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Book’s topic Nanotechnology has become one of the fastest growing branches of modern science, significantly impacting on the world’s economy and people’s lives. The unique physical and chemical properties of nanomaterials provide... more
Book’s topic Nanotechnology has become one of the fastest growing branches of modern science, significantly impacting on the world’s economy and people’s lives. The unique physical and chemical properties of nanomaterials provide interesting new opportunities for their utilization in water quality management. At present, the main emphasis in this field is on water remediation, such as desalination, the removal of heavy metal ions and oil, and the elimination of pathogens, biotoxins, and water-soluble organic contaminants. Another direction is water monitoring with reliable, highly sensitive, low-cost, miniaturized, and robust biosensors that permit realtime, multi-analyte detection. Such biosensors make use of biofunctionalized smart nanomaterials such as carbon nanotubes, metal oxides, noble metals, and quantum dots (QDs) to maintain human health and environmental safety. The book Nanomaterials for water management: signal amplification for biosensing from nanostructures, which is the 4th volume of the Pan Stanford Series on the High-Tech of Biotechnology and is edited by IbrahimAbdulhalim and Robert S. Marks, is a reference work on this topic. It highlights a number of modern approaches aimed at signal amplification by collecting together articles written by experts on the subject.
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This article reports current research efforts towards designing bespoke microscale extraction approaches exploiting the versatility of 3D printing for fast prototyping of novel geometries of sorptive devices. This is demonstrated via the... more
This article reports current research efforts towards designing bespoke microscale extraction approaches exploiting the versatility of 3D printing for fast prototyping of novel geometries of sorptive devices. This is demonstrated via the so-called 3D printed spinning cup-based platform for immunoextraction of emerging contaminants using diclofenac as a model analyte. A new format of rotating cylindrical scaffold (containing a semispherical upper cavity) with enhanced coverage of biorecognition elements, and providing elevated enhancement factors with no need of eluate processing as compared with other microextraction stirring units is proposed. Two distinct synthetic routes capitalized upon modification of the acrylate surface of stereolithographic 3D printed parts with hexamethylenediamine or branched polyethyleneimine chemistries were assayed for covalent binding of monoclonal diclofenac antibody.Under the optimized experimental conditions, a LOD of 108 ng L−1 diclofenac, dynamic ...
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Resumen de la publicación de una participación en formato <strong>µVídeo</strong> en en el congreso Divulga NextGen (1ª edición) que se celebrará online, de manera gratuita y en las redes sociales los días 26, 27 y 28 de mayo... more
Resumen de la publicación de una participación en formato <strong>µVídeo</strong> en en el congreso Divulga NextGen (1ª edición) que se celebrará online, de manera gratuita y en las redes sociales los días 26, 27 y 28 de mayo de 2021.
Research Interests: Chemistry and Trace Metal
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The non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF) is found worldwide in the aqueous environment. Therefore, it has raised increased public concern on potential long-term impact on human health and wildlife. The importance... more
The non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF) is found worldwide in the aqueous environment. Therefore, it has raised increased public concern on potential long-term impact on human health and wildlife. The importance of DCF has been emphasized by the European Union recently by including this pharmaceutical in the first watch list of priority hazardous substances in order to gather Union-wide monitoring data. Rapid and cheap methods of analysis are therefore required for fresh and wastewater monitoring with high sample load. Here, for the first time, well-characterized monoclonal antibodies (mAbs) against DCF were generated and a highly sensitive ELISA developed. The best antibody (mAb 12G5) is highly affine (KD = 1.5 × 10(-10) M), stable to potential matrix interferences such as pH value (pH range 5.2-9.2), calcium ion concentration (up to 75 mg/L), and humic acid content (up to 20 mg/L). The limit of detection (LOD, S/N = 3) and IC50 of the ELISA calibration curve were 7.8 and 44 ng/L, respectively. The working range was defined between 11 and 180 ng/L. On average, about 10 % cross-reactivity (CR) was found for DCF metabolites 5-OH-DCF, 4&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-OH-DCF, and DCF-acyl glucuronide, but other structurally related NSAIDs showed binding &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 % compared to the parent compound. While DCF concentrations at the low ppt range were measured in river and lake water, higher values of 2.9 and 2.1 μg/L were found in wastewater influents and effluents, respectively. These results could be confirmed by solid phase extraction combined with LC-MS.
