Optical Fluorescence Microscopy Research Articles

Development of a Three-Dimensional Multi-Modal Perfusion-Thermal Electrode System for Complete Tumor Eradication.

Simple SummaryImage-guided thermal-ablation techniques, such as radiofrequency ablation (RFA), have become the principal tools for treatment of unresectable primary and secondary tumors. However, tumor recurrences post-thermal ablation of medium to large-sized tumors frequently occur due to incomplete ablation of tumor margins. In the present study, we aim to specifically conquer this clinical problem through revolutionizing current thermal ablation technology by development of an innovative three-dimensional, multi-modal, perfusion-thermal electrode system, with the evidence of potential to simultaneously deliver therapeutics and RFA-medicated peritumoral hyperthermia into the difficult-to-treat tumor margins, to further eradicate the residual tumor cells during the thermal ablation.Background: Residual viable tumor cells after ablation at the tumor periphery serve as the source for tumor recurrence, leading to treatment failure. Purpose: To develop a novel three-dimensional (3D) multi-modal perfusion-thermal electrode system completely eradicating medium-to-large malignancies. Materials and Methods: This study included five steps: (i) design of the new system; (ii) production of the new system; (iii) ex vivo evaluation of its perfusion-thermal functions; (iv) mathematic modeling and computer simulation to confirm the optimal temperature profiles during the thermal ablation process, and; (v) in vivo technical validation using five living rabbits with orthotopic liver tumors. Results: In ex vivo experiments, gross pathology and optical imaging demonstrated the successful spherical distribution/deposition of motexafin gadolinium administered through the new electrode, with a temperature gradient from the electrode core at 80 °C to its periphery at 42 °C. An excellent repeatable correlation of temperature profiles at varying spots, from the center to periphery of the liver tumor, was found between the mathematic simulation and actual animal tumor models (Pearson coefficient ≥0.977). For in vivo validation, indocyanine green (ICG) was directly delivered into the peritumoral zones during simultaneous generation of central tumoral lethal radiofrequency (RF) heat (>60 °C) and peritumoral sublethal RF hyperthermia (<60 °C). Both optical imaging and fluorescent microscopy confirmed successful peritumoral ICG distribution/deposition with increased heat shock protein 70 expression. Conclusion: This new 3D, perfusion-thermal electrode system provided the evidence on the potential to enable simultaneous delivery of therapeutic agents and RF hyperthermia into the difficult-to-treat peritumoral zones, creating a new strategy to address the critical limitation, i.e., the high incidence of residual and recurrent tumor following thermal ablation of unresectable medium-to-large and irregular tumors.

Combined optical fluorescence microscopy and X-ray tomography reveals substructures in cell nuclei in 3D.

The function of a biological cell is fundamentally defined by the structural architecture of packaged DNA in the nucleus. Elucidating information about the packaged DNA is facilitated by high-resolution imaging. Here, we combine and correlate hard X-ray propagation-based phase contrast tomography and visible light confocal microscopy in three dimensions to probe DNA in whole cell nuclei of NIH-3T3 fibroblasts. In this way, unlabeled and fluorescently labeled substructures within the cell are visualized in a complementary manner. Our approach enables the quantification of the electron density, volume and optical fluorescence intensity of nuclear material. By joining all of this information, we are able to spatially localize and physically characterize both active and inactive heterochromatin, euchromatin, pericentric heterochromatin foci and nucleoli.

Visible radiophotoluminescence of colour centres in lithium fluoride: from lasers to versatile radiation sensors

The peculiar photoluminescence characteristics of radiation-induced colour centres in lithium fluoride (LiF), well known for applications in optically-pumped tuneable lasers and broad-band miniaturised light-emitting photonic devices operating at room-temperature, are under exploitation in passive imaging detectors and dosimeters based on visible radiophotoluminescence in LiF crystals and polycrystalline thin films. Their high intrinsic spatial resolution, wide dynamic range and large field of view, combined with easy handling, ambient-light operation and no development need, allow to successfully extend their use from X-ray imaging to proton-beam advanced diagnostics and dosimetry, even at those low dose values that are typical of hadrontherapy. After exposure, the latent images stored in LiF as local formations of F2 and F3 + aggregate defects are read with an optical fluorescence microscope under illumination in the blue spectral range. Their visible emission intensity was found to be linearly proportional to the dose over at least three orders of magnitude, so that bi-dimensional LiF solid-state dosimeters based on spectrally-integrated radiophotoluminescence reading can be envisaged. Taking advantage of the low thickness of LiF thin films, transversal proton beam dose mapping was demonstrated at low proton energies, even at high doses. Recent results and advances concerning LiF crystals and polycrystalline thin film characterisation in the linearity range are presented and discussed with the aim of highlighting challenges related to increasing the LiF film detector radiation sensitivity to both particles (protons) and photons (X-rays), although therapeutic dose values typical of clinical radiotherapy are still a big challenge.

