Showing papers by "Giuseppe Coppola published in 2014"

Optical properties of diatom nanostructured biosilica in Arachnoidiscus sp: micro-optics from mother nature.

Abstract: Some natural structures show three-dimensional morphologies on the micro- and nano- scale, characterized by levels of symmetry and complexity well far beyond those fabricated by best technologies available. This is the case of diatoms, unicellular microalgae, whose protoplasm is enclosed in a nanoporous microshell, made of hydrogenated amorphous silica, called frustule. We have studied the optical properties of Arachnoidiscus sp. single valves both in visible and ultraviolet range. We found photonic effects due to diffraction by ordered pattern of pores and slits, accordingly to an elaborated theoretical model. For the first time, we experimentally revealed spatial separation of focused light in different spots, which could be the basis of a micro-bio-spectrometer. Characterization of such intricate structures can be of great inspiration for photonic devices of next generation.

4D tracking of clinical seminal samples for quantitative characterization of motility parameters

Abstract: In this paper we investigate the use of a digital holographic microscope, with partial spatial coherent illumination, for the automated detection and tracking of spermatozoa. This in vitro technique for the analysis of quantitative parameters is useful for assessment of semen quality. In fact, thanks to the capabilities of digital holography, the developed algorithm allows us to resolve in-focus amplitude and phase maps of the cells under study, independently of focal plane of the sample image. We have characterized cell motility on clinical samples of seminal fluid. In particular, anomalous sperm cells were characterized and the quantitative motility parameters were compared to those of normal sperm.

Shedding light on diatom photonics by means of digital holography.

Abstract: Diatoms are among the dominant phytoplankters in the world's oceans, and their external silica investments, resembling artificial photonic crystals, are expected to play an active role in light manipulation. Digital holography allowed studying the interaction with light of Coscinodiscus wailesii cell wall reconstructing the light confinement inside the cell cytoplasm, condition that is hardly accessible via standard microscopy. The full characterization of the propagated beam, in terms of quantitative phase and intensity, removed a long-standing ambiguity about the origin of the light confinement. The data were discussed in the light of living cell behavior in response to their environment.

Association between intrafollicular concentration of benzene and outcome of controlled ovarian stimulation in IVF/ICSI cycles: a pilot study.

Abstract: Background: Several studies have shown that exposure to benzene is associated to menstrual disorders, miscarriages and other disorders of the reproductive system. We performed an observational prospective pilot study to evaluate if levels of benzene in follicular fluid were correlated with response to controlled ovarian stimulation. Method: Thirty-four normogonadotrophic women undergoing IVF were enrolled. Intra-follicular benzene levels were evaluated by chromatography/mass spectrometry. Based on median benzene level, we divided the study population in two groups: Group A with a “low” intra-follicular benzene concentration (n=19, benzene <0.54 ng/mL) and Group B with a “high” intra-follicular benzene concentration (n=15, benzene ≥0.54 ng/mL). The ovarian response to gonadotrophins and the outcome of IVF were analyzed in the two groups. Results: The two groups did not differ in terms of demographic or anthropometric characteristics. Group B had significantly higher basal FSH levels, lower estradiol peak concentration, and fewer oocytes retrieved and embryos transferred (p<0.05). Number of gonadotrophin vials, length of controlled ovarian stimulation and ongoing pregnancy rate were similar in the two groups. Conclusion: In conclusion, ovarian response to endogenous and exogenous gonadotrophins appeared to be influenced by intra-follicular benzene levels.

Non-invasive sex assessment in bovine semen by Raman spectroscopy

Abstract: X- and Y-chromosome-bearing sperm cell sorting is of great interest, especially for animal production management systems and genetic improvement programs. Here, we demonstrate an optical method based on Raman spectroscopy to separate X- and Y-chromosome-bearing sperm cells, overcoming many of the limitations associated with current sex-sorting protocols. A priori Raman imaging of bull spermatozoa was utilized to select the sampling points (head-neck region), which were then used to discriminate cells based on a spectral classification model. Main variations of Raman peaks associated with the DNA content were observed together with a variation due to the sex membrane proteins. Next, we used principal component analysis to determine the efficiency of our device as a cell sorting method. The results (>90% accuracy) demonstrated that Raman spectroscopy is a powerful candidate for the development of a highly efficient, non-invasive, and non-destructive tool for sperm sexing.

