Biosensing strategies using recombinant luminescent proteins and their use for food and environmental analysis.

Progress in synthetic biology and nanotechnology plays at present a major role in the fabrication of sophisticated and miniaturized analytical devices that provide the means to tackle the need for new tools and methods for environmental and food safety. Significant research efforts have led to biosensing experiments experiencing a remarkable growth with the development and application of recombinant luminescent proteins (RLPs) being at the core of this boost. Integrating RLPs into biosensors has resulted in highly versatile detection platforms.

Immobilization of controlled Pu:Am ratio on actinide-specific affinity monolith support developed in capillary and coupled to inductively coupled plasma mass spectrometry.

The objective of this work was to develop an actinide-specific monolithic support in capillary designed to immobilize precise Pu:Am ratios and its coupling to inductively coupled plasma mass spectrometry (ICP-MS) for immobilized metal affinity chromatography applications. This format offers many advantages, such as reducing the sample amount and waste production, which are of prime importance when dealing with highly active radioelements. Four organic phosphorylated-based monoliths were synthesized in situ through UV photo-polymerization in capillary and characterized.

Determining the selectivity of a tetra-phosphorylated biomimetic peptide towards uranium in the presence of competing cations through the simultaneous coupling of HILIC to ESI-MS and ICP-MS.

A cyclic tetra-phosphorylated biomimetic peptide (pS1368) has been proposed as a promising starting structure to design a decorporating agent of uranyl (UO) due to its affinity being similar to that of osteopontin (OPN), a target UO protein in vivo. The determination of this peptide's selectivity towards UO in the presence of competing endogenous elements is also crucial to validate this hypothesis. In this context, the selectivity of pS1368 towards UO in the presence of Ca, Cu and Zn was determined by applying the simultaneous coupling of hydrophilic interaction chromatography (HILIC) to electrospray ionization (ESI-MS) and inductively coupled plasma (ICP-MS) mass spectrometry.

Determination of the affinity of biomimetic peptides for uranium through the simultaneous coupling of HILIC to ESI-MS and ICP-MS.

Several proteins have been identified in the past decades as targets of uranyl (UO) in vivo. However, the molecular interactions responsible for this affinity are still poorly known which requires the identification of the UO coordination sites in these proteins. Biomimetic peptides are efficient chemical tools to characterize these sites.

How Does Iron Storage Protein Ferritin Interact with Plutonium (and Thorium)?

The impact of the contamination of living organisms by actinide elements has been a constant subject of attention since the 1950s. But to date still little is understood. Ferritin is the major storage and regulation protein of iron in many organisms, it consists of a protein ring and a ferrihydric core at the center.

Functionalized phosphorescent nanoparticles in (bio)chemical sensing and imaging - A review.

Inorganic nanoparticles are a fascinating class of materials which promise great potential in numerous fields, including optical (bio)sensing. Many different kinds of such nanoparticles have been widely used for fluorescent sensing and imaging due to the different merits of fluorescent nanoparticles compared to molecular fluorophores. Progress made in the rational design of nanomaterials also allowed the synthesis of hybrid phosphorescent nanoparticles, that finds growing applications in sensing due to the combination of the interesting size- and shape-dependent properties of nanomaterials with a phosphorescence-type emission.

Sensitive prostate specific antigen quantification using dihydrolipoic acid surface-functionalized phosphorescent quantum dots.

Herein, high-quality Mn-doped ZnS quantum dots (QDs) have been synthesized using a facile approach directly in aqueous media. The surface of the obtained QDs was further modified by cap-exchange of the native cysteine shell with dihydrolipoic acid (DHLA) ligands resulting in nanocrystals with high water-stability having an intense phosphorescent signal. Covalent bioconjugation of the DHLA-coated nanoparticles with an anti-IgG antibody was then carried out.

Assessment of the removal of side nanoparticulated populations generated during one-pot synthesis by asymmetric flow field-flow fractionation coupled to elemental mass spectrometry.

Coupling of asymmetric flow field-flow fractionation (AF4) to an on-line elemental detection (inductively coupled plasma-mass spectrometry, ICP-MS) has been recently proposed as a powerful diagnostic tool for characterization of the bioconjugation of CdSe/ZnS core-shell Quantum Dots (QDs) to antibodies. Such approach has been used herein to demonstrate that cap exchange of the native hydrophobic shell of core/shell QDs with the bidentate dihydrolipoic acid ligands directly removes completely the eventual side nanoparticulated populations generated during simple one-pot synthesis, which can ruin the subsequent final bioapplication. The critical assessment of the chemical and physical purity of the surface-modified QDs achieved allows to explain the transmission electron microscopy findings obtained for the different nanoparticle surface modification assayed.

Capping of Mn-Doped ZnS Quantum Dots with DHLA for Their Stabilization in Aqueous Media: Determination of the Nanoparticle Number Concentration and Surface Ligand Density.

Colloidal Mn-doped ZnS quantum dots (QDs) were synthesized, surface modified, and thoroughly characterized using a pool of complementary techniques. Cap exchange of the native l-cysteine coating of the QDs with dihydrolipoic acid (DHLA) ligands is proposed as a strategy to produce nanocrystals with a strong phosphorescent-type emission and improved aqueous stability. Moreover, such a stable DHLA coating can facilitate further bioconjugation of these QDs to biomolecules using established reagents such as cross-linker molecules.

Highly sensitive nanoparticle-based immunoassays with elemental detection: Application to Prostate-Specific Antigen quantification.

One of the major challenges in developing novel assay methods for the detection of biomolecules is achieving high sensitivity, because of the ultralow concentrations typically in clinical samples. Here, a Mn-doped ZnS quantum dots-based immunoassay platform is presented for highly sensitive detection of cancer biomarkers. Ultrahigh sensitivity is achieved through gold deposition on the surface of the nanoparticle tags acting as catalytic seeds, thus effectively amplifying the size of the metallic nanoparticles after the immunoassay and before the tag detection.

Sensitive targeted multiple protein quantification based on elemental detection of quantum dots.

A generic strategy based on the use of CdSe/ZnS Quantum Dots (QDs) as elemental labels for protein quantification, using immunoassays with elemental mass spectrometry (ICP-MS), detection is presented. In this strategy, streptavidin modified QDs (QDs-SA) are bioconjugated to a biotinylated secondary antibody (b-Ab2). After a multi-technique characterization of the synthesized generic platform (QDs-SA-b-Ab2) it was applied to the sequential quantification of five proteins (transferrin, complement C3, apolipoprotein A1, transthyretin and apolipoprotein A4) at different concentration levels in human serum samples.