36 results on '"Guillermo Lasarte-Aragonés"'
Search Results
2. Self assembling nanoparticle enzyme clusters provide access to substrate channeling in multienzymatic cascades
- Author
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Joyce C. Breger, James N. Vranish, Eunkeu Oh, Michael H. Stewart, Kimihiro Susumu, Guillermo Lasarte-Aragonés, Gregory A. Ellis, Scott A. Walper, Sebastián A. Díaz, Shelby L. Hooe, William P. Klein, Meghna Thakur, Mario G. Ancona, and Igor L. Medintz
- Subjects
Science - Abstract
Channeling between enzymes is a uniquely nanoscale phenomenon that can improve multienzymatic reaction rates. Here, the authors demonstrate that multistep enzyme cascades can self-assemble with nanoparticles into nanoclusters that access channeling and improve the underlying catalytic flux by several fold.
- Published
- 2023
- Full Text
- View/download PDF
3. Effervescence-Assisted Microextraction—One Decade of Developments
- Author
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Guillermo Lasarte-Aragonés, Rafael Lucena, and Soledad Cárdenas
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dispersion ,micro-solid phase extraction ,dispersive liquid–liquid extraction ,effervescence ,Organic chemistry ,QD241-441 - Abstract
Dispersive microextraction techniques are key in the analytical sample treatment context as they combine a favored thermodynamics and kinetics isolation of the target analytes from the sample matrix. The dispersion of the extractant in the form of tiny particles or drops, depending on the technique, into the sample enlarges the contact surface area between phases, thus enhancing the mass transference. This dispersion can be achieved by applying external energy sources, the use of chemicals, or the combination of both strategies. Effervescence-assisted microextraction emerged in 2011 as a new alternative in this context. The technique uses in situ-generated carbon dioxide as the disperser, and it has been successfully applied in the solid-phase and liquid-phase microextraction fields. This minireview explains the main fundamentals of the technique, its potential and the main developments reported.
- Published
- 2020
- Full Text
- View/download PDF
4. Application of Switchable Hydrophobicity Solvents for Extraction of Emerging Contaminants in Wastewater Samples
- Author
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Guillermo Lasarte-Aragonés, Alejandro Álvarez-Lueje, Ricardo Salazar, and Carla Toledo-Neira
- Subjects
emerging contaminants ,switchable hydrophobicity solvents ,homogeneous liquid-liquid microextraction ,high-performance liquid chromatography ,partition coefficient ,Organic chemistry ,QD241-441 - Abstract
In the present work, the effectiveness of switchable hydrophobicity solvents (SHSs) as extraction solvent (N,N-Dimethylcyclohexylamine (DMCA), N,N-Diethylethanamine (TEA), and N,N-Benzyldimethylamine (DMBA)) for a variety of emerging pollutants was evaluated. Different pharmaceutical products (nonsteroidal anti-inflammatory drugs (NSAIDs), hormones, and triclosan) were selected as target analytes, covering a range of hydrophobicity (LogP) of 3.1 to 5.2. The optimized procedure was used for the determination of the target pharmaceutical analytes in wastewater samples as model analytical problem. Absolute extraction recoveries were in the range of 51% to 103%. The presented method permits the determination of the target analytes at the low ng mL−1 level, ranging from 0.8 to 5.9 (except for Triclosan, 106 ng mL−1) with good precision (relative standard deviation lower than 6%) using high-pressure liquid chromatography (HPLC) combined with ultraviolet (DAD) and fluorescence (FLR) detection. The microextraction alternative resulted in a fast, simple, and green method for a wide variety of analytes in environmental water sample. The results suggest that this type of solvent turns out to be a great alternative for the determination of different analytes in relatively complex water samples.
- Published
- 2019
- Full Text
- View/download PDF
5. Mechanochemically designed bismuth-based halide perovskites for efficient photocatalytic oxidation of vanillyl alcohol
- Author
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José Estrada-Pomares, Susana Ramos-Terrón, Guillermo Lasarte-Aragonés, Rafael Lucena, Soledad Cárdenas, Daily Rodríguez-Padrón, Rafael Luque, and Gustavo de Miguel
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Renewable Energy, Sustainability and the Environment ,General Materials Science ,General Chemistry - Abstract
Mechanochemically synthesized bismuth-based halide perovskites are reported as efficient and stable photocatalytic nanomaterials for vanillyl alcohol oxidation to vanillin.
- Published
- 2022
6. Flurescence Sensors for the Food Industry
- Author
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Guillermo Lasarte-Aragonés, Laura Soriano-Dotor, Ángela I. López-Lorente, Rafael Lucena, and Soledad Cárdenas
- Published
- 2023
7. List of contributors
- Author
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Diego W. Allgaier-Díaz, Sergio Armenta, Julián Eduardo Ballen Castiblanco, Ezel Boyaci, Cecilia Cagliero, Soledad Cárdenas, Francisco A. Casado-Carmona, Nathália de Aguiar Porto, Beatriz De Caroli Vizioli, Francesc A. Esteve-Turrillas, Salvador Garrigues, Emanuela Gionfriddo, German Augusto Gómez-Ríos, Miguel de la Guardia, Adrián Gutiérrez-Serpa, Leandro Wang Hantao, Ana I. Jiménez-Abizanda, Guillermo Lasarte-Aragonés, Rafael Lucena, Arianna Marengo, Amilton Moreira de Oliveira, Verónica Pino, Orfeas-Evangelos Plastiras, Nathaly Reyes-Garcés, Patrizia Rubiolo, Victoria F. Samanidou, Barbara Sgorbini, and Marcos Tascon
- Published
- 2023
8. Green sample preparation techniques in environmental analysis
- Author
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Francisco A. Casado-Carmona, Guillermo Lasarte-Aragonés, Rafael Lucena, and Soledad Cárdenas
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- 2023
9. Deep eutectic solvent coated paper: Sustainable sorptive phase for sample preparation
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Inmaculada López-Ruiz, Guillermo Lasarte-Aragonés, Rafael Lucena, and Soledad Cárdenas
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Organic Chemistry ,General Medicine ,Biochemistry ,Analytical Chemistry - Published
- 2023
10. Femtosecond Laser Pulse Excitation of DNA-Labeled Gold Nanoparticles: Establishing a Quantitative Local Nanothermometer for Biological Applications
- Author
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Matthew Chiriboga, Eunkeu Oh, Joseph S. Melinger, Sebastián A. Díaz, Carl W. Brown, David A. Hastman, Paul D. Cunningham, Igor L. Medintz, Zachary J. Salvato, Thomas M. Salvato, Guillermo Lasarte Aragonés, and Divita Mathur
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Materials science ,Metal Nanoparticles ,General Physics and Astronomy ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,law.invention ,Nucleic acid thermodynamics ,law ,General Materials Science ,Plasmonic nanoparticles ,Lasers ,Photothermal effect ,Temperature ,General Engineering ,DNA ,Photothermal therapy ,021001 nanoscience & nanotechnology ,Laser ,0104 chemical sciences ,Chemical physics ,Colloidal gold ,Femtosecond ,Gold ,0210 nano-technology - Abstract
Femtosecond (fs) laser pulsed excitation of plasmonic nanoparticle (NP)-biomolecule conjugates is a promising method to locally heat biological materials. Studies have demonstrated that fs pulses of light can modulate the activity of DNA or proteins when attached to plasmonic NPs; however, the precision over subsequent biological function remains largely undetermined. Specifically, the temperature the localized biomolecules "experience" remains unknown. We used 55 nm gold nanoparticles (AuNPs) displaying double-stranded (ds) DNA to examine how, for dsDNA with different melting temperatures, the laser pulse energy fluence and bulk solution temperature affect the rate of local DNA denaturation. A universal "template" single-stranded DNA was attached to the AuNP surface, and three dye-labeled probe strands, distinct in length and melting temperature, were hybridized to it creating three individual dsDNA-AuNP bioconjugates. The dye-labeled probe strands were used to quantify the rate and amount of DNA release after a given number of light pulses, which was then correlated to the dsDNA denaturation temperature, resulting in a quantitative nanothermometer. The localized DNA denaturation rate could be modulated by more than threefold over the biologically relevant range of 8-53 °C by varying pulse energy fluence, DNA melting temperature, and surrounding bath temperature. With a modified dissociation equation tailored for this system, a "sensed" temperature parameter was extracted and compared to simulated AuNP temperature profiles. Determining actual biological responses in such systems can allow researchers to design precision nanoscale photothermal heating sources.
