation layer on PAMB has significantly reduced the non-specific interaction as compared to the traditional pull-down assay. For proof-of-concept, by using this newly developed assay method, we have identified a set of proteins that can interact with a specific methylation site on Flap Endonuclease 1 (FEN1) protein. Less interfering proteins (decreased over 80%) and more proteins sub-classes are profiled as compared to the traditional biotin-avidin pull-down system. Therefore, this new pull-down method may provide a useful tool for the study of low-affinity PPIs, and contribute to the discovery of potential targets for renewed PTM-mediated interactions that is fundamentally needed in biomedical research. Leishmaniasis is a disease caused by a parasite of the genus Leishmania that affects millions of people worldwide. These parasites are characterized by the presence of a DNA-containing granule, the kinetoplastid, located in the single mitochondrion at the base of the cell’s flagellum. Interestingly, these flagellates do not condense chromatin during mitosis, possibly due to the specific molecular features of their histones. Although histones are extremely conserved proteins, kinetoplastid core histone sequences diverge significantly from those of higher eukaryotes. This divergence makes kinetoplastid core histones potential diagnostic and/or therapeutic targets. Aptamers are short single-stranded nucleic acids that are able to recognize target molecules with high affinity and specificity. Their binding capacity is a consequence of the particular three-dimensional structure acquired depending on their sequence. These molecules are currently used for detection, diagnosis and therapeutic purpose. Starting from a previously obtained ssDNA aptamer population against rLiH3 protein we have isolated two individual aptamers, AptLiH3#4 and AptLiH3#10.