MALDI-TOF Mass Spectrometry Based on Parylene-Matrix Chip for the Analysis of Lysophosphatidylcholine in Sepsis Patient Sera

Molecularly Imprinted Heterostructure-Assisted Laser Desorption Ionization Mass Spectrometry Analysis and Imaging of Quinolones

Quinolone residues resulting from body metabolism and waste discharge pose a significant threat to the ecological environment and to human health. Therefore, it is essential to monitor quinolone residues in the environment. Herein, an efficient and sensitive matrix-assisted laser desorption/ionization mass spectrometry (MALDI/MS) method was devised by using a novel molecularly imprinted heterojunction (MIP-TNs@GCNs) as the matrix. Molecularly imprinted titanium dioxide nanosheets (MIP-TNs) and graphene-like carbon nitrides (GCNs) were associated at the heterojunction interface, allowing for the specific, rapid, and high-throughput ionization of quinolones. The mechanism of MIP-TNs@GCNs was clarified using their adsorption properties and laser desorption/ionization capability. The prepared oxygen-vacancy-rich MIP-TNs@GCNs heterojunction exhibited higher light absorption and ionization efficiencies than TNs and GCNs. The good linearity (in the quinolone concentration range of 0.5-50 pg/μL, R2 > 0.99), low limit of detection (0.1 pg/μL), good reproducibility (n = 8, relative standard deviation [RSD] < 15%), and high salt and protein resistance for quinolones in groundwater samples were achieved using the established MIP-TNs@GCNs-MALDI/MS method. Moreover, the spatial distributions of endogenous compounds (e.g., amino acids, organic acids, and flavonoids) and xenobiotic quinolones from Rhizoma Phragmitis and Rhizoma Nelumbinis were visualized using the MIP-TNs@GCNs film as the MALDI/MS imaging matrix. Because of its superior advantages, the MIP-TNs@GCNs-MALDI/MS method is promising for the analysis and imaging of quinolones and small molecules.

Electrochemical analysis of total phospholipids in human serum for severe sepsis diagnosis

Electrochemical analysis of total phospholipids was performed for the diagnosis of sepsis. The influence of electrode materials on the analysis of the chromogenic substrate was analyzed using Au, graphite, and pyrolyzed carbon electrodes. The total phospholipid analysis based on electrochemical analysis with pyrolyzed carbon was used for diagnosis of sepsis using sera from healthy volunteers, systemic inflammatory response syndrome (SIRS), and severe sepsis patients. The analysis results using the optical measurement and the electrochemical analysis were compared for the serum samples from sepsis patients and healthy controls. Additionally, the interference of human serum on the optical measurement and electrochemical analysis was estimated by signal-to-noise (S/N) calculation. The assay results of the levels of other biomarkers for sepsis (C-reactive protein and procalcitonin) and the total phospholipid levels obtained using the optical measurement and electrochemical analysis methods were statistically similar. Finally, the mortality of patients, indicated by the results of the total phospholipid assay performed using the electrochemical analysis of the patient samples collected daily (1, 3, and 7 day(s) after admission to hospital), was compared with the patient mortality assessed via conventional severity indexes, such as the SOFA and APACHE Ⅱ scores. The 28-day survival rate was estimated by Kaplan-Meier survival analysis based on the total phospholipid level of patient samples that were obtained after 1, 3, and 7 day(s) from hospital admission.

Effect of Silane Monolayers and Nanoporous Silicon Surfaces on the Matrix-Assisted Laser Desorption Ionization Mass Spectrometry Detection of Sepsis Metabolites Biomarkers Mixed in Solution

