Octadecyl functionalized core-shell magnetic silica nanoparticle as a powerful nanocomposite sorbent to extract urinary volatile organic metabolites

Development of a headspace-solid phase microextraction gas chromatography-high resolution mass spectrometry method for analyzing volatile organic compounds in urine: Application in breast cancer biomarker discovery

BACKGROUND AND AIM

Breast cancer (BC) is the leading cause of cancer-related death in females. The development of non-invasive methods for the early diagnosis of BC still remains challenge. Here, we aimed to discover the urinary volatile organic compounds (VOCs) pattern of BC patients and identify potential VOC biomarkers for BC diagnosis.

METHODS

Urine samples were analyzed by headspace-solid phase microextraction (HS-SPME) combined with gas chromatography-high resolution mass spectrometry (GC-HRMS). To assure reliable analysis, the factors influencing HS-SPME extraction efficiency were comprehensively investigated and optimized by combing the Plackett-Burman design (PBD) with the central composite design (CCD). The established HS-SPME/GC-HRMS method was validated and applied to analyze urine samples from BC patients (n = 80) and healthy controls (n = 88).

RESULTS

A total number of 134 VOCs belonging to distinct chemical classes were identified by GC-HRMS. BC patients demonstrated unique urinary VOCs pattern. Orthogonal partial least squares-discriminant analysis (OPLS-DA) showed a clear separation between BC patients and healthy controls. Eight potential VOC biomarkers were identified using multivariate and univariate statistical analysis. The predictive ability of candidate VOC biomarkers was further investigated by the random forest (RF) algorithm. The candidate VOC biomarkers yielded 76.3% sensitivity and 85.4% specificity on the training set, and achieved 76.0% sensitivity and 92.3% specificity on the validation set.

CONCLUSIONS

Overall, this work not only established a standardized HS-SPME/GC-HRMS approach for urinary VOCs analysis, but also highlighted the value of urinary VOCs for BC diagnosis. The knowledge gained from this study paves the way for early diagnosis of BC using urine in a non-invasive manner.

NH2NH-MOF: a reaction matrix for the specific determination of small aldehydes by MALDI-MS

Efficient determination of aldehydes by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is hampered mainly by the low mass and unstable nature of analytes. In the present work, we propose a combined strategy of a reactive metal-organic framework (MOF) matrix for the derivatization and detection of aldehydes. A novel reactive MOF matrix (NH₂NH-MOF) was synthesized in two steps. First, NR₃⁺-MOF was synthesized via Cu²⁺ and the quaternary amine ligand 4,4'-bipyridinium, 1,1″-(1,2-ethanediyl)bis-, dibromide (PyEtBr). Then, -NHNH₂ was introduced to NR₃⁺-MOF through electrostatic adsorption between the -NR₃⁺ and -HSO₃^- of 4-hydrazinylbenzenesulfonic acid to synthesize NH₂NH-MOF. The acid-base chemistry of NH₂NH-MOF led to uniform cocrystallization of the aldehyde-matrix mixtures and helped to achieve the detection of low-weight aldehydes with good relative standard deviations (RSDs = 0.07-12.35%). It was confirmed that this strategy can accurately quantify formaldehyde, valeraldehyde, and benzaldehyde with good linearity (r > 0.97). Furthermore, this strategy was applied to quantitatively detect benzaldehyde in wastewater, thus showing potential applications in environmental pollutant detection.

Recent development of nanoparticle-assisted metabolites analysis with mass spectrometry

Metabolomics systematically studies the changes of metabolites in biological systems in the temporal or spatial dimensions. It is a challenging task for comprehensive analysis of metabolomics because of diverse physicochemical properties and wide concentration distribution of metabolites. Used as enrichment sorbents, chemoselective probes, chromatographic stationary phases, MS ionization matrix, nanomaterials play excellent roles in improving the selectivity, separation performance, detection sensitivity and identification efficiency of metabolites when mass spectrometry is employed as the detection technique. This review summarized the recent development of nanoparticle-assisted metabolites analysis in terms of assisting the pretreatment of biological samples, improving the separation performance and enhancing the MALDI-MS detection.

