Preparation and analysis of a two-components breath figure at the nanoscale

International audienceSolid/liquid two-components Ga-Pb structures in isolated nanometer sized particles have been produced and studied by electron microscopy. Production is based on the breath figure technique and we investigate the way the two components are distributed. We clearly identify two growth regimes associated with the two different ways a Pb atom incorporates into a Ga nanodrop. Using TEM and SEM, the shape and microstructure of the nanoparticles are studied and the results obtained are in good agreement with the proposed model. The experimental technique used appears to be appropriate to produce Pb nanocrystals in liquid Ga nano-containers

Rod-shaped nanostructures based on superparamagnetic nanocrystals as viscosity sensors in liquid

The following article appeared in Journal of Applied Physics 110.6 (2011): 064907 and may be found at http://scitation.aip.org/content/aip/journal/jap/110/6/10.1063/1.3638695Superparamagnetic nanostructures are becoming increasingly important as tools for biological and medical applications. We report the study of the movement of rod-shaped assemblies of superparamagnetic nanocrystals under the action of a rotating magnetic field. The dynamic was characterized by means of light scattering detection at different frequencies and for different values of the intensity of the applied external field. The possibility to correlate the motion to the viscosity of the medium is used to monitor viscosity changes inside the liquid. We propose this technique as a valuable tool to monitor viscosity at microscale for application in biological studies.This work was partially supported by the European project Magnifyco (Contract NMP4-SL-2009-228622)

Science communication and concept of risk in bio-tech-sciences: Is it a part of neo-liberalism, or foucaultian bio-politics?

In this work a Raman flow cytometer is presented. It consists of a microfluidic device that takes advantages of the basic principles of Raman spectroscopy and flow cytometry. The microfluidic device integrates calibrated microfluidic channels- where the cells can flow one-by-one -, allowing single cell Raman analysis. The microfluidic channel integrates plasmonic nanodimers in a fluidic trapping region. In this way it is possible to perform Enhanced Raman Spectroscopy on single cell. These allow a label-free analysis, providing information about the biochemical content of membrane and cytoplasm of the each cell. Experiments are performed on red blood cells (RBCs), peripheral blood lymphocytes (PBLs) and myelogenous leukemia tumor cells (K562)

Three-dimensional optical data storage through multi-photon confocal microscopy and imaging

Three dimensional optical data storage is one of the most promising tools to respond to the always growing demand for high data storage capacity. Here, we focused a femtosecond laser source by means of a confocal microscope onto different transparent recording media. The purpose of the study is to probe the capability of the system to independently address different data layers within the storage medium achieving thus three dimensional data storage. We demonstrated the possibility to write superposed independent layers of data due to either multiphoton excitation or to local optical breakdown and the performances observed in the different types of media used are compared

Infections caused by filamentous fungi in patients with hematologic malignancies. A report of 391 cases by GIMEMA Infection Program.

BACKGROUND AND OBJECTIVES: To evaluate the clinical characteristics of patients with hematologic malignancies developing a filamentous fungi infection (FFI) and to define the prognostic factors for their outcome. DESIGN AND METHODS: A retrospective study, conducted on patients admitted to 14 Hematology divisions of tertiary care or university hospitals, participating in the GIMEMA Infection Program, over a ten-year period (1988-1997). The study included patients with hematological malignancies and a histologically and/or microbiologically proven or probable FFI. RESULTS: We included 391 patients (male/female: 262/129, median age 49 years) with hematologic malignancies (225 acute myeloid leukemia, 67 acute lymphocytic leukemia, 30 chronic myeloid leukemia, 22 non-Hodgkin's lymphoma, 12 myelodysplastic syndrome, 10 aplastic anemia, 7 Hodgkin's disease, 8 chronic lymphocytic leukemia, 5 multiple myeloma, and 5 hairy cell leukemia) who developed a proven FFI. Eighty percent of the patients had been neutropenic for an average of 14 days before the infection, and 71% had an absolute neutrophil count lower than 0.5 x 10(9)/L at the time of FFI diagnosis. The primary sites of infection were: lungs (85%), nose and paranasal sinus (10%), and other sites (5%). The diagnosis was made while still alive in 310 patients (79%), and at autopsy in the remaining 81 patients (21%). Chest X-ray was diagnostic in 77% of patients with pulmonary FFI, while computed tomography (CT) scan of the thorax was positive in 95% of cases. A significant diagnostic advantage for CT scan was observed in 145 patients who had both a chest X-ray and CT scan. Aspergillus was identified as the cause of FFI in 296 patients, Mucorales in 45 patients, Fusarium in 6 patients and other filamentous fungi species in 4 patients, while in a further 40 patients no agent was identifiable. The overall mortality rate three months after the diagnosis of FFI was 74%, and fungal infection had been the cause of death in 51% of patients. INTERPRETATION AND CONCLUSIONS: Our retrospective study shows that FFI still remains a life-threatening complication in neutropenic patients. Despite appropriate treatment, half of the patients die due to this complication. The use of glucocorticoids and recovery from neutropenia are the most important prognostic factors. Mucorales infections are associated with a significantly poorer prognosis than those due to Aspergillus spp