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-ToF MS) is a promising strategy for clinical diagnosis based on metabolite detection. However, several bottlenecks (such as the lack of reproducibility in analysis, the presence of an important background in low-mass range, and the lack of organic matrix for some molecules) prevent its transfer to clinical cases. These limitations can be addressed by using nanoporous silicon surfaces chemically functionalized with silane monolayers. In the present study, sepsis metabolite biomarkers were used to investigate the effects of silane monolayers and porous silicon substrates on MALDI-ToF MS analysis (signal-to-noise value (S/N), relative standard deviation of the S/N of triplicate samples (STDmean), and intra-substrates uniformity). Also, the impact of the physicochemical properties of metabolites, with different isoelectric points and hydrophobic-hydrophilic balances, was assessed. Four different silane molecules, with various alkyl chain lengths and head-group charges, were self-assembled in monolayers on plane and porous silicon surfaces. Their surface coverage and conformity were investigated by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The seven metabolites detected on the stainless-steel target plate (lysophosphatidylcholine, caffeine, phenylalanine, creatinine, valine, arginine, and glycerophosphocholine) are also detected on the silanized and bare, plane and porous silicon surfaces. Moreover, two metabolites, glycine and alanine, which are not detected on the stainless-steel target plate, are detected on all silanized surfaces, except glycine which is not detected on CH3 short-modified porous silicon and on the bare plane silicon substrate. In addition, whatever the metabolites (except phenylalanine and valine), at least one of the silicon surfaces allows to increase the S/N value in comparison with the stainless-steel target plate. Also, the heterogeneity of matrix crystallization features is linked to the STDmean which is poor on the NH3+ monolayer on plane substrate and better on the NH3+ monolayer on porous substrate, for most of the metabolites. Nevertheless, matrix crystallization features are not sufficient to systematically get high STDmean and uniformity in MALDI-ToF MS analysis. Indeed, the physicochemical properties of metabolites and surfaces, limitations in metabolite extraction from the pores, and improvement in metabolite desorption due to the pores are shown to significantly impact MS analysis. In particular, in the case of the most hydrophobic metabolites studied, the highest S/N values and the best STDmean and uniformity (the lowest values) are reached by using porous substrates, while in the case of the most hydrophilic metabolites studied, plane substrates demonstrated the highest S/N and the lowest STDmean. No clear trend of surface chemistry was evidenced.

Effects of Silane Monolayers on Lysophosphatidylcholine (LysoPC) Detection by Desorption Ionization on Silicon Mass Spectrometry (DIOS-MS) in Solution and Plasma

Desorption ionization on silicon mass spectrometry (DIOS-MS) enables high throughput analysis of low-molecular-weight biomolecules. However, detection of metabolite biomarkers in complex fluids such as plasma requires sample pretreatment, limiting clinical application. Here, we show that porous silicon, chemically modified using monolayers of n-propyldimethylmethoxysilane molecules, is a good candidate for fingerprinting lysophosphatidylcholine (lysoPC) in plasma, without sample pretreatment, for DIOS-MS-based diagnosis (e.g., sepsis). Results were correlated to lysoPC molecule location inside/outside the pores, determined by time-of-flight secondary ion mass spectrometry profiling, and to physicochemical properties.

Circulating protein and lipid markers of early sepsis diagnosis and prognosis: a scoping review

PURPOSE OF REVIEW

Sepsis is the extreme response to infection associated with high mortality, yet reliable biomarkers for its identification and stratification are lacking.

RECENT FINDINGS

Our scoping review of studies published from January 2017 to September 2022 that investigated circulating protein and lipid markers to inform non-COVID-19 sepsis diagnosis and prognosis identified interleukin (IL)-6, IL-8, heparin-binding protein (HBP), and angiopoietin-2 as having the most evidence. Biomarkers can be grouped according to sepsis pathobiology to inform biological data interpretation and four such physiologic processes include: immune regulation, endothelial injury and coagulopathy, cellular injury, and organ injury. Relative to proteins, the pleiotropic effects of lipid species' render their categorization more difficult. Circulating lipids are relatively less well studied in sepsis, however, low high-density lipoprotein (HDL) is associated with poor outcome.

SUMMARY

There is a lack of robust, large, and multicenter studies to support the routine use of circulating proteins and lipids for sepsis diagnosis or prognosis. Future studies will benefit from standardizing cohort design as well as analytical and reporting strategies. Incorporating biomarker dynamic changes and clinical data in statistical modeling may improve specificity for sepsis diagnosis and prognosis. To guide future clinical decisions at the bedside, point-of-care circulating biomarker quantification is needed.

