1,721,208 research outputs found
Organically modified silica nanoparticles doped with new acridine-1,2-dioxetane analogues as thermochemiluminescence reagentless labels for ultrasensitive immunoassays
No full textDoped organically modified silica nanoparticles (ORMOSIL NPs) with luminescent molecules represent a potent approach to signal amplification in biomolecule labeling. Herein, we report the synthesis of new ORMOSIL NPs incorporating thermochemiluminescent (TCL) 1,2-dioxetane derivatives to prepare TCL labels for ultrasensitive immunoassay, displaying a detectability comparable to those offered by other conventional luminescence-based systems. Amino-functionalized ORMOSIL NPs were synthesized for inclusion of acridine-containing 1,2-dioxetane derivatives with a fluorescence energy acceptor. The doped ORMOSIL NPs were further functionalized with biotin for binding to streptavidin-labeled species to be used as universal detection reagents for immunoassays. A quantitative non-competitive immunoassay for streptavidin has been developed by immobilizing anti-streptavidin antibody to capture streptavidin, then the antibody-bound streptavidin was detected by the biotinylated TCL ORMOSIL NPs. The analytical performance was similar to that obtained by chemiluminescent (CL) detection using horseradish peroxidase (HRP) as label, being the limits of detection 2.5-3.8 and 0.8 ng mL(-1) for TCL and CL detection, respectively. In addition, since the TCL emission is simply initiated by thermolysis of the label, chemical reagents were not required, thus allowing reagentless detection with a simplification of the analytical protocols. A compact mini dark box device based on the use of a cooled charge-coupled device (CCD) and a miniaturized heater has been developed and used to quantify the light emission after heat decomposition of the label at a temperature of 90-120 °C. These characteristics make TCL-doped ORMOSIL NPs ideal universal nanoprobes for ultrasensitive bioassays such as immuno- and DNA-based assay
MOF Univariate and multivariate regression
No full textThis dataset contains calibration measurements for hydrogen peroxide (H₂O₂) acquired for two complementary purposes: (1) a multivariate PLS regression, based on time-resolved signal traces of blanks and standards; and (2) a univariate calibration, based on the relationship between concentration and response (AUC minus blank). The data include blank replicates and H₂O₂ standards at multiple levels (approximately 15–65 µM), each measured in triplicate (IDs 0001–0003). The CSV is comma-separated, encoded in ISO-8859-1, and preserves special characters (e.g., the micro sign µ). Typical uses of this dataset include building and validating PLS models, fitting a univariate calibration line, teaching/benchmarking chemometric workflows, and ensuring reproducible analysis from raw tabular data
Transparent Carbon Nanotube Network for Efficient Electrochemiluminescence Devices
Full text linkA carbon nanotube-based electrode that combines transparency and good conductivity was used for the first time to develop an electrochemiluminescence (ECL) device. It resulted in an excellent material for ECL applications thanks to the very favorable overpotential of amine oxidation that represents the rate-determining step for the signal generation in both research systems and commercial instrumentation. The use of carbon nanotubes resulted in a ten times higher emission efficiency compared with commercial transparent indium tin oxide (ITO) electrodes. Moreover, application of this material for proof-of-principle ECL imaging was demonstrated, in which micro-beads were used to mimic a real biological sample in order to prove the possibility of obtaining single cell visualization
Immunochemical Micro Imaging Analyses for the Detection of Proteins in Artworks
No full textThe present review is aimed at reporting on the most advanced and recent applications of immunochemical imaging techniques for the localization of proteins within complex and multilayered paint stratigraphies. Indeed, a paint sample is usually constituted by the superimposition of different layers whose characterization is fundamental in the evaluation of the state of conservation and for addressing proper restoration interventions. Immunochemical methods, which are based on the high selectivity of antigen–antibody reactions, were proposed some years ago in the field of cultural heritage. In addition to enzyme-linked immunosorbent assays for protein identification, immunochemical imaging methods have also been explored in the last decades, thanks to the possibility to localize the target analytes, thus increasing the amount of information obtained and thereby reducing the number of samples and/or analyses needed for a comprehensive characterization of the sample. In this review, chemiluminescent, spectroscopic and electrochemical imaging detection methods are discussed to illustrate potentialities and limits of advanced immunochemical imaging systems for the analysis of paint cross-sections
Chemiluminescent high-throughput microassay for evaluation of acetylcholinesterase inhibitors
No full textCurrent drug therapies for Alzheimer’s disease are mainly based on acetylcholinesterase (AChE) inhibitors. However, such inhibitors may possess non-optimal pharmacological properties or cause adverse effects, therefore research for the development of new drugs is still in progress. In this paper a rapid and simple chemiluminescent assay for the in vitro evaluation of AChE inhibitors, in which the activity of AChE is measured through a series of coupled enzymatic reactions leading to light emission, is described. The assay is performed in microtiter plates, both in the 96- and 384-well formats. In the latter format up to 30 compounds can be simultaneously analyzed in a very short time (the chemiluminescence measurement lasts 5 minutes) and using small volumes of samples and reagents (the assay volume is less than 60 microL), thus allowing high throughput screening. The assay proved to be reliable, as demonstrated by the analysis of known AChE inhibitors, and the reproducibility of the results was satisfying for a screening assay (CV% in the order of 20%). It could therefore represent a valuable alternative to other methods for the preliminary evaluation of new potential AChE inhibitors
A portable device for on site detection of chicken ovalbumin in artworks by chemiluminescent immunochemical contact imaging
No full textThe development of user-friendly devices for on site analysis and characterization of painting materials is one of the most challenging objectives in the diagnostics for cultural heritage. Thanks to the specificity of antigen-antibody reactions, immunological methods have been already successfully applied for the detection of proteins and for their localization within painting stratigraphies. Moreover, by combining the advantages of the immunological techniques with the high detectability offered by chemiluminescence detection, it has been possible to achieve good analytical performance and very low detection limits. This work was aimed at developing a portable analytical device for the detection of chicken ovalbumin (a protein found in egg tempera and in egg-based protective varnishes) in painting samples employing ready-to-use analytical cartridges and a thermoelectrically-cooled CCD camera as a chemiluminescence detector. The protein was extracted from using a simple procedure and revealed by a non-competitive immunoassay with chemiluminescence contact imaging detection. The assay was simple, fast and suitable for the detection of ovalbumin in small samples. This analytical system provided positive identification of ovalbumin in samples obtained from both fresh or artificially aged paint reconstructions and historical paintings. It might be easily employed in different contexts (such as small museums, restoration laboratories or even on site) by restorers to obtain prompt information during restoration actions, such as cleaning operations. In perspective this device could be also employed for the detection of other proteinaceous and organic painting component
METHOD FOR THE PRODUCTION OF THERMOCHEMILUMINESCENT SILICA NANOPARTICLES AND THEIR USE AS MARKERS IN BIOANALYTIC METHODS
No full textThe invention relates to thermochemiluminescent silica nanoparticles containing in dispersion in the silica matrix molecules of a thermochemiluminescent acridine-based 1,2-dioxetane and additional chemical species, such as a fluorescent energy acceptor with the function of improving the efficiency of the thermochemiluminescent reaction and/or modifying the emission wavelength, and a method for the synthesis thereof. The nanoparticles are functionalized on the surface with reactive groups (e.g. amines) and procedures are described for bonding them to biospecific probes (e.g. antibodies) and enabling their use as thermochemiluminescent markers in bioanalytical methods (e.g. immunometric methods) based on thermochemi luminescence measurements
A simple smartphone-based thermochemiluminescent immunosensor for valproic acid detection using 1,2-dioxetane analogue-doped nanoparticles as a label
No full textPoint-of-care testing devices for companion diagnostic applications is a growing area in immunobiosensor technology. With the widespread diffusion of smartphones and improved enclosed photocamera technology, fast and accurate point-of-care diagnosis could be developed for delivering optical biosensing abilities to the general population. Herein, we propose a smartphone-based immunosensor employing a paper-based format coupled with thermochemiluminescence (TCL) detection, that was optimized for valproic acid (VPA) detection in blood and saliva samples. TCL is a chemical luminescence phenomenon in which photons are emitted upon thermally-induced fragmentation of a suitable molecule, with production of a moiety in its singlet electronically excited state. The latter emits a photon while decaying to its ground state. TCL peculiar characteristics combine high detectability and reagent-less nature of the measurement. A one-step competitive immunoassay for VPA detection based on vertical flow immunoassay (VFIA) format was developed, employing silica nanoparticles doped with a TCL 1,2-dioxetane derivative as a label. The VFIA sensor is a stack of paper-based layers functionalized with reagents stored in a stable form, allowing to complete the test in 12 min simply upon sample addition. By 3D printing, simple accessories were produced to turn a smartphone into a biosensing device that provides a power source for the heat shock required to trigger the TCL reaction and a sensitive camera for measuring emitted photons. The developed biosensor allowed VPA detection in blood and saliva, with limits of detection (4 and 0.05 μg mL−1 respectively) and dynamic ranges (4–300 and 0.05–20 μg mL-1) suitable for therapeutic drug monitoring. The integrated device offers an innovative analytical platform for rapid one-step biosensors exploitable in a variety of point-of-care applications
Progress in chemical luminescence-based biosensors: A critical review
Full text linkBiosensors are a very active research field. They have the potential to lead to low-cost, rapid, sensitive, reproducible, and miniaturized bioanalytical devices, which exploit the high binding avidity and selectivity of biospecific binding molecules together with highly sensitive detection principles. Of the optical biosensors, those based on chemical luminescence detection (including chemiluminescence, bioluminescence, electrogenerated chemiluminescence, and thermochemiluminescence) are particularly attractive, due to their high-to-signal ratio and the simplicity of the required measurement equipment.
Several biosensors based on chemical luminescence have been described for quantitative, and in some cases multiplex, analysis of organic molecules (such as hormones, drugs, pollutants), proteins, and nucleic acids. These exploit a variety of miniaturized analytical formats, such as microfluidics, microarrays, paper-based analytical devices, and whole-cell biosensors. Nevertheless, despite the high analytical performances described in the literature, the field of chemical luminescence biosensors has yet to demonstrate commercial success.
This review presents the main recent advances in the field and discusses the approaches, challenges, and open issues, with the aim of stimulating a broader interest in developing chemical luminescence biosensors and improving their commercial exploitation
- …