The prognostic value of basal DNA damage level in peripheral blood lymphocytes of patients affected by bladder cancer

Bladder cancer (BC) is one of the most aggressive malignancies of the urinary tract, with the highest lifetime treatment costs per patient of all cancers, due to the high rate of recurrences requiring continuous surveillance. An early diagnosis is essential to improve survival of patients with BC. Noninvasive and sensitive molecular biomarkers are needed to improve current strategies for the detection and monitoring of BC. Previous studies suggested that elevated DNA damage levels and suboptimal nucleotide excision DNA repair (NER) may be associated with BC

Dual Drug Loaded Nanotheranostic Platforms as a Novel Synergistic Approach to Improve Pancreatic Cancer Treatment

This study focuses on the development of theranostic, dual drug-loaded nanocarriers to propose a proof-of-principle therapeutic approach in the treatment of pancreatic ductal adenocarcinoma (PDAC). The nanoconstructs consist of a core of zinc oxide nanocrystals doped with gadolinium, useful as a potential contrast agent in magnetic resonance imaging applications. After functionalizing their surface with amino-propyl groups, the physical adsorption of two hydrophobic drugs is performed: Vismodegib and Sorafenib. Their synergistic use might improve PDAC treatment and stroma depletion when co-delivered in the tumor microenvironment for future in vivo applications. To enhance the nanoconstructs’ biostability, the ensemble is coated by a lipid bilayer and a tumor targeting peptide is incorporated on the outer shell surface. As a first proof of concept, the resulting nanoconstructs are tested against two pancreatic cancer cell lines, showing a modest increase in treatment efficacy compared to the free drug counterparts and proving to spare healthy pancreatic cells. In a second testing set, the dual-drug loaded nanoconstructs are tested on both cell lines previously sensitized to a firstline chemotherapeutic drug, Gemcitabine, showing an improved treatment response. From these preliminary results, the nanotheranostic platforms might constitute a good starting point for future PDAC therapy and diagnosis studies

Localized formation and size tuning of CdS nanocrystals upon irradiation of metal precursors embedded in polymer matrices

We present a method of spatial and dimensional controlled formation of CdS quantum dots into polymer matrices by light irradiation. The initial samples consist of Cd thiolate precursors doped in TOPAS polymer matrix. Under pulsed UV laser irradiation the precursors are photolysed driving to the nucleation of CdS nanocrystals, with increasing size and concentration, related to the number of UV pulses. The formed quantum dots are localized in the irradiated area, while the host polymer remains macroscopically unaffected by the UV irradiation. In this study we investigate how the formation of the nanocrystals (size, dimensions, and concentration) is affected by the use of different irradiation conditions (wavelength, number of pulses), revealing information about the different pathways followed during the formation. The change of the size of the dots results in the change of the peak of their emission due to the quantum size effect, which is studied by fluorescence measurements. The results are reinforced by TEM microscopy and by XRD measurements. The main advantages of the presented method are the size tuning of the produced dots and their spatial confinement inside the host matrix, not possible by the other methods used until now (thermal annealing, mixing etc.)

A simple implementation of an optical biosensor based on Raman Spectroscopy

In this work we present the implementation of a biosensors integrating optical waveguides and Surface Enhanced Raman scattering (SERS) surfaces for the label-free detection of biological compounds

Hybrid Piezoresistive 2D MoS2/PEGDA/PANI Covalent Hydrogels for the Sensing of Low‐to‐Medium Pressure

Wearable technologies are attracting increasing attention in the materials science field, prompting a quest for active components with beneficial functional attributes whilst ensuring human and environmental safety. Hydrogels are highly biocompatible platforms with interesting mechanical properties, which can be exploited for the construction of strain sensors. In order to improve the directionality of their strain response and combine it with electrical properties to fabricate piezoresistive devices, it is possible to incorporate various types of nanofillers within the polymeric network of the hydrogels. 2D materials are ideal nanofillers thanks to their intrinsic two-dimensional anisotropy and unique electronic properties. Herein, the covalent functionalization of 2D 1T-MoS2 is exploited to build robust hybrid cross-linked networks with a polyethylene glycol diacrylate gel (PEGDA). The conductivity of this nanocomposite is also further improved by inducing the interfacial polymerization of aniline. The resulting free-standing samples demonstrate a linear and highly reversible piezoresistive response in a pressure range compatible with that of peripheral blood, while also featuring good compatibility with human skin cells, thereby making them interesting options for incorporation into wearable strain sensors