Research Interests: Engineering, Chemistry, Chromatography, Medicine, Biological Sciences, and 14 moreHumans, Wastewater, Solid Phase Extraction, Monoclonal Antibodies, CHEMICAL SCIENCES, Time Factors, Waste Water, Fresh water, Diclofenac, Effluent, Analytical and Bioanalytical Chemistry, Monoclonal Antibody, Enzyme Linked Immunosorbent Assay, and limit of detection
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... We still found an excellent recovery of 101%. Conclusions As shown with the 1-NP, the sol-gel glass possesses ideal properties for the use as support matrix in IAC. ... IRL Press, Oxford 3. Hermanson GT, Mallia AK, Smith PK (1992)... more
... We still found an excellent recovery of 101%. Conclusions As shown with the 1-NP, the sol-gel glass possesses ideal properties for the use as support matrix in IAC. ... IRL Press, Oxford 3. Hermanson GT, Mallia AK, Smith PK (1992) Immobi-lized affinity ligand techniques. ...
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The non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF) is found worldwide in the aqueous environment. Therefore, it has raised increased public concern on potential long-term impact on human health and wildlife. The importance... more
The non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF) is found worldwide in the aqueous environment. Therefore, it has raised increased public concern on potential long-term impact on human health and wildlife. The importance of DCF has been emphasized by the European Union recently by including this pharmaceutical in the first watch list of priority hazardous substances in order to gather Union-wide monitoring data. Rapid and cheap methods of analysis are therefore required for fresh and wastewater monitoring with high sample load. Here, for the first time, well-characterized monoclonal antibodies (mAbs) against DCF were generated and a highly sensitive ELISA developed. The best antibody (mAb 12G5) is highly affine (KD = 1.5 × 10(-10) M), stable to potential matrix interferences such as pH value (pH range 5.2-9.2), calcium ion concentration (up to 75 mg/L), and humic acid content (up to 20 mg/L). The limit of detection (LOD, S/N = 3) and IC50 of the ELISA calibration curve were 7.8 and 44 ng/L, respectively. The working range was defined between 11 and 180 ng/L. On average, about 10 % cross-reactivity (CR) was found for DCF metabolites 5-OH-DCF, 4&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-OH-DCF, and DCF-acyl glucuronide, but other structurally related NSAIDs showed binding &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 % compared to the parent compound. While DCF concentrations at the low ppt range were measured in river and lake water, higher values of 2.9 and 2.1 μg/L were found in wastewater influents and effluents, respectively. These results could be confirmed by solid phase extraction combined with LC-MS.
Research Interests: Engineering, Chemistry, Chromatography, Medicine, Biological Sciences, and 14 moreHumans, Wastewater, Solid Phase Extraction, Monoclonal Antibodies, CHEMICAL SCIENCES, Time Factors, Waste Water, Fresh water, Diclofenac, Effluent, Analytical and Bioanalytical Chemistry, Monoclonal Antibody, Enzyme Linked Immunosorbent Assay, and limit of detection
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Mycotoxins are secondary metabolites produced by fungal species, which pose significant risk to humans and livestock. The mycotoxins which are produced from Aspergillus, Penicillium, and Fusarium are considered most important and... more
Mycotoxins are secondary metabolites produced by fungal species, which pose significant risk to humans and livestock. The mycotoxins which are produced from Aspergillus, Penicillium, and Fusarium are considered most important and therefore regulated in food- and feedstuffs. Analyses are predominantly performed by official laboratory methods in centralized labs by expert technicians. There is an urgent demand for new low-cost, easy-to-use, and portable analytical devices for rapid on-site determination. Most significant advances were realized in the field bioanalytical techniques based on molecular recognition. This review aims to discuss recent progress in the generation of native biomolecules and new bioinspired materials towards mycotoxins for the development of reliable bioreceptor-based analytical methods. After brief presentation of basic knowledge regarding characteristics of most important mycotoxins, the generation, benefits, and limitations of present and emerging biorecogn...
