Paper Spray Ionization Mass Spectrometry Coupled with Paper-Based Three-Dimensional Tumor Model for Rapid Metabolic Gradient Profiling.

The tumor microenvironment (TME), especially with its complicated metabolic characteristics, will dynamically affect the proliferation, migration, and drug response of tumor cells. Rapid metabolic analysis brings out a deeper understanding of the TME, while the susceptibility and environmental dependence of metabolites extremely hinder real-time metabolic profiling since the TME is easily disrupted. Here, we directly integrated paper spray ionization mass spectrometry with a paper-based three-dimensional (3D) tumor model, realizing the rapid capture of metabolic gradients.

Metabolite profiling and identification in living cells by coupling stable isotope tracing and induced electrospray mass spectrometry.

Direct observation of metabolites in living cells by mass spectrometry offers a bright future for biological studies but also suffers a severe challenge to untargeted peak assignment to tentative metabolite candidates. In this study, we developed a method combining stable isotope tracing and induced electrospray mass spectrometry for living-cells metabolite measurement and identification. By using C-glucose and ammonium chloride-N as the sole carbon and nitrogen sources for cell culture, Escherichia coli synthesized metabolites with N and C elements.

Lipskynoids A-G, New Acyclic Diterpenes from the Flowers of Carpesium lipskyi.

Seven new acyclic diterpenes, namely lipskynoids A-G (1-7), were isolated from the flowers of Carpesium lipskyi, a traditional Tibetan herbal medicine with anti-inflammatory and antipyretic-analgesic effects. These new compounds were elucidated by analysis of extensive spectroscopic data including ESI-MS, 1D, 2D NMR, and DP4+ analyses. Biological assays showed that 1-7 display significant inhibitory effects against the NO production in LPS-induced RAW264.

Native Mass Spectrometry for Peptide-Metal Interaction in Picoliter Cell Lysate.

Native mass spectrometry, which takes a high concentration of ammonium acetate (NHOAc) for ionization, coupled with tedious and solvent-consuming purification, which separates proteins from complicated environments, has shown great potential for proteins and their complexes. A high level of nonvolatile salts in the endogenous intracellular environment results in serious ion suppression and has been one of the bottlenecks for native mass spectrometry, especially for protein complexes. Herein, an integrated protocol utilizing the inner surface of a micropipette for rapid purification, desorption, and ionization of peptide-metal interaction at subfemtomole level in cell lysate was demonstrated for native mass spectrometry.

Rapid Profiling of Metabolic Perturbations to Antibiotics in Living Bacteria by Induced Electrospray Ionization Mass Spectrometry.

Rapid monitoring of real bacterial metabolic perturbations to antibiotics may be helpful to better understand the mechanisms of action and more targeted treatment. In this study, the real metabolic responses to antibiotic treatment in living bacteria were profiled rapidly by induced electrospray ionization mass spectrometry. Significant metabolic perturbations were profiled after antibiotic treatment compared with untreated bacteria.

Agarose hydrogel-enhanced paper spray ionization mass spectrometry for metabolite detection in raw urine.

Rapid analysis of metabolites in biofluids is of great importance for disease diagnosis or new-born disease screening. Herein, we introduce an agarose hydrogel conditioning method to enhance the performance of paper spray ionization mass spectrometry. With facile and fast hydrogel conditioning, the signal intensity of therapeutic drugs spiked in urine was 5 to 15 fold higher than that in direct paper spray ionization mass spectrometry analysis.