MALDI-TOF MS monitoring of PBMC activation status in sepsis

Discrimination of the chemotherapy resistance status of human leukemia and glioblastoma cell lines by MALDI-TOF-MS profiling

Chemotherapy mistreatment is partially due to a lack of rapid and reliable tools to discriminate between sensitive and resistant phenotypes. In many cases, the resistance mechanism is not fully understood, contributing to the diagnostic tools' absence. This work aims to determine the capacity of MALDI-TOF-MS profiling to discriminate between chemotherapy-resistant and sensitive phenotypes in leukemia and glioblastoma cells. A multivariate analysis of two therapy-resistant leukemia cell lines (Ki562 and Kv562) and two TMZ-resistant glioblastoma cell lines (U251-R and LN229-R) and their sensitive counterparts was performed. In this work, we first show MALDI-TOF-MS patterns analysis ability to differentiate these cancer cell lines by their chemotherapy-resistant status. We present a rapid and inexpensive tool that would guide and complement the therapeutic decision.

Non-covalent π-π functionalized Gii-senseⓇ graphene foam for interleukin 10 impedimetric detection

Monitoring Interleukin 10 (IL-10) is essential for understanding the vast responses of T-cells in cancer, autoimmunity, and internal homeostasis after physical stress. However, current diagnostic methods are complex and more focused on medical screening rather than point-of-care monitoring. Biosensors based on graphene's conductivity and flexibility are attractive to offer simple single-use and reduced handling. However, oxidation of its carbon lattice to develop functional moieties for biomolecule immobilization cuts down its electronic conductivity potential. In this work, the authors present a microfluidic lab-on-chip device for simple impedimetric monitoring of IL-10 based on graphene foam (GF) flexible electrodes. Graphene's structure was maintained by employing π-π non-covalent functionalization with pyrene carboxylic acid (PCA). Impedimetric measurements could be performed in low ionic strength phosphate-buffered saline (LI-PBS). The PCA-antibody modification showed to endure the incubation, measurement, and washing processes performed in the microfluidic device. Electrode modification and measurements were characterized by, electrochemical impedance spectroscopy (EIS), contact angle, and scanning electron microscopy. From the contact angle results, we found that the wettability of the graphene surface increased gradually after each modification step. Detection measurements performed in the 3D-printed microfluidic device showed a linear response between 10 fg/mL to 100 fg/mL with a limit of detection (LOD) of 7.89 fg/mL in artificial saliva. With these features, the device was used to quantify IL-10 samples by the standard addition method for 10 fg and 50 fg with recoveries between 82% and 99%. Specificity was evaluated towards interleukin 6, TNF-⍺ and bovine serum albumin.

Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry in veterinary medicine: Recent advances (2019-present)

Matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) has become a valuable laboratory tool for rapid diagnostics, research, and exploration in veterinary medicine. While instrument acquisition costs are high for the technology, cost per sample is very low, the method requires minimal sample preparation, and analysis is easily conducted by end-users requiring minimal training. Matrix-assisted laser desorption ionization-time-of-flight MS has found widespread application for the rapid identification of microorganisms, diagnosis of dermatophytes and parasites, protein/lipid profiling, molecular diagnostics, and the technique demonstrates significant promise for 2D chemical mapping of tissue sections collected postmortem. In this review, an overview of the MALDI-TOF technique will be reported and manuscripts outlining current uses of the technology for veterinary science since 2019 will be summarized. The article concludes by discussing gaps in knowledge and areas of future growth.

Low-Density Granulocyte Contamination From Peripheral Blood Mononuclear Cells of Patients With Sepsis and How to Remove It - A Technical Report

Elucidating the mechanisms contributing to the dysregulated host response to infection as part of the syndrome is a current challenge in sepsis research. Peripheral blood mononuclear cells are widely used in immunological studies. Density gradient centrifugation, a common method, is of limited use for blood drawn from patients with sepsis. A significant number of low-density granulocytes co-purify contributing to low purity of isolated peripheral blood mononuclear cells. Whole blood anticoagulated with lithium heparin was drawn from patients with sepsis (n=14) and healthy volunteers (n=11). Immediately after drawing, the plasma fraction was removed and PBMC were isolated from the cellular fraction by density gradient centrifugation. Samples derived from patients with sepsis were subsequently incubated with cluster of differentiation 15 MicroBeads and granulocytes were depleted using magnetic-activated cell sorting. Core cellular functions as antigen presentation and cytokine secretion were analyzed in cells isolated from healthy volunteers (n=3) before and after depletion to confirm consistent functionality. We report here that depleting CD15⁺ cells after density gradient centrifugation is a feasible way to get rid of the low-density granulocyte contamination. Afterwards, the purity of isolated, functionally intact peripheral blood mononuclear cells is comparable to healthy volunteers. Information on the isolation purity and identification of the containing cell types are necessary for good comparability between different studies. Depletion of CD15⁺ cells after density gradient centrifugation is an easy but highly efficient way to gain a higher quality and more reliability in studies using peripheral blood mononuclear cells from septic patients without affecting the functionality of the cells.

Mass Spectrometry for COVID-19

In the United States, response to the COVID-19 coronavirus pandemic has been hampered by inadequate testing resources for the causative virus SARS-CoV-2. In the early part of the pandemic, United States laboratories were initially heavily regulated and slow to provide testing. As the pandemic has progressed, the supply chain for instruments and reagents has been inconsistent and has revealed weaknesses in traditional sophisticated infectious disease testing. Testing capabilities of clinical laboratories could be substantially improved by assays that are more simplified and do not require multiple consumable reagents for extraction, purification, amplification and detection. One such technology with the potential to require minimal reagents is matrix-assisted laser desorption/ionization combined with mass spectrometry (MALDI-MS). Recently, Nachtigall and colleagues reported the development of a MALDI-MS method for the diagnosis of SARS-CoV-2 infection (1).