Rapid identification of organophosphorus pesticides on contaminated skin and confirmation of adequate decontamination by ambient mass spectrometry in emergency settings

Investigation of potential biomarkers for psoriasis in skin with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and ambient ionization mass spectrometry

Background

Psoriasis is a chronic inflammatory disease with an unclear etiology that affects skin, nails, and joints and often accompanies comorbidities. Recent studies indicate that alterations in metabolites within psoriatic lesions might be linked to inflammation. Studying bioactive lipid mediators or metabolites in skin inflammation and immunity might provide new potential biomarkers and therapeutic prediction factors.

Methods

Lipids and peptides in the scale extracts from psoriasis patients and healthy controls were characterized by thermal desorption-electrospray ionizationmass spectrometry and matrix-assisted laser desorption/ionization time-of-flightmass spectrometry, respectively. Principal component analysis (PCA) was then applied to these data to identify potential differences between psoriasis patients and healthy controls.

Results

Psoriatic plaques show reduced wax esters and triglycerides and a predominant increase in human neutrophil defensins (HNPs), compared to non-lesional sites of psoriatic patients and healthy control. Additionally, when medical treatments were administered to psoriasis patients, levels of HNPs were significantly reduced, suggesting that they may serve as potential biomarkers to evaluate therapeutic efficacy for psoriasis.

Conclusion

Two mass spectrometric techniques were used to rapidly and non-invasively identify and monitor potential biomarkers between psoriasis patients and healthy controls. However, PCA results only showed slight differences, and we intend to broaden the sample base in the future to increase the statistical power of the investigation.

Rapid Characterization of Undeclared Pharmaceuticals in Herbal Preparations by Ambient Ionization Mass Spectrometry for Emergency Care

In Asia, some herbal preparations have been found to be adulterated with undeclared synthetic medicines to increase their therapeutic efficiency. Many of these adulterants were found to be toxic when overdosed and have been documented to bring about severe, even life-threatening acute poisoning events. The objective of this study is to develop a rapid and sensitive ambient ionization mass spectrometric platform to characterize the undeclared toxic adulterated ingredients in herbal preparations. Several common adulterants were spiked into different herbal preparations and human sera to simulate the clinical conditions of acute poisoning. They were then sampled with a metallic probe and analyzed by the thermal desorption-electrospray ionization mass spectrometry. The experimental parameters including sensitivity, specificity, accuracy, and turnaround time were prudently optimized in this study. Since tedious and time-consuming pretreatment of the sample is unnecessary, the toxic adulterants could be characterized within 60 s. The results can help emergency physicians to make clinical judgments and prescribe appropriate antidotes or supportive treatment in a time-sensitive manner.

Rapid identification of mushroom toxins by direct electrospray probe mass spectrometry for emergency care

Mushroom poisoning occurs frequently after the ingestion of toxic wild mushrooms misidentified as edible species. The goal of this study is to develop a mass spectrometric platform to bypass the need for morphological recognition of poisonous mushrooms by experts and rapidly identify the toxins in the mushrooms for emergency care. Trace mushroom toxins were collected by penetrating and removing the mushrooms surface for 3 mm with a direct electrospray probe (DEP). The analytes on the DEP were then dissolved in the solution (70% isopropanol containing 0.1% acetic acid) flowing out of a solvent reservoir on the DEP. Electrospray ionization was induced from the sample solution as a high electric field was generated between the DEP and MS inlet. The obtaining mass spectrometric results were further analyzed with principal component analysis (PCA) to classify mushroom toxins. The mass spectrometric platform for detecting mushroom toxins was assessed for its sensitivity, precision, and efficiency by determining its limit-of-detection (LOD), repeatability, and turnaround time, respectively. As a result, the LODs of the mushroom toxins in pure methanol and spiked in human vomitus by DEP/MS were within 0.001-0.5 ng/μL and 0.01-1 ng/μL, respectively. Linear responses of the mushroom toxins in pure methanol with concentrations between 0.01 and 5 ng/μL (R2 between 0.9922 and 0.998) were obtained. The repeatability of the approach (n = 10) was shown in the low relative standard deviation value (<15%) from ten repeat analysis of mushroom toxins standard solution. The corresponding toxic compounds were identified through matching of the obtained mass spectrometric data with those provided by its companion database library of mushroom toxins. Since no time-consuming pretreatment of the samples is required, identification of mushroom toxins with DEP/MS was complete within 1 min. This will be helpful for the emergency physicians to make correct clinical judgment and prescribe appropriate medical treatment in a timely manner.

