Surface-Enhanced Raman Scattering to Evaluate Nanomaterial Cytotoxicity on Living Cells

© 2016 American Chemical Society.The increasing number of reports about false positive or negative results from conventional cytotoxicity assays of nanomaterials (NMs) suggests that more reliable NM toxicity assessment methods should be developed. Here, we report a novel approach for nanotoxicity evaluation based on surface-enhanced Raman spectroscopy (SERS). Three model NMs were tested on two model cell lines and the results were validated by WST-1 cytotoxicity assay and annexin V-FITC/propidium iodide (PI) staining as apoptosis-necrosis assay. The localization of nanoparticles (NPs) in the cells and the cellular conditions upon NP incubation were visualized by transmission electron microscopy (TEM) and enhanced dark-field (EDF) microscopy. SERS revealed a broader view on the consequences of cell-NM interactions compared to the conventional cytotoxicity assays where only one aspect of toxicity can be measured by one assay type. The results suggest that SERS can significantly contribute to the cytotoxicity evaluation bypassing NM or assay component-related complications with less effort

Nanostructured Silver Substrates With Stable and Universal SERS Properties: Application to Organic Molecules and Semiconductor Nanoparticles

Nanostructured silver films have been prepared by thermal deposition on silicon, and their properties as SERS substrates investigated. The optimal conditions of the post-growth annealing of the substrates were established. Atomic force microscopy study revealed that the silver films with relatively dense and homogeneous arrays of 60–80-nm high pyramidal nanoislands are the most efficient for SERS of both organic dye and inorganic nanoparticles analytes. The noticeable enhancement of the Raman signal from colloidal nanoparticles with the help of silver island films is reported for the first time

Towards a target label-free suboptimum oligonucleotide displacement-based detection system

A novel method for the future development of label-free DNA sensors is proposed here. The approach is based on the displacement of a labelled suboptimum mutated oligonucleotide hybridised with the immobilised biotin-capture probe. The target fully complementary to the biotin-capture probe can displace the labelled oligonucleotide causing a subsequent decrease of the signal that verifies the presence of the target. The decrease of signal was demonstrated to be proportional to the target concentration. A study of the hybridisation of mutated and complementary labelled oligonucleotides with an immobilised biotin-capture probe was carried out. Different kinetic and thermodynamic behaviour was observed for heterogeneous hybridisation of biotin-capture probe with complementary or suboptimum oligonucleotides. The displacement method evaluated colourimetrically achieved the objective of decreasing the response time from 1 h for direct hybridisation of 19-mer oligonucleotides in the direct enzyme-linked oligonucleotide assay (ELONA) to 5 min in the case of displacement detection in the micromolar concentration range

Comparability of Raman Spectroscopic Configurations: A Large Scale Cross-Laboratory Study

This is the final version. Available on open access from the American Chemical Society via the DOI in this recordThe variable configuration of Raman spectroscopic platforms is one of the major obstacles in establishing Raman spectroscopy as a valuable physicochemical method within real-world scenarios such as clinical diagnostics. For such real world applications like diagnostic classification, the models should ideally be usable to predict data from different setups. Whether it is done by training a rugged model with data from many setups or by a primary-replica strategy where models are developed on a 'primary' setup and the test data are generated on 'replicate' setups, this is only possible if the Raman spectra from different setups are consistent, reproducible, and comparable. However, Raman spectra can be highly sensitive to the measurement conditions, and they change from setup to setup even if the same samples are measured. Although increasingly recognized as an issue, the dependence of the Raman spectra on the instrumental configuration is far from being fully understood and great effort is needed to address the resulting spectral variations and to correct for them. To make the severity of the situation clear, we present a round robin experiment investigating the comparability of 35 Raman spectroscopic devices with different configurations in 15 institutes within seven European countries from the COST (European Cooperation in Science and Technology) action Raman4clinics. The experiment was developed in a fashion that allows various instrumental configurations ranging from highly confocal setups to fibre-optic based systems with different excitation wavelengths. We illustrate the spectral variations caused by the instrumental configurations from the perspectives of peak shifts, intensity variations, peak widths, and noise levels. We conclude this contribution with recommendations that may help to improve the inter-laboratory studies.COST (European Cooperation in Science and Technology)Portuguese Foundation for Science and TechnologyNational Research Fund of Luxembourg (FNR)China Scholarship Council (CSC)BOKU Core Facilities Multiscale ImagingDeutsche Forschungsgemeinschaft (DFG, German Research Foundation

