Carme Nogués

Analysis of sex chromosome aneuploidy in sperm from fathers of Turner syndrome patients

Numerical sex chromosome abnormalities were analyzed in sperm from four fathers of Turner syndrome patients of paternal origin to determine whether there was an increased frequency of sex chromosome aneuploidy and to elucidate whether meiotic malsegregation mechanisms could be involved in the origin of Turner syndrome. Determination of the parental origin of the single X chromosome (maternal in all four cases) and exclusion of X and Y mosaicism were carried out by polymerase chain reaction amplification of five X chromosome polymorphisms and three Y chromosome segments. A total of 45,299 sperm nuclei from Turner fathers and 85,423 sperm nuclei from eight control donors was analyzed by three-color fluorescence in situ hybridization. The four patients showed a significant increase in the percentages of XY sperm (mean 0.22%; range 0.20% to 0.22%) compared with control donors (mean 0.11%; range 0.06% to 0.18%). These results suggest that the four individuals have an increased frequency of nondisjunctional errors in meiosis I, resulting in the production of an increased proportion of XY spermatozoa and of sperm lacking a sex chromosome.

Simple monitoring of cancer cells using nanoparticles.

Here we present a new strategy for a simple and fast detection of cancer circulating cells (CTCs) using nanoparticles. The human colon adenocarcinoma cell line (Caco2) was chosen as a model CTC. Similarly to other adenocarcinomas, colon adenocarcinoma cells have a strong expression of EpCAM, and for this reason this glycoprotein was used as the capture target. We combine the capturing capability of anti-EpCAM functionalized magnetic beads (MBs) and the specific labeling through antibody-modified gold nanoparticles (AuNPs), with the sensitivity of the AuNPs-electrocatalyzed hydrogen evolution reaction (HER) detection technique. The fully optimized process was used for the electrochemical detection of Caco2 cells in the presence of monocytes (THP-1), other circulating cells that could interfere in real blood samples. Therefore we obtained a novel and simple in situ-like sensing format that we applied for the rapid quantification of AuNPs-labeled CTCs in the presence of other human cells.

Improved mechanical performance and delayed corrosion phenomena in biodegradable Mg–Zn–Ca alloys through Pd-alloying

The influence of partial substitution of Mg by Pd on the microstructure, mechanical properties and corrosion behaviour of Mg(72-x)Zn(23)Ca(5)Pd(x) (x=0, 2 and 6 at.%) alloys, synthesized by copper mould casting, is investigated. While the Mg(72)Zn(23)Ca(5) alloy is mainly amorphous, the addition of Pd decreases the glass-forming ability, thus favouring the formation of crystalline phases. From a mechanical viewpoint, the hardness increases with the addition of Pd, from 2.71 GPa for x=0 to 3.9 GPa for x=6, mainly due to the formation of high-strength phases. In turn, the wear resistance is maximized for an intermediate Pd content (i.e., Mg(70)Zn(23)Ca(5)Pd(2)). Corrosion tests in a simulated body fluid (Hanks solution) indicate that Pd causes a shift in the corrosion potential towards more positive values, thus delaying the biodegradability of this alloy. Moreover, since the cytotoxic studies with mouse preosteoblasts do not show dead cells after culturing for 27 h, these alloys are potential candidates to be used as biomaterials.

Detection of Circulating Cancer Cells Using Electrocatalytic Gold Nanoparticles

A rapid cancer cell detection and quantification assay, based on the electrocatalytic properties of gold nanoparticles towards the hydrogen evolution reaction, is described. The selective labeling of cancer cells is performed in suspension, allowing a fast interaction between the gold nanoparticle labels and the target proteins expressed at the cell membrane. The subsequent electrochemical detection is accomplished with small volumes of sample and user-friendly equipment through a simple electrochemical method that generates a fast electrochemical response used for the quantification of nanoparticle-labeled cancer cells. The system establishes a selective cell-detection assay capable of detecting 4 × 10(3) cancer cells in suspension that can be extended to several other cells detection scenarios.

Intracellular polysilicon barcodes for cell tracking.

During the past decade, diverse types of barcode have been designed in order to track living cells in vivo or in vitro, but none of them offer the possibility to follow an individual cell up to ten or more days. Using silicon microtechnologies a barcode sufficiently small to be introduced into a cell, yet visible and readily identifiable under an optical microscope, is designed. Cultured human macrophages are able to engulf the barcodes due to their phagocytic ability and their viability is not affected. The utility of the barcodes for cell tracking is demonstrated by following individual cells for up to ten days in culture and recording their locomotion. Interestingly, silicon microtechnology allows the mass production of reproducible codes at low cost with small features (bits) in the micrometer range that are additionally biocompatible.