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Immunoaffinity chromatography (IAC) offers a fast method to selectively enrich single analytes. Immobilization of an antibody (IgG) against the herbicide 2,4-dichlorophenoxy acetic acid (2,4-D) on a modified agarose gel enabled the... more
Immunoaffinity chromatography (IAC) offers a fast method to selectively enrich single analytes. Immobilization of an antibody (IgG) against the herbicide 2,4-dichlorophenoxy acetic acid (2,4-D) on a modified agarose gel enabled the development of an immunoadsorber column with a high efficiency. First some techniques for the isolation and coupling of antibodies were examined. A column loaded with 1,4 mg IgG extracted up to 320 ng 2,4-D from a standard solution. From several methods of elution, an elution with 40 % acetonitrile was chosen, because of its compatibility with the properties of the antibodies. The efficiency of elution varied between 86 and 97 %. Extraction from a solution with a lower concentration of 2,4-D (0,1 μg/l) was also successful. An enrichment factor of 340 was calculated.
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Plasmonic enzyme-linked immunosorbent assays (ELISA) using the localized surface plasmon resonance (LSPR) of metal nanoparticles has emerged as an appealing alternative to conventional ELISA counterparts for ultrasensitive naked-eye... more
Plasmonic enzyme-linked immunosorbent assays (ELISA) using the localized surface plasmon resonance (LSPR) of metal nanoparticles has emerged as an appealing alternative to conventional ELISA counterparts for ultrasensitive naked-eye detection of biomolecules and small contaminants. However, batchwise plasmonic ELISA involving end-point detection lacks ruggedness inasmuch as the generation or etching of NP is greatly dependent on every experimental parameter of the analytical workflow. To tackle the above shortcomings, this paper reports on an automatic flow methodology as a reliable detection scheme of hydrogen peroxide related enzymatic bioassays for ultrasensitive detection of small molecules. Here, a competitive ELISA is combined with the in-line generation of plasmonic gold nanoparticles (AuNPs) followed by the real-time monitoring of the NP nucleation and growth rates and size distribution using a USB miniaturized photometer. Glucose oxidase was labeled to the secondary antibody and yielded hydrogen peroxide that acted as the measurand and the reducing agent of the Au(III)/citrate system in the flow network. High-throughput plasmonic assays were feasible by assembling a hybrid flow system composed of two microsyringe pumps, a perfluoroalkoxy alkane reaction coil and a 26-port multiposition valve, and operated under computer-controllable flow conditions. The ultratrace determination of diclofenac in high matrix samples, e.g., seawater, without any prior sample treatment was selected as a proof-of-concept application of the flow-based platform for determination of emerging contaminants via plasmonic ELISA. The detection limit (0.001 µg L-1) was one order of magnitude below than that endorsed by the first EU Watch List for diclofenac as a potentially emerging contaminant in seawater, and also than that of a conventional colorimetric ELISA, which in turn resulted inappropriate for determination of diclofenac in seawater at the levels endorsed by the EU regulation. The proposed automatic fluidic approach is characterized by the reproducible timing in AuNPs nucleation and growth along with the unsupervised LSPR absorbance detection of AuNPs with a dynamic range for diclofenac spanning from 0.01 - 10 µg L-1. Repeatability and intermediate precision (given as normalized signal readouts) values in seawater were < 4 % and < 14%, respectively, as compared to RSDs as high as 30% as obtained with the batchwise plasmonic ELISA.
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Herein we describe the development of a homogeneous competitive colorimetric immunoassay using antigen-functionalized magnetic beads (MBs) and antibody-immobilized gold nanoparticles (AuNPs) combined with the established gold staining... more
Herein we describe the development of a homogeneous competitive colorimetric immunoassay using antigen-functionalized magnetic beads (MBs) and antibody-immobilized gold nanoparticles (AuNPs) combined with the established gold staining method for the determination of microcystin-leucine-arginine (MC-LR) in surface water.