The emerging roles of next-generation metabolomics in critical care nutrition

Critical illness leads to millions of deaths worldwide each year, with a significant surge due to the COVID-19 pandemic. Patients with critical illness are frequently associated with systemic metabolic disorders and malnutrition. The idea of intervention for critically ill patients through enteral and parenteral nutrition has been paid more and more attention gradually. However, current nutritional therapies focus on evidence-based practice, and there have been lacking holistic approaches for nutritional support assessment. Metabolomics is a well-established omics technique in system biology that enables comprehensive profiling of metabolites in a biological system and thus provides the underlying information expressed and modulated by all other omics layers. In recent years, with the development of high-resolution and accurate mass spectrometry, metabolomics entered a new "generation", promoting its broader applications in critical care nutrition. In this review, we first described the technological development and milestones of next-generation metabolomics in the past 20 years. We then discussed the emerging roles of next-generation metabolomics in advancing our understanding of critical care nutrition, such as nutritional deficiency risk evaluation, metabolic mechanisms of nutritional therapies, and novel nutrition target identification.

Expression of Peripheral Blood DCs CD86, CD80, and Th1/Th2 in Sepsis Patients and Their Value on Survival Prediction

Objective. To explore the expression of peripheral blood dendritic cells (DCs) CD86, CD80, and Th1/Th2 in patients with sepsis and their value on survival prediction. Methods. 118 patients with sepsis from January 2019 to December 2020 were selected, According to the prognosis, the patients were divided into the death group ( $n=46$ ) and survival group ( $n=72$ ). The general data and pathogen division of the two groups were collected, and the levels of peripheral blood DCs CD86, CD80, and Th1/Th2; APACHE II score; inflammatory factor (procalcitonin (PCT)); and cell growth chemokine (GRO) were compared between the two groups heparin-binding protein (HBP) and myocardial enzyme indexes (creatine kinase (CK), creatine kinase isozyme (CK-MB), and lactate dehydrogenase (LDH)) to explore the relationship between CD86, CD80, Th1/Th2, and various serological indexes and the evaluation value of prognosis. Results. 124 strains of pathogenic bacteria were isolated from 118 patients, including 78 strains of gram-negative bacteria (62.90%), 31 strains of Gram-positive bacteria (25.00%), and 15 strains of fungi (12.10%). The scores of CD86, CD80, Th1, Th2, Th1/Th2, and APACHE II in the dead group were higher than those in the surviving group, and the difference was statistically significant ( $P<0.05$ ). PCT, GRO-α, HBP, LDH, CK-MB, and CK levels of patients in death group were higher than those in survival group, and the difference was statistically significant ( $P<0.05$ ). The levels of peripheral blood DCs CD86, CD80, and Th1/Th2 were positively correlated with PCT, GRO-α, HBP, LDH, CK-MB, and CK ( $P<0.05$ ). ROC curve analysis showed that the AUC of the combined detection of DCs CD86, CD80, and Th1/Th2 in peripheral blood was 0.951, which was higher than 0.882, 0.883, and 0.734 of single index ( $P<0.05$ ). Conclusion. All patients with sepsis have immune imbalance, and the peripheral blood CD86, CD80, and Th1/Th2 of the dead patients are higher than those of the survivors. The combined detection of these three indicators has the highest predictive value for the prognosis of patients.

