Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this work, we developed a sensitive and efficient ratiometric electrochemical method for lipopolysaccharide (LPS) detection using Cu-based metal-organic frameworks (Cu-MOFs) as a catalyst and target-triggered quadratic cycles for signal amplification. First, in the presence of target LPS, the conformation change of the specifically designed hairpin probes 1 (HP1) triggered the target cyclic-induced polymerization to produce the output DNA with the aid of phi29 DNA polymerase (phi29). Then, the obtained output DNA hybridized with ferrocene-labeled hairpin probes 2 (Fc-HP2, which were immobilized on the electrode) to generate a nicking endonuclease (N.BstNBI) cleavage site. Thus, with N.BstNBI, the original signal molecules of Fc left from the electrode, and the single-stranded capture-probe-modified sensing interface was obtained. At this time, signal probes conducted by Au-nanoparticles-functionalized Cu-MOFs and labeled hairpin probes 3 (HP3/AuNPs/Cu-MOFs) were hybridized with capture probes for hairpin assembly. Herein, AuNPs/Cu-MOFs were not only used as nanocarriers for immobilizing HP3 but also acted as electroactive materials for signal reporting. With the proposed target-triggered quadratic cycles, the cleavage sites of Fc-HP2 were cut, and capture probes were obtained to hybridize with HP3/AuNPs/Cu-MOFs, which caused the signal decrease of Fc. Then Cu-MOFs were closed to the electrode for the signal increase of Cu-MOFs. Furthermore, when glucose was present in the detection solution, AuNPs/Cu-MOFs catalyzed the oxidation of glucose to realize the enzyme-free signal amplification. By measuring the peak currents ratio of the Cu-MOFs and Fc, the proposed aptasenor for LPS detection showed a low detection limit (0.33 fg/mL) and a wide linear range from 1.0 fg/mL to 100 ng/mL with high accuracy and sensitivity. This ratiometric electrochemical approach is expected to be a valuable strategy for detection of other analytes.
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PMID:Cu-Based Metal-Organic Frameworks as a Catalyst To Construct a Ratiometric Electrochemical Aptasensor for Sensitive Lipopolysaccharide Detection. 2646 56

This work reports a strategy for glutathione-loaded liposome-encoded magnetic beads initiated by palindromic fragment-mediated single-chain amplification (PFMSCA) for high-precision quantification of a low-abundance aminoglycoside antibiotic (kanamycin; Kana) by using In2O3-ZnIn2S4 (IO-ZIS) as a photoactive matrix. In this strategy, a Kana-recognition region, primer-like palindromic fragment, and polymerization/nicking template are reasonably integrated into one oligonucleotide (hairpin HP1) for target recognition, magnetic separation, and target amplification. Upon target Kana introduction, the Kana-aptamer region in HP1 specifically recognizes the Kana and triggers the palindromic tails intramolecular self-hybridization, amplifying a large number of short fragments in the presence of Klenow fragment polymerase and Nt.BbvCI. The as-generated nick fragments act as a linker to introduce the free hairpin HP2-functionalized glutathione-loaded liposomes (HP2-GLL) onto the surface of the hairpin HP3-modified magnetic beads (HP3-MB), constructing liposome-encoded magnetic beads (HP3-MB-nick-HP2-GLL). Following magnetic separation, the detached glutathione-loaded liposomes (GLL) are lysed by treatment with 1% Triton X-100 to release the glutathione within it, which were then detected as an amplified photocurrent at the IO-ZIS-based photoelectrode. Importantly, this method can be readily carried out by using one oligonucleotide to achieve an exponential amplification effect and open new opportunities for advanced development of robust biodetection systems.
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PMID:Palindromic Fragment-Mediated Single-Chain Amplification: An Innovative Mode for Photoelectrochemical Bioassay. 3111 10