Digital holographic microscopy for the evaluation of human sperm structure.

Abstract: The morphology of the sperm head has often been correlated with the outcome of in vitro fertilization, and has been shown to be the sole parameter in semen of value in predicting the success of intracytoplasmic sperm injection and intracytoplasmic morphologically selected sperm injection. In this paper, we have studied whether digital holographic microscopy (DHM) may be useful to obtain quantitative data on human sperm head structure and compared this technique with high-power digitally enhanced Nomarski optics. The main advantage of digital holography is that high-resolution three-dimensional quantitative sample imaging may be automatically produced by numerical refocusing of a two-dimensional image at different object planes without any mechanical scanning. We show that DHM generates useful information on the dimensions and structure of human sperm, not revealed by conventional phase-contrast microscopy, in particular the volume of vacuoles, and suggest its use as an additional prognostic tool in assisted reproduction technology.

Silicon photodetectors based on internal photoemission effect: The challenge of detecting near infrared light

Abstract: In this paper an advance overview of our activity in the field of near-infrared silicon photodetectors, is presented. Proposed photodetectors are based on the internal photoemission effect through a Schottky junction and their fabrication results completely compatible with the silicon technology. Taking advantages by both new structures and new two-dimensional emerging materials a progressive increase in device performance has been demonstrated along the last years. Our insights show that silicon devices based on the internal photoemission effect are already suitable for power monitoring application and they could play a key role in the telecommunications opening new frontiers in the field of low-cost silicon photonic.

Maternal non-Mendelian inheritance of a reduced lifespan? A hypothesis

Abstract: Purpose A negative correlation exists between advanced maternal age and reproduction. Current data suggest that this correlation is due to a decline in oocyte quality with respect to female age. Since a new individual is derived from the fusion of a single sperm and egg, we tested whether the quality of this material could influence the long-term physiological health of offspring, by examining whether a link between parental age and lifespan of offspring exists.

Progress towards a high-performing a-Si:H-based electro-optic modulator

Abstract: Hydrogenated amorphous silicon (a-Si:H) has recently emerged as a promising material to provide microchips with passive and active photonic functions through a back-end and CMOS-compatible technological process. In this paper, we discuss the performance achieved with different configurations of a-Si:H-based electro-optical amplitude modulators integrated into passive waveguides. All of the analysed devices are based on the plasma dispersion effect, a phenomenon that allows us to reach useful performance at the communication wavelength of ? ? 1.55??m. The behaviour of the various proposed modulation approaches has been tested by ad hoc interferometric structures, such as Fabry?Perot integrated resonators or integrated Mach?Zehnder interferometer, as well as by multistack devices to enhance the static modulation efficiency. The performance of each modulator has been analysed through several figures of merit.

Holographic imaging of unlabelled sperm cells for semen analysis: a review

Abstract: Male reproductive health in both humans and animals is an important research field in biological study. In order to characterize the morphology, the motility and the concentration of the sperm cells, which are the most important parameters to feature them, digital holography demonstrated to be an attractive technique. Indeed, it is a labelfree, non-invasive and high-resolution method that enables the characterization of live specimen. The review is intended both for summarize the state-of-art on the semen analysis and recent achievement obtained by means of digital holography and for exploring new possible applications of digital holography in this field.

3D manipulation and visualization of in-vitro cells by optical tweezers and digital holographic microscopy

Abstract: We present the possibility to trap cells (mouse fibroblasts, bovine spermatozoa and diatoms), to manage their position and to induce rotation, by using optical tweezers. The aim is to place them in desired positions, in order to record holographic images in a microscope configuration. Then we are able to recover the 3D shape and to calculate the biovolume of the cells starting from the reconstructed quantitative phase maps (QPMs).