- Published
- 2020
11. Artificial Multienzyme Scaffolds: Pursuing in Vitro Substrate Channeling with an Overview of Current Progress
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Gregory A. Ellis, Igor L. Medintz, Meghna Thakur, William P. Klein, Scott A. Walper, and Guillermo Lasarte-Aragonés
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Synthetic biology ,Health services ,Materials science ,010405 organic chemistry ,Substrate channeling ,Nanotechnology ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences - Abstract
Artificial multienzyme scaffolds are being developed for in vitro cascaded biocatalytic activity and, in particular, accessing substrate channeling. This review covers progress in this field over t...
- Published
- 2019
12. Nanoparticle–Peptide–Drug Bioconjugates for Unassisted Defeat of Multidrug Resistance in a Model Cancer Cell Line
- Author
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Eleonora Petryayeva, W. Russ Algar, Eunkeu Oh, Guillermo Lasarte-Aragonés, Kimihiro Susumu, Ajmeeta Sangtani, Igor L. Medintz, James B. Delehanty, and Alan L. Huston
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Drug ,Endosome ,media_common.quotation_subject ,Endocytic cycle ,Biomedical Engineering ,Pharmaceutical Science ,Antineoplastic Agents ,Bioengineering ,Nanoconjugates ,02 engineering and technology ,Drug resistance ,01 natural sciences ,Cell Line, Tumor ,Neoplasms ,Humans ,Internalization ,media_common ,Pharmacology ,Drug Carriers ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,021001 nanoscience & nanotechnology ,Drug Resistance, Multiple ,0104 chemical sciences ,3. Good health ,Multiple drug resistance ,Cell killing ,Doxorubicin ,Drug Resistance, Neoplasm ,Cancer cell ,Cancer research ,Peptides ,0210 nano-technology ,Biotechnology - Abstract
Multidrug resistance (MDR) is a significant challenge in the treatment of many types of cancers as membrane-associated transporters actively pump drugs out of the cell, limiting therapeutic efficacy. While nanoparticle (NP)-based therapeutics have emerged as a mechanism for overcoming MDR, they often rely on the delivery of multiple anticancer drugs, nucleic acid hybrids, or MDR pump inhibitors. The effectiveness of these strategies, however, can be limited by their off-target toxicity or the need for genetic transfection. In this paper, we describe a NP-peptide-drug bioconjugate that achieves significant cell killing in MDR-positive cancer cells without the need for additional drugs. We use a quantum dot (QD) as a central scaffold to append two species of peptide, a cell-uptake peptide to facilitate endocytic internalization and a peptide-drug conjugate that is susceptible to cleavage by esterases found within the endocytic pathway. This approach relies on spatiotemporal control over drug release, where endosomes traffic drug away from membrane-resident pumps and release it closer to the nucleus. Cellular internalization studies showed high uptake of the NP-drug complex and nuclear localization of the drug after 48 h in MDR-positive cells. Additionally, cellular proliferation assays demonstrated a 40% decrease in cell viability for the NP-drug bioconjugate compared to free drug, confirming the utility of this system in overcoming MDR in cancer cells.
- Published
- 2019
13. Switchable solvents
- Author
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Inmaculada Lopez-Ruiz, Guillermo Lasarte-Aragonés, Rafael Lucena, and Soledad Cárdenas
- Published
- 2021
14. Selectivity-enhanced sorbents
- Author
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Rafael Lucena, Soledad Cárdenas, Ángela I. López-Lorente, Guillermo Lasarte-Aragonés, and María Del Carmen Díaz-Liñán
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Chemistry ,Selectivity ,Combinatorial chemistry - Published
- 2021
15. List of contributors
- Author
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Usama Alshana, Juan L. Benedé, Dimitrios Bitas, Noelia Caballero-Casero, Eduardo Carasek, Soledad Cárdenas, Enrique Javier Carrasco-Correa, Alberto Chisvert, María Del Carmen Díaz-Liñán, Jun Ding, Ronald V. Emmons, Yuqi Feng, Beatriz Fresco-Cala, Emanuela Gionfriddo, G. Gómez Ríos, Miguel Ángel González-Curbelo, Javier González-Sálamo, Javier Hernández-Borges, José Manuel Herrero-Martínez, Gabriel Jiménez-Skrzypek, Abuzar Kabir, Guillermo Lasarte-Aragonés, Mauricio Llaver, Ángela Inmaculada López-Lorente, Inmaculada Lopez-Ruiz, Rafael Lucena, Gabriela Mafra, Josias Merib, Jaime Millán-Santiago, M. Miró, Attilio Naccarato, Aghogho A. Olomukoro, Cecilia Ortega-Zamora, Idaira Pacheco-Fernández, Stig Pedersen-Bjergaard, Xitian Peng, Verónica Pino, Feliciano Priego-Capote, Elefteria Psillakis, Soledad Rubio, Victoria Samanidou, Mohammad Saraji, Ali Shahvar, Mustafa Soylak, María Vergara-Barberán, and Rodolfo G. Wuilloud
- Published
- 2021
16. Quantum Dot Lipase Biosensor Utilizing a Custom-Synthesized Peptidyl-Ester Substrate
- Author
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Guillermo Lasarte-Aragonés, Igor L. Medintz, Sebastián A. Díaz, Jesper Brask, Joyce C. Breger, and Kimihiro Susumu
- Subjects
Fluid Flow and Transfer Processes ,chemistry.chemical_classification ,biology ,Chemistry ,Process Chemistry and Technology ,Nanoparticle ,Bioengineering ,Peptide ,Esters ,Biosensing Techniques ,Lipase ,Acceptor ,Combinatorial chemistry ,Hydrolysis ,Förster resonance energy transfer ,Quantum dot ,Quantum Dots ,biology.protein ,Fluorescence Resonance Energy Transfer ,Instrumentation ,Biosensor - Abstract
Lipases are an important class of lipid hydrolyzing enzymes that play significant roles in many aspects of cell biology and digestion; they also have large roles in commercial food and biofuel preparation and are being targeted for pharmaceutical development. Given these, and many other biotechnological roles, sensitive and specific biosensors capable of monitoring lipase activity in a quantitative manner are critical. Here, we describe a Forster resonance energy transfer (FRET)-based biosensor that originates from a custom-synthesized ester substrate displaying a peptide at one end and a dye acceptor at the other. These substrates were ratiometrically self-assembled to luminescent semiconductor quantum dot (QD) donors by metal affinity coordination using the appended peptide's terminal hexahistidine motif to give rise to the full biosensing construct. This resulted in a high rate of FRET between the QD donor and the proximal substrate's dye acceptor. The lipase hydrolyzed the intervening target ester bond in the peptide substrate which, in turn, displaced the dye acceptor containing component and altered the rate of FRET in a concentration-dependent manner. Specifics of the substrate's stepwise synthesis are described along with the sensors assembly, characterization, and application in a quantitative proof-of-concept demonstration assay that is based on an integrated Michaelis-Menten kinetic approach. The utility of this unique nanoparticle-based architecture within a sensor configuration is then discussed.
