ABSTRACT
Whilst allowing for easy access to synthetically versatile motifs and for modification of bioactive molecules, the chemoselective benzylic oxidation reactions of functionalized alkyl arenes remain challenging. Reported in this study is a new non-heme Mn catalyst stabilized by a bipiperidine-based tetradentate ligand, which enables methylene oxidation of benzylic compounds by H2 O2 , showing high activity and excellent chemoselectivity under mild conditions. The protocol tolerates an unprecedentedly wide range of functional groups, including carboxylic acid and derivatives, ketone, cyano, azide, acetate, sulfonate, alkyne, amino acid, and amine units, thus providing a low-cost, more sustainable and robust pathway for the facile synthesis of ketones, increase of complexity of organic molecules, and late-stage modification of drugs.
Subject(s)
Ketones , Manganese , Alkynes , Catalysis , Ions , Ketones/chemistry , Oxidation-ReductionABSTRACT
A gold nanoparticle (GNP) probe-based assay (GNPA) modified from the bio-barcode assay (BCA) was developed for ultrasensitive detection of ricin, a potential biothreat agent. In the GNPA, a chain of ricin was captured by a GNP probe coated with polyclonal antibodies and single-stranded signal DNA. A magnetic microparticle (MMP) probe coated with ricin A chain monoclonal antibody was then added to form an immuno-complex. After being magnetically separated, the immuno-complex containing the single-stranded signal DNA was characterized by PCR and real-time PCR. A detection limit of 10(-2) fg/ml was determined for the ricin A chain; this is eight orders of magnitude more sensitive than that achieved with an ELISA and two orders more sensitive than that obtained with the BCA. The coefficients of variation (CV) of the intra- and inter-assay values ranged from 3.82-6.46%. The results here show that this novel assay is an ultrasensitive method for detection of ricin proteins and may be suitable for the ultrasensitive detection of other proteins.
Subject(s)
Antibodies, Monoclonal/metabolism , Chemical Warfare Agents/analysis , DNA, Single-Stranded/metabolism , Magnetite Nanoparticles/statistics & numerical data , Ricin/analysis , Gold/chemistry , Humans , Immunosorbent Techniques , Magnetite Nanoparticles/chemistry , Observer Variation , Ricin/immunology , Sensitivity and SpecificityABSTRACT
A simple gold nanoparticle (GNP) probe based assay (GNPA) that was modified from a bio-barcode assay (BCA) technique, was developed for ultra-sensitive, rapid detection of the bluetongue virus (BTV) VP7 outer-core protein. This assay captures the VP7 target antigen using the GNP probe coated with anti-VP7 polyclonal antibodies and single-stranded signal DNA. Magnetic microparticle (MMP) probes coated with anti-VP7 monoclonal antibodies were then added to form a sandwich immuno-complex. The single-stranded signal DNA coated onto the GNP probe present in the immuno-complex could then be detected by PCR and real-time fluorescence PCR using a TaqMan probe. The assay has a purified VP7 detection limit of 10(-2)fg/ml which is 8 orders of magnitude greater than that of conventional antigen capture ELISAs and 1 order of magnitude more sensitive than that of a conventional BCA. These results indicate that the GNPA is a highly sensitive method for easy detection of BTV proteins and that it can be modified as needed to measure the presence of other proteins.
Subject(s)
Bluetongue virus/isolation & purification , Bluetongue/diagnosis , Clinical Laboratory Techniques/methods , Nanoparticles , Veterinary Medicine/methods , Viral Core Proteins/analysis , Virology/methods , Animals , Antibodies, Viral , Antigens, Viral/analysis , Bluetongue/virology , Immunoassay/methods , Polymerase Chain Reaction/methods , Sensitivity and Specificity , SheepABSTRACT
The ultrasensitive bio-barcode amplification assay (BCA) technique was developed for the specific detection of the A chain of ricin toxin. The target antigen A chain was first captured by gold nanoparticles (GNPs) coated with polyclonal antibodies. Magnetic microparticles (MMPs) coated with A chain monoclonal antibody were then added to form a sandwich immuno-complex. After the immuno-complex was formed, signal DNA annealed to DNA strands covalently bound to the GNPs were released by heating and characterized by PCR and real-time fluorescence PCR. A detection limit of 1fg/ml was measured for A chain, six orders of magnitude more sensitive than that of conventional antigen-capture ELISA. The coefficient of variation (CV) of intra-assay and inter-assay ranged from 3.39% to 6.84%. The BCA can detect the A chain in milk and water mimic samples. In the following work it is demonstrated that this assay is a highly sensitive method for the detection of ricin proteins that could be adapted to measure other proteins.
Subject(s)
Immunoassay/methods , Ricin/analysis , Antigens/analysis , Antigens/chemistry , DNA Barcoding, Taxonomic , Gold , Limit of Detection , Magnetics , Metal Nanoparticles , Plant Proteins/analysis , Plant Proteins/chemistry , Reproducibility of Results , Ricin/chemistryABSTRACT
The ultrasensitive bio-barcode amplification assay (BCA) technique was developed for the specific detection of the outer-core protein VP7 of bluetongue virus (BTV). The target antigen VP7 was first captured by gold nanoparticles (GNPs) coated with polyclonal antibodies. Magnetic microparticles (MMP) coated with VP7 monoclonal antibody were then added to form a sandwich immuno-complex. After the immuno-complex was formed, signal DNA annealed to DNA strands covalently bound to the GNPs were released by heating and characterized by PCR and real-time fluorescence PCR. A detection limit of 0.1fg/ml was measured for purified VP7, seven orders of magnitude more sensitive than that of conventional antigen capture ELISA. The BCA demonstrated the same enhanced sensitivity for detecting BTV in serum samples from sheep. In the following work it is demonstrated that this assay is a highly sensitive method for the detection of BTV proteins that could be adapted to measure other proteins.