Archaeometric investigations of the Molali pottery complex (Bronze Age, Uzbekistan): New data on technology and exchanges at the end of the Oxus Civilization

The recent excavations at the site of Molali, located in southern Uzbekistan and dated to the mid-second millennium BCE, offer new insights into the definition of the Final Bronze Age pottery complex in southern Uzbekistan and the technological and stylistic links between the potting traditions of the various cultural groups at this period. An archaeometric study has been conducted in order to characterize the various wares, investigate the compositional variability of the ceramic assemblage, and determine the provenance of the raw materials. The results from a combination of techniques (Wavelength Dispersive X-Ray Fluorescence, X-Ray Diffraction, and thin section Optical Microscopy) allowed us to identify a local pottery production of wheel-made fine ware and to determine the local/regional origin of the handmade, coarse, shell-tempered ware. Exchange relationships with ‘steppe’ populations have been confirmed; they involved not only vessels (coarse rock-tempered pots) but also pottery traditions (specific ‘steppe’-like decorations on pots of regional origin). Although not numerous, they are nonetheless evidence of large-scale connections between the settlements in the Surkhan Darya valley and other peripheral cultures and areas in the mid-second millennium BCE. The diversity of fabrics (use of various raw materials and different technological processes) is also discussed regarding the choices made for intrinsic material properties required for specific functions, highlighting the strong expertise and management acquired by the potters for the production of diverse ceramic functional categories.

Biobased Spore Microcapsules for Asphalt Self-Healing.

Asphalt pavements and bituminous composites are majorly damaged by bitumen aging and fatigue cracking by traffic load. To add, maintenance and reparation of asphalt pavements is expensive and also releases significant amounts of greenhouse gases. These issues can be mitigated by promoting asphalt self-healing mechanisms with encapsulated rejuvenators. The ability of the required microcapsules to be resilient against high temperatures, oxidation, and mechanical stress is essential to promote such self-healing behavior without compromising the field performance of the asphalt pavement. This work proposes, for the first time, the use of extremely resistant biobased spores for the encapsulation of recycled oil-based rejuvenators to produce more resilient self-healing pavements. Spore encapsulants were obtained from natural spores (Lycopodium clavatum) by applying different chemical treatments, which enabled the selection of the best morphologically intact and clean spore encapsulant. The physical, morphological, and physicochemical changes were examined using fluorescence images, ATR-FTIR, SEM, size distribution, XRD, TGA and DSC analyses. Sunflower oil was used as the encapsulated rejuvenator with an optimal sol colloidal mixture for sporopollenin-oil of 1:5 (gram-to-gram). Vacuum, passive, and centrifugal encapsulation techniques were tested for loading the rejuvenator inside the clean spores and for selecting the best encapsulation technology. The encapsulation efficiency and the profiles of the accelerated release of the rejuvenator from the loaded spores over time were studied, and these processes were visualized with optical and inverted fluorescence microscopy. Vacuum encapsulation was identified as the best loading technique with an encapsulation efficiency of 93.02 ± 3.71%. The rejuvenator was successfully encapsulated into the clean spores, as observed by optical and SEM morphologies. In agreement with the TGA and DSC, the microcapsules were stable up to 204 °C. Finally, a self-healing test was conducted through fluorescence tests to demonstrate how these biobased spore microcapsules completely heal a crack into an aged bitumen sample in 50 min.