- Published
- 2020
17. Application of Switchable Hydrophobicity Solvents for Extraction of Emerging Contaminants in Wastewater Samples
- Author
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Carla Toledo-Neira, Alejandro Álvarez-Lueje, Ricardo Salazar, and Guillermo Lasarte-Aragonés
- Subjects
Analyte ,Pharmaceutical Science ,010501 environmental sciences ,switchable hydrophobicity solvents ,Wastewater ,partition coefficient ,01 natural sciences ,High-performance liquid chromatography ,Article ,Analytical Chemistry ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,Drug Discovery ,Sodium Hydroxide ,Physical and Theoretical Chemistry ,high-performance liquid chromatography ,Homogeneous liquid-liquid microextraction ,0105 earth and related environmental sciences ,emerging contaminants ,Emerging contaminants ,Cyclohexylamines ,Chromatography ,Switchable hydrophobicity solvents ,010401 analytical chemistry ,Organic Chemistry ,Extraction (chemistry) ,Solid Phase Extraction ,Absolute (perfumery) ,0104 chemical sciences ,Triclosan ,Partition coefficient ,Solvent ,Partition coefficient ,chemistry ,Pharmaceutical Preparations ,Chemistry (miscellaneous) ,Solvents ,Molecular Medicine ,homogeneous liquid-liquid microextraction ,Hydrophobic and Hydrophilic Interactions ,Water Pollutants, Chemical - Abstract
In the present work, the effectiveness of switchable hydrophobicity solvents (SHSs) as extraction solvent (N,N-Dimethylcyclohexylamine (DMCA), N,N-Diethylethanamine (TEA), and N,N-Benzyldimethylamine (DMBA)) for a variety of emerging pollutants was evaluated. Different pharmaceutical products (nonsteroidal anti-inflammatory drugs (NSAIDs), hormones, and triclosan) were selected as target analytes, covering a range of hydrophobicity (LogP) of 3.1 to 5.2. The optimized procedure was used for the determination of the target pharmaceutical analytes in wastewater samples as model analytical problem. Absolute extraction recoveries were in the range of 51% to 103%. The presented method permits the determination of the target analytes at the low ng mL&minus, 1 level, ranging from 0.8 to 5.9 (except for Triclosan, 106 ng mL&minus, 1) with good precision (relative standard deviation lower than 6%) using high-pressure liquid chromatography (HPLC) combined with ultraviolet (DAD) and fluorescence (FLR) detection. The microextraction alternative resulted in a fast, simple, and green method for a wide variety of analytes in environmental water sample. The results suggest that this type of solvent turns out to be a great alternative for the determination of different analytes in relatively complex water samples.
- Published
- 2019
18. Detecting Biothreat Agents: From Current Diagnostics to Developing Sensor Technologies
- Author
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Scott A. Walper, Clare E. Rowland, Igor L. Medintz, Guillermo Lasarte Aragonés, Carl W. Brown, Kim E. Sapsford, and Joyce C. Breger
- Subjects
Point-of-Care Systems ,Early detection ,Biological Warfare Agents ,Bioengineering ,Context (language use) ,Biosensing Techniques ,02 engineering and technology ,01 natural sciences ,Limit of Detection ,Humans ,Instrumentation ,Toxins, Biological ,Immunoassay ,Fluid Flow and Transfer Processes ,Bacteria ,Process Chemistry and Technology ,010401 analytical chemistry ,021001 nanoscience & nanotechnology ,Pathogenicity ,0104 chemical sciences ,Risk analysis (engineering) ,Virus Diseases ,Viruses ,Terrorism ,Business ,0210 nano-technology - Abstract
Although a fundamental understanding of the pathogenicity of most biothreat agents has been elucidated and available treatments have increased substantially over the past decades, they still represent a significant public health threat in this age of (bio)terrorism, indiscriminate warfare, pollution, climate change, unchecked population growth, and globalization. The key step to almost all prevention, protection, prophylaxis, post-exposure treatment, and mitigation of any bioagent is early detection. Here, we review available methods for detecting bioagents including pathogenic bacteria and viruses along with their toxins. An introduction placing this subject in the historical context of previous naturally occurring outbreaks and efforts to weaponize selected agents is first provided along with definitions and relevant considerations. An overview of the detection technologies that find use in this endeavor along with how they provide data or transduce signal within a sensing configuration follows. Current "gold" standards for biothreat detection/diagnostics along with a listing of relevant FDA approved in vitro diagnostic devices is then discussed to provide an overview of the current state of the art. Given the 2014 outbreak of Ebola virus in Western Africa and the recent 2016 spread of Zika virus in the Americas, discussion of what constitutes a public health emergency and how new in vitro diagnostic devices are authorized for emergency use in the U.S. are also included. The majority of the Review is then subdivided around the sensing of bacterial, viral, and toxin biothreats with each including an overview of the major agents in that class, a detailed cross-section of different sensing methods in development based on assay format or analytical technique, and some discussion of related microfluidic lab-on-a-chip/point-of-care devices. Finally, an outlook is given on how this field will develop from the perspective of the biosensing technology itself and the new emerging threats they may face.