Raman sex sorting of bovine spermatozoa

Abstract: This work relates to the problem of sex predetermination in animals based on the separation of Xand Y -bearing sperm cells before insemination. We developed a device for efficient, non-destructive and label-free sorting of X-and Y -bearing sperm cells based on their Raman spectroscopic characteristics. Raman spectroscopy (RS) is a non-invasive technique that allows the biochemical analysis of the cellular components and the characterization of molecular structure from their stretching and bending vibrational transitions. RS offers detailed information on the conformation, composition and molecular interactions of important cellular macromolecules, such as DNA, proteins and lipids, and can be used to characterize and study individual living cells. In this paper, we present a Raman spectroscopy-based method for selective and sensitive discrimination of Xand Ybearing bovine sperm cells.

Method and apparatus for discriminating x and y sperms based upon raman spectroscopy

Abstract: The invention relates to a method based upon the use of Raman spectroscopy to face the problem of the biochemical analysis and of the differentiation of the X sperm and Y sperm in the animal species, in particular bovine species, with approaches which make possible the subsequent use in fecundation techniques. A method addressed to the resolution of this problem is based upon the separation between X sperm and Y sperm before insemination. An apparatus is also described implementing such method which allows to distinguish and characterize the difference between X sperm and Y sperm by acquiring and analyzing Raman spectra noninvasively and in a not destructive way. By means of a statistical approach, such as for example the analysis of the main components and the linear discriminating analysis, the spectroscopic difference between X sperm and Y sperm is evaluated, processed and used to separate the two types of cells. The invention also relates to the development of a cytofluorimeter combining the Raman microscope with a system for trapping optically the sperms and a microfluidic chamber. More precisely, the optical trapping system, equipped with an objective with high numerical aperture, is used to immobilize the cells and, the same objective is used to excite and gather Raman spectra. At last, the microfluidic chamber is used to make the sample to flow, with the final purpose of providing a quick, precise and not invasive separation of X sperm and Y sperm, (figure 5A).

NIR silicon Schottky photodetector: From metal to graphene

Abstract: In this work an advanced overview in the field of near-infrared silicon photodetectors, is presented. Proposed photodetectors are based on the internal photoemission effect through a Schottky junction and their fabrication results completely compatible with the silicon technology. Taking advantage of both new structures and new two-dimensional emerging materials, a progressive increase in device performance has been demonstrated along the last years. Our insights show that silicon devices based on the internal photoemission effect are already suitable for power monitoring applications and they could play a key role in the telecommunications opening new frontiers in the field of low-cost silicon photonics.

CMOS-compatible amorphous silicon photonic layer integrated with VLSI electronics

Abstract: Hydrogenated amorphous silicon (a-Si:H) is recently emerging as a promising material to provide microchips with passive and active photonic functions through a back-end and CMOS-compatible technological process. In this paper, we discuss the performances achieved with different configurations of a-Si:H-based electro-optical amplitude modulators integrated into passive waveguides. All of the analyzed devices are based on the plasma dispersion effect, a phenomenon that allows to reach useful performances at the communication wavelengths of λ~1.55 μm. Mixed electro-optic simulations, in both steady state and transient conditions, for optimized active photonic devices are finally presented.

Biovolume calculation and three-dimensional imaging of bovine spermatozoa by digital holography

Abstract: Optical tweezers and digital holography are used for the purpose of trapping and analyze bovine spermatozoa in microfluidic devices. 3D imaging and estimation of volume of the cells are provided.

3D visualization and biovolume estimation of motile cells by digital holography

Abstract: For the monitoring of biological samples, physical parameters such as size, shape and refractive index are of crucial importance. However, up to now the morphological in-vitro analysis of in-vitro cells has been limited to 2D analysis by classical optical microscopy such as phase-contrast or DIC. Here we show an approach that exploits the capability of optical tweezers to trap and put in self-rotation bovine spermatozoa flowing into a microfluidic channel. At same time, digital holographic microscopy allows to image the cell in phase-contrast modality for each different angular position, during the rotation. From the collected information about the cell’s phase-contrast signature, we demonstrate that it is possible to reconstruct the 3D shape of the cell and estimate its volume. The method can open new pathways for rapid measurement of in-vitro cells volume in microfluidic lab-on-a-chip platform, thus having access to 3D shape of the object avoiding tomography microscopy, that is an overwhelmed and very complex approach for measuring 3D shape and biovolume estimation.