A novel sorptive extraction method based on polydimethylsiloxane frit for determination of lung cancer biomarkers in human serum

A new sol-gel fluorescent sensor to track carbonyl compounds

Carbonyl compounds are ubiquitous quality trackers that provide information about food product degradation as well as air and water pollution levels. In addition, they are used as biomarkers for medical diagnoses. With more user-friendly sensors, their fast detection and easy quantification are highly relevant. The synthesis, characterization, and performance assessment of a new sensor based on aniline fluorescence to monitor carbonyls in real time is reported. A cost-effective synthesis using a straightforward sol-gel process led to the construction of a nontoxic silica-based material with high porosity, which can be used with almost no sample preparation. The material exhibits a rapid (< 1 min) fluorescence decrease upon interaction with carbonyl groups. The limit of detection is as low as ca. 5 × 10-4 mol·L-1 for hexanal, while fluorescence extinction occurs at much higher concentrations (5 × 10-1·mol L-1), which enables the sensor to be used with a very broad range of detection. Real-time monitoring is possible since the fluorescence loss correlates with the concentration of carbonyl moieties. The performance was validated in simulating as well as in real media, making this sensor suitable for use in a wide range of applications.

Determination of hexanal and heptanal in saliva samples by an adapted magnetic headspace adsorptive microextraction for diagnosis of lung cancer

In this work, an analytical method for the determination of two endogenous aldehydes (hexanal and heptanal) as lung cancer biomarkers in saliva samples is presented for the first time. The method is based on a modification of magnetic headspace adsorptive microextraction (M-HS-AME) followed by gas chromatography coupled to mass spectrometry (GC-MS). For this purpose, an external magnetic field generated by a neodymium magnet is used to hold the magnetic sorbent (i.e., CoFe₂O₄ magnetic nanoparticles embedded into a reversed-phase polymer) in the headspace of a microtube to extract the volatilized aldehydes. Subsequently, the analytes are desorbed in the appropriate solvent and the extract is injected into the GC-MS system for separation and determination. Under the optimized conditions, the method was validated and showed good analytical features in terms of linearity (at least up to 50 ng mL^-1), limits of detection (0.22 and 0.26 ng mL^-1 for hexanal and heptanal, respectively), and repeatability (RSD ≤12%). This new approach was successfully applied to saliva samples from healthy volunteers and those with lung cancer, obtaining notably differences between both groups. These results reveal the prospect of the method as potential diagnostic tool for lung cancer by saliva analysis. This work contributes to the Analytical Chemistry field presenting a double novelty: on the one hand, the use of M-HS-AME in bioanalysis is unprecedentedly proposed, thus expanding the analytical potential of this technique, and, on the other hand, the determination of hexanal and heptanal is carried out in saliva samples for the first time.

Urinary Volatomic Expression Pattern: Paving the Way for Identification of Potential Candidate Biosignatures for Lung Cancer

The urinary volatomic profiling of Indian cohorts composed of 28 lung cancer (LC) patients and 27 healthy subjects (control group, CTRL) was established using headspace solid phase microextraction technique combined with gas chromatography mass spectrometry methodology as a powerful approach to identify urinary volatile organic metabolites (uVOMs) to discriminate among LC patients from CTRL. Overall, 147 VOMs of several chemistries were identified in the intervention groups-including naphthalene derivatives, phenols, and organosulphurs-augmented in the LC group. In contrast, benzene and terpenic derivatives were found to be more prevalent in the CTRL group. The volatomic data obtained were processed using advanced statistical analysis, namely partial least square discriminative analysis (PLS-DA), support vector machine (SVM), random forest (RF), and multilayer perceptron (MLP) methods. This resulted in the identification of nine uVOMs with a higher potential to discriminate LC patients from CTRL subjects. These were furan, o-cymene, furfural, linalool oxide, viridiflorene, 2-bromo-phenol, tricyclazole, 4-methyl-phenol, and 1-(4-hydroxy-3,5-di-tert-butylphenyl)-2-methyl-3-morpholinopropan-1-one. The metabolic pathway analysis of the data obtained identified several altered biochemical pathways in LC mainly affecting glycolysis/gluconeogenesis, pyruvate metabolism, and fatty acid biosynthesis. Moreover, acetate and octanoic, decanoic, and dodecanoic fatty acids were identified as the key metabolites responsible for such deregulation. Furthermore, studies involving larger cohorts of LC patients would allow us to consolidate the data obtained and challenge the potential of the uVOMs as candidate biomarkers for LC.

13-Plex UHPLC-MS/MS Analysis of Hexanal and Heptanal Using Multiplex Tags Chemical Isotope Labeling Technology

In this work, a new series of chemical isotope labeling reagents, levofloxacin-hydrazide-based mass tags (LHMTs) named as LHMT359/360/361/362/363/364/365/366/373/375/376/378/379/381 were first designed and synthesized for the high-throughput analysis of potential biomarkers containing hexanal and heptanal of lung cancer. We exploited a new core structure of levofloxacin-d₃, which significantly enhanced the multiplexing capability. Among them, LHMT359 was used for labeling standard compounds as internal standards for quantification. Using LHMT373-heptanal as dummy template, dummy magnetic molecularly imprinted polymers (DMMIPs) were prepared for magnetic dispersive solid-phase extraction after derivatization procedure. Other 12 LHMTs were established for high-throughput labeling hexanal and heptanal in human serum samples. The presynthesized DMMIPs can selectively extract LHMTs-derivatives of hexanal and heptanal from equally mixed derivatization solutions. The enriched derivatives of hexanal and heptanal were quantified by ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). A single UHPLC-MS/MS run enabled simultaneously quantifying hexanal and heptanal from 12 serum samples only within 2 min. The limits of detection were all 0.5 pM for hexanal and heptanal. The accuracies from human serum samples ranged from -10.2% to +11.0% with the intra- and interday precisions less than 11.3%. Meanwhile, this method was successfully applied for the analysis of hexanal and heptanal in serum samples from healthy people and lung cancer patients. The results show that this method has the significant advantages of high sensitivity, accuracy, selectivity, and analysis-throughput. The method application indicates that the developed method is promising in the screening of suspected lung cancer patients.

New application of old methods: Development of colorimetric sensor array based on Tollen's reagent for the discrimination of aldehydes based on Tollen's reagent

Qualitative and quantitative testing of aldehydes is meaningful for chemical toxin detection, food inspection, and disease monitoring. Herein, we reported a simple, accurate, and selective Tollen's reagent-based colorimetric sensor array for determination and detection of aldehydes. Three kinds of negatively charged gold nanoparticles (Au NPs) with different sizes (13, 22, and 40 nm) were synthesized and characterized by transmission electron microscopy and zeta potential measurement. In the presence of aldehydes, Ag+ from Tollen's reagent was attracted by the negative charge on the surface of Au NPs. Ag+ was reduced into Ag0 in situ, forming Au@Ag core-shell nanostructure and resulting in a significant color change. Detailed morphological and dimensional changes were observed by transmission electron microscopy. ΔRGB values (the value changes in the red, green, and blue color model) of Au NPs were captured as the optical signal for further data processing. Results of pattern recognition indicated the outstanding discrimination performance of the system for identification of aldehydes. Moreover, the array possessed quantitative detection capability for formaldehyde, selectivity, and reproducibility and thus has great potential in practical detection.

Phylogenetic affiliation and determination of bioactive compounds of bacterial population associated with organs of mud crab, Scylla olivacea

Mud crab belongs to the genus Scylla is an economically valuable and preferred species for costal aquaculture in Asian countries, including India. In recent years, there has been a tremendous expansion of Scylla farming, which has led to increasing research on its habit and habitats. However, there has been no study undertaken to understand the role of the bacterial population associated with the different organs of the mud crab, Scylla olivacea. In total, 43 isolates were recovered from four selected parts of the crab (carapace, n = 18; abdomen n = 11; leg, n = 8; and hand, n = 6), and the 16S rRNA gene was used to identify the bacterial isolates. The antimicrobial potential along with the detection of modular polyketide synthase (PKSI), cytochrome P450 hydroxylase (CYP) and non-ribosomal peptide synthetase (NRPS) gene clusters were investigated to show a relationship among the biosynthetic genes with their useful aspects. Additionally, the potential three strains (BPS_CRB12, BPS_CRB14 and BPS_CRB41), which showed significant antimicrobial activities, also showed the presence of twenty volatile compounds (VOCs) using GC-MS analysis. We conclude that the strain Aneurinibacillus aneurinilyticus BPS_CRB41 could be source for the production of bioactive compounds.

TD-GC-MS Investigation of the VOCs Released from Blood Plasma of Dogs with Cancer

An analytical TD-GC-MS method was developed and used for the assessment of volatile organic compounds (VOCs) released from the blood plasma of dogs with/without cancer. VOCs released from 40 samples of diseased blood and 10 control samples were compared in order to examine the difference between both sample groups that were showing qualitatively similar results independent from the disease's presence. However, mild disturbances in the spectra of dogs with cancer in comparison with the control group were observed, and six peaks (tentatively identified by comparison with mass spectral library as hexanal, octanal, toluene, 2-butanone, 1-octen-3-ol and pyrrole) revealed statistically significant differences between both sample groups, thereby suggesting that these compounds are potential biomarkers that can be used for cancer diagnosis based on the blood plasma TD-GC-MS analysis. Statistical comparison with the application of principal component analysis (PCA) provided accurate discrimination between the cancer and control groups, thus demonstrating stronger biochemical perturbations in blood plasma when cancer is present.