Lab-on-a-Tip Based on a Bimetallic Nanoarchitecture Enabling Catalytic 4-Nitrophenol Switch-off

Mono-and multi-metal nanoparticles (MNPs), thanks to their unique and tunable features, still fascinate the analytical sciences, from their widespread use in sensing and biosensing as nanoplasmonic tags or catalysts up to MNPs-decorated surfaces. Here, a lab µ-Tip decorated with plasmonic-active polymeric films embodying gold/silver nanostructures is presented. The proposed lab-on-a-tip device speed-up the 4-nitrophenol conversion in 4-aminophenol, retaining the performances for more than 10 consecutive measures, acting as an enzyme-like catalyst

Green Synthesis of Molecularly Imprinted Polymers for Dispersive Magnetic Solid-Phase Extraction of Erythrosine B Associated with Smartphone Detection in Food Samples

Monitoring synthetic colorants in foods is important due to their potential toxicity and pathogenicity. We propose here a new and simple method for the extraction and determination of erythrosine B (ERT-B) in food samples. A composite of polydopamine-based molecularly imprinted polymers coating magnetic nanoparticles (Fe3O4@PDA@MIP) was synthesized using a green approach and exploited for the magnetic dispersive solid-phase extraction (MDSPE) of ERT-B. Fe3O4@PDA@MIP provides a rapid extraction of ERT-B, exhibiting good reusability and preconcentration ability. Moreover, the MIP showed a relatively good imprinting factor (3.0 +/- 0.05), demonstrating excellent selectivity against patent blue (an interfering dye) and other food matrix components. The proposed MDSPE was coupled to colorimetric smartphone-based detection that allowed us to obtain similar performances of UV-Vis spectroscopy detection. The smartphone-based optical detection facilitated the determination of ERT-B in the 0.5-10 mg/L range, with a limit of detection of 0.04 mg/L. The developed method was successfully employed to determine ERT-B in food samples (juice, candy, and candied cherries) with good recovery values (82-97%)

Peptides binding cocaine: A strategy to design biomimetic receptors

A computational methodology for designing and rationalizing the selection of small peptides as biomimetic receptors for cocaine is proposed. The method started by searching and filtering proteins X-ray and NMR data of biological receptor-cocaine complexes. On the basis of different cocaine zones, the amino acids involved in biological binding sites were selected as pivots to design an initial library of 768 penta-peptides. The peptides flexibility was studied determining the minimum number of conformers required to make a reliable computed binding score. The 25 highest ranked penta-peptides were selected and used as starting point to generate a 3000 hexapeptides library by inserting each of the 20 natural amino acids in all sequence positions. All structures were energy minimized and docking runs were carried out using FRED tool from OpenEye scientific. The binding scores calculated by FRED were compared with a preliminary in vivo experimental test, using two different peptides as selective sorbent material used for cocaine in Solid Phase Extraction (SPE) technique coupled with Mass Spectrometry (MS). The simulation data were found to be in agreement with experimental laboratory results, supporting the methodology proposed in this work. © 2013 Perez G, et al

Disposable electrodes for direct enzyme-free H2O2 sensing in a Parkinson’s disease in-vitro model

Reactive Oxygen Species (ROS) are reduced forms of oxygen such as superoxide anion, hydroxyl radical or hydrogen peroxide. These molecules have a critical role in physiological processes like cellular signalling, immunological activity. However, an overproduction may cause the so-called oxidative stress (OS) which is able to cause damage to lipids, proteins or DNA. These alterations promote pathophysiological conditions such as diabetes, cancer, Alzheimer’s and Parkinson’s disease. In this work, we present the combination of Carbon Black (CB) and electrodeposited Prussian Blue (PB) covered with a Nafion layer on disposable Screen-Printed electrodes (CB/PB-SPE) used for non-enzymatic H2O2 sensing in Neuroblastoma cell line SH-SY5Y. These cells were challenged with 6-hidroxidopamine (6-OHDA) for modelling Parkinson’s disease. The electrode’s surface was investigated using Scanning Electron Microscopy (SEM) and electrochemically characterized, in terms of electroactivity and stability. Electrochemical sensing of H2O2 was carried out at very low potentials (-50mV), allowing interference-free detection of H2O2 in the selected cell culture. The H2O2 concentration was successfully monitored in an experimental model of Parkinson’s disease at different times. These results could pave the way to a method for the monitoring of H2O2 in culture medium for future studies of the role of H2O2 and oxidative stress in Parkinson’s disease