Comparison of microscopic techniques to study the diversity of the bitumen microstructure

Bitumen characterisation and differentiation usually involve a combination of mechanical and chemical analyses. However, these methods provide limited information on the diversity caused by the binders’ origin or processing method. Thus, the question arises whether the bitumen microstructure can be used to identify these issues. In this study, microscopic methods, including brightfield, darkfield and fluorescence optical inverse microscopy (OIM), as well as confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM), were used to investigate the bitumen surface. Five different binders varying in their origin and production method were selected. The results show that CLSM, AFM and OIM darkfield can adequately capture a specific surface microstructure known as the bee structure, whereas brightfield in the OIM and optical CLSM show the surrounding peri phase, which exhibits a strong fluorescence. All visbroken binders show bee structures surrounded by a pronounced peri phase. On the other hand, one of the straight distilled binders does not show any microstructure, while the second straight distilled binder displays smaller bee structures surrounded by a small peri phase. Results from the image processing evaluation reveal that the area covered by bee structures is in the range of 2.4 – 4.3% for those binders that developed a surface microstructure. These results indicate a good accordance between the three microscopic techniques selected. However, a clear differentiation between the binders is difficult to obtain. Nonetheless, this work shows how these techniques can be used to their maximum capabilities regarding the obtained microstructural information and may help solve future questions regarding ageing, modification or rejuvenation.

Atomic Force Microscopy to Study the Physical Properties of Epidermal Cells of Live Arabidopsis Roots.

A method is described here to characterize the physical properties of the cell wall of epidermal cells of living Arabidopsis roots through nanoindentations with an atomic force microscope (AFM) coupled with an optical inverted fluorescence microscope. The method consists of applying controlled forces to the sample while measuring its deformation, allowing quantifying parameters such as the apparent Young's modulus of cell walls at subcellular resolutions. It requires a careful mechanical immobilization of the sample and correct selection of indenters and indentation depths. Although it can be used only in external tissues, this method allows characterizing mechanical changes in plant cell walls during development and enables the correlation of these microscopic changes with the growth of an entire organ.

Bimetallic gold-platinum nanoparticles as a drug delivery system coated with a new drug to target glioblastoma

A drug delivery nanosystem of noble bimetallic nanoparticles (NPs) which consists of Au NPs capped with Pt NPs (Au@Pt NPs) is constructed and functionalised with a quinazoline based small molecule (Au@Pt@Q NPs), acting as a theranostic agent against glioblastoma. Two different hydrothermal synthetic procedures for bimetallic Au@Pt NPs are presented and the resulting nanostructures are fully characterised by means of spectroscopic and microscopic methods. The imaging and targeting capacity of the new drug delivery system is assessed through fluorescent optical microscopy and cytotoxicity evaluations. The constructed Au@Pt NPs consist a monodispersed colloidal solution of 25 nm with photoluminescent, fluorescent and X-Ray absorption properties that confirm their diagnostic potential. Haemolysis testing demonstrated that Au@Pt NPs are biocompatible and fluorescent microscopy confirmed their entering the cells. Cytological evaluation of the NPs through MTT assay showed that they do not inhibit the proliferation of control cell line HEK293, whereas they are toxic in U87MG, U251 and D54 glioblastoma cell lines; rendering them selective targeting agents for treating glioblastoma.

Mesoporous Silica-Coated Gold Nanoparticles for Multimodal Imaging and Reactive Oxygen Species Sensing of Stem Cells.

Stem cell (SC)-based therapies hold the potential to revolutionize therapeutics by enhancing the body’s natural repair processes. Currently, there are only three SC therapies with marketing authorization within the European Union. To optimize outcomes, it is important to understand the biodistribution and behavior of transplanted SCs in vivo. A variety of imaging agents have been developed to trace SCs; however, they mostly lack the ability to simultaneously monitor the SC function and biodistribution at high resolutions. Here, we report the synthesis and application of a nanoparticle (NP) construct consisting of a gold NP core coated with rhodamine B isothiocyanate (RITC)-doped mesoporous silica (AuMS). The MS layer further contained a thiol-modified internal surface and an amine-modified external surface for dye conjugation. Highly fluorescent AuMS of three different sizes were successfully synthesized. The NPs were non-toxic and efficiently taken up by limbal epithelial SCs (LESCs). We further showed that we can functionalize AuMS with a reactive oxygen species (ROS)-sensitive fluorescent dye using two methods, loading the probe into the mesopores, with or without additional capping by a lipid bilayer, and by covalent attachment to surface and/or mesoporous-functionalized thiol groups. All four formulations displayed a ROS concentration-dependent increase in fluorescence. Further, in an ex vivo SC transplantation model, a combination of optical coherence tomography and fluorescence microscopy was used to synergistically identify AuMS-labeled LESC distribution at micrometer resolution. Our AuMS constructs allow for multimodal imaging and simultaneous ROS sensing of SCs and represent a promising tool for in vivo SC tracing.