Effects of aging on the zona pellucida surface of mouse oocytes

In a scanning microscopy study of mouse oocytes from immature, young, and aged females and of oocytes agedin vivo orin vitro, we have observed four types of zona pellucida, which we classify as types A, B, C, and D. Oocyte aging gives rise to a significant increase in predegenerative (type C) oocytes; this type of zona pellucida surface could result from a zona hardening effect and decrease the rate of fertilization of the oocytes affected.

Cell analysis using a multiple internal reflection photonic lab-on-a-chip

Here we present a protocol for analyzing cell cultures using a photonic lab-on-a-chip (PhLoC). By using a broadband light source and a spectrometer, the spectrum of a given cell culture with an arbitrary population is acquired. The PhLoC can work in three different regimes: light scattering (using label-free cells), light scattering plus absorption (using stained cells) and, by subtraction of the two former regimes, absorption (without the scattering band). The acquisition time of the PhLoC is ∼30 ms. Hence, it can be used for rapid cell counting, dead/live ratio estimation or multiparametric measurements through the use of different dyes. The PhLoC, including microlenses, micromirrors and microfluidics, is simply fabricated in a single-mask process (by soft lithographic methods) using low-cost materials. Because of its low cost it can easily be implemented for point-of-care applications. From raw substrates to final results, this protocol can be completed in 29 h.

Zona pellucida surface of immature and in vitro matured mouse oocytes: Analysis by scanning electron microscopy

PurposeThe aim of this work was to determine the morphology of the zona pellucida surface of immature and in vitro matured mouse oocytes by scanning electron microscopy. For this purpose two groups of immature oocytes (germinal vesicle group and metaphase I group) were studied either before or after in vitro maturation.ResultsBefore in vitro maturation, the germinal vesicle immature group showed mainly an unstructured zona pellucida surface with smooth cumulus cells. The metaphase I immature group showed a more structured zona pellucida with smooth or blebbing cumulus cells. After in vitro maturation, development of the zona pellucida toward a mature surface, related to the initial degree of oocyte maturity, was observed in both groups.ConclusionsThese observations show a correlation between the morphology of the zona pellucida surface and the degree of oocyte maturity; the in vitro maturation process can give rise to a proper development of this endowment when immature oocytes are used.

Cell Screening Using Disposable Photonic Lab on a Chip Systems

A low-cost photonic lab on a chip with three different working regimes for cell screening is presented. The proposed system is able to perform scattering, scattering + absorption, and absorption measurements without any modification. Opposite to the standard flow cytometers, in this proposed configuration, a single 30 ms scan allows to obtain information regarding the cell optical properties. An additional novelty is that the whole spectrum is obtained and analyzed, being then possible to determine for each regime which is the optimal working wavelength that would provide the best performance in terms of sensitivity and limit of detection (LOD). Experimental results have provided with an LOD of 54.9 +/- 0.7 cells (in the scattering regime using unlabeled cells), 53 +/- 1 cells (in the scattering + absorption regime using labeled cells), and 105 +/- 4 cells (in the absorption regime using labeled cells). Finally, the system has also been used for measuring the dead/live cell ratio, obtaining LODs between 7.6 +/- 0.4% and 6.7 +/- 0.3%, depending on the working regime used.

Surface modification of microparticles causes differential uptake responses in normal and tumoral human breast epithelial cells

The use of micro- and nanodevices as multifunctional systems for biomedical applications has experienced an exponential growth during the past decades. Although a large number of studies have focused on the design and fabrication of new micro- and nanosystems capable of developing multiple functions, a deeper understanding of their interaction with cells is required. In the present study, we evaluated the effect of different microparticle surfaces on their interaction with normal and tumoral human breast epithelial cell lines. For this, AlexaFluor488 IgG functionalized polystyrene microparticles (3 μm) were coated with Polyethyleneimine (PEI) at two different molecular weights, 25 and 750 kDa. The effect of microparticle surface properties on cytotoxicity, cellular uptake and endocytic pathways were assessed for both normal and tumoral cell lines. Results showed a differential response between the two cell lines regarding uptake efficiency and mechanisms of endocytosis, highlighting the potential role of microparticle surface tunning for specific cell targeting.