Metal-mediated nucleobase pairing can play a central role in the expression of metal-responsive DNA functions. We report the Cu-mediated stabilisation of DNA duplexes bearing damaged nucleobases, 1,-ethenoadenine (εA), as metal-binding sites, which was utilised to construct a metal-responsive DNAzyme. Consecutive incorporation of three or more εA-εA mismatch pairs allowed for Cu-dependent significant duplex stabilisation through metal-mediated εA-Cu-εA base pairing. Subsequently, a split DNAzyme with three εA-Cu-εA base pairs was strategically designed. The activity of the εA-modified DNAzyme was enhanced by 5.3-fold upon addition of Cu ions. This study demonstrates the utility of εA lesions for building metal-responsive DNA architectures.
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http://dx.doi.org/10.1039/d2cc06179a | DOI Listing |
Fenton catalytic medicine that catalyzes the production of ·OH without external energy input or oxygen as a substrate has reshaped the landscape of conventional cancer therapy in recent decades, yet potential biosafety concerns caused by non-safety-approved components restrict their clinical translation from the bench to the bedside. Herein, to overcome this dilemma, we elaborately utilizate safety-approved hetastarch, which has been extensively employed in the clinic as a plasma substitute, as a stabilizer participating in the copper chloride-initiated polymerization of pyrrole monomer before loading it with DOX. The constructed DOX-loaded hetastarch-doped Cu-based polypyrrole (HES@CuP-D) catalyzes the excess HO in tumor cells to ·OH through a Cu-mediated Fenton-like reaction, which not only causes oxidative damage to tumor cells but also leads to the structural collapse and DOX release.
View Article and Find Full Text PDFACS Appl Mater Interfaces
March 2023
Molecular Electrochemistry Laboratory, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China.
Selective electrochemical upgrading of CO to multicarbon (C) products requires a C-C coupling process, yet the underlying promoting mechanism of widely involved Cu oxidation states remains largely unclear, hindering the subtle design of efficient catalysts. Herein, we unveil the critical role of Cu in promoting C-C coupling via coordination with a CO intermediate during electrochemical CO reduction. We find that, relative to other halogen anions, iodide (I) in HCO electrolytes accelerates the generation of strongly oxidative hydroxyl radicals that accounts for the formation of Cu, which can be dynamically stabilized by I via the formation of CuI.
View Article and Find Full Text PDFDalton Trans
December 2022
Department of Chemistry, University of Washington, Seattle, WA 98195, USA.
A density functional theory study of copper-mediated dehydroacylation of 4-phenyl-2-butanone to the corresponding olefin reveals a flexible N-H transfer process and a metal-independent C-C cleavage mechanism. When '-methylpicolinohydrazonamide (MPHA) acts as the activating reagent, N-H cleavage can easily take place stepwise proton transfer/electron transfer (PT/ET) and the rate-determining step is C-C homolysis with a total free energy barrier of 22.6 kcal mol, which is consistent with experimental observation of no kinetic isotope effects (KIE) at β-H.
View Article and Find Full Text PDFLangmuir
October 2022
Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, School of Materials and Energy, Southwest University, Chongqing 400715, China.
Chemodynamic therapy (CDT) is a promising hydroxyl radical (•OH)-mediated tumor therapeutic method with desirable tumor specificity and minimal side effects. However, the efficiency of CDT is restricted by the pH condition, insufficient HO level, and overexpressed reductive glutathione (GSH), making it challenging to solve these problems simultaneously to improve the efficacy of CDT. Herein, a kind of polyvinylpyrrolidone-stabilized, sorafenib-loaded copper peroxide (CuO-PVP-SRF) nanoparticle (NPs) was designed and developed for enhanced CDT against tumor cells through the synergetic pH-independent Fenton-like, HO self-supplying, and GSH depletion strategy.
View Article and Find Full Text PDFOrg Biomol Chem
November 2022
Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark.
The low binding affinity of unmodified triplex-forming oligonucleotides (TFO) is the main drawback to their promising utilization in gene therapy. In the present study, we have synthesized DNA intercalator 5-(pyren-1-ylethynyl)indole Y, known as twisted intercalating nucleic acid (TINA), by a Cu-mediated Sonogashira palladium-catalyzed coupling reaction of 1-ethynylpyrene with 5-iodoindole at a high temperature under anaerobic conditions. Coupling with indole C-5 was far more preferable in obtaining stable TINA-indole than enamine site C-3, as neither hydration of the triple bond to ketones nor competitive Glaser-type homocoupling of acetylenes was observed.
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