Co-condensation of proteins with single- and double-stranded DNA

SignificanceBiomolecular condensates are intracellular organelles that are not bounded by membranes and often show liquid-like, dynamic material properties. They typically contain various types of proteins and nucleic acids. How the interaction of proteins and nucleic acids finally results in dynamic condensates is not fully understood. Here we use optical tweezers and fluorescence microscopy to study how the prototypical prion-like protein Fused-in-Sarcoma (FUS) condenses with individual molecules of single- and double-stranded DNA. We find that FUS adsorbs on DNA in a monolayer and hence generates an effectively sticky FUS-DNA polymer that collapses and finally forms a dynamic, reversible FUS-DNA co-condensate. We speculate that protein monolayer-based protein-nucleic acid co-condensation is a general mechanism for forming intracellular membraneless organelles.

Design and Study of a Photo-Switchable Polymeric System in the Presence of ZnS Nanoparticles under the Influence of UV Light Irradiation.

Recent progress in the field of photosensitive materials has prompted a need to develop efficient methods to synthesize materials with basic intermolecular architectural designs and novel properties. Accordingly, in this work we design and study a photoactive polymer as a photo-switchable polymeric system in the presence and absence of ZnS nanoparticles (average size < 10 nm) at 5 wt.%. The influence of UV light irradiation on its properties were also studied. The photoactive block copolymer was obtained from styrene (S) and methyl methacrylate (MMA) as monomers and 1-(2-hydroxyethyl)-3,3-dimethylindoline-6-nitrobenzopyran (SP) was grafted to the block copolymer backbone as a photochromic agent. Furthermore, the incorporation of ZnS (NPs) as photo-optical switch component into the system enhances the purple colored photo-emission, with the open form of the spiropyran derivative (merocyanine, MC). The ZnS stabilize the isomeric equilibrium in the MC interconversion of the photochromic agent. The photo-switchable properties of the PS-b-PMMA-SP in the presence of ZnS (NPs) were examined using UV-VIS spectroscopy, Photoluminescence (PL) spectroscopy, optical fluorescence and scanning electronic microscopy (SEM-EDX.). The observed changes in the absorbance, fluorescence and morphology of the system were associated to the reversible interconversion of the two states of the photochromic agent which regulates the radiative deactivation of the luminescent ZnS NPs component. After UV irradiation the photoactive polymer becomes purple in color. Therefore, these basic studies can lead to the development of innovative functional and nanostructured materials with photosensitive character as photosensitive molecular switches.

Duplex DNA and BLM regulate gate opening by the human TopoIII\u03b1-RMI1-RMI2 complex

Topoisomerase IIIα is a type 1A topoisomerase that forms a complex with RMI1 and RMI2 called TRR in human cells. TRR plays an essential role in resolving DNA replication and recombination intermediates, often alongside the helicase BLM. While the TRR catalytic cycle is known to involve a protein-mediated single-stranded (ss)DNA gate, the detailed mechanism is not fully understood. Here, we probe the catalytic steps of TRR using optical tweezers and fluorescence microscopy. We demonstrate that TRR forms an open gate in ssDNA of 8.5 ± 3.8 nm, and directly visualize binding of a second ssDNA or double-stranded (ds)DNA molecule to the open TRR-ssDNA gate, followed by catenation in each case. Strikingly, dsDNA binding increases the gate size (by ~16%), while BLM alters the mechanical flexibility of the gate. These findings reveal an unexpected plasticity of the TRR-ssDNA gate size and suggest that TRR-mediated transfer of dsDNA may be more relevant in vivo than previously believed.

