Fast epi-detected broadband multiplex CARS and SHG imaging of mouse skull cells.

We present a bimodal imaging system able to obtain epi-detected mutiplex coherent anti-Stokes Raman scattering (M-CARS) and second harmonic generation (SHG) signals coming from biological samples. We studied a fragment of mouse parietal bone and could detect broadband anti-Stokes and SHG responses originating from bone cells and collagen respectively. In addition we compared two post-processing methods to retrieve the imaginary part of the third-order nonlinear susceptibility related to the spontaneous Raman scattering.

In vitro toxicity of nanoceria: effect of coating and stability in biofluids.

Due to the increasing use of nanometric cerium oxide in applications, concerns about the toxicity of these particles have been raised and have resulted in a large number of studies. We report here on the interactions between 7 nm anionically charged cerium oxide particles and living mammalian cells. By a modification of the particle coating including low-molecular weight ligands and polymers, two generic behaviours are compared: particles coated with citrate ions that precipitate in biofluids and particles coated with poly(acrylic acid) that are stable and remain nanometric.

Thirty-femtogram detection of iron in mammalian cells.

Inorganic nanomaterials and particles with enhanced optical, mechanical, or magnetic attributes are currently being developed for a wide range of applications. Safety issues have developed however concerning their potential cyto- and genotoxicity. For in vivo and in vitro experimentations, recent developments have heightened the need for simple and facile methods to measure the amount of nanoparticles taken up by cells or tissues.

Spectroscopic and magnetic properties of the metastable states in the coordination network [{Co(prm)2}2{Co(H2O)2}{W(CN)8}2]·4H2O (prm = pyrimidine).

The study of the metastable states, obtained by thermal quenching or by light irradiation in the [{Co(prm)(2)}(2){Co(H(2)O)(2)}{W(CN)(8)}(2)]·4H(2)O complex, is reported using powder X-ray diffraction, Raman spectroscopy, optical reflectivity, and magnetic measurements. This compound is characterized by a electron-transfer (ET) phase transition occurring between a high-temperature phase (HT phase) formed by paramagnetic Co(II)-W(V) units and a low-temperature phase (LT phase) formed by diamagnetic Co(III)-W(IV) units. Metastable phases can be induced at low temperature either by thermal quenching rapidly cooling phase named RC or by irradiation photo-induced phase named PI similar to the well-known Light-Induced Excited Spin State Trapping effect.

Ligand strain and the nature of spin crossover in binuclear complexes: two-step spin crossover in a 4,4'-bipyridine-bridged iron(II) complex [{Fe(dpia)(NCS)(2)}(2)(4,4'-bpy)] (dpia = di(2-picolyl)amine; 4,4'-bpy = 4,4'-bipyridine).

The synthesis and detailed characterization of the new spin crossover (SCO) binuclear complex [{Fe(dpia)(NCS)(2)}(2)(4,4'-bpy)] (1; dpia=di(2-picolyl)amine, 4,4'-bpy = 4,4'-bipyridine) are reported. Variable-temperature magnetic susceptibility measurements show a relatively cooperative two-step spin transition suggesting the occurrence of three spin-state isomers: [HS-HS], [HS-LS], and [LS-LS] (HS: high spin, LS: low spin). A short plateau at 204 K separates the two steps and conforms with about 50% of the complexes having undergone a thermal spin conversion.