Laser desorption/ionization mass spectrometry of L-thyroxine (T4) using combi-matrix of α-cyano-4-hydroxycinnamic acid (CHCA) and graphene

An optimal combi-matrix for MALDI-TOF mass spectrometry was presented for the analysis of L-thyroxine (T4) in human serum. For the selection of the optimal combi-matrix, several kinds of combi-matrices were prepared by mixing the conventional organic matrix of CHCA with nanomaterials, such as graphene, carbon nanotubes, nanoparticles of Pt and TiO2. In order to select the optimal combi-matrix, the absorption at the wavelength of laser radiation (337 nm) for the ionization of sample was estimated using UV–Vis spectrometry. And, the heat absorption properties of these combi-matrices were also analyzed using differential scanning calorimetry (DSC), such as onset temperature and fusion enthalpy. In the case of the combi-matrix of CHCA and graphene, the onset temperature and fusion enthalpy were observed to be lower than those of CHCA, which represented the enhanced transfer of heat to the analyte in comparison with CHCA. From the analysis of optical and thermal properties, the combi-matrix of CHCA and graphene was selected to be an optimal combination for the transfer of laser energy during MALDI-TOF mass spectrometry. The feasibility of the combi-matrix composed of CHCA and graphene was demonstrated for the analysis of T4 molecules using MALDI-TOF mass spectrometry. The combi-matrix of CHCA and graphene was estimated to have an improved limit of detection and a wider detection range in comparison with other kinds of combi-matrices. Finally, the MALDI-TOF MS results of T4 analysis using combi-matrix were statistically compared with those of the conventional immunoassay.

Quantitative analysis of vitamin D using m/MALDI-TOF mass spectrometry based on a parylene matrix chip

Vitamin D deficiency is associated with various disorders and is diagnosed based on the concentration of 25-hydroxy vitamin D3 (25(OH)D3) in serum. The parylene matrix chip was fabricated to reduce the matrix background noise, and the homogenous distribution of the matrix was retained for the quantitative analysis of 25(OH)D3. The Amplex Red assay was performed to confirm that the sample-matrix mixing zone of the parylene matrix chip was formed below the surface of the parylene-N film. The homogeneous distribution of the matrix was verified from the fluorescence image. For effective analysis using a parylene matrix chip, 25(OH)D3 was modified through the nucleophilic addition of betaine aldehyde (BA) to form a hemiacetal salt. Such modified 25(OH)D3 with a positive charge from BA could be effectively analyzed using MALDI-TOF mass spectrometry. Serum 25(OH)D3 was extracted by liquid–liquid extraction (LLE) and quantified using MALDI-TOF mass spectrometry based on the parylene matrix chip. The intensity of the mass peak of 25(OH)D3 was linearly correlated (r2 = 0.992) with the concentration of 25(OH)D3 spiked in serum, and the LOD was 0.0056 pmol/μL. Energy drinks and vitamin D3 tablets were also employed for the real sample analysis. Finally, the results of the chemiluminescence binding assay and MALDI-TOF mass spectrometry were statistically analyzed to determine the applicability of the method using the Bland–Altman test and Passing–Bablok regression.

A new update of MALDI-TOF mass spectrometry in lipid research

Matrix-assisted laser desorption and ionization (MALDI) mass spectrometry (MS) is an indispensable tool in modern lipid research since it is fast, sensitive, tolerates sample impurities and provides spectra without major analyte fragmentation. We will discuss some methodological aspects, the related ion-forming processes and the MALDI MS characteristics of the different lipid classes (with the focus on glycerophospholipids) and the progress, which was achieved during the last ten years. Particular attention will be given to quantitative aspects of MALDI MS since this is widely considered as the most serious drawback of the method. Although the detailed role of the matrix is not yet completely understood, it will be explicitly shown that the careful choice of the matrix is crucial (besides the careful evaluation of the positive and negative ion mass spectra) in order to be able to detect all lipid classes of interest. Two developments will be highlighted: spatially resolved Imaging MS is nowadays well established and the distribution of lipids in tissues merits increasing interest because lipids are readily detectable and represent ubiquitous compounds. It will also be shown that a combination of MALDI MS with thin-layer chromatography (TLC) enables a fast spatially resolved screening of an entire TLC plate which makes the method competitive with LC/MS.

