Fe₃O₄ nanoparticles (MNP, a) synthesized in organic solvent and transferred to a water solution using PMA amphiphilic polymer (PMNP, b).

<p>MNP and PMNP were highly monodisperse in size as it is shown by TEM images (scale bars = 40 nm,). Part of the highly concentrated PMNP suspension (8 mg mL^–1) was incorporated in a w/o cream (0.8 wt % concentration) (c).</p

Cytofluorimetric analysis showing PMNP nanoparticles uptake by mouse skin and lymph node cells.

<p>PMNP suspension (a, upper panels). Skin CD45-positive and negative cells showing CFSE incorporation. Note that most of the skin cells uptake PMNP nanoparticles administered with the cream formulation. (a, lower panels) CFSE-positive cells in the lymph nodes of mice that received PMNP nanoparticles via cream formulation or via sc administration. Note that only with sc PMNP administration, nanoparticle-positive cells can be detected in the draining lymph nodes. (b) Lymph node macrophages and dendritic cells, identified as CD11b- and CD11c-positive cells respectively, showing CFSE incorporation. Note that only when PMNP are administered sc, CFSE positive macrophages and dendritic cells can be detected in the lymph nodes.</p

Fates of nanoparticles depending on the route of skin administration.

<p>Nanoparticle administered in a cream formulation are taken up by all the skin cell types and do no reach the draining lymph nodes. Nanoparticle administered with a sc injection in aqueous suspension are efficiently transported to the draining lymph nodes.</p

Histological microphotograph of normal human skin section.

<p>Haematoxylin and eosin staining (original magnification 40×) (a). <i>In vitro</i> diffusion studies of PMNP colloidal suspension or cream in human skin were carried out using Franz diffusion cells and diffused PMNP were quantified by ICP-OES analysis (b).</p

Luminescent Rhenium and Ruthenium Complexes of an Amphoteric Poly(amidoamine) Functionalized with 1,10-Phenanthroline

A new amphoteric copolymer, <b>PhenISA</b>, has been obtained by copolymerization of 4-(4′-aminobutyl)-1,10-phenanthroline (BAP) with 2-methylpiperazine and bis­(acrylamido)­acetic acid (BAC) (6% of phenanthroline-containing repeating units). The copolymer showed excellent solubility in water, where it self-aggregated to give clear nanoparticle suspensions (hydrodynamic diameter = 21 ± 2 nm, by dynamic light scattering (DLS) analysis). The phenanthroline pendants of the polymer stably coordinated either Re­(CO)₃⁺ or Ru­(phen)₂²⁺ fragments, affording luminescent <b>Re-PhenISA</b>, <b>Re-Py-PhenISA</b>, and <b>Ru-PhenISA</b> polymer complexes, emitting from triplet metal-to-ligand charge transfer (³MLCT) excited states (with λ_em = 608, 571, and 614 nm, respectively, and photoluminescence quantum yields Φ_em = 0.7%, 4.8%, and 4.1%, in aerated water solution, respectively). DLS analyses indicated that the polymer complexes maintained the nanosize of <b>PhenISA</b>. All the complexes were stable under physiological conditions (pH 7.4, 0.15 M NaCl) in the presence of an excess of the ubiquitous competitor cysteine. In vitro viability assays showed no toxicity of <b>Re-Py-PhenISA</b> and <b>Ru-PhenISA</b> complexes, at concentrations in the range of 0.5–50 μM (calculated on the metal-containing unit), toward HEK-293 (human embryonic kidney) cells. A preliminary investigation of internalization in HEK-293 cells, by means of fluorescence confocal microscopy, showed that <b>Ru-PhenISA</b> enters cells via an endocytic pathway and, subsequently, homogeneously diffuse within the cytoplasm across the vesicle membranes