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Aflatoxins are highly toxic secondary metabolites produced by a number of different fungi and present in a wide range of food and feed commodities. Herein, we designed a simple and low-cost immunosensing platform for highly sensitive... more
Aflatoxins are highly toxic secondary metabolites produced by a number of different fungi and present in a wide range of food and feed commodities. Herein, we designed a simple and low-cost immunosensing platform for highly sensitive detection of mycotoxins (aflatoxin B1, AFB1, used as a model) on polyethylenimine (PEI)-coated mesoporous silica nanocontainers (PEI-MSN). The assay was carried out by using a portable personal glucometer (PGM) as the readout based on a competitive displacement reaction mode between target AFB1 and its pseudo-hapten (PEI-MSN) for monoclonal anti-AFB1 antibody (mAb). To construct such an assay protocol, two nanostructures including mAb-labeled gold nanoparticle (mAb-AuNP) and PEI-MSN were initially synthesized, and then numerous glucose molecules were gated into the pores based on the interaction between negatively charged mAb-AuNP and positively charged PEI-MSN. In the presence of target AFB1, a competitive-type displacement reaction was implemented bet...
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Due to its highly carcinogenic and mutagenic effect on humans, a maximum tolerable limit of 10 ng/L of benzo[a]pyrene (B[a]P) in drinking water was set by the European Commission (Council Directive 98/83/EC). Although several polyclonal... more
Due to its highly carcinogenic and mutagenic effect on humans, a maximum tolerable limit of 10 ng/L of benzo[a]pyrene (B[a]P) in drinking water was set by the European Commission (Council Directive 98/83/EC). Although several polyclonal and monoclonal antibodies (mAb) for the detection of B[a]P and other polycyclic aromatic hydrocarbons (PAH) have been developed by others, a traditional enzyme-linked immunosorbent assay (ELISA) with a limit of quantification of 10 ng/L for monitoring B[a]P has not been developed. With this in mind, several single-chain variable fragment (scFv) antibodies were created using existing mAbs against the extremely hydrophobic hapten B[a]P, and their heavy and light chains recombined to make unique variable light (V(L)) and heavy (V(H)) chain combinations. Their binding behaviour was investigated using microtiter plate ELISA and surface plasmon resonance techniques. Specifically, the coding sequences for V(L) and V(H) chains of 10 murine anti-B[a]P antibody producing hybridoma cell lines were isolated by degenerate oligonucleotide primer sets, cloned in phagemid pIT2 and transferred into Escherichia coli HB2151. To systematically investigate the interaction of the V(L) and V(H) domains, three high-affinity B[a]P-specific and one nonspecific clone were selected and recombined to build a set of 16 different V(L) and V(H) combinations. On the basis of our data, it was shown that the V(H) plays the major role for specific binding of B[a]P, whilst the V(L) can, in some cases, increase the final sensitivity of the assay by one order of magnitude. Furthermore, the sequence analysis of scFvs indicates that the complementarity determining region H3 plays a major role in affinity, whilst cross-reactivity to seven other PAHs demonstrates the importance of the V(L) in providing cross-reactivity.
Research Interests: Engineering, Analytical Chemistry, Kinetics, Biological Sciences, Cell line, and 15 moreMice, Animals, Meat, Alkaline phosphatase, CHEMICAL SCIENCES, Reproducibility of Results, Food Contamination, Amino Acid Sequence, Sensitivity and Specificity, Protein Binding, Fusion Protein, Enzyme Linked Immunosorbent Assay, Molecular Sequence Data, Haptens, and Phenethylamines
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Potential martian molecular targets include those supplied by meteoritic carbonaceous chondrites such as amino acids and polycyclic aromatic hydrocarbons and true biomarkers stemming from any hypothetical martian biota (organic... more
Potential martian molecular targets include those supplied by meteoritic carbonaceous chondrites such as amino acids and polycyclic aromatic hydrocarbons and true biomarkers stemming from any hypothetical martian biota (organic architectures that can be directly related to once living organisms). Heat extraction and pyrolysis-based methods currently used in planetary exploration are highly aggressive and very often modify the target molecules making their identification a cumbersome task. We have developed and validated a mild, nondestructive, multiplex inhibitory microarray immunoassay and demonstrated its implementation in the SOLID (Signs of Life Detector) instrument for simultaneous detection of several nonvolatile life- and nonlife-derived organic molecules relevant in planetary exploration and environmental monitoring. By utilizing a set of highly specific antibodies that recognize D- or L- aromatic amino acids (Phe, Tyr, Trp), benzo[a]pyrene (B[a]P), pentachlorophenol, and su...
