Smart Synthesis of Trimethyl Ethoxysilane (TMS) Functionalized Core-Shell Magnetic Nanosorbents Fe3O4@SiO2: Process Optimization and Application for Extraction of Pesticides.

In the current study, a smart approach for synthesizing trimethyl ethoxysilane-decorated magnetic-core silica-nanoparticles (TMS-mcSNPs) and its effectiveness as nanosorbents have been exploited. While the magnetite core was synthesized using the modified Mössbauer method, Stöber method was employed to coat the magnetic particles. The objective of this work is to maximize the magnetic properties and to minimize both particle size (PS) and particle size distribution (PSD). Using a full factorial design (2k-FFD), the influences of four factors on the coating process was assessed by optimizing the three responses (magnetic properties, PS, and PSD). These four factors were: (1) concentration of tetraethyl-orthosilicate (TEOS); (2) concentration of ammonia; (3) dose of magnetite (Fe3O4); and (4) addition mode. Magnetic properties were calculated as the attraction weight. Scanning electron microscopy (SEM) was used to determine PS, and standard deviation (±SD) was calculated to determine the PSD. Composite desirability function (D) was used to consolidate the multiple responses into a single performance characteristic. Pareto chart of standardized effects together with analysis of variance (ANOVA) at 95.0 confidence interval (CI) were used to determine statistically significant variable(s). Trimethyl ethoxysilane-functionalized mcSNPs were further applied as nanosorbents for magnetic solid phase extraction (TMS-MSPE) of organophosphorus and carbamate pesticides.

Investigation of the Effect of PD-L1 Blockade on Triple Negative Breast Cancer Cells Using Fourier Transform Infrared Spectroscopy.

Interactions between programmed death-1 (PD-1) with its ligand PD-L1 on tumor cells can antagonize T cell responses. Inhibiting these interactions using immune checkpoint inhibitors has shown promise in cancer immunotherapy. MDA-MB-231 is a triple negative breast cancer cell line that expresses PD-L1. In this study, we investigated the biochemical changes in MDA-MB-231 cells following treatment with atezolizumab, a specific PD-L1 blocker. Our readouts were Fourier Transform Infrared (FTIR) spectroscopy and flow cytometric analyses. Chemometrical analysis, such as principal component analysis (PCA), was applied to delineate the spectral differences. We were able to identify the chemical alterations in both protein and lipid structure of the treated cells. We found that there was a shift from random coil and α-helical structure to ß-sheet conformation of PD-L1 on tumor cells due to atezolizumab treatment, which could hinder binding with its receptors on immune cells, ensuring sustained T cell activation for potent immune responses. This work provides novel information about the effects of atezolizumab at molecular and cellular levels. FTIR bio-spectroscopy, in combination with chemometric analyses, may expedite research and offer new approaches for cancer immunology.

An Innovative Platform Merging Elemental Analysis and Ftir Imaging for Breast Tissue Analysis.

Histopathology and immunohistology remain the gold standard for breast cancer diagnostic. Yet, these approaches do not usually provide a sufficiently detailed characterization of the pathology. The purpose of this work is to demonstrate for the first time that elemental analysis and Fourier transform infrared spectroscopy microscopic examination of breast tissue sections can be merged into one dataset to provide a single set of markers based on both organic molecules and inorganic trace elements. For illustrating the method, 6 mammary tissue sections were used. Fourier transform infrared (FTIR) spectroscopy images reported a fingerprint of the organic molecules present in the tissue section and laser ablation elemental analysis (LA-ICP-MS) images brought inorganic element profiles. The 6 tissue sections provided 31 106 and 150,000 spectra for FTIR and LA-ICP-MS spectra respectively. The results bring the proof of concept that breast tissue can be analyzed simultaneously by FTIR spectroscopy and laser ablation elemental analysis (LA-ICP-MS) to provide in both case reasonably high resolution images. We show how to bring the images obtained by the two methods to a same spatial resolution and how to use image registration to analyze the data originating from both techniques as one block of data. We finally demonstrates the elemental analysis is orthogonal to all FTIR markers as no significant correlation is found between FTIR and LA-ICP-MS data. Combining FTIR and LA-ICP-MS imaging becomes possible, providing two orthogonal methods which can bring an unprecedented diversity of information on the tissue. This opens a new avenue of tissue section analyses providing unprecedented diagnostic potential.

Correction: Discrimination of breast cancer from benign tumours using Raman spectroscopy.

[This corrects the article DOI: 10.1371/journal.pone.0212376.].

Discrimination of breast cancer from benign tumours using Raman spectroscopy.

