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An increasing number of promising applications for future technology is arising from size constraints in nanoparticles (NPs) and from the chemical manipulation of their surfaces. In this work, we analyse the finite-size and surface effects on polyacrylic acidcoated Fe 3 O 4 NPs and oleic acid-coated g-Fe 2 O 3 NPs by studying their magnetization curves at different temperatures. The measured thermal dependence of the saturation magnetization is no longer explained by the typical T 3/2 Bloch law, yielding higher values than those expected for its exponent. When incorporated in polymeric matrixes to form magnetic transparent nanocomposites, the oleic acid-coated g-Fe 2 O 3 NPs also deviate from Bloch's law, but following the opposite trend observed in free coated NPs.

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Advances in the life sciences are now closely linked to the availability of new experimental tools that allow for the manipulation of biomolecules and the study of biological processes at the molecular level. In this context, we have optimized a synthesis process to obtain glutathione‐capped fluorescent CdS nanoparticles to specifically detect Glutathione S‐Transferase (GST) ‐tagged proteins. Using our method, based on five different heating steps, brightly fluorescent and biocompatible CdS quantum dots of different sizes can be obtained. QD optical behaviour has been evaluated studying both absorbance and fluorescence. For all the samples, the excitonic absorption onset clearly shows a blue shift at 512nm in comparison with that of bulk CdS, due to the quantum confinement effect. At increased average sizes of the nanocrystal, the emission fluorescent band shows a red shift, from 440nm to 540nm. Among different QD solutions, we demonstrate an expansion of the emission range up to ~100 nm, thus improving their features as biomarkers. Moreover we show that optimized glutathionecapped quantum dots can directly bind GST blotted onto polyvinylidene difluoride (PVDF) membranes, and thus are suitable for the direct detection of GST fusion proteins

Bulk monolithic samples of γ-Fe2O3/SiO2 composites with different iron oxide/silica ratios have been prepared by the sol-gel technique. Iron oxide nanoparticles are obtained in-situ during heat treatment of samples and silica matrix consolidation.