The short-term interactions of chondrosarcoma cells with polyelectrolyte multilayer films built up by the alternate adsorption of poly(L-lysine) (PLL) and poly(L-glutamic acid) (PGA) was studied in the presence and in the absence of serum. The films and their interaction with serum proteins were first characterized by means of optical waveguide lightmode spectroscopy, quartz crystal microbalance, and zeta potential measurements. In a serum-containing medium, the detachment forces measured by the micropipet technique were about eight times smaller on PGA-ending than on PLL-ending films. For these latter ones, the adhesion force decreased when the film thickness increased. In a serum-free medium, the differences between the negative- and positive-ending films were enhanced: adhesion forces on PLL-ending films were 40-100% higher, whereas no cellular adherence was found on PGA-terminating films. PGA-ending films were found to prevent the adsorption of serum proteins, whereas important protein adsorption was always observed on PLL-ending films. These results show how cell interactions with polyelectrolyte films can be tuned by the type of the outermost layer, the presence of proteins, and the number of layers in the film.

After labelling DNA with the specific vital fluorophore Hoechst 33342, oocytes, isolated by puncture from antral follicles in adult mice, have two essentially different configurations of their nuclear fluorescence images. These have been called SN (where the nucleolus is surrounded by chromatin) and NSN (where the nucleolus is not surrounded by chromatin). Intermediate configurations are also found, although with a lower frequency. The proportion of each class is on the average equal and depends neither on the presence of cumulus cells nor on the age of the mouse. Electron microscopy confirms several ultrastructural differences between these two nuclear configurations, namely, the structure of the nucleolus, which is vacuolated in NSN-type and compact in SN-type oocytes. Using video-enhanced fluorescence microscopy at low level of excitation light, we could follow directly in vitro the meiotic maturation of both classes, without impairing their viability. We show that in germinal vessicle (GV) state, the chromatin does not change from one configuration into the other and that both classes are able to mature to metaphase II, although the maturation has slightly different characteristics.

The deposition of surface coatings using a step-by-step approach from mutually interacting species allows the fabrication of so called "multilayered films". These coatings are very versatile and easy to produce in environmentally friendly conditions, mostly from aqueous solution. They find more and more applications in many hot topic areas, such as in biomaterials and nanoelectronics but also in stimuli-responsive films. We aim to review the most recent developments in such stimuli-responsive coatings based on layer-by-layer (LBL) depositions in relationship to the properties of these coatings. The most investigated stimuli are based on changes in ionic strength, temperature, exposure to light, and mechanical forces. The possibility to induce a transition from linear to exponential growth in thickness and to change the charge compensation from "intrinsic" to "extrinsic" by controlling parameters such as temperature, pH, and ionic strength are the ways to confer their responsiveness to the films. Chemical post-modifications also allow to significantly modify the film properties.

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