Three-colored Sancai glazed ceramics excavated from Bohai sites in Primorye (Russia)

This paper presents the analytical results of polychrome and monochrome lead-glazed ceramic classified as Sancai that was excavated from the Bohai sites of Kraskino and Gorbatka walled towns, and the Chernyatino-2 settlement (Bohai layer) (Primorye, Russia). Thirty ceramic fragments were analyzed using non-destructive X-ray fluorescence analysis (pXRF), optical microscopy, and scanning electron microscopy (SEM) with energy-dispersive x-ray spectroscopy (EDS). This work presents new data on the elemental composition of lead glazes and discusses some aspects of their technology, including assumptions about the medieval potters' skill level and technological awareness. Data pertaining to the sample's elemental composition indicates their origin from various workshops practicing different approaches to pottery production. These ceramics have no slip layer with the glaze coating having been applied directly onto the surface of the ceramic vessels. The intensity of the lead component in the glaze composition varies significantly, in the range of concentration between 36 and 79 wt%. Surface features of filling and shine, as well as the nature of glaze defects demonstrates a low probability of the peak firing approach that was applied in the technological process. The results presented in this paper contribute to expanding our understanding of the Bohai (CE 698–926) and Tang (CE 618–907) periods for Sancai ceramics.

One-Dimensional STED Microscopy in Optical Tweezers.

Optical tweezers and fluorescence microscopy are powerful methods for investigating the mechanical and structural properties of biomolecules and for studying the dynamics of the biomolecular processes that these molecules are involved in. Here we provide an outline of the concurrent use of optical tweezers and fluorescence microscopy for analyzing biomolecular processes. In particular, we focus on the use of super-resolution microscopy in optical tweezers, which allows visualization of molecules at the higher molecular densities that are typically encountered in living systems. We provide specific details on the alignment procedures of the optical pathways for confocal fluorescence microscopy and 1D-STED microscopy and elaborate on how to diagnose and correct optical aberrations and STED phase plate misalignments.

Unique orientation of 1D and 2D nanoparticle assemblies confined in smectic topological defects.

New collective optical properties have emerged recently from organized and oriented arrays of closely packed semiconducting and metallic nanoparticles (NPs). However, it is still challenging to obtain NP assemblies which are similar everywhere on a given sample and, most importantly, share a unique common orientation that would guarantee a unique behavior everywhere on the sample. In this context, by combining optical microscopy, fluorescence microscopy and synchrotron-based grazing incidence X-ray scattering (GISAXS) of assemblies of gold nanospheres and of fluorescent nanorods, we study the interactions between NPs and liquid crystal smectic topological defects that can ultimately lead to unique NP orientations. We demonstrate that arrays of one-dimensional - 1D (dislocations) and two-dimensional - 2D (grain boundaries) topological defects oriented along one single direction confine and organize NPs in closely packed networks but also orient both single nanorods and NP networks along the same direction. Through the comparison between smectic films associated with different kinds of topological defects, we highlight that the coupling between the NP ligands and the smectic layers below the grain boundaries may be necessary to allow for fixed NP orientation. This is in contrast with 1D defects, where the induced orientation of the NPs is intrinsically induced by the confinement independently of the ligand nature. We thus succeeded in achieving the fixed polarization of assemblies of single photon emitters in defects. For gold nanospheres confined in grain boundaries, a strict orientation of hexagonal networks has been obtained with the 〈10〉 direction strictly parallel to the defects. With such closely packed and oriented NPs, new collective properties are now foreseen.

Epithelial and Neural Cadherin in Mammalian Fertilization: Studies in the Mouse Model.