- Published
- 2018
19. A Quantum Dot-Protein Bioconjugate That Provides for Extracellular Control of Intracellular Drug Release
- Author
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Scott A. Walper, Lauren D. Field, Guillermo Lasarte-Aragonés, Igor L. Medintz, Eunkeu Oh, James B. Delehanty, and Kimihiro Susumu
- Subjects
Biomedical Engineering ,Pharmaceutical Science ,Bioengineering ,02 engineering and technology ,010402 general chemistry ,Binding, Competitive ,01 natural sciences ,Maltose-Binding Proteins ,Maltose-binding protein ,Drug Delivery Systems ,Chlorocebus aethiops ,Quantum Dots ,Extracellular ,Animals ,Humans ,Maltose ,Pharmacology ,Binding Sites ,Bioconjugation ,biology ,Chemistry ,beta-Cyclodextrins ,Organic Chemistry ,021001 nanoscience & nanotechnology ,Ligand (biochemistry) ,0104 chemical sciences ,Drug Liberation ,Förster resonance energy transfer ,COS Cells ,Drug delivery ,Biophysics ,biology.protein ,0210 nano-technology ,Intracellular ,Biotechnology ,Conjugate - Abstract
The ability to control the intracellular release of drug cargos from nanobioconjugate delivery scaffolds is critical for the successful implementation of nanoparticle (NP)-mediated drug delivery. This is particularly true for hard NP carriers such as semiconductor quantum dots (QDs) and gold NPs. Here, we report the development of a QD-based multicomponent drug release system that, when delivered to the cytosol of mammalian cells, is triggered to release its drug cargo by the simple addition of a competitive ligand to the extracellular medium. The ensemble construct consists of the central QD scaffold that is decorated with a fixed number of maltose binding proteins (MBPs). The MBP binding site is loaded with dye or drug conjugates of the maltose analogue beta-cyclodextrin (βCD) to yield a QD-MBP-βCD ensemble conjugate. The fidelity of conjugate assembly is monitored by Förster resonance energy transfer (FRET) from the QD donor to the dye/drug acceptor. Microplate-based FRET assays demonstrated that the βCD conjugate was released from the MBP binding pocket by maltose addition with an affinity that matched native MBP-maltose binding interactions. In COS-1 cells, the microinjected assembled conjugates remained stably intact in the cytosol until the addition of maltose to the extracellular medium, which underwent facilitated uptake into the cell. Live cell FRET-based confocal microscopy imaging captured the kinetics of realtime release of the βCD ligand as a function of extracellular maltose concentration. Our results demonstrate the utility of the self-assembled QD-MBP-βCD system to facilitate intracellular drug release that is triggered extracellularly through the simple addition of a well-tolerated nutrient and is not dependent on the use of light, magnetic field, ultrasound, or other traditional methods of stimulated drug release. We expect this extracellularly triggered drug release modality to be useful for the in vitro characterization of new drug candidates intended for systemic delivery/actuation and potentially for on-demand drug release in vivo.
- Published
- 2018
20. Quantum Dots as Förster Resonance Energy Transfer Acceptors of Lanthanides in Time-Resolved Bioassays
- Author
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Sebastián A. Díaz, Kimihiro Susumu, Guillermo Lasarte-Aragonés, Igor L. Medintz, Aniket, James N. Vranish, William P. Klein, and Robert G. Lowery
- Subjects
chemistry.chemical_element ,Terbium ,02 engineering and technology ,Conjugated system ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,Acceptor ,0104 chemical sciences ,Adenosine diphosphate ,chemistry.chemical_compound ,Förster resonance energy transfer ,chemistry ,Quantum dot ,General Materials Science ,0210 nano-technology ,Biosensor - Abstract
We report a flexible and modular design for biosensors based on exploiting semiconductor quantum dots (QDs) and their excellent Forster resonance energy transfer (FRET) acceptor properties along with the long-lived fluorescent lifetimes of lanthanide donors. We demonstrate the format’s wide application by developing a broad adenosine diphosphate (ADP) sensor with quantitative and high-throughput capabilities as a kinase/ATPase assay method. The sensor is based on a Terbium (Tb)-labeled antibody (Ab) that selectively recognizes ADP versus ATP. The Tb-labeled Ab (Ab-Tb) acts as a FRET donor to a QD, which has an ADP modified His6-peptide conjugated to its surface via metal-affinity coordination. This strategy of using self-assembly, modified peptides to present antibody epitopes on QD surfaces is readily transferable to other assays of interest. We utilize time-resolved FRET (TR-FRET) to measure the amounts of Ab-Tb bound to the QD by looking at the emission ratio of the QD and Tb in a time-gated manner, mi...
- Published
- 2018
21. Fan-based device for integrated air sampling and microextraction
- Author
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Francisco Antonio Casado-Carmona, Guillermo Lasarte-Aragonés, Soledad Cárdenas, Rafael Lucena, Kenneth G. Furton, and Abuzar Kabir
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Residue (complex analysis) ,Cyclohexane ,010401 analytical chemistry ,Extraction (chemistry) ,Xylene ,Analytical chemistry ,Sampling (statistics) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Toluene ,Computer fan ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Thermal stability ,0210 nano-technology - Abstract
In this article, a new air sampler based on a conventional computer fan is presented and evaluated. The fan has a double role as it acts as the air pumping system and supports the sorptive phases, which are located on its blades. The compact design and the reduced energy consumption (it can operate with a standard cell phone charger) confers high portability to the device. Also, a simple alternative integrated into the fan is proposed for using an internal standard during the sampling, thus increasing the precision of the measurements. In this first communication, sol-gel Carbowax 20 M coated fabric phases are used as sorptive membranes thanks to their planar geometry, mechanical and thermal stability, and their versatility covering different interaction chemistries. After sampling, the fabric phases are placed in a headspace vial, which is finally analyzed by gas chromatography-mass spectrometry. The sampler has been characterized for the extraction of selected volatile organic compounds (chloroform, benzaldehyde, toluene, and cyclohexane) from air and its versatility has also been evaluated by the identification of semi-volatile compounds in working place (toluene and xylene in laboratory residue storage room) and biogenic volatile compounds in natural samples (terpenes in fresh pine needles and orange peel samples).
- Published
- 2021
22. Elucidating Surface Ligand-Dependent Kinetic Enhancement of Proteolytic Activity at Surface-Modified Quantum Dots
- Author
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Carl W. Brown, Igor L. Medintz, Petr Král, Jeffrey R. Deschamps, Michael H. Stewart, Lauren D. Field, Eunkeu Oh, Soumyo Sen, Guillermo Lasarte Aragonés, Kelly Boeneman Gemmill, Kimihiro Susumu, Joyce C. Breger, and Sebastián A. Díaz
- Subjects
chemistry.chemical_classification ,medicine.diagnostic_test ,Chemistry ,Ligand ,Biomolecule ,Proteolysis ,General Engineering ,General Physics and Astronomy ,Nanoparticle ,Peptide ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Trypsin ,01 natural sciences ,Michaelis–Menten kinetics ,0104 chemical sciences ,Quantum dot ,medicine ,Biophysics ,General Materials Science ,0210 nano-technology ,medicine.drug - Abstract
Combining biomolecules such as enzymes with nanoparticles has much to offer for creating next generation synergistically functional bionanomaterials. However, almost nothing is known about how these two disparate components interact at this critical biomolecular-materials interface to give rise to improved activity and emergent properties. Here we examine how the nanoparticle surface can influence and increase localized enzyme activity using a designer experimental system consisting of trypsin proteolysis acting on peptide-substrates displayed around semiconductor quantum dots (QDs). To minimize the complexity of analyzing this system, only the chemical nature of the QD surface functionalizing ligands were modified. This was accomplished by synthesizing a series of QD ligands that were either positively or negatively charged, zwitterionic, neutral, and with differing lengths. The QDs were then assembled with different ratios of dye-labeled peptide substrates and exposed to trypsin giving rise to progress curves that were monitored by Förster resonance energy transfer (FRET). The resulting trypsin activity profiles were analyzed in the context of detailed molecular dynamics simulations of key interactions occurring at this interface. Overall, we find that a combination of factors can give rise to a localized activity that was 35-fold higher than comparable freely diffusing enzyme-substrate interactions. Contributing factors include the peptide substrate being prominently displayed extending from the QD surface and not sterically hindered by the longer surface ligands in conjunction with the presence of electrostatic and other productive attractive forces between the enzyme and the QD surface. An intimate understanding of such critical interactions at this interface can produce a set of guidelines that will allow the rational design of next generation high-activity bionanocomposites and theranostics.
