Avidin-gated mesoporous silica nanoparticles for signal amplification in electrochemical biosensor

[EN] We report herein a novel sensing strategy for electrochemical biosensors, by using mesoporous silica nanoparticles loaded with the redox probe methylene blue and capped with an avidin/imminobiotin stimulus-responsive gate-like ensemble as signal amplification element. As a proof of concept, an aptasensor for carcinoembryonic antigen (CEA) was constructed by attaching a biotin and thiol-functionalized anti-CEA DNA hairpin aptamer on gold nanoparticles modified carbon screen-printed electrodes. The biosensing approach relied on the unfolding of the aptamer molecule after specific recognition of CEA, unmasking the biotin residue and allowing further association with the avidin-capped mesoporous nanocarrier. Incubation with H2SO4 trigger the release of the encapsulated redox probe allowing the detection of the cancer biomarker from 1.0 pg/mL to 160 ng/mL.Financial support from the Spanish Ministry of Economy and Competitiveness (projects CTQ2014-58989-P, CTQ2015-71936-REDT, CTQ2017-87954-P and RTI2018-100910-B-C41, fellowship BES-2015-073565 to SJF) and the Generalitat Valencia (Project PROMETEO/2018/024) are gratefully acknowledged.Jimenez-Falcao, S.; Parra-Nieto, J.; Pérez-Cuadrado, H.; Martínez-Máñez, R.; Martínez-Ruiz, P.; Villalonga, R. (2019). Avidin-gated mesoporous silica nanoparticles for signal amplification in electrochemical biosensor. Electrochemistry Communications. 108:1-4. https://doi.org/10.1016/j.elecom.2019.1065561410

Gold Nanozymes: Smart Hybrids with Outstanding Applications

Acknowledgments: We gratefully acknowledge financial support from the Ministerio de Universidades de España and the Resilience Funds Next Generation of the European Union (Margarita Salas Grant for S.J.-F. and A.A.G.-V.). We would also like to thank Agencia Estatal de Investigación and Ministerio de Ciencia e Innovación of Spain, to “ERDF A way of making Europe”, to the “European Union” (for RTI) and to the “European Union NextGenerationEU/PRTR” (for TED) for supporting our projects.Nanozymes are nanostructured artificial enzymes that have attracted great attention among researchers because of their ability to mimic relevant biological reactions carried out by their natural counterparts, but with the capability to overcome natural enzymes’ drawbacks such as low thermostability or narrow substrate scope. The promising enzyme-like properties of these systems make nanozymes excellent candidates for innovative solutions in different scientific fields such as analytical chemistry, catalysis or medicine. Thus, nanozymes with different type of activities are of special interest owing to their versatility since they can reproduce several biological reactions according to the substrates and the environmental conditions. In this context, gold-based nanozymes are a representative example of multifunctional structures that can perform a great number of enzymelike activities. In addition, the combination of gold-based materials with structures of organic and inorganic chemical nature yields even more powerful hybrid nanozymes, which enhance their activity by providing improved features. This review will carry out a deep insight into gold-based nanozymes, revisiting not only the different type of biological enzymatic reactions that can be achieved with these kinds of systems, but also structural features of some of the most relevant hybrid gold-based nanozymes described in the literature. This literature review will also provide a representative picture of the potential of these structures to solve future technological challenges.RTI2018-094322-B-I00 and TED2021-132175B-I00 funded byMCIN/AEI/10.13039/501100011033ERDF A way of making EuropeEuropean UnionEuropean Union NextGenerationEU/PRT

Gold Nanozymes: Smart Hybrids with Outstanding Applications

Nanozymes are nanostructured artificial enzymes that have attracted great attention among researchers because of their ability to mimic relevant biological reactions carried out by their natural counterparts, but with the capability to overcome natural enzymes’ drawbacks such as low thermostability or narrow substrate scope. The promising enzyme-like properties of these systems make nanozymes excellent candidates for innovative solutions in different scientific fields such as analytical chemistry, catalysis or medicine. Thus, nanozymes with different type of activities are of special interest owing to their versatility since they can reproduce several biological reactions according to the substrates and the environmental conditions. In this context, gold-based nanozymes are a representative example of multifunctional structures that can perform a great number of enzyme-like activities. In addition, the combination of gold-based materials with structures of organic and inorganic chemical nature yields even more powerful hybrid nanozymes, which enhance their activity by providing improved features. This review will carry out a deep insight into gold-based nanozymes, revisiting not only the different type of biological enzymatic reactions that can be achieved with these kinds of systems, but also structural features of some of the most relevant hybrid gold-based nanozymes described in the literature. This literature review will also provide a representative picture of the potential of these structures to solve future technological challenges

Dithioacetal-mechanized mesoporous nanosensor for Hg(II) determination

This work describes the construction of a novel colorimetric nanosensor for Hg(II), based on mechanized mesoporous silica nanoparticles (MSN). The nanodevice is constructed by grafting new dithiocetal-based stimulus-responsive molecular gates on MSN loaded with a reporter dye. This nanosensor is able to detect Hg(II) in the range of concentrations from 154 pM to 31 nM, with a sensitivity of 29.9 a.u/μM and a detection limit as low as 60 pM. The device also shows high selectivity for Hg(II)

Glucose-responsive enzyme-controlled mesoporous nanomachine with a layer-by-layer supramolecular architecture

\u3cp\u3eHere we describe the construction of an integrated and pH-sensitive nanomachine with layer-by-layer supramolecular design and enzymatic control for on-command delivery. The nanodevice comprises a first layer of β-cyclodextrin-coated gold nanoparticles as capping element of benzimidazole functionalized mesoporous silica nanoparticles, and a second control layer based on an adatamantane-modified glucose oxidase derivative. The nanomachine was selectively fuelled by glucose and successfully employed for the autonomous release of doxorubicin in HeLa cancer cells.\u3c/p\u3

Neotropical freshwater fisheries : A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications