1,721,074 research outputs found
Label free Affinity sensing: application to food analysis
No full textIn this paper real‐time, label free sensing principle based on Surface Plasmon Resonance (SPR) and gravimetric, i.e. Quartz Crystal Microbalance (QCM) are described and some applications to food analysis problems are reported. Affinity receptors are introduced and examples using antibodies, nucleic acid probes and biomimetic receptors i.e. molecular imprinted polymers (MIP) are reported. In particular pesticides, endotoxins, pathogens, Genetically Modified Organism (GMOs) detection and food origin analysis are reviewed
SPR-Based Affinity Biosensors as Innovative Analytical Devices
No full textSurface plasmon resonance (SPR) affinity biosensors and the new technology named SPR imaging (SPRi) are successful analytical devices that represent useful and versatile analytical tools for a variety of applications in bioanalytical chemistry. The selectivity of these systems relies mainly on the bioreceptor immobilized on the biochip surface, which can range from nucleic acid sequence to antibodies, proteins, and new synthetic bioreceptors. Thanks to SPRi, the parallel immobilization of tens bioreceptors allows the multianalyte detection in real time and label-free manner. Moreover, different assay designs can be tailored for a broad range of different molecular weight target analytes, from small molecules (hundreds of Da) to living cells. In this chapter, we will focus on examples relative to SPR-based affinity biosensors developed for medicine applications. © 1983-2012 IEEE
Surface Nanostructuring For Surface Plasmon Resonance Imaging
No full textImproving the performances of a sensor is a prominent objective in developing innovative for clinical applications. Sensitivity is key features for a biosensor such applications. An improvement in sensitivity is reported when nanoparticles (NPs) are exploited for functionalizing the interacting surface. In this work an original nanostructure was investigated. Gold nanoparticles are immobilized on a gold surface of a Surface Plasmon Resonance imaging (SPRi) sensor. The surface structuring strategy was studied in its steps, for obtaining a reproducible immobilization of NPs on biochip gold surface. In order to improve our system, we modified SPRi chip with gold NPs attached on the surface trough a dithiol molecule. Further functionalization was achieved using thiolated DNA probes. The possibility to modify the biochip in an array format was really helpful for following the different steps of the procedure. The bioreceptors immobilization protocol was studied following the plasmon curves, confirming the presence of the nanostructure on the biochip surface. © 2011 IEEE
Affinity-Based Biosensors As Promising Tools For Gene Doping Detection
No full textInnovative bioanalytical approaches can be foreseen as interesting means for solving relevant emerging problems
in anti-doping control. Sport authorities fear that the newer form of doping, so-called gene doping, based on a misuse of gene therapy, will be undetectable and thus much less reventable. The World Anti-Doping Agency has already asked scientists to assist in finding In this Opinion article we discuss the main aspects of gene doping, from the putative target analytes to suitable sampling strategies. Moreover, we discuss the potential application of affinity sensing in this field, which so far has been successfully applied to a variety
of analytical problems, from clinical diagnostics to food and environmental analysis
Coupling non invasive and fast sampling of proteins from work of art surfaces to surface plasmon resonance biosensing: Differential and simultaneous detection of egg components for cultural heritage diagnosis and conservation
No full textDespite the wide application of surface plasmon resonance (SPR) to a broad area of interests, from en- vironment to food analysis, from drug discovery to diagnostics, its exploitation in cultural heritage conservation is still unexplored. Water-based highly viscous polymeric dispersions (HVPD) composed by partially hydrolyzed polyvinyl acetate (PVA), borax, and water, were recently developed and successfully applied for the selective removal of surface degradation patinas (i.e. protein materials, natural resins etc.) from paintings of historical and artistic interest. This approach is here coupled for the first time to a SPR biosensor to simultaneously recognize albumen, yolk, or their mixtures in HVPD extracts. Ovalbumin and immunoglobulin Y are selected as analytes for egg white and yolk recognition, respectively. The bio- sensor was first characterized on standard analytes within the range 0–400 mg L 1 and then on fresh and dried egg albumen and yolk down to 2 10^4 and 1 10^5 dilution factors, respectively. Once optimized, the biosensor was combined to the HVPD application on simulated and real art samples for the eva- luation of hen egg presence in the extract, i.e. albumen, yolk, or their co-presence in the matrix. For a contemporary ‘sacred icon’, realized by the traditional egg tempera procedure described by Cennino Cennini, the biosensor successfully distinguished different uses of egg components for the realization of painted and gilded areas, i.e. yolk and albumen, respectively. Finally, a XVIII century italian painting whose the realization technique is unknown, was tested confirming its egg tempera-based realization technique
Direct detection of genomic DNA by surface plasmon resonance imaging: an optimized approach
No full textnew sensors for Single Nucleotide Polymorphism detection (SNP) using SRP imagin
KIT FOR COLORIMETRIC DETERMINATION OF CHLORINE LEVELS IN SAMPLES OF RECREATIONAL WATER