Successful mammalian fertilization requires a well-orchestrated sequence of molecular events leading to gamete fusion. Since this interaction involves Ca2+-dependent adhesion events, the participation of the Ca+2-dependent cell-cell adhesion proteins Epithelial (E-cad) and Neural (N-cad) cadherin is envisaged. We have previously reported the expression of E-cad and N-cad in human gametes and showed evidence of their involvement in sperm-oocyte adhesion events leading to fertilization. To overcome ethical limitations associated with the use of human gametes in fertilization-related studies, the mouse has been selected worldwide as the experimental model for over 4 decades. Herein, we report a detailed study aimed at characterizing the expression of E-cad and N-cad in murine gametes and their involvement in murine fertilization using specific antibodies and blocking peptides towards both adhesion proteins. E-cad and N-cad protein forms, as well as other members of the adhesion complex, specifically β-catenin and actin, were identified in spermatozoa, cumulus cells and oocytes protein extracts by means of Western immunoblotting. In addition, subcellular localization of these proteins was determined in whole cells using optical fluorescent microscopy. Gamete pre-incubation with anti-E-cad (ECCD-1) or N-cad (H-63) antibodies resulted in decreased (p < 0.05) In Vitro Fertilization (IVF) rates, when using both cumulus-oocytes complexes and cumulus-free oocytes. Moreover, IVF assays done with denuded oocytes and either antibodies or blocking peptides against E-cad and N-cad led to lower (p < 0.05) fertilization rates. When assessing each step, penetration of the cumulus mass was lower (p < 0.05) when spermatozoa were pre-incubated with ECCD-1 or blocking peptides towards E-cad or towards both E- and N-cad. Moreover, sperm-oolemma binding was impaired (p < 0.0005) after sperm pre-incubation with E-cad antibody or blocking peptide towards E-cad, N-cad or both proteins. Finally, sperm-oocyte fusion was lower (p < 0.05) after sperm pre-incubation with either antibody or blocking peptide against E-cad or N-cad. Our studies demonstrate the expression of members of the adherent complex in the murine model, and the use of antibodies and specific peptides revealed E-cad and N-cad participation in mammalian fertilization.

Fluorescent Probes for STED Optical Nanoscopy.

Progress in developing fluorescent probes, such as fluorescent proteins, organic dyes, and fluorescent nanoparticles, is inseparable from the advancement in optical fluorescence microscopy. Super-resolution microscopy, or optical nanoscopy, overcame the far-field optical resolution limit, known as Abbe’s diffraction limit, by taking advantage of the photophysical properties of fluorescent probes. Therefore, fluorescent probes for super-resolution microscopy should meet the new requirements in the probes’ photophysical and photochemical properties. STED optical nanoscopy achieves super-resolution by depleting excited fluorophores at the periphery of an excitation laser beam using a depletion beam with a hollow core. An ideal fluorescent probe for STED nanoscopy must meet specific photophysical and photochemical properties, including high photostability, depletability at the depletion wavelength, low adverse excitability, and biocompatibility. This review introduces the requirements of fluorescent probes for STED nanoscopy and discusses the recent progress in the development of fluorescent probes, such as fluorescent proteins, organic dyes, and fluorescent nanoparticles, for the STED nanoscopy. The strengths and the limitations of the fluorescent probes are analyzed in detail.

The Role of PTEN/PI3K/AKT Signaling Pathway in Apoptosis of Liver Cells in Cocks with Manganese Toxicity.

PTEN/PI3K/AKT signaling pathway is an important pathway for cell proliferation and apoptosis. Exposure to excess manganese (Mn) can cause damage in organisms. However, whether Mn toxicity can cause apoptosis is still not clear. In order to explore the mechanism of PTEN/PI3K/AKT signaling pathway responsible for Mn-induced apoptotic injury, 160 Hyline cocks were divided into four groups; there were the control group (Con group), the low-dose Mn group (L group), the medium-dose Mn group (M group), and the high-dose Mn group (H group). The cocks in Con group, L group, M group, and H group were fed with MnCl2 diet containing 100, 600, 900, and 1800mg/kg, respectively. The growth status of cocks in each group was observed on days 30, 60, and 90. Thirty cocks were randomly selected from each group and sacrificed on day 90 for optical microscope observation and fluorescence microscopic observation, as well as for transcription-level expression of apoptosis-related genes and heat shock proteins (HSPs) in the liver. The results showed that the growth status of cocks was gradually depressed with the extension of feeding time and with the increase of Mn dose. On day 90, the results of optical microscope observation and fluorescence microscope observation showed that damage and apoptosis appeared in the cock liver cells under Mn exposure groups. The results of transcription-level detection of apoptosis-related genes and HSPs indicated that Mn exposure upregulated eleven pro-apoptotic genes (including RIP1, RIP3, MLKL, Bax, Caspase-3, FADD, Cyt-C, ERK, JNK, Caspase-8, and P38) and downregulated one anti-apoptotic gene Bcl-2, further meaning that exposure to Mn-induced apoptosis in cock liver cells and PTEN/PI3K/AKT signaling pathway took part in molecular mechanism of apoptosis caused by excess Mn. Moreover, in our experiment, the increase of four HSPs (including HSP27, HSP40, HSP60, and HSP70) was found after Mn treatment for 90days, which indicated that Mn stress triggered HSPs and HSPs were involved in molecular mechanism of Mn poisoning in cock livers. In addition, we also found there was upregulated dose-dependent manner in fifteen detected genes and there was downregulated dose-dependent manner in Bcl-2, indicating that the apoptosis caused by Mn poisoning in cock liver cells was dose-dependent.