Selective solid phase extraction of JWH synthetic cannabinoids by using computationally designed peptides

The objective of the present work is to demonstrate a rational way to prepare selective sorbents able to extract simultaneously several structural analogs. For this purpose the binding specificity of two hexapeptides computationally designed (VYWLVW and YYIGGF) versus four synthetic cannabinoids Naphthalen-1-yl-(1- pentylindol-3-yl)methanone (JWH 018), naphthalen-1-yl-(1-butylindol-3-yl)methanone (JWH 073), (R)-(1- ((1-methylpiperidin-2-yl)methyl)-1H-indol-3-yl)(naphthalen-1-yl)methanone (AM 1220) and (R)-(+)-[2,3- Dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-napthalenylmethanone (WIN 55) was computationally studied and then experimentally tested by solid-phase extraction (SPE) clean-up and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. The two peptides were chosen using a semi combinatorial virtual technique by generating 4 cycles of peptide libraries (around 2.3×104 elements). To select the two peptides, the simulated binding scores between synthetic cannabinoids and peptides was used by maximizing the recognition properties of amino acid motif between the two JWH and the other synthetic cannabinoids. In particular, the peptide YYIGGF, having also affinity for AM 120, was selected as control because it was the only one without tryptophan residues within the best peptides obtained from simulation. Experimentally, the two hexapeptides were tested as SPE sorbent using nanomolar solutions of the four drugs. After optimization of best retentions the binding constants were calculated by loading synthetic cannabinoids solutions at different concentrations. The results indicated a strong interaction between hexapeptide VYWLVW and JWH 018 (15.58 ± 2.03×106 M–1 ), 3-fold and 40-fold larger compared to the analog JWH 073 and both AM 1220 and the WIN 55. Similar trend was observed for the hexapeptide YYIGGF but the binding constants were at least three times lower highlighting the key role of the tryptophan. To demonstrate the hexapeptides specific interaction with only synthetic cannabinoids, a cross-reactivity study was carried out using other drugs (cocaine, morphine, phencyclidine and methamphetamine) in the same SPE condition. Finally the practical utility of these peptide modified sorbent materials was further demonstrated by detecting the synthetic cannabinoids in real samples using hair matrix.Depto. de Química AnalíticaFac. de Ciencias QuímicasTRUEUnión Europea. H2020NBCRpu

Preliminary Study to Develop an Alternative Method for the Non-targeted Determination of Xenobiotics in Food by Means of Ultra High Performance Liquid Chromatography Coupled to High Resolution and Accuracy Mass Spectrometry

This preliminary study describes the use of high resolution and accuracy mass spectrometry techniques combined with new generation chemical software products for detecting and identifying contaminants in food commodities. As a first step, the extracts of routine target analysis samples (obtained in our official laboratory responsible for food residues control) were acquired and processed with this method in order to search unknown and non-targeted contaminants in food. In order to verify the feasibility of the presented method, the research has been firstly addressed to untargeted pesticides and their metabolites in stone fruits commodities and tomatoes. The differential analysis carried with Compound Discoverer 2.0 between the investigated unknown sample and the blank matrix sample allowed to remove all the matrix molecular components; Aggregated Computational Toxicology Resource (ACToR) helped to understand and predict chemical interpretation of substances. The acquisition in FullScan-AIF and FullScanddMS2 allowed the clear detection and identification of isobaric compounds such as quinalphos and phoxim. In order to verify that the proposed method is suitable to the scope of application, the main points of SANTE/11813/2017 Document have been followed. The results demonstrate that no false positives and no false negatives have been detected from the analysis of samples spiked with pesticides at 0.010 and 0.10 mg kg−1. This preliminary study has been also tested with a Proficiency Test (EUPT-FV-SM08) and, according to EUPT-FV-SM08 Final Report, our laboratory has been included in the 67% (56) that clearly detected over 70% pesticides. Finally, this method has been extended to other matrices and contaminants