- Published
- 2017
23. Time-gated FRET from terbium labeled antibodies to quantum dot acceptors for broad ADP sensing
- Author
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Kimihiro Susumu, Robert G. Lowery, William P. Klein, Guillermo Lasarte-Aragonés, Igor L. Medintz, James N. Vranish, and Sebastián A. Díaz
- Subjects
Analyte ,Förster resonance energy transfer ,Chemistry ,Quantum dot ,chemistry.chemical_element ,Terbium ,Conjugated system ,Photochemistry ,Acceptor ,Small molecule ,Fluorescence - Abstract
Time-gated Forster resonance energy transfer (TR-FRET) introduces a time-gate before the detection of the fluorescence spectra or photon count. If the donor is sufficiently long-lived TR-FRET allows for any initial acceptor sensitization to decay before the measurement. TR-FRET in the μs range is particularly advantageous for small molecule assays as it eliminates background fluorescence from screening compounds, which typically have ns lifetimes. The sensor we developed utilizes Terbium (Tb)-labeled antibodies (Ab) that selectively recognizes adenosine diphosphate (ADP). The Tb emitters have fluorescence lifetimes on the ms scale, making them excellent candidates for TR-FRET donors. In an attempt to increase the FRET signal we utilized a semiconductor quantum dot (QD) as an acceptor. The QD presented an ADP modified His6-peptide conjugated to its surface via self-assembly metal-affinity coordination, which bound the Tb labeled Ab to the QD surface. QDs have large extinction coefficients, broad absorption, brightness, and sharp emission peaks, optimal for sensitive and multiplexed detection. By using a QD acceptor the Forster radius was increased by approximately 2 nm as compared to traditional organic dyes. We were able to demonstrate a Tb-to-QD based TR-FRET bioassay for broadly applicable ADP sensing, working at nM concentrations for sensor, analyte, and enzyme. Quantitative values were obtained for the kinetics of a model enzyme (glucokinase). The specific sensor was also capable of discriminating enzyme inhibitor capabilities of structurally similar compounds. The strategy of using modified peptides to present antibody epitopes on QD surfaces is readily transferable to other assays.
- Published
- 2019
24. Ionic liquids-based dispersive liquid-liquid microextraction for determination of carcinogenic polycyclic aromatic hydrocarbons in tea beverages: Evaluation of infusion preparation on pollutants release
- Author
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Daniela Muñoz-Lira, Manuel Bravo, Guillermo Lasarte-Aragonés, Carla Toledo-Neira, Ricardo Salazar, and Camilo Rivera-Vera
- Subjects
Pollutant ,Detection limit ,Analyte ,Chromatography ,010401 analytical chemistry ,04 agricultural and veterinary sciences ,040401 food science ,01 natural sciences ,Fluorescence spectroscopy ,0104 chemical sciences ,chemistry.chemical_compound ,0404 agricultural biotechnology ,chemistry ,Ionic liquid ,Liquid liquid ,Carcinogen ,Black tea ,Food Science ,Biotechnology - Abstract
A rapid, and sensitive analytical method based on the use of Dispersive Liquid-Liquid Microextraction, ionic liquids and High-performance liquid chromatography equipped with a fluorescence detector for determination of six carcinogenic Polycyclic Aromatic Hydrocarbons (PAHs) in tea infusions samples was developed. The effects of various parameters associated to analytical method and tea infusions preparation were studied. Under the optimized conditions the method exhibited good precision, with relative standard deviation values between 2% and 5%, for the six PAHs. Limits of detection of the method achieved for all the analytes were between 2.0 and 30.8 ng L−1, and the recoveries ranged from 56% to 94%. The proposed method was successfully applied to the analysis of twenty-five tea marketed in Chile. The concentration found for the six carcinogenic PAHs were reported for the first time in this study and the values are found between 0.4 and 9.7 μg L−1 for black tea, 7.0–16.3 μg L−1 for green tea and 1.4–8.25 μg L−1 for white tea.
- Published
- 2019
25. Enhancing Coupled Enzymatic Activity by Colocalization on Nanoparticle Surfaces: Kinetic Evidence for Directed Channeling of Intermediates
- Author
-
Eunkeu Oh, Scott A. Walper, Igor L. Medintz, Joyce C. Breger, Kimihiro Susumu, Guillermo Lasarte Aragonés, Mario G. Ancona, and James N. Vranish
- Subjects
Surface Properties ,Substrate channeling ,Pyruvate Kinase ,General Physics and Astronomy ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,chemistry.chemical_compound ,Lactate dehydrogenase ,Lactobacillus leichmannii ,Quantum Dots ,General Materials Science ,Enzyme kinetics ,Lactate Dehydrogenases ,chemistry.chemical_classification ,Chemistry ,General Engineering ,021001 nanoscience & nanotechnology ,Enzymes, Immobilized ,0104 chemical sciences ,Kinetics ,Enzyme ,Biocatalysis ,Biophysics ,Nanoparticles ,0210 nano-technology ,Phosphoenolpyruvate carboxykinase ,Pyruvate kinase - Abstract
Multistep enzymatic cascades are becoming more prevalent in industrial settings as engineers strive to synthesize complex products and pharmaceuticals in economical, environmentally friendly ways. Previous work has shown that immobilizing enzymes on nanoparticles can enhance their activity significantly due to localized interfacial effects, and this enhancement remains in place even when that enzyme's activity is coupled to another enzyme that is still freely diffusing. Here, we investigate the effects of displaying two enzymes with coupled catalytic activity directly on the same nanoparticle surface. For this, the well-characterized enzymes pyruvate kinase (PykA) and lactate dehydrogenase (LDH) were utilized as a model system; they jointly convert phosphoenolpyruvate to lactate in two sequential steps as part of downstream glycolysis. The enzymes were expressed with terminal polyhistidine tags to facilitate their conjugation to semiconductor quantum dots (QDs) which were used here as prototypical nanoparticles. Characterization of enzyme coassembly to two different sized QDs showed a propensity to cross-link into nanoclusters consisting of primarily dimers and some trimers. Individual and joint enzyme activity in this format was extensively investigated in direct comparison to control samples lacking the QD scaffolds. We found that QD association enhances LDH activity by50-fold and its total turnover by at least 41-fold, and that this high activation appears to be largely due to stabilization of its quarternary structure. When both enzymes are simultaneously bound to the QD surfaces, their colocalization leads to100-fold improvements in the overall rates of coupled activity. Experimental results in conjunction with detailed kinetic simulations provide evidence that this significant improvement in coupled activity is partially attributable to a combination of enhanced enzymatic activity and stabilization of LDH. More importantly, experiments aimed at disrupting channeled processes and further kinetic modeling suggest that the bulk of the performance enhancement arises from intermediary "channeling" between the QD-colocalized enzymes. A full understanding of the underlying processes that give rise to such enhancements from coupled enzymatic activity on nanoparticle scaffolds can provide design criteria for improved biocatalytic applications.