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Because multianalyte methods are highly desirable in order to keep analysis time and costs low, the biosensor development increasingly focuses on parallel analysis of several mycotoxins. Here, we describe an indirect competitive... more
Because multianalyte methods are highly desirable in order to keep analysis time and costs low, the biosensor development increasingly focuses on parallel analysis of several mycotoxins. Here, we describe an indirect competitive immunoassay on regenerable, reusable glass microchips for the parallel determination of aflatoxins, ochratoxin A, deoxynivalenol, and fumonisin B1 in oat extracts, using a fully automated flow-through device with chemiluminescence readout.
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Aflatoxin B1 (AFB1) monitoring has attracted extensive attention because food safety is a worldwide public health problem. Herein, we design a novel simultaneously visual and photoelectrochemical (PEC) immunosensing system for rapid... more
Aflatoxin B1 (AFB1) monitoring has attracted extensive attention because food safety is a worldwide public health problem. Herein, we design a novel simultaneously visual and photoelectrochemical (PEC) immunosensing system for rapid sensitive detection of AFB1 in foodstuff. The immunoreaction was carried out on anti-AFB1 antibody-modified magnetic beads by using glucose oxidase (GOx)-labeled AFB1-bovine serum albumin (AFB1-BSA) conjugates as the tags with a competitive-type immunoassay format, while the visual and PEC evaluation was performed via carbon quantum dots (CQDs)-functionalized MnO2 nanosheets. Accompanying the formation of immunocomplexes, the carried GOx initially oxidized the substrate (glucose) for the generation of H2O2, which reduced/etched MnO2 nanosheets into Mn(2+) ions, thereby resulting in the dissociation of CQDs from the electrode. Within the applied potentials, the photocurrent of MnO2-CQDs-modified electrode decreased with the increasing H2O2 level in the de...
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A new molecularly imprinted polymer (MIP) for trace analysis of diclofenac in environmental water samples was prepared by a non-covalent protocol in which diclofenac was used as a template molecule. Diclofenac is a member of the class of... more
A new molecularly imprinted polymer (MIP) for trace analysis of diclofenac in environmental water samples was prepared by a non-covalent protocol in which diclofenac was used as a template molecule. Diclofenac is a member of the class of drugs termed non-steroidal anti-inflammatory drugs (NSAIDs) which belong to the most frequently detected pharmaceuticals in the water-cycle in Europe. The MIP was synthesized using 2-vinylpyridine (2-VP) and ethylene glycol dimethacrylate (EGDMA) as a functional monomer and cross-linker, respectively, and bulk thermal polymerization method. (1)H NMR spectroscopy was used to study the interaction between diclofenac and 2-VP mixed in toluene-d(8) in pre-polymerization complex. Two non-covalent bonds were formed i.e. ionic interaction and hydrogen bonding. The binding characteristics of the MIP and diclofenac were evaluated using equilibrium binding experiments. Scatchard plot analysis revealed that two classes of binding sites were formed with dissociation constants of 55.6 micromol L(-1) and 1.43 mmol L(-1), respectively. Various parameters affecting the extraction efficiency of the polymers have been evaluated to achieve the selective preconcentration of diclofenac from aqueous samples and to reduce non-specific interactions. This resulted in an MISPE-LC/DAD method allowing the direct extraction of the analyte from sample matrix with a selective wash using dichloromethane/acetonitrile (94:6, v/v) followed by elution with dichloromethane/methanol (85:15, v/v). The recovery of a 100 ng diclofenac standard spiked into 200 mL of blank surface water was 96%, with good precision (RSD=3.3%, n=3). The MISPE was demonstrated to be applicable to the analysis of diclofenac in raw influent and final effluent wastewater samples from sewage treatment plant and revealed diclofenac concentrations of 1.31+/-0.055 microg L(-1) (n=3) and 1.60+/-0.049 microg L(-1) (n=3), respectively. Yielded results were in good agreement with the corresponding LC/TIS/MS/MS data obtained by an independent laboratory which were 1.40 and 1.50 microg L(-1) for influent and effluent samples.
