Martina Mugnano

Bio: Martina Mugnano is an academic researcher from National Research Council. The author has contributed to research in topics: Digital holography & Holography. The author has an hindex of 13, co-authored 57 publications receiving 713 citations. Previous affiliations of Martina Mugnano include University of Naples Federico II.

Tomographic flow cytometry by digital holography.

Abstract: High-throughput single-cell analysis is a challenging task. Label-free tomographic phase microscopy is an excellent candidate to perform this task. However, in-line tomography is very difficult to implement in practice because it requires a complex set-up for rotating the sample and examining the cell along several directions. We demonstrate that by exploiting the random rolling of cells while they are flowing along a microfluidic channel, it is possible to obtain in-line phase-contrast tomography, if smart strategies for wavefront analysis are adopted. In fact, surprisingly, a priori knowledge of the three-dimensional position and orientation of rotating cells is no longer needed because this information can be completely retrieved through digital holography wavefront numerical analysis. This approach makes continuous-flow cytotomography suitable for practical operation in real-world, single-cell analysis and with a substantial simplification of the optical system; that is, no mechanical scanning or multi-direction probing is required. A demonstration is given for two completely different classes of biosamples: red blood cells and diatom algae. An accurate characterization of both types of cells is reported, despite their very different nature and material content, thus showing that the proposed method can be extended by adopting two alternate strategies of wavefront analysis to many classes of cells.

A skin-over-liquid platform with compliant microbumps actuated by pyro-EHD pressure

Abstract: The unique deformability and the compliance ability of thin sheets on soft substrates attract much interest for studying the phenomena related to elastic instabilities as well as for sensing very weak forces such as those generated by live cells in vitro. However, the techniques used currently for producing such platforms are affected by a high degree of complexity and poor repeatability. Moreover, their deformability is usually used as a passive response to the action of an external force. Herein we propose a novel concept for a reliable and dynamic skin-over-liquid system made of a periodic array of highly compliant microbumps actuated through electrode-free electrohydrodynamic (EHD) pressure. We demonstrate that these structures are highly repeatable and capable of swelling and deflating easily under a simple thermal stimulation driven by the pyroelectric effect, thus providing a challenging platform that can be actively controlled at the microscale. Furthermore, we show the proof of principle by swelling these microbumps for mechanically stimulating live cells in vitro, thus opening the route to more reliable and easy to accomplish assays in the field of mechanobiology. Researchers curious about how mechanical stress impacts cell growth can now turn to silicone plastics that grow microbumps on demand. Simonetta Grilli from Italy’s Institute of Applied Sciences and Intelligent Systems in Pozzuoli and colleagues created a controllable ‘skin-over-liquid’ system by coating a silicone polymer solution onto lithium niobate, a crystal that contains patterned regions of electric charge. An initial plasma treatment produced a flat stiff film on top of the liquid silicone. Thermal heating caused the skin to swell and form dimpled, air mattress-like patterns, corresponding to the underlying lithium niobate domains. Removal of heat restored the sheet to its initial state. The chemically inert skin supported live fibroblast cells and was used to determine reactions to mechanical stress. Significant variations in nuclei and cytoskeletons were observed between cells grown under flat or swollen-skin conditions. We propose an innovative skin-over-liquid system made of a periodic array of highly compliant microbumps actuated through an electrode-free electrohydrodynamic (EHD) pressure. We demonstrate that these structures are highly repeatable and are capable to swell and deflate easily under a simple thermal stimulation driven by pyroelectric effect, thus providing a challenging platform that can be actively controlled at microscale. We show the proof of principle by swelling these microbumps for stimulating mechanically live cells in vitro, thus opening the route to more reliable and easy to accomplish assays in the field of mechanobiology.

Full-angle tomographic phase microscopy of flowing quasi-spherical cells.

Abstract: We report a reliable full-angle tomographic phase microscopy (FA-TPM) method for flowing quasi-spherical cells along microfluidic channels. This method lies in a completely passive optical system, i.e. mechanical scanning or multi-direction probing of the sample is avoided. It exploits the engineered rolling of cells while they are flowing along a microfluidic channel. Here we demonstrate significant progress with respect to the state of the art of in-flow TPM by showing a general extension to cells having almost spherical shapes while they are flowing in suspension. In fact, the adopted strategy allows the accurate retrieval of rotation angles through a theoretical model of the cells' rotation in a dynamic microfluidic flow by matching it with phase-contrast images resulting from holographic reconstructions. So far, the proposed method is the first and the only one that permits to get in-flow TPM by probing the cells with full-angle, achieving accurate 3D refractive index mapping and the simplest optical setup, simultaneously. Proof of concept experiments were performed successfully on human breast adenocarcinoma MCF-7 cells, opening the way for the full characterization of circulating tumor cells (CTCs) in the new paradigm of liquid biopsy.

Holographic microscope slide in a spatio-temporal imaging modality for reliable 3D cell counting.