- Published
- 2018
26. Nanoparticle bioconjugate for controlled cellular delivery of doxorubicin
- Author
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Miao Wu, Kimihiro Susumu, Ajmeeta Sangtani, Alan L. Huston, Eunkeu Oh, James B. Delehanty, Igor L. Medintz, Guillermo Lasarte-Aragonés, Eleonora Petryayeva, and W. Russ Algar
- Subjects
chemistry.chemical_classification ,Förster resonance energy transfer ,Bioconjugation ,Chemistry ,Drug delivery ,Biophysics ,medicine ,Cell-penetrating peptide ,Peptide ,Doxorubicin ,Cytotoxicity ,Endocytosis ,medicine.drug - Abstract
Nanoparticle (NP)-mediated drug delivery offers the potential to overcome limitations of systemic delivery, including the ability to specifically target cargo and control release of NP-associated drug cargo. Doxorubicin (DOX) is a widely used FDA-approved cancer therapeutic; however, multiple side effects limit its utility. Thus, there is wide interest in modulating toxicity after cell delivery. Our goal here was to realize a NP-based DOX-delivery system that can modulate drug toxicity by controlling the release kinetics of DOX from the surface of a hard NP carrier. To achieve this, we employed a quantum dot (QD) as a central scaffold which DOX was appended via three different peptidyl linkages (ester, disulfide, hydrazone) that are cleavable in response to various intracellular conditions. Attachment of a cell penetrating peptide (CPP) containing a positively charged polyarginine sequence facilitates endocytosis of the ensemble. Polyhistidine-driven metal affinity coordination was used to self-assemble both peptides to the QD surface, allowing for fine control over both the ratio of peptides attached to the QD as well as DOX dose delivered to cells. Microplate-based Forster resonance energy transfer assays confirmed the successful ratiometric assembly of the conjugates and functionality of the linkages. Cell delivery experiments and cytotoxicity assays were performed to compare the various cleavable linkages to a control peptide where DOX is attached through an amide bond. The role played by various attachment chemistries used in QD-peptide-drug assemblies and their implications for the rationale in design of NPbased constructs for drug delivery is described here.
- Published
- 2018
27. Intracellularly Actuated Quantum Dot-Peptide-Doxorubicin Nanobioconjugates for Controlled Drug Delivery via the Endocytic Pathway
- Author
-
James B. Delehanty, Miao Wu, Alan L. Huston, Eleonora Petryayeva, Ajmeeta Sangtani, Eunkeu Oh, Guillermo Lasarte-Aragonés, Kimihiro Susumu, Igor L. Medintz, and W. Russ Algar
- Subjects
Endocytic cycle ,Biomedical Engineering ,Pharmaceutical Science ,Bioengineering ,Context (language use) ,Peptide ,02 engineering and technology ,Cell-Penetrating Peptides ,Nanoconjugates ,010402 general chemistry ,01 natural sciences ,Neoplasms ,Quantum Dots ,Humans ,Pharmacology ,chemistry.chemical_classification ,Liposome ,Antibiotics, Antineoplastic ,Chemistry ,Organic Chemistry ,021001 nanoscience & nanotechnology ,Controlled release ,Endocytosis ,0104 chemical sciences ,Doxorubicin ,Delayed-Action Preparations ,Drug delivery ,Biophysics ,0210 nano-technology ,Peptides ,Biotechnology ,Conjugate ,HeLa Cells - Abstract
Nanoparticle (NP)-mediated drug delivery (NMDD) has emerged as a novel method to overcome the limitations of traditional systemic delivery of therapeutics, including the controlled release of the NP-associated drug cargo. Currently, our most advanced understanding of how to control NP-associated cargos is in the context of soft nanoparticles (e.g., liposomes), but less is known about controlling the release of cargos from the surface of hard NPs (e.g., gold NPs). Here we employ a semiconductor quantum dot (QD) as a prototypical hard NP platform and use intracellularly triggered actuation to achieve spatiotemporal control of drug release and modulation of drug efficacy. Conjugated to the QD are two peptides: (1) a cell-penetrating peptide (CPP) that facilitates uptake of the conjugate into the endocytic pathway and (2) a display peptide conjugated to doxorubicin (DOX) via three different linkages (ester, disulfide, and hydrazone) that are responsive to enzymatic cleavage, reducing conditions, and low pH, respectively. Formation of the QD-[peptide-DOX]-CPP complex is driven by self-assembly that allows control over both the ratio of each peptide species conjugated to the QD and the eventual drug dose delivered to cells. Förster resonance energy transfer assays confirmed successful assembly of the QD-peptide complexes and functionality of the linkages. Confocal microscopy was employed to visualize residence of the QD-[peptide-DOX]-CPP complexes in the endocytic pathway, and distinct differences in DOX localization were noted for the ester linkage, which showed clear signs of nuclear delivery versus the hydrazone, disulfide, and amide control. Finally, delivery of the QD-[peptide-DOX]-CPP conjugate resulted in cytotoxicity for the ester linkage that was comparable to free DOX. Attachment of DOX via the hydrazone linkage facilitated intermediary toxicity, while the disulfide and amide control linkages showed minimal toxicity. Our data demonstrate the utility of hard NP-peptide bioconjugates to function as multifunctional scaffolds for simultaneous control over cellular drug uptake and toxicity and the vital role played by the nature of the chemical linkage that appends the drug to the NP carrier.
- Published
- 2017
28. Use of switchable solvents in the microextraction context
- Author
-
Miguel Valcárcel, Guillermo Lasarte-Aragonés, Rafael Lucena, and Soledad Cárdenas
- Subjects
Solvent ,Detection limit ,chemistry.chemical_compound ,Anthracene ,Chromatography ,chemistry ,Sodium hydroxide ,Reagent ,Extraction (chemistry) ,Analytical chemistry ,Context (language use) ,Gas chromatography ,Analytical Chemistry - Abstract
In this article, a new homogeneous liquid-liquid microextraction alternative, based on the use of switchable hydrophilicity solvents (SHS), is presented for the first time. The extraction technique makes use of a water-immiscible solvent (N,N-Dimethylcyclohexylamine) that can be solubilised in 1:1 ratio using CO2 as reagent. After the extraction, phases' separation is induced by the addition of sodium hydroxide, which produces a change on the ionisation state of the amine, centrifugation not being necessary. The extraction technique has been optimised and characterised using the determination of benz[a]anthracene by fluorimetric measurements in water samples as model analytical problem. Although the native fluorescence of the compound is quenched in the organic phase, this attenuation is reduced by diluting the extractant (1:1) in acetic acid. The fluorescence intensity is 35% higher in the SHS-acetic acid mixture than that obtained in pure methanol. The proposed method allows the determination of the target analyte with limit of detection of 0.08 μg/L and good precision (relative standard deviation of 6.7% at the limit of quantification level). The recoveries were in the range of 72-100% fulfilling the Environmental Protection Agency criterion. Finally, the potential use of this microextraction technique in combination with gas chromatography is shown for several polycyclic aromatic hydrocarbons.