Thermal desorption ambient ionization mass spectrometry for emergency toxicology

In the emergency department, it is important to rapidly identify the toxic substances that have led to acute poisoning because different toxicants or toxins cause poisoning through different mechanisms, requiring disparate therapeutic strategies and precautions against contraindicating actions, and diverse directions of clinical course monitoring and prediction of prognosis. Ambient ionization mass spectrometry, a state-of-the-art technology, has been proved to be a fast, accurate, and user-friendly tool for rapidly identifying toxicants like residual pesticides on fruits and vegetables. In view of this, developing an analytical platform that explores the application of such a cutting-edge technology in a novel direction has been initiated a research program, namely, the rapid identification of toxic substances which might have caused acute poisoning in patients who visit the emergency department and requires an accurate diagnosis for correct clinical decision-making to bring about corresponding data-guided management. This review includes (i) a narrative account of the breakthrough in emergency toxicology brought about by the advent of ambient ionization mass spectrometry and (ii) a thorough discussion about the clinical implications and technical limitations of such a promising innovation for promoting toxicological tests from tier two-level to tier one level.

A Fluidics-Based Biosensor to Detect and Characterize Inhibition Patterns of Organophosphate to Acetylcholinesterase in Food Materials

A chip-based electrochemical biosensor is developed herein for the detection of organophosphate (OP) in food materials. The principle of the sensing platform is based on the inhibition of dimethoate (DMT), a typical OP that specifically inhibits acetylcholinesterase (AChE) activity. Carbon nanotube-modified gold electrodes functionalized with polydiallyldimethylammonium chloride (PDDA) and oxidized nanocellulose (NC) were investigated for the sensing of OP, yielding high sensitivity. Compared with noncovalent adsorption and deposition in bovine serum albumin, bioconjugation with lysine side chain activation allowed the enzyme to be stable over three weeks at room temperature. The total amount of AChE was quantified, whose activity inhibition was highly linear with respect to DMT concentration. Increased incubation times and/or DMT concentration decreased current flow. The composite electrode showed a sensitivity 4.8-times higher than that of the bare gold electrode. The biosensor was challenged with organophosphate-spiked food samples and showed a limit of detection (LOD) of DMT at 4.1 nM, with a limit of quantification (LOQ) at 12.6 nM, in the linear range of 10 nM to 1000 nM. Such performance infers significant potential for the use of this system in the detection of organophosphates in real samples.

Fluorescent and colorimetric dual-response sensor based on copper (II)-decorated graphitic carbon nitride nanosheets for detection of toxic organophosphorus

An efficient and convenient detection method for organophosphorus pesticide (OP) residues is needed because of their high neurotoxicity and severe threat to food safety. OPs effectively reduce the production of thiocholine in the acetylcholinesterase/acetylthiocholine reaction by inhibiting the activity of acetylcholinesterase. Therefore, we developed a feasible and convenient fluorescent and colorimetric dual-response sensor based on the competitive complexation of Cu²⁺ between graphitic carbon nitride nanosheets and thiocholine for the rapid detection of OPs with high sensitivity. Malathion was used as a model OP, and a linear range of 70-800 nM with a detection limit of 6.798 nM for a fluorescent signaling platform and 2.5-25 nM with a detection limit of 1.204 nM for a colorimetric probe were attained. The constructed probe was successfully applied to determine OP in actual samples of cabbages leaves and tap water. The results indicated that the dual-response probe was reliable and sensitive to actual samples.