Photothermal Structural Dynamics of Au Nanofurnace for In Situ Enhancement in Desorption and Ionization

Fundamental properties of nanostructured substrates govern the performance of laser desorption/ionization mass spectrometry (LDI-MS); however, limited studies have elucidated the desorption/ionization mechanism based on the physicochemical properties of substrates. Herein, the enhancement in desorption/ionization is investigated using a hybrid matrix of Au nanoisland-functionalized ZnO nanotubes (AuNI-ZNTs). The underlying origin is explored in terms of the photo-electronic and -thermal properties of the matrix. This is the first study to report the effect of laser-induced surface restructuring/melting phenomenon on the LDI-MS performance. AuNI plays a central role as a photothermal nanofurnace, which facilitates the internal energy transfer from the AuNI to the adsorbed analytes by reconstruction in the structurally dynamic AuNI and therefore favors the desorption process. Moreover, piezoelectricity is driven in situ in the AuNI-ZNT hybrid, which modulates the overall band structure and thereby promotes the ionization process. Ultimately, high LDI-MS performance is demonstrated by analyzing small metabolites of fatty acids and monosaccharides, which are challenged to be detected in conventional LDI-MS. This study emphasizing the understanding of matrix properties can provide insights into the design and development of a novel nanomaterial as an efficient LDI matrix. Furthermore, the developed hybrid matrix can overcome the major hurdles existing in conventional LDI-MS.

Quantitative analysis of galactose using LDI-TOF MS based on a TiO2 nanowire chip

A novel method for quantifying galactose was developed to serve as a newborn screening test for galactosemia using laser desorption/ionization time-of-flight (LDI-TOF) mass spectrometry (MS) with a TiO2 nanowire chip. Herein, phosphate citrate buffer, serum, and dried blood spot (DBS) were employed for the quantitative analysis of galactose. To quantitatively analyze galactose, its reduction potential was used to oxidize o-phenylene diamine (OPD) into 2,3-diaminophenazine (DA), which were both detected using LDI-TOF MS with a TiO2 nanowire chip according to the concentration of galactose. The reproducibility and the interference of glucose were determined to demonstrate the applicability of this method. Moreover, mixtures of galactose, phenylalanine, and 17 α-OHP were analyzed to determine the interference induced by other biomarkers of metabolic disorders. The OPD oxidation of galactose was found to be selectively achieved under high-glucose conditions, similar to human blood, thereby showing good reproducibility. The intensities of the mass peaks of OPD and DA based on LDI-TOF MS with a TiO2 nanowire chip were linearly correlated in the galactose concentration range of 57.2–220.0 μg/mL (r2 = 0.999 and 0.950, respectively) for serum samples and 52.5–220.0 μg/mL (r2 = 0.993 and 0.985, respectively) for DBS after methanol precipitation/extraction. The enzyme immunoassay and LDI-TOF MS analysis results were statistically analyzed, and a mixture of phenylalanine, 17 α-OHP, and galactose was simultaneously investigated quantitatively at the cutoff level.

The lipid biology of sepsis

Sepsis, defined as the dysregulated immune response to an infection leading to organ dysfunction, is one of the leading causes of mortality around the globe. Despite the significant progress in delineating the underlying mechanisms of sepsis pathogenesis, there are currently no effective treatments or specific diagnostic biomarkers in the clinical setting. The perturbation of cell signaling mechanisms, inadequate inflammation resolution, and energy imbalance, all of which are altered during sepsis, are also known to lead to defective lipid metabolism. The use of lipids as biomarkers with high specificity and sensitivity may aid in early diagnosis and guide clinical decision making. In addition, identifying the link between specific lipid signatures and their role in sepsis pathology may lead to novel therapeutics. In this review, we discuss the recent evidence on dysregulated lipid metabolism both in experimental and human sepsis focused on bioactive lipids, fatty acids, and cholesterol as well as the enzymes regulating their levels during sepsis. We highlight not only their potential roles in sepsis pathogenesis but also the possibility of using these respective lipid compounds as diagnostic and prognostic biomarkers of sepsis.