- Published
- 2015
29. Effervescence assisted dispersive liquid–liquid microextraction with extractant removal by magnetic nanoparticles
- Author
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Rafael Lucena, Guillermo Lasarte-Aragonés, Soledad Cárdenas, and Miguel Valcárcel
- Subjects
Chromatography ,Chemistry ,Analytical technique ,Extraction (chemistry) ,Effervescence ,Mass spectrometry ,Biochemistry ,Analytical Chemistry ,Solvent ,Environmental Chemistry ,Magnetic nanoparticles ,Gas chromatography ,Dispersion (chemistry) ,Spectroscopy - Abstract
In this article, effervescence assisted dispersive liquid–liquid microextraction with extractant removal by magnetic nanoparticles is presented for the first time. The extraction technique makes use of a mixture of 1-octanol and bare Fe 3 O 4 magnetic nanoparticles (MNPs) in acetic acid. This mixture is injected into the sample, which is previously fortified with carbonate, and as a consequence of the effervescence reaction, CO 2 bubbles are generated making possible the easy dispersion of the extraction solvent. In addition, the MNPs facilitates the recovery of the 1-octanol after the extraction thanks to the interaction between hydroxyl groups present at the surface of the MNPs and the alcohol functional group of the solvent. The extraction mode has been optimized and characterized using the determination of six herbicides in water samples as model analytical problem. The enrichment factors obtained for the analytes were in the range 21–185. These values permit the determination of the target analytes at the low microgram per liter range with good precision (relative standard deviations lower than 11.7%) using gas chromatography (GC) coupled to mass spectrometry (MS) as analytical technique.
- Published
- 2014
30. Effervescence-assisted carbon nanotubes dispersion for the micro-solid-phase extraction of triazine herbicides from environmental waters
- Author
-
Miguel Valcárcel, Rafael Lucena, Guillermo Lasarte-Aragonés, and Soledad Cárdenas
- Subjects
Sorbent ,Chromatography ,Herbicides ,Nanotubes, Carbon ,Elution ,Solid Phase Extraction ,Extraction (chemistry) ,Effervescence ,Biochemistry ,High-performance liquid chromatography ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Solid phase extraction ,Dispersion (chemistry) ,Sodium carbonate ,Chromatography, High Pressure Liquid ,Water Pollutants, Chemical - Abstract
Extraction techniques are surface-dependent processes since their kinetic directly depends on the contact area between the sample and the extractant phase. The dispersion of the extractant (liquid or solid) increases this area improving the extraction efficiency. In this article, the dispersion of a nanostructured sorbent at the very low milligram level is achieved by effervescence thanks to the in situ generation of carbon dioxide. For this purpose, a special tablet containing the effervescence precursors (sodium carbonate as carbon dioxide source and sodium dihydrogen phosphate as proton donor) and the sorbent [multiwalled carbon nanotubes (MWCNTs)] is prepared. All the microextraction steps take place in a glass beaker containing 100 mL of the sample. After the extraction, the MWCNTs, enriched with the extracted analytes, are recovered by vacuum filtration. Methanol was selected to elute the retained analytes. The extraction mode is optimized and characterized using the determination of nine herbicides in water samples as model analytical problem. The absolute recoveries of the analytes were in the range 48-76 %, while relative recoveries were close to 100 % in all cases. These values permit the determination of these analytes at the low microgram per liter range with good precision (relative standard deviations lower than 9.3 %) using ultra performance liquid chromatography (UPLC) combined with ultraviolet detection (UV).
- Published
- 2013
31. Hybridization of commercial polymeric microparticles and magnetic nanoparticles for the dispersive micro-solid phase extraction of nitroaromatic hydrocarbons from water
- Author
-
Rafael Lucena, Guillermo Lasarte-Aragonés, Soledad Cárdenas, Miguel Valcárcel, and Emilia M. Reyes-Gallardo
- Subjects
Analyte ,Sorbent ,Analytical chemistry ,Fresh Water ,Sensitivity and Specificity ,Biochemistry ,Analytical Chemistry ,Phase (matter) ,Benzene Derivatives ,Solid phase extraction ,Magnetite Nanoparticles ,Chromatography, High Pressure Liquid ,Nitrobenzenes ,Detection limit ,Chromatography ,Chemistry ,Methanol ,Solid Phase Extraction ,Organic Chemistry ,Extraction (chemistry) ,Reproducibility of Results ,General Medicine ,Magnetic nanoparticles ,Sulfonic Acids ,Hybrid material ,Water Pollutants, Chemical - Abstract
In this article, the combination of commercial polymeric microparticles (OASIS MCX) and cobalt ferrite nanoparticles is evaluated in dispersive micro-solid phase extraction (D-μSPE) for the determination of six nitroaromatic hydrocarbons in water. The high affinity of the polymeric material toward the target analytes as well as the magnetic behavior of cobalt ferrite nanoparticles are combined in a synergic way to developed an efficient and simple D-μSPE approach. The sorptive performance of the hybrid material is compared with that most usual sorbents and the effect of its synthesis steps on the extraction capability is also evaluated in depth. After the optimization of selected variables, D-μSPE method was assessed in terms of linearity, sensitivity, precision and accuracy. The new extraction method allows the determination of the target compounds with limits of detection in the range from 0.12 to 1.26 μg/L and relative standard deviations lower than 9.6%. The recovery study was performed in two different water samples obtaining percentages from 71 to 103%, which demonstrated the applicability of the hybrid sorbent for the selected analytical problem.