Research Interests: Analytical Chemistry, NMR Spectroscopy, Molecular Imprinting, Polymers, Magnetic Resonance Spectroscopy, and 15 morePolymerization, Sample Preparation, Methanol, Efficiency, Hydrogen Bond, Liquid Chromatography, Diclofenac, Effluent, Sewage Treatment Plant, Environment, Binding Site, Dissociation Constant, Ethylene Glycol, Molecular Structure, and Direct Method
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The development of a direct competitive ELISA for the detection of a broad range of sulfonylurea herbicides (SUs) is described. Polyclonal antibodies were generated in rabbits using three different immunizing haptens. Antiserum with the... more
The development of a direct competitive ELISA for the detection of a broad range of sulfonylurea herbicides (SUs) is described. Polyclonal antibodies were generated in rabbits using three different immunizing haptens. Antiserum with the broadest specificity was obtained with a mesosulfuronbenzylamine derivative which was coupled via a succinic acid spacer to keyhole limpet hemocyanine. A heterologous enzyme tracer which did not contain the succinic acid bridge was prepared using activated horseradish peroxidase. The direct competitive ELISA was optimized and applied for spiked tap and surface water samples. From 30 SUs, 8 compounds showed a molar cross-reactivity (CR) higher than 100% (this value was set for the hapten) and 11 compounds CRs between 10% and 100%. The ELISA can detect 16 SUs at a concentration of 0.1 microg/L or lower. Different surface and tap water samples were spiked with chlorimuron ethyl, metsulfuron methyl, or primisulfuron methyl at concentrations of 100, 200, or 500 ng/L and subsequently analyzed by both ELISA and HPLC-UV. Correlation analysis revealed good agreement between both methods (r2 = 0.983/0.948/0.982; n = 21 for each analyte). Using ELISA, no sample pretreatment other than filtration was necessary.
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Mycotoxins, highly toxic secondary metabolites produced by many invading species of filamentous fungi, contaminate different agricultural commodities under favorable temperature and humidity conditions. Herein we successfully devised a... more
Mycotoxins, highly toxic secondary metabolites produced by many invading species of filamentous fungi, contaminate different agricultural commodities under favorable temperature and humidity conditions. Herein we successfully devised a novel signal-on photoelectrochemical immunosensing platform for the quantitative monitoring of mycotoxins (aflatoxin B1, AFB1, used as a model) in foodstuffs on the basis of silver nanolabels-assisted ion-exchange reaction with CdTe quantum dots (QDs) mediated the hole-trapping. Initially, a competitive-type immunoreaction was carried out on a high-binding microplate by using silver nanoparticle (AgNP)-labeled AFB1-bovine serum albumin (AFB1-BSA) conjugates as the tags. Then, the carried AgNPs with AFB1-BSA were dissolved by acid to release numerous silver ions, which could induce ion-exchange reaction with the CdTe QDs immobilized on the electrode, thus resulting in formation of surface exciton trapping. Relative to pure CdTe QDs, the formed exciton ...
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Photon-upconverting nanoparticles (UCNPs) emit light of shorter wavelength under near-infrared excitation and thus avoid optical background interference. We have exploited this unique photophysical feature to establish a sensitive... more
Photon-upconverting nanoparticles (UCNPs) emit light of shorter wavelength under near-infrared excitation and thus avoid optical background interference. We have exploited this unique photophysical feature to establish a sensitive competitive immunoassay for the detection of the pharmaceutical micropollutant diclofenac (DCF) in water. The so-called upconversion-linked immunosorbent assay (ULISA) was critically dependent on the design of the upconversion luminescent detection label. Silica-coated UCNPs (50 nm in diameter) exposing carboxyl groups on the surface were conjugated to a secondary anti-IgG antibody. We investigated the structure and monodispersity of the nanoconjugates in detail. Using a highly affine anti-DCF primary antibody, the optimized ULISA reached a detection limit of 0.05 ng DCF per mL. This performance comes close to a conventional ELISA without the need for an enzyme-mediated signal amplification step. The ULISA was further employed for analyzing drinking and su...