Biosensing Extracellular Vesicle Subpopulations in Neurodegenerative Disease Conditions.

Extracellular vesicles (EVs) are secreted nanoparticles that are involved in intercellular communication and that modulate a wide range of biological processes in normal and disease conditions. However, EVs are highly heterogeneous in terms of origin in the cell, size, and density. As a result, complex protocols are required to identify and characterize specific EV subpopulations, limiting biomedical applications, notably in diagnostics.

Design and Analytical Performances of a Diclofenac Biosensor for Water Resources Monitoring.

Because the broadly consumed pain killer diclofenac (DCF) is a recognized pollutant, monitoring of its concentration is routinely performed in surface waters. As a valuable alternative to chromatographic and immunochemical assays, we developed a piezoelectric immunosensor to quantify DCF, first in buffer (PBS) and then in river water samples. A sensing layer comprising DCF was built up on the surface of silica-coated quartz sensors using a robust coupling chemistry.

Gold Nanorods for LSPR Biosensing: Synthesis, Coating by Silica, and Bioanalytical Applications.

Nanoparticles made of coinage metals are well known to display unique optical properties stemming from the localized surface plasmon resonance (LSPR) phenomenon, allowing their use as transducers in various biosensing configurations. While most of the reports initially dealt with spherical gold nanoparticles owing to their ease of synthesis, the interest in gold nanorods (AuNR) as plasmonic biosensors is rising steadily. These anisotropic nanoparticles exhibit, on top of the LSPR band in the blue range common with spherical nanoparticles, a longitudinal LSPR band, in all respects superior, and in particular in terms of sensitivity to the surrounding media and LSPR-biosensing.

Antibody-Gold Nanoparticle Bioconjugates for Biosensors: Synthesis, Characterization and Selected Applications.

Antibody-Gold nanoparticle (Ab-AuNP) bioconjugates are widely used in the field of biosensing. This prompted researchers to set up various strategies to conjugate antibodies to gold nanoparticles. Optimal conjugation is of critical importance, as the Ab-AuNP bioconjugates should be stable while maintaining the ability of the antibody to recognize and bind its corresponding antigen.

Core-Shell Gold/Silver Nanoparticles for Localized Surface Plasmon Resonance-Based Naked-Eye Toxin Biosensing.

The localized surface plasmon resonance (LSPR) phenomenon provides a versatile property for biodetection. Herein, this unique feature was employed to build a homogeneous optical biosensor to detect staphylococcal enterotoxin A (SEA) in solution down to very low levels by naked-eye readout. If the initial position of the LSPR band is located in the cyan region, even a small red shift (∼2-3 nm) induced by a refractive index change close to the surface of nanoparticles (NPs) could make the light absorption transit from cyan to green and become visually detectable via a concomitant change in the complementary colors.

Cubic versus hexagonal - effect of host crystallinity on the T shortening behaviour of NaGdF nanoparticles.

Sodium gadolinium fluoride (NaGdF4) nanoparticles are promising candidates as T1 shortening magnetic resonance imaging (MRI) contrast agents due to the paramagnetic properties of the Gd3+ ion. Effects of size and surface modification of these nanoparticles on proton relaxation times have been widely studied. However, to date, there has been no report on how T1 relaxivity (r1) is affected by the different polymorphs in which NaGdF4 crystallizes: cubic (α) and hexagonal (β).