MG@PD@TiO2 nanocomposite based magnetic solid phase extraction coupled with LC-MS/MS for determination of lysophosphatidylcholines biomarkers of plasma in psoriasis patients

Lysophosphatidylcholine (LPC) was commonly known as a class of significant differential metabolites of high relevance with many diseases including psoriasis, of which the accurate determination is of great importance to diagnosis or prediction to many diseases. However, it is challenging and complicated because of the enormous biological sample complexity and impurities interference. In this study, we synthesized a magnetic nanocomposite MG@PD@TiO₂ and took advantage of the interactions of Lewis acid-base between the phosphate groups in LPCs and Ti ions on MG@PD@TiO₂ nanomaterials for selective separation and enrichment of LPCs from complex biological matrix. The solid-phase extraction sample pretreatment process by means of MG@PD@TiO₂ nanomaterials coupled with LC-MS/MS method was then applied to actual determination of six typical LPCs (LPC 10:0, 14:0, 16:0, 18:0, 18:1, 22:0) in human plasma. The extraction conditions were scientifically optimized by single-factor test (adsorbent amount, adsorption and desorption time, elution solvent type, eluant volume). Under the optimal conditions, the detection limits (LOD, S/N = 3) and quantification limits (LOQ, S/N = 10) were 1 and 5 ng/mL for LPC 10:0 and LPC 14:0, 0.02 and 0.1 ng/mL for LPC 16:0 and LPC 18:1, 0.05 and 0.2 ng/mL LPC 18:0 and LPC 22:0, respectively. The intra- and inter-day precisions were 3.82-12.60 % (n = 6) and 3.29-13.50 % (n = 6) respectively, the recoveries were in the range of 91.92-113.69 % and the stability of the analytes in the matrix performed well with RSDs≤15.51 %. Finally, the developed method was successfully applied to the accurate determination of six LPCs biomarkers of plasma in patients with psoriasis (n = 10) and control groups (n = 10).

Diagnosis of severe sepsis using phospholipids enzymatic assay based on cyclic voltammetry

In this work phospholipid quantification was carried out using an enzymatic assay based on cyclic voltammetry of the condensation product of N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3,5-dimethoxyaniline sodium salt (DAOS) and 4-aminoantipyrine (4-AP) with a graphite electrode. For the optimization of electrochemical measurement for the product, electrochemical properties such as the electrochemical window, double layer capacitance (Cdl) and electron transfer rate (kapp) were analyzed for a graphite-electrode and Au-electrode. The phospholipid enzymatic assay based the on electrochemical measurement using the graphite electrode was applied to the diagnosis of sepsis for sera from healthy volunteers (n = 16), patients with systemic inflammatory response syndrome (SIRS, n = 16) and severe sepsis patients (n = 24). Finally, the phospholipid quantification results from the electrochemical measurement were statistically compared with the conventional method based on optical density measurement.

Diagnosis and mortality prediction of sepsis via lysophosphatidylcholine 16:0 measured by MALDI-TOF MS

Sepsis remains a critical problem with high mortality worldwide, but there is still a lack of reliable biomarkers. We aimed to evaluate the serum lysophosphatidylcholine (LPC) 16:0 as a biomarker of sepsis using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Patients admitted to intensive care unit at Severance Hospital from March 2017 through June 2018 were prospectively enrolled. The inclusion criteria were the fulfillment of at least two criteria of systemic inflammatory response syndrome (SIRS) or the presence of sepsis. Of the 127 patients, 14 had non-infectious SIRS, 41 had sepsis, and 72 had septic shock. The mean serum LPC 16:0 concentration (µmol/L) in non-infectious SIRS was significantly higher than in patients with sepsis and septic shock (101.1 vs. 48.92, p < 0.05; 101.1 vs. 25.88, p < 0.001, respectively). The area under the curve (AUC) predicting 28-day mortality using ΔLPC16:0 (D1-D0) levels was 0.7, which was comparable with the APACHE II score (AUC 0.692) and SOFA score (AUC 0.67). Mechanical ventilation, CRRT, lactate, Δ LPC16:0 (D1-D0) less than the cut-off value were significantly associated with 28-day mortality in multivariable analysis. Our results suggest that LPC16:0 could be a useful biomarker for sepsis diagnosis and mortality prediction in ICU patients.