Breast cancer is the most common cancer among women worldwide, with an estimated 1.7 million cases and 522,000 deaths in 2012. Breast cancer is diagnosed by histopathological examination of breast biopsy material but this is subjective and relies on morphological changes in the tissue. Raman spectroscopy uses incident radiation to induce vibrations in the molecules of a sample and the scattered radiation can be used to characterise the sample. This technique is rapid and non-destructive and is sensitive to subtle biochemical changes occurring at the molecular level. This allows spectral variations corresponding to disease onset to be detected. The aim of this work was to use Raman spectroscopy to discriminate between benign lesions (fibrocystic, fibroadenoma, intraductal papilloma) and cancer (invasive ductal carcinoma and lobular carcinoma) using formalin fixed paraffin preserved (FFPP) tissue. Haematoxylin and Eosin stained sections from the patient biopsies were marked by a pathologist. Raman maps were recorded from parallel unstained tissue sections. Immunohistochemical staining for estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2/neu) was performed on a further set of parallel sections. Both benign and cancer cases were positive for ER while only the cancer cases were positive for HER2. Significant spectral differences were observed between the benign and cancer cases and the benign cases could be differentiated from the cancer cases with good sensitivity and specificity. This study has shown the potential of Raman spectroscopy as an aid to histopathological diagnosis of breast cancer, in particular in the discrimination between benign and malignant tumours.

Mishandling and exposure of farm workers in Qatar to organophosphate pesticides.

We used a combination of subjective (questionnaire) and objective (urinary metabolites) measurements to evaluate factors that can predict the exposure of farm workers in Qatar to organophosphate pesticides and to assess whether the levels of exposure are associated with any self-reported health outcomes. The results show that pesticides were being extensively mishandled in the farms. Very few (<2%) of the farm workers knew the names of the pesticide they were using, and about one-third of the participants did not know the amount of pesticides to be applied to the crops. Nearly all (96%) of the participants had participated in mixing pesticides together before use and few (29%) used protective clothing while engaged in this operation. A significant number of participants (18%) had no knowledge that pesticides are a health hazard. At least one dialkyllphosphate (DAP) metabolite was detected in every worker. The geometric mean (GM) concentration of the dimethylalkylphosphates (DMAP) was 108 nM (range, from below the limit of detection (LOD) to 351 nM), and the GM for the diethylalkylphosphates (DEAP) was 43 nM (range, LOD-180 nM). The GM for total concentration of the metabolites (DAP) of 146 nM (maximum value estimated to be 531 nM) is below the values that have been reported for farmers in some countries, but higher than the levels in the general populations of many countries. We explored the influence of metal exposure and found consistent and negative relationships between the DAP metabolites and the concentrations of most of the trace elements in the urine of the farm workers; the negative associations were statistically significant for Cr, Mn, Fe, Ni, As, and Pb. We suspect that the negative associations are not source-dependent but may be reflective of antagonistic relationships in human metabolism of OPPs and trace metals; hence we recommend that metals should be included as co-factors in assessing the health effects of OPP exposure.

Collision/reaction cell ICP-MS with shielded torch and sector field ICP-MS for the simultaneous determination of selenium isotopes in biological matrices.

The determinations of selenium isotopes in biological samples were performed using both inductively coupled plasma collision/reaction cell quadruple mass spectrometer (CRC-ICP-QMS) and inductively coupled plasma sector field mass spectrometers (SF-ICP-MS). To significantly decrease the argon-based interferences at m/z 74 ((36)Ar(38)Ar), 76 ((38)Ar(38)Ar, (40)Ar(36)Ar), 78 ((38)Ar(40)Ar), and 80 ((40)Ar(40)Ar), the gas-flow rates of a helium and hydrogen mixture used in the collision cell were optimized to 1.0 mL/min H(2) and 3.5 mL/min He. Under the optimized condition, the precisions for natural selenium isotope ratio measurements of both instruments were evaluated and compared using 100 ppb Se standard solution. A modified external calibration quantification method was applied for the simultaneous determination of clinically used enriched selinocompounds ((77)Se-selenate, (82)Se-selenite, (76)Se-methylseleninic acid(IV), (78)Se-methylselenonic acid(VI)) and to examine their fate in rat organs (liver, kidney, and lung).

Rapid screening for S-adenosylmethionine-dependent methylation products by enzyme-transferred isotope patterns analysis.

We report here an isotopic labeling and mass spectrometric method to rapidly identify S-adenosylmethionine (AdoMet)-dependent methylation products. In the presence of CH(3)- and CD(3)-labeled AdoMet, a methyl transfer product appears as a doublet separated by 3 Da in a mass spectrum, while other compounds show their normal isotopic distribution. Based on this unique isotopic pattern, methylation product(s) can be easily detected even from a mixture of cellular components. To validate our method, the product of human thiopurine methyltransferase (TPMT, EC 2.1.1.67) has been successfully identified from both an in vitro assay and a whole-cell assay. This method is generally applicable to AdoMet-dependent transmethylation and other group-transfer reactions, and constitutes the first example of a general strategy of enzyme-transferred isotope patterns (ETIPs) analysis.