Search arXivSearch

arXiv · 2402.02505

Multi-functional oxidase-like activity of praseodymia nanorods and nanoparticles

Abstract

The ability to mimic protein-based oxidase with multi-functional inorganic nanozymes would greatly advance biomedical and clinical practices. Praseodymia (PrOx) nanorods (NRs) and nanoparticles (NPs) have been synthesized using hydrothermal and precipitation methods. Both PrOx catalysts with different morphologies exhibit significantly higher oxidase-like activities (Michaelis-Menten constant Km < 0.026 mM) than commercial PrOx and most so-far-reported artificial enzymes. One of the substrates, dopamine, can be oxidized and further polymerized to generate polydopamine in acidic conditions. Akin to CeO2, which is a well-studied nanozyme, a different mechanism involving holes+, oxygen vacancies and oxygen mobility over PrOx catalysts has been proposed in this work. However, fluoride ions were found to impose opposite effects on the oxidase-mimicking activity of PrOx and CeO2, implying a promising path for the exploration of new nanozymes. In support of this, PrOx was further applied in colorimetric sensing of L-cysteine and fluoride with high sensitivity.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Jiang Lei, Yaning Han, Susana Fernández-García, Miguel Tinoco Rivas, Zhuang Li, Pengli Nan, Jingtao Sun, Juan José Delgado Jaén, Huiyan Pan, Ginesa Francisco Martínez-López Blanco, Ana Belén Hungría, José Juan Calvino, Xiaowei Chen. 2024-02-04. Multi-functional oxidase-like activity of praseodymia nanorods and nanoparticles. https://doi.org/10.1016/j.apsusc.2022.155502

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Global approximations to the error function of real argument for vectorized computation

The error function of real argument can be approximated to a given uniform relative accuracy by a single closed-form expression for the whole variable range either in terms of addition, multiplication, division, and square root operations only, or also using the exponential function. The coefficients have been tabulated for up to 128-bit precision. Tests of a computer code implementation using the standard single- and double-precision floating-point arithmetic show good performance and vectorizability. Approximations to the complementary error function have also been found, including those where only additions, multiplications, and one division are needed to reach a uniform absolute accuracy.

physics.chem-ph

From Heuristics to Machine Learning: The Performance Ceiling for Single-Ion Magnets and Its Electronic Origin

Machine learning (ML) is expected to speed up the discovery of single-ion magnets (SIMs), but does the structural information available before synthesis allow such predictions? For 1215 lanthanide complexes from the SIMDAVIS 1.2.1 database we compared three increasing levels of structural description: tabular features of the coordination site, continuous symmetry measures of the coordination polyhedron, and the complete 3D arrangement of atoms. All three converge to an accuracy near 76%, only slightly above the 71% of the single rule "predict SIM for Dy3+". To explain the failures, we combined multireference ab initio calculations with an inspection of the structures behind the high-confidence errors. The SIMs missed by the geometric models are field-induced relaxers whose ground Kramers doublets are prone to tunnelling, a property invisible to geometric descriptors. Many false positives contain several lanthanide centers or radicals, so their relaxation is collective and outside the single-ion picture. The electronic-structure and connectivity information needed to identify SIMs is therefore not accessible to geometric methods alone. Geometric models remain useful: restricting the screening to compounds with high prediction confidence raises the accuracy to 88% while retaining 48% of the dataset. Building on the analysis of the failures, we propose a strategy that combines simple filters for nuclearity and for radicals with ligand-field descriptors from ab initio calculations.

physics.chem-ph

Composition-Dependent Self-Diffusion Coefficients in Liquid Mixtures from Hybrid Machine Learning

Self-diffusion coefficients are key descriptors of molecular mobility, yet experimental data remain scarce, highlighting the need for reliable prediction methods. In previous work, we introduced the hybrid Enhanced Stokes-Einstein (ESE) model, which advanced the state of the art in the physically consistent prediction of self-diffusion coefficients of solutes at infinite dilution in pure solvents by integrating the Stokes-Einstein equation with machine learning (ML). Here, we extend this approach to concentration-dependent self-diffusion coefficients and multicomponent solvents with HADES. This hybrid architecture leverages a deep-set neural network to connect pure-component and mixture prediction within a single framework. HADES predicts self-diffusion coefficients in liquid mixtures with any number of components at any composition and temperature. The only required inputs are SMILES-encoded molecular structures of the components and the pure-component viscosities, making the method broadly applicable. Trained and evaluated on a comprehensive dataset of 2526 data points for 600 systems, HADES significantly outperforms benchmark prediction methods. The trained model and its source code are fully disclosed, and the application is available via an interactive website https://ml-prop.mv.rptu.de/.

physics.chem-ph