Abstract: In the current trend of miniaturization and simplification of imaging flow cytometry, Lab-on-a-Chip (LoC) microfluidic devices represent an innovative and cost-effective solution. In this framework, we propose for the first time a novel platform based on the compactness of a holographic microscope slide (HMS) in combination with the new computational features of space-time digital holography (STDH) that uses a 1D linear sensor array (LSA) instead of 2D CCD or CMOS cameras to respond to real diagnostic needs. In this LoC platform, computational methods, holography, and microfluidics are intertwined in order to provide an imaging system with a reduced amount of optical components and capability to achieve reliable cell counting even in the absence of very accurate flow control. STDH exploits the sample motion into the microfluidic channel to obtain an unlimited field-of-view along the flow direction, independent of the magnification factor. Furthermore, numerical refocusing typical of a holographic modality allows imaging and visualization of the entire volume of the channel, thus avoiding loss of information due to the limited depth of focus of standard microscopes. Consequently, we believe that this platform could open new perspectives for enhancing the throughput by 3D volumetric imaging.

Label-Free Optical Marker for Red-Blood-Cell Phenotyping of Inherited Anemias

Abstract: The gold-standard methods for anemia diagnosis are complete blood counts and peripheral-smear observations. However, these do not allow for a complete differential diagnosis as that requires biochemical assays, which are label-dependent techniques. On the other hand, recent studies focus on label-free quantitative phase imaging (QPI) of blood samples to investigate blood diseases by using video-based morphological methods. However, when sick cells are very similar to healthy ones in terms of morphometric features, identification of a blood disease becomes challenging even with QPI. Here, we introduce a label-free optical marker (LOM) to detect red-blood-cell (RBC) phenotypes, demonstrating that a single set of all-optical parameters can clearly identify a signature directly related to an erythrocyte disease through modeling each RBC as a biological lens. We tested this novel biophotonic analysis by proving that several inherited anemias, such as iron-deficiency anemia, thalassemia, hereditary spherocytosi...

Quantitative phase imaging in biomedicine

Abstract: Quantitative phase imaging (QPI) has emerged as a valuable method for investigating cells and tissues. QPI operates on unlabelled specimens and, as such, is complementary to established fluorescence microscopy, exhibiting lower phototoxicity and no photobleaching. As the images represent quantitative maps of optical path length delays introduced by the specimen, QPI provides an objective measure of morphology and dynamics, free of variability due to contrast agents. Owing to the tremendous progress witnessed especially in the past 10–15 years, a number of technologies have become sufficiently reliable and translated to biomedical laboratories. Commercialization efforts are under way and, as a result, the QPI field is now transitioning from a technology-development-driven to an application-focused field. In this Review, we aim to provide a critical and objective overview of this dynamic research field by presenting the scientific context, main principles of operation and current biomedical applications. Over the past 10–15 years, quantitative phase imaging has moved from a research-driven to an application-focused field. This Review presents the main principles of operation and representative basic and clinical science applications.

Soft matter with hard skin : From skin wrinkles to templating and material characterization

Abstract: The English-language dictionary defines wrinkles as "small furrows, ridges, or creases on a normally smooth surface, caused by crumpling, folding, or shrinking". In this paper we review the scientific aspects of wrinkling and the related phenomenon of buckling. Specifically, we discuss how and why wrinkles/buckles form in various materials. We also describe several examples from everyday life, which demonstrate that wrinkling or buckling is indeed a commonplace phenomenon that spans a multitude of length scales. We will emphasize that wrinkling is not always a frustrating feature (e.g., wrinkles in human skin), as it can help to assemble new structures, understand important physical phenomena, and even assist in characterizing chief material properties.

Dielectrophoretic cell separation and gene expression profiling on microelectronic chip arrays

Abstract: Cell membrane dielectric properties of five different cultivated cell lines and human peripheral blood mononuclear cells (PBMC) were determined from dielectrophoretic crossover frequency measurements on a 5 x 5 microelectronic chip array. Based on distinct dielectric property differences between individual cell types, efficient cell separations were achieved by dielectrophoresis on this 5 x 5 array, which included separation of monocytic cells (U937) or human T cell leukemia virus type 1 (HTLV-1) tax-transformed cells (Ind-2) from PBMC, as well as separation of neuroblastoma cells (SH-SY5Y) from glioma cells (HTB). The purity of dielectrophoretically separated cells can be greater than 95%. Expression profiles of IL-1, TNF-alpha, and TGF-beta genes for U937 cells mixed with PBMC before and after the separation were determined by a means of electric field-facilitated hybridization on a 10 x 10 microelectronic chip array. By using the expression levels of pure U937 cells as a control, it was shown that the gene expression profiles of the postseparation cells were significantly different from those of the preseparation cell mixtures. The increase in gene expression levels for U937 cells upon lipopolysaccharide induction could be accurately determined only in the postseparation cells, while the preseparation samples masked these changes. Furthermore, by cultivating the separated HTB and SH-SY5Y cells and measuring expression of the stress-related gene c-fos, dielectrophoretic forces were shown to have little effect on cell survival and stress. The presented approach of using microelectronic chip arrays for both cell separation and gene expression profiling provides a great potential for accurate genetic analysis of specific cell subpopulations in heterogeneous samples.