Lipidomic profile and candidate biomarkers in septic patients

Sepsis is a severe disease with a high mortality rate. Identification and treatment in the initial hours of the disease improve outcomes. Some biomarkers like procalcitonin and C-reactive protein are used for diagnosis and to access sepsis prognosis and they can help in clinical decision-making, but none has sufficient specificity or sensitivity to be routinely employed in clinical practice. This review seeks to evaluate lipid metabolism alterations in patients with sepsis and the possibility of using the respective metabolites as biomarkers of the disease. A search of the main electronic biomedical databases was conducted for the 20-year period ending in February 2020, focused on primary research articles on biomarkers in sepsis. The keywords included sepsis, septic shock, biomarker, metabolomic, lipidomic and lysophosphatidylcoline.

. It concludes that altered lipid profiles, along with the progress of the disease should provide new insights, enabling a better understanding of the pathogenic mechanisms and making it possible to design new early diagnosis and therapeutic procedures for sepsis.

Simultaneous Analysis of Multiple Cancer Biomarkers Using MALDI-TOF Mass Spectrometry Based on a Parylene-Matrix Chip

Recently, the parylene-matrix chip was developed for quantitative analysis of small molecules less than 1 kDa. In this study, MALDI-TOF MS based on the parylene-matrix chip was performed to clinically diagnose intrahepatic cholangiocarcinoma (IHCC) and colorectal cancer (CRC). The parylene-matrix chip was applied for the detection of small cancer biomarkers, including N-methyl-2-pyridone-5-carboxamide (2PY), glutamine, lysophosphatidylcholine (LPC) 16:0, and LPC 18:0. The feasibility of MALDI-TOF MS based on the parylene-matrix chip was confirmed via analysis of spot-to-spot and shot-to-shot reproducibility. Serum metabolite markers of IHCC, N-methyl-2-pyridone-5-carboxamide (2PY), and glutamine were quantified using MALDI-TOF MS based on the parylene-matrix chip. For clinical diagnosis of CRC, two water-insoluble (barely soluble) biomarkers, lysophosphatidylcholine (LPC) 16:0 and LPC 18:0, were quantified. Finally, glutamine and LPC 16:0 were simultaneously detected at a range of concentrations in sera from colon cancer patients using the parylene-matrix chip. Thus, this method yielded high-throughput detection of cancer biomarkers for the mixture samples of water-soluble analytes (2PY and glutamine) and water-insoluble analytes (LPC 16:0 and LPC 18:0).

Rapid direct identification of positive paediatric blood cultures by MALDI-TOF MS technology and its clinical impact in the paediatric hospital setting

OBJECTIVE

Rapid diagnostic tools are imperative for timely clinical decision making, particularly in bacteraemic patients. This study evaluated the performance of a fast, inexpensive novel in house method for processing positive blood cultures for immediate identification of microorganisms by matrix-assisted laser desorption ionization-time of flight mass spectrometry (Vitek MS bioMérieux). We prospectively analyzed the clinical impact of such method on the management of pediatric patients.

RESULT

In total, 360 positive blood cultures were included. Among 318 mono-microbial cultures, in-house method achieved correct identification in 270 (85%) cultures to the species level, whilst 43 (13.5%) gave no identification, and 7 (2.2%) gave discordant identifications. Identification of Gram-negative organisms was accurate to both species and genus level in 99% of isolates, and for Gram positives accuracy was 84% to genus and 81% to species level overall, with accuracy of 100% for Staphylococcus aureus and Enterococcus to the species level. Assessment of the potential impact of direct identification in sixty sequential cases revealed a clear clinical benefit in 35.5% of cases. Benefits included timely antibiotic rationalization, change of medical intervention, and early confirmation of contamination. This study demonstrates a highly accurate in-house method with considerable potential clinical benefits for paediatric care.