No full textA kit for the colorimetric determination by TMB of the concentration of active chlorine in drinking water or water used for recreational purposes comprises a liquid container suitable for housing a predetermined amount of liquid of which the concentration of active chlorine is to be measured, a colorimetric reference scale, and a chlorine indicator reagent designed to be placed in said container in a specified amount. The reagent contains a weighted amount of TMB so that the whole recommended range of values of chlorine concentration in water is shown by the change in at least three different colours of the solution comparable with corresponding colours of the reference scale, so that visual evaluation of the measurement results with the naked eye is simple, accurate and rapid
Surface Plasmon Resonance Imaging For Affinity-Based Sensing: An Analytical Approach
No full textSurface Plasmon Resonance imaging (SPRi) is at the forefront of optical sensing, allowing multi-analyte detection in real-time and without labeling. SPRi is applied to a variety of bio-interactions, from proteins to sensitive DNA detection. Despite the high number of recently appeared papers, very few deal with analyte detection in complex matrices. We here report SPRi affinity-based sensing with application to analytes detection in real matrices, i.e. proteins and DNA marker sequences for possible applications in different fields. In particular, we quantified Bovine IgG in cow milk avoiding matrix pre-treatments, and showing the simultaneous evaluation of different immobilization chemistries on a single biochip. We summarize results obtained in terms of perspectives for a real application of the biosensor in the field of food controls. About the detection of DNA sequences in complex matrices, we focused on DNA sequences in human transgenic cells for gene doping controls. Experimental results are briefly showed here in terms of advantages related to the application of SPRi technique to this emerging issue. © 2011 IEEE
Detecting Alzheimer's disease biomarkers: From antibodies to new bio-mimetic receptors and their application to established and emerging bioanalytical platforms - A critical review
No full textThe failure of therapeutic treatment of Alzheimer's disease (AD) patients can be related to the late onset of symptoms and, consequently, to a delayed pharmacological aid to counteract neurodegenerative progression. This is coupled to the fact that the diagnosis based on clinical criteria alone introduces high misdiagnosis rate. The availability of assessed biomarkers is therefore of crucial importance not only to counteract late diagnosis, but also to manage patients at high risk of AD development eligible for novel therapies. At the present time, amyloid-β peptides (Aβ1-40 and Aβ1-42 isoforms), alone or in combination with Tau protein (total and phosphorylated forms (p-tau)) constitute reliable AD biomarkers and result highly predictive of progression to AD dementia in patients with mild cognitive impairment (MCI), the earliest clinical presentation of AD. Improvement of existing diagnostic tools must take advantage of innovative bioanalytical approaches. In this review, starting from commercially available diagnostic platforms based on antibodies as recognition elements, we intended to provide a double point of view on the issue: 1) progresses achieved on innovative bioanalytical platforms (mainly sensors and biosensors) by using antibodies as consolidated receptors; 2) advance on promising bio-mimetic receptors alternative to antibodies in AD research, and their applications on conventional or innovative analytical platforms. In particular, we first focused on optical- (Propagating and Localized Surface Plasmon Resonance, named here SPR and LSPR) and electrochemical (voltammetric and impedimetric) transduction principles. Together with bioanalytical assays for AD biomarkers quantification, works aimed to investigate and understand their behavior, characteristics, and roles will also be considered in the discussion. An increasing interest in new emerging biomimetic receptors for AD diagnosis, as a promising alternative to antibodies is noticed, thus the description of peptides, peptoids, nanobodies, aptamers, and molecularly imprinted polymers and their role as recognition elements in different bioanalytical platforms is also reviewed. Features and limits are discussed, together with potentialities and perspectives of their further applicability to clinical routine AD analysis
A LysLysLys-tag as trigger in polynorepinephrine epitope imprinting: The case study of soluble PD-L1 detection in serum by optical-based sensing
Full text linkPolycatecholamines (pCAs)-based molecularly imprinted polymers (MIPs) represent the new performing generation of biocompatible ligand/receptor mimetics. In this context, dealing with MIPs synthesis for bio-macromolecules detection/extraction, one of the critical steps in ensuring effective binding affinity for the parent molecule is the selection of suitable epitopes for pCAs imprinting. To address this challenge, here we investigated the ability of lysine (K) residues to trigger the epitope imprinting process into a polynorepinephrine (PNE) matrix. To this aim, we first designed a set of model epitopes composed of three K and six alanine (A) residues to investigate the influence of each 'KA' combination on the imprinting process and the resulting binding performance by Surface Plasmon Resonance (SPR). Only the case of three flanking K residues in N-terminus arose as an excellent trigger for epitope imprinting. The efficacy of the 3K-tag strategy was then evaluated on two peptide templates belonging to soluble programmed cell death protein 1 ligand (PD-L1), which is of great interest as a cancer biomarker in liquid biopsies. These templates were selected due to their negligible natural ability to be imprinted into the PNE matrix and were modified with 3K-tags, in N-, C-, and N/C- positions, respectively. The SPR sensor developed by exploiting the N-3K tag strategy allowed us to achieve excellent sensitivity (0.31 ± 0.04 ng mL-1) and repeatability (avCV% = 4.5) in human serum samples. This strategy opens new insights both for epitopes' design for pCAs-based mimetics and as triggering tags when native epitopes display negligible imprinting capabilities
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