Non-invasive paper-based sensors containing rare-earth-doped nanoparticles for the detection of D-glucose.

Today, diabetes mellitus is one of the most common diseases that affects the population on a worldwide scale. Patients suffering from this disease are required to control their blood-glucose levels several times a day through invasive methods such as piercing their fingers. Our NaGdF: 5% Er, 3% Nd nanoparticles demonstrate a remarkable ability to detect D-glucose levels by analysing alterations in their red-to-green ratio, since this sensitivity arises from the interaction between the nanoparticles and the OH groups present in the D-glucose molecules, resulting in discernible changes in the emission of the green and red bands.

Gold nanorod assisted intracellular optical manipulation of silica microspheres.

We report on the improvement of the infrared optical trapping efficiency of dielectric microspheres by the controlled adhesion of gold nanorods to their surface. When trapping wavelength was equal to the surface plasmon resonance wavelength of the gold nanorods (808 nm), a 7 times improvement in the optical force acting on the microspheres was obtained. Such a gold nanorod assisted enhancement of the optical trapping efficiency enabled the intracellular manipulation of the decorated dielectric microsphere by using a low power (22 mW) infrared optical trap.

A highly sensitive luminescent lectin sensor based on an α-D-mannose substituted Tb3+ antenna complex.

Lectin-carbohydrate interactions are the basis of many biological processes and essentially they constitute the language through which intercellular communications are codified. Thus they represent powerful tools in the examination and interpretation of changes that occur on cell surfaces during both physiological and, more importantly, pathological events. The development of optical techniques that exploit the unique properties of luminescent lanthanoid metal complexes in the investigation of lectin-carbohydrate recognition can foster research in the field of ratiometric biosensing and disease detection.

Bio-functionalization of ligand-free upconverting lanthanide doped nanoparticles for bio-imaging and cell targeting.

We report on the functionalization of ligand-free NaGdF(4):Er(3+), Yb(3+) upconverting nanoparticles with heparin and basic fibroblast growth factor (bFGF). These upconverting nanoparticles are used to obtain high-contrast images of HeLa cells. These images reveal that the heparin-bFGF functionalized nanoparticles show specific binding to the cell membrane.

Toxicity of PAMAM-coated gold nanoparticles in different unicellular models.

Polyamidoamine (PAMAM) dendrimers are used for many pharmaceutical and biomedical applications. However, the toxicological risks of several PAMAM-based compounds are still not fully evaluated, despite evidences of PAMAM deleterious effects on biological membranes, leading to toxicity. In this report, we investigated the toxicity of generation 0 PAMAM-coated gold nanoparticles (AuG0 NPs) in four different models to determine how different cellular systems are affected by PAMAM-coated NPs.

High resolution fluorescence imaging of cancers using lanthanide ion-doped upconverting nanocrystals.

During the last decade inorganic luminescent nanoparticles that emit visible light under near infrared (NIR) excitation (in the biological window) have played a relevant role for high resolution imaging of cancer. Indeed, semiconductor quantum dots (QDs) and metal nanoparticles, mostly gold nanorods (GNRs), are already commercially available for this purpose. In this work we review the role which is being played by a relatively new class of nanoparticles, based on lanthanide ion doped nanocrystals, to target and image cancer cells using upconversion fluorescence microscopy.

Interaction of gold nanoglycodendrimers with algal cells (Chlamydomonas reinhardtii) and their effect on physiological processes.

With the rise of nanotechnologies, the risk of contamination of aquatic ecosystems with nanoparticles is increasing. Glycodendrimer-coated gold nanoparticles have been developed for biomedical applications; however, their effect on microalgae has never been studied. In this report, their interactions with algae were investigated using two strains of Chlamydomonas reinhardtii, a wild type having cell wall and a cell wall-deficient mutant.

Synthesis of ligand-free colloidally stable water dispersible brightly luminescent lanthanide-doped upconverting nanoparticles.

The synthesis using the thermal decomposition of metal trifluoroacetates is being widely used to prepare oleate-capped lanthanide-doped upconverting NaYF(4):Er(3+)/Yb(3+) nanoparticles (Ln-UCNPs). These nanoparticles have no inherent aqueous dispersibility and inconvenient postsynthesis treatments are required to render them water dispersible. Here, we have developed a novel and facile approach to obtain water-dispersible, ligand-free, brightly upconverting Ln-UCNPs.