63 research outputs found
Photo-induced chemistry for the design of oligonucleotide conjugates and surfaces
A photocaged diene is introduced at the 5â˛-end of oligonucleotides using the H-phosphonate approach. The photoenol-functionalized DNA is subsequently employed for the conjugation to a protein and the spatially controlled immobilization onto surfaces using a light-induced DielsâAlder cycloaddition. Fully functional proteinâDNA conjugates and patterned DNA surfaces are obtained under mild irradiation conditions
Activity-enhanced DNAzyme for design of label-free copper( ii ) biosensor
Metal ion-driven, DNA-cleaving DNAzymes are characterised by high selectivity and specificity. However, their use for metal ion sensing remains largely unexplored due to long reaction times and poor reaction yields relative to RNA-cleaving DNAzymes and other sensing strategies. Herein we present a study demonstrating a significant rate enhancement of a copper-selective DNA cleaving DNAzyme by both polydopamine (PDA) and gold (Au) nanoparticles (NPs). PDA NPs enhance the reaction through the production of hydrogen peroxide, while for AuNPs the enhancement is aided by the presence of citrate surface moeities, both of which drive the oxidative cleavage of the substrate. A 50-fold enhancement for PDA NPs makes the combination of PDA and DNAzyme suitable for a practical application as a sensitive biosensor for Cu(II) ions. Using DNAzyme deposition onto a gold electrode followed by Polydopamine Assisted DNA Immobilisation (PADI), we achieve a cost-effective, label-free and fast (within 15 min) electrochemical biosensor with a limit of detection of 180 nmol (11 ppm), thus opening a route for the rational design of a new generation of hybrid DNAzyme-based biosensors
Hetero-Diels-Alder-Cycloaddition mit RAFT-Polymeren als Biokonjugationsplattform
Wir stellen die Biokonjugation von Polymeren vor, die durch RAFTâPolymerisation mittels HeteroâDielsâAlderâCycloaddition durch ihren inhärenten terminalen Thiocarbonylthiorest mit einem dienmodifizierten Modellprotein synthetisiert wurden und keine spezifische funktionelle Endgruppe tragen. Die quantitative Konjugation erfolgt im Verlauf einiger Stunden bei Raumtemperatur und nahezu neutralem pHâWert und in Abwesenheit jeglichen Katalysators. Unsere Technologieplattform liefert thermoresponsive Biokonjugate, deren Aggregation allein durch die Polymerketten gesteuert wird
Bimetallic Copper-Heme-Protein-DNA Hybrid Catalyst for Diels Alder Reaction
A bimetallic heme-DNA cofactor, containing an iron and a copper center, was synthesized for
the design of novel hybrid catalysts for stereoselective synthesis. The cofactor was used for the
reconstitution of apo-myoglobin. Both the cofactor alone and its myoglobin adduct were used to catalyze
a model Diels Alder reaction. Stereoselectivity of this conversion was analyzed by chiral HPLC.
Reactions carried out in the presence of myoglobin-heme-Cu-DNA catalyst showed greater product
conversion and stereoselectivity than those carried out with the heme-Cu-DNA cofactor. This observation
suggested that the protein shell plays a significant role in the catalytic conversion.(doi: 10.5562/cca1828
Hetero-DielsâAlder Cycloaddition with RAFT Polymers as Bioconjugation Platform
We introduce the bioconjugation of polymers synthesized by RAFT polymerization, bearing no specific functional end group, by means of heteroâDielsâAlder cycloaddition through their inherent terminal thiocarbonylthio moiety with a dieneâmodified model protein. Quantitative conjugation occurs over the course of a few hours, at ambient temperature and neutral pH, and in the absence of any catalyst. Our technology platform affords thermoresponsive bioconjugates, whose aggregation is solely controlled by the polymer chains
Photo-induced chemistry for the design of oligonucleotide conjugates and surfaces
A photocaged diene is introduced at the 5â˛-end of oligonucleotides using the H-phosphonate approach. The photoenol-functionalized DNA is subsequently employed for the conjugation to a protein and the spatially controlled immobilization onto surfaces using a light-induced Diels-Alder cycloaddition. Fully functional protein-DNA conjugates and patterned DNA surfaces are obtained under mild irradiation conditions. Š 2016 The Royal Society of Chemistry
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