MIKROBIYOLOJI BULTENI

Leishmaniasis, seen in tropical and subtropical regions, is an infectious disease caused by the protozoan parasite Leishmania species. There are three main forms of leishmaniasis: cutaneous, mucocutaneous and visceral leishmaniasis. Cutaneous leishmaniasis (CL) has become an increasing problem as the number of travels around the world increases and people go to work in endemic areas. Turkey has received great numbers of immigrants in recent years, from its neighboring countries like Iraq, Islamic Republic of Iran, Afghanistan, Turkmenistan and the Syrian Arab Republic because of the political instabilities in these countries as well as the job opportunities caused by large-scale development projects undertaken by Turkey. In this report, imported CL cases detected in five truck drivers transporting from Hatay to Turkmenistan, Syria, Saudi Arabia, Iran and Georgia, Uzbekistan and Azarbaijan countries were presented. The patients admitted to Mustafa Kemal University, Faculty of Medicine Dermatology Policlinic, with wound complaints on their bodies were directed to the Department of Parasitology to obtain smear samples from their wounds. The age range of the patients were 38 to 43 years. Patients with wound trail for a period ranging from one month to one year had a number of lesions varying between 2-7 and in all cases, a smear preparation was prepared from the lesions for diagnostic purposes. Clinical material obtained from five patients with pre-diagnosis of CL was firstly examined with Giemsa stain. Samples taken from the patients were inoculated into modified NNN (Novy-MacNeal-Nicolle) medium for the evaluation of the presence of the promastigotes. Promastigotes obtained from the inoculated medium were also genotyped using the ITS1 region. In all of the slides prepared from the clinical material taken from the patients amastigotes were determined. The growth of promastigotes were observed in only three of the clinical specimen inoculated media. The genotyped three species were Leishmania tropica, Leishmania infantum/donovani and Leishmania major. In this study, the importance of support for the diagnosis of different microbiological methods used in the diagnosis of leishmaniasis infection which occurred during the outbreaks of the disease has been put forward. In addition, it was aimed to draw attention to the importance of imported CL cases in our country diagnosed in five truck drivers making transportation from Hatay to Turkmenistan, Syria, Saudi Arabia, Iran, Georgia, Uzbekistan and Azerbaijan

IRANIAN JOURNAL OF PARASITOLOGY

Background: Cutaneous leishmaniasis (CL) is endemic in Southeastern Anatolia, mainly in Sanliurfa and Hatay provinces, and the causative agents are mostly Leishmania tropica and less frequently L. infantum. Here, we report the first MALDI-TOF analyses of Leishmania promastigotes obtained from the cultures of two CL cases from Osmaniye and Hatay provinces who were initially diagnosed by microscopy, culture and identified as L. infantum with Real-Time PCR (RT-PCR). Methods: Samples obtained from the skin lesions of patients were initially stained with Giemsa and cultivated in NNN medium. Examination of the smears and cultures revealed Leishmania amastigotes and promastigotes, respectively. The promastigotes (MHOM/TR/2012/CBU15 and MHOM/TR/2012/MK05) obtained from the cultures of both patients were used for RT-PCR targeting the ITS-1 region in the SSU of rRNA. The reference strains of four Leishmania species (L. infantum, L. donovani, L. tropica and L. major) were initially assessed with MALDI-TOF and their data were added to MALDI-TOF Biotyper Library. Results: Both RT-PCR and MALDI-TOF analyses indicated that the causative agent in both patient samples was L. infantum. Conclusion: Despite disadvantages such as requirement of culture fluid with nothing but promastigotes and high cost, MALDI-TOF analysis may be a fast, sensitive and specific diagnostic tool in especially large-scale research studies, where the cost declines, relatively

Alterations in serum levels of trace elements in cutaneous leishmaniasis patients in endemic region of Hatay (Antioch)

Immune cells, like all other types of cells, require an adequate supply of trace elements for the structure and function of metalloproteins that participate in housekeeping processes such as energy production and protection against reactive oxygen species. In addition, trace elements are required for the activity of a number of enzymes that directly participate in host defense processes. In the present study we evaluated the alterations of zinc, copper, selenium and iron concentrations in serum of patients treated with meglumine antimonate (glucantime) and untreated cutaneous leishmaniasis. Serum levels of zinc, copper, selenium and iron were measured by atomic emission spectrometer. The serum levels of these elements were found to be significantly higher in untreated patients compared to those of healthy controls. However, the levels of zinc, copper and iron in serum were significantly reuced and selenium levels were increased in treated patients. These suggest that the increasing levels of trace elements in serum may be host defense strategies of organism infection. In addition the high trace element levels were a sequel of the disease rather than a cause