Chemical Imaging of Pharmaceuticals in Biofilms for Wastewater Treatment Using Secondary Ion Mass Spectrometry.

The occurrence of pharmaceuticals in the aquatic environment is a global water quality challenge for several reasons, such as deleterious effects on ecological and human health, antibiotic resistance development, and endocrine-disrupting effects on aquatic organisms. To optimize their removal from the water cycle, understanding the processes during biological wastewater treatment is crucial. Time-of-flight secondary ion mass spectrometry imaging was successfully applied to investigate and analyze the distribution of pharmaceuticals as well as endogenous molecules in the complex biological matrix of biofilms for wastewater treatment.

Striatal Dopamine Transporter Function Is Facilitated by Converging Biology of α-Synuclein and Cholesterol.

Striatal dopamine transporters (DAT) powerfully regulate dopamine signaling, and can contribute risk to degeneration in Parkinson's disease (PD). DATs can interact with the neuronal protein α-synuclein, which is associated with the etiology and molecular pathology of idiopathic and familial PD. Here, we tested whether DAT function in governing dopamine (DA) uptake and release is modified in a human-α-synuclein-overexpressing (-OVX) transgenic mouse model of early PD.

Mass Spectrometry Imaging Suggests That Cisplatin Affects Exocytotic Release by Alteration of Cell Membrane Lipids.

We used time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging to investigate the effect of cisplatin, the first member of the platinum-based anticancer drugs, on the membrane lipid composition of model cells to see if lipid changes might be involved in the changes in exocytosis observed. Platinum-based anticancer drugs have been reported to affect neurotransmitter release resulting in what is called the "chemobrain"; however, the mechanism for the influence is not yet understood. TOF-SIMS imaging was carried out using a high energy 40 keV (CO) gas cluster ion beam with improved sensitivity for intact lipids in biological samples.

Single cell amperometry reveals curcuminoids modulate the release of neurotransmitters during exocytosis from PC12 cells.

We used single cell amperometry to examine whether curcumin and bisdemethoxycurcumin (BDMC), substances that are suggested to affect learning and memory, can modulate monoamine release from PC12 cells. Our results indicate both curcumin and BDMC need long-term treatment (72 h in this study) to influence exocytosis effectively. By analyzing the parameters calculated from single exocytosis events, it can be concluded that curcumin and BDMC affect exocytosis through different mechanisms.

Intact lipid imaging of mouse brain samples: MALDI, nanoparticle-laser desorption ionization, and 40 keV argon cluster secondary ion mass spectrometry.

We have investigated the capability of nanoparticle-assisted laser desorption ionization mass spectrometry (NP-LDI MS), matrix-assisted laser desorption ionization (MALDI) MS, and gas cluster ion beam secondary ion mass spectrometry (GCIB SIMS) to provide maximum information available in lipid analysis and imaging of mouse brain tissue. The use of Au nanoparticles deposited as a matrix for NP-LDI MS is compared to MALDI and SIMS analysis of mouse brain tissue and allows selective detection and imaging of groups of lipid molecular ion species localizing in the white matter differently from those observed using conventional MALDI with improved imaging potential. We demonstrate that high-energy (40 keV) GCIB SIMS can act as a semi-soft ionization method to extend the useful mass range of SIMS imaging to analyze and image intact lipids in biological samples, closing the gap between conventional SIMS and MALDI techniques.

Optimizing sample preparation for anatomical determination in the hippocampus of rodent brain