Quantitative analysis of fentanyl, several analogues and metabolites in urine by parallel artificial liquid membrane extraction and liquid chromatography tandem mass spectrometry analysis

The rapid introduction of new psychoactive substances (NPS) has definitively changed the drug market. Among the several NPS that were identified in the last decades, fentanyl and its analogues deserve special attention. These are synthetic opioids with high potency and are associated with increasing number of deaths; for this reason, forensic toxicologists are paying close attention to these analytes and sensitive analytical methods for their detection in biological samples of drug users are needed. The aim of this study was the development of a LC–MS/MS method for the determination of fentanyl, 23 analogues and metabolites in urine by exploiting parallel artificial liquid membrane extraction (PALME). This technique was shown to be particularly suitable for fentanyl extraction and allowed to obtain a high enrichment factor by using a few microliters of organic solvent (1-octanol) immobilized into a polyvinylidene fluoride (PVDF) membrane. The extraction was carried out on a 96 well plate providing high laboratory throughput. The applied strategy allowed to measure concentrations ranging from 0.1 ng mL − 1 for fentanyl and most analogues to 5 ng mL − 1 for metabolites, by using an entry level mass spectrometer. Because of the different concentration levels generally found in real samples, linearity was studied in different ranges i.e. LOQ to 50 ng mL − 1 for parent drugs and LOQ to 200 ng mL − 1 for metabolites. All the validation parameters were found within the imposed limits, and notably matrix effect was not significant for all the analytes, showing the selectivity achieved by PALME extraction

Analysis of Polyphenols in the Lamiaceae Family by Matrix Solid-Phase Dispersion Extraction Followed by Ultra-High-Performance Liquid Chromatography–Tandem Mass Spectrometry Determination

Polyphenolic compounds (PCs) are natural-occurring secondary metabolites with considerable physiological and morphological importance in plants and different biological functions. In this work, a matrix solid-phase dispersion extraction/purification procedure, followed by an ultra-high-performance liquid chromatography–tandem mass spectrometry analysis, has been developed and validated for the quantification of 17 PCs in Ocimum basilicum L., Origanum vulgare L., and Thymus vulgaris L. from the Lamiaceae family. The use of a limited sample amount, combined with small solvent consumption, marks the convenience of this technique for the extraction/isolation of compounds of interest. The validation showed good results, with recoveries ranged between 75 and 105%, relative standard deviation values ≤12%, and very low matrix effects. The experimental results demonstrated the variability of the phenolic pattern of the samples and the need for accurate assessment of the phenolic pattern to establish the real nutra..

Phenol Profiling and Nutraceutical Potential of Lycium spp. Leaf Extracts Obtained with Ultrasound and Microwave Assisted Techniques

In recent years, agricultural and industrial residues have attracted a lot of interest in the recovery of phytochemicals used in the food, pharmaceutical, and cosmetic industries. In this paper, a study on the recovery of phenol compounds from Lycium spp. leaves is presented. Ultrasound‐assisted extraction (UAE) and microwave‐assisted extraction (MAE) have been used with alcoholic and hydroalcoholic solvents. Methanolic UAE was the most successful technique for extracting phenols from Lycium leaves, and we used on leaves from L. barbarum and L. chinense cultivated in Italy. The extracts were then characterized as regards to the antioxidant properties by in vitro assays and the phenol profiling by a high performance liquid chromatography‐diode array detector (HPLC‐DAD). Chlorogenic acid and rutin were the main phenol compounds, but considerable differences have been observed between the samples of the two Lycium species. For example, cryptochlorogenic acid was found only in L. barbarum samples, while quercetin‐3‐O‐rutinoside‐7‐O‐glucoside and quercetin‐3‐O‐sophoroside‐7‐O‐rhamnoside only in L. chinense leaves. Finally, multivariate statistical analysis techniques applied to the phenol content allowed us to differentiate samples from different Lycium spp. The results of this study confirm that the extraction is a crucial step in the analytical procedure and show that Lycium leaves represent an interesting source of antioxidant compounds, with potential use in the nutraceutical field