Living Bacteria Directly Embedded into Electrospun Nanofibers: Design of New Anode for Bio-Electrochemical Systems

The aim of this work is the optimization of electrospun polymeric nanofibers as an ideal reservoir of mixed electroactive consortia suitable to be used as anodes in Single Chamber Microbial Fuel Cells (SCMFCs). To reach this goal the microorganisms are directly embedded into properly designed nanofibers during the electrospinning process, obtaining so called nanofiber-based bio-composite (bio-NFs). This research approach allowed for the designing of an advanced nanostructured scaffold, able to block and store the living microorganisms inside the nanofibers and release them only after exposure to water-based solutions and electrolytes. To reach this goal, a water-based polymeric solution, containing 5 wt% of polyethylene oxide (PEO) and 10 wt% of environmental microorganisms, is used as the initial polymeric solution for the electrospinning process. PEO is selected as the water-soluble polymer to ensure the formation of nanofiber mats offering features of biocompatibility for bacteria proliferation, environment-friendliness and, high ionic conductivity. In the present work, bio-NFs, based on living microorganisms directly encapsulated into the PEO nanofiber mats, were analyzed and compared to PEO-NFs made of PEO only. Scanning electron microscopy allowed researchers to confirm the rise of a typical morphology for bio-NFs, evidencing the microorganisms’ distribution inside them, as confirmed by fluorescence optical microscopy. Moreover, the latter technique, combined with optical density measurements, allowed for demonstrating that after electrospinning, the processed microorganisms preserved their proliferation capability, and their metabolic activity after exposure to the water-based electrolyte. To demonstrate that the energy-production functionality of exo-electrogenic microorganisms was preserved after the electrospinning process, the novel designed nanomaterials, were directly deposited onto carbon paper (CP), and were applied as anode electrodes in Single Chamber Microbial Fuel Cells (SCMFCs). It was possible to appreciate that the maximum power density reached by bio-NFs, which resulted in being double of the ones achieved with PEO-NFs and bare CP. SCMFCs with bio-NFs applied as anodic electrodes reached a current density value, close to (250 ± 5.2) mA m−2, which resulted in being stable over time and was comparable with the one obtained with carbon-based electrode, thus confirming the good performance of the whole device.

A novel foam system stabilized by hydroxylated multiwalled carbon nanotubes for enhanced oil recovery: Preparation, characterization and evaluation

Carbon nanotube (CNT) is one of promising materials for stabilizing foam. However, the aggregation of CNT seriously affects its foam-stabilizing performance. Herein, this study employed the ultrasonic waves to improve the dispersity of hydroxylated multiwalled carbon nanotube (HMCNT) in SDBS solution. The ultrasonic treatment can disentangle the HMCNT through cavitation and chip effects and the SDBS molecules adsorbed on the HMCNT may increase the electrostatic repulsion between nanotubes, leading to a good dispersion of HMCNT. Besides the conventional evaluations in bulk phase, this study developed a visualized cylinder filled with quartz glass beads to estimate the foam properties in porous media. Experimental results indicate that the novel SDBS/HMCNT foam has a good foaming and foam-stabilizing performance both in bulk solution and porous media. A series of analysis experiments have been conducted to reveal the foam-stabilizing mechnism of HMCNT, including the surface tension and dilational viscoelastic modulus measurements, and the optical microscope and fluorescence microscope observations. This study found that the SDBS-modified HMCNT can adsorb on the gas-liquid interface and gather around the bubbles. As a result, the dilational viscoelasticity and thickness of foam films increase, which help to slow down the gas diffusion rate and restrain the film drainage. Finally, the fractured-core flooding tests showed that the SDBS/HMCNT foam system can effectively plug the millimeter-sized cracks in low-permeability cores and have a good potential in enhanced oil recovery.