- Published
- 2013
32. Selective Nanoparticles in Microextraction
- Author
-
Soledad Cárdenas, Guillermo Lasarte-Aragonés, Rafael Lucena, and Julia Ríos-Gómez
- Subjects
Matrix (chemical analysis) ,Bioanalysis ,Sorbent ,Materials science ,Aptamer ,Molecularly imprinted polymer ,Nanoparticle ,Context (language use) ,Nanotechnology ,Selectivity - Abstract
Sorption capacity is a critical issue in microextraction techniques where the amount of sorbent is reduced to the low milligram range and even lower. In this context, the use of sorbents with a high superficial area is really desirable. Nanoparticles (NPs) fulfill this main requirement while, at the same time, provide the analyst with a wide variety of interaction chemistries that can be easily selected depending on the analytical problem under study. In addition, certain NPs present especial properties (e.g. superparamagnetism) that make them so attractive in the microextraction context. Focusing on sorption capacity is meaningless when complex samples, the usual situation in Bioanalysis, are processed as matrix components may overload the sorbent avoiding the extraction of the target analytes. In this scenario, selectivity then becomes a critical variable of concern. This article discusses the role of selectivity in microextraction and provides a general overview of the main coatings used to boost the selectivity of NPs. In particular, this article describes the use of two groups of coatings as selectivity enhancers. On the one hand, the use of synthetic polymers including molecularly imprinted polymers (MIPs) and restricted access materials (RAMs) is a well-established alternative in analytical sciences. On the other hand, biopolymers, such as antibodies and aptamers, exploit biorecognition that is by far the most selective interaction. Both alternatives are described in detail in this article. Keywords: nanoparticles; selectivity; molecularly imprinted polymers; restricted access materials; antibodies; aptamers
- Published
- 2016
33. Use of switchable hydrophilicity solvents for the homogeneous liquid-liquid microextraction of triazine herbicides from environmental water samples
- Author
-
Guillermo, Lasarte-Aragonés, Rafael, Lucena, Soledad, Cárdenas, and Miguel, Valcárcel
- Abstract
A homogeneous liquid-liquid microextraction alternative, based on the use of switchable hydrophilicity solvents, is presented. The extraction technique makes use of 125 μL of a water-immiscible solvent (N,N-dimethylcyclohexylamine) that can be solubilized in the aqueous phase in 1:1 ratio using CO2 as a reagent. After the extraction, phase separation is induced by the addition of sodium hydroxide that produces a change on the ionization state of the amine, and centrifugation was not necessary. The extraction technique has been optimized and characterized using the determination of triazine herbicides by gas chromatography with mass spectrometry in water samples. The presence of metallic ions in environmental waters as interferents is easily avoided by the addition of ethylenediaminetetraacetic acid before the microextraction procedure. The proposed method allows the determination of the target analytes at the low microgram per liter range with good precision (relative standard deviation lower than 12.5%).
- Published
- 2014
34. Aptamers in Analytical Chemistry
- Author
-
Rafael Lucena Rodríguez, Ma Soledad Cárdenas Aranzana, and Guillermo Lasarte Aragonés
- Subjects
Drug discovery ,Aptamer ,Analytical chemistry ,Nanotechnology ,Biology ,Biosensor ,Reusability - Abstract
Aptamers have gained importance in the recent years. They can be defined as specific nucleic acid sequences that are able to bind to target molecules with high affinity and specificity. They can be synthesized using combinatorial libraries of nucleic acids in an iterative process, each cycle comprising several sequential steps (selection, partition, and amplification). Their exceptional selectivity has been exploited in different areas such as proteomics or drug discovery. Analytical chemistry has also made use of the exceptional binding capacity of aptamers for the development of more selective analytical devices. In this context, they have appeared as an alternative to antibodies, thanks to their versatility, stability, reusability, and better batch-to-batch reproducibility and to their in vitro synthesis. Concerning the analytical applications of aptamers, their use as recognition element in biosensors is the most reported in literature. Indeed, a specific term, aptasensors, has been coined to refer to such devices. Aptamers can be immobilized in a variety of supports, which can be coupled to different transducers in order to generate the most appropriate analytical signal. This article first presents an overview of the synthetic selection process of aptamers. Next, their advantages over antibodies are discussed. Finally, their main uses in biosensors development and fruitful combination with nanoparticles are outlined to conclude with future perspectives in the analytical context.
- Published
- 2012
35. Nanoparticle-based microextraction techniques in bioanalysis
- Author
-
Rafael Lucena, Guillermo Lasarte-Aragonés, Miguel Valcárcel, and Soledad Cárdenas
- Subjects
chemistry.chemical_classification ,Bioanalysis ,Materials science ,Biocompatibility ,Liquid Phase Microextraction ,Nanotubes, Carbon ,Biomolecule ,Clinical Biochemistry ,Biomedical Technology ,Nanoparticle ,Metal Nanoparticles ,Nanotechnology ,Context (language use) ,General Medicine ,Analytical Chemistry ,Medical Laboratory Technology ,chemistry ,Humans ,Nanoparticles ,General Pharmacology, Toxicology and Pharmaceutics ,Electronic properties - Abstract
Nanoparticles (NPs) have attracted a great deal of attention in the last decade due to their exceptional mechanical, optical and electronic properties. This article deals with the use of NPs as probes for the extraction of biomolecules from biological samples. In this context, NPs present some advantages compared with conventional sorbents. Their high surface-to-volume ratio, easy synthetic (especially for inorganic NPs) and derivatization procedures, and their biocompatibility make them a powerful alternative. In order to provide a systematic approach to the topic, NPs have been divided into two general groups attending to their chemical nature. Carbon-based (e.g., fullerene and nanotubes) and inorganic NPs (e.g., gold and magnetic NPs) are considered in depth, explaining their main properties and applications. After these critical considerations, the most important conclusions and essential trends in this field are also outlined.
- Published
- 2011
36. Effervescence-assisted dispersive micro-solid phase extraction
- Author
-
Rafael Lucena, Miguel Valcárcel, Guillermo Lasarte-Aragonés, and Soledad Cárdenas
- Subjects
Sorbent ,Acetonitriles ,Analytical chemistry ,Carbonates ,Biochemistry ,High-performance liquid chromatography ,Analytical Chemistry ,Phosphates ,Rivers ,Limit of Detection ,Benzene Derivatives ,Solid phase extraction ,Chromatography, High Pressure Liquid ,Nitrobenzenes ,Solid Phase Microextraction ,Detection limit ,Chromatography ,Chemistry ,Elution ,Organic Chemistry ,Extraction (chemistry) ,Reproducibility of Results ,Water ,General Medicine ,Effervescence ,Carbon Dioxide ,Benzaldehydes ,Adsorption ,Dispersion (chemistry) ,Toluene - Abstract
Extraction techniques are surface dependent processes since their kinetic directly depends on the contact area between the sample and the extractant phase. The dispersion of the extractant (liquid or solid) increases this area improving the extraction efficiency. In this article, the dispersion of the sorbent at the very low milligram level is achieved by effervescence thanks to the in situ generation of carbon dioxide. For this purpose a special tablet containing the effervescence precursors (sodium carbonate as carbon dioxide source and sodium dihydrogen phosphate as proton donor) and the sorbent (OASIS-HLB) is fabricated. All the microextraction process takes place in a 10 mL-glass syringe and the solid, enriched with the extracted analytes, is recovered by filtration. Acetonitrile was selected to elute the retained analytes. The extraction mode is characterized and optimized using the determination of five nitroaromatic compounds in water. The absolute recoveries of the analytes were in the range 61-85% while relative recoveries close to 100% in all cases, which demonstrates the absence of matrix effect on the extraction. These values permit the determination of these analytes at the microgram per liter range with good precision (relative standard deviations lower than 6.1%) using ultra performance liquid chromatography (UPLC) combined with ultraviolet (UV) detection as instrumental technique.
- Published
- 2011
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