Development of carbohydrate functionalized magnetic nanoparticles for aminoglycosides magnetic solid phase extraction

Magnetic nanoparticles decorated with d-galactose and galactitol (Fe₃O₄@SiN-galactose and Fe₃O₄@SiN-galactitol) were synthesized and employed as sorbent in a magnetic solid phase extraction (MSPE) procedure prior the analysis of aminoglycosides (AGs) in honey samples by LC-MS/MS. AGs are broad spectrum antibiotics, characterized by aminosugars, widespread used in therapeutic and veterinary applications. AGs can be found in the environment and food of animal origin. Fe₃O₄@SiN-galactose and Fe₃O₄@SiN-galactitol were synthesized via copper catalyzed alkyne azide cycloaddition and the synthesis was efficiently followed by infrared spectroscopy. They were characterized by electron microscopy, thermogravimetric analysis and magnetization curves. The nature of the loading (acetonitrile:water, 50:50 v/v) and elution solution (formic acid 190 mM) were studied in order to optimize the MSPE. Quantitative difference between MSPE with Fe₃O₄@SiN-galactose and MSPE with Fe₃O₄@SiN-galactitol in terms of recovery was found. The final optimized method using Fe₃O₄@SiN-galactose and Fe₃O₄@SiN-galactitol was applied in the determination of AGs in honey. The MSPE performance of Fe₃O₄@SiN-galactitol was found to be superior to that of MSPE with Fe₃O₄@SiN-galactose. The limits of quantification were between 2 and 19 μg kg^-1 for amikacin, dihydrostreptomycin, tobramicyn and gentamycin. A good correlation between predicted and nominal values of AGs in honey was found (trueness from 84% to 109%). This MSPE procedure not only requires a minimum amount of sorbent (1 mg) and sample (0.2 g), but it can also be accomplish in a rather short time.

A hierarchically porous composite monolith polypyrrole/octadecyl silica/graphene oxide/chitosan cryogel sorbent for the extraction and pre-concentration of carbamate pesticides in fruit juices

A hierarchically porous structured composite monolith sorbent of polypyrrole-coated graphene oxide and octadecyl silica incorporated in chitosan cryogel (PPY/GOx/C18/chitosan) was synthesized and used as solid-phase extraction sorbent for the determination of carbamate pesticides. Various factors affecting the characteristics of the adsorbents (chemistry of the sorbent, polymerization time, concentrations of graphene oxide and octadecyl silica) and the extraction efficiency using the prepared sorbents, such as sample loading, desorption conditions, sample volume, sample flow rate, sample pH, and ionic strength, were investigated and optimized. Under the optimal conditions of sorbent preparation and extraction, the developed composite monolith sorbent provided wide linear responses from 1.0 to 500 μg L^-1 for carbofuran and diethofencarb, from 0.5 to 500 μg L^-1 for carbaryl, and from 2.0 to 500 μg L^-1 for isoprocarb. The limits of detection using HPLC-UV at 203, 220, and 208 nm were in the range of 0.5-2.0 μg L^-1. When the composite monolith sorbent was applied for the pre-concentration and determination of carbamate in fruit juices, good recoveries (84.1-99.5%) were achieved. The developed sorbents were porous and exhibited low back pressure enabling their use at high flow rates during sample loading. Extraction and clean-up were highly efficient, and the good physical and chemical stability of the sorbent enables reuse up to 13 times. Graphical abstract ᅟ.

Furan and p-xylene as candidate biomarkers for prostate cancer

BACKGROUND

Prostate cancer (PCa) is the most frequently diagnosed noncutaneous malignant tumor among males in the Western world. Prostate-specific antigen has been considered the most important biomarker for PCa detection; however, it lacks specificity, leading to the search for alternative biomarkers. Volatile organic compounds (VOCs) are released during cell metabolism and can be found in exhaled breath, urine, and other fluids. VOCs have been used in the diagnosis of lung, breast, ovarian, and colorectal cancers, among others. The objective of this study was to identify urinary VOCs that may be sensitive and specific biomarkers for PCa.

METHODS

The study included 29 patients with PCa and 21 with benign prostatic hyperplasia. Urine samples were obtained from all participants before and after prostate massage. VOCs were identified by gas chromatography-mass spectrometry. IBM SPSS Statistics v.20 was used for statistical analysis. Sample normality and homogeneity of variances were studied and, according to the distribution normality, ANOVA or the Kruskal-Wallis test was applied to evaluate significant differences between groups. The Pearson test was used to establish correlations.

RESULTS

Fifty-seven VOCs were identified. Samples gathered before prostate massage showed significant between-group differences in urinary levels of furan (P≤ 0.001), 2-ethylhexanol (P = 0.032), 3,5-dimethylbenzaldehyde (P = 0.027), santolin triene (P = 0.032), and 2,6-dimethyl-7-octen-2-ol (P = 0.003). Samples gathered after prostate massage showed significant differences in urinary levels of furan (P≤ 0.001), 3- methylphenol (P = 0.014), p-xylene (P = 0.002), phenol (P≤ 0.001), and 2-butanone (P = 0.001).

CONCLUSIONS

Significant differences between PCa and BPH patients were found in urinary levels of certain VOCs both before and after prostate massage, supporting the proposal that VOCs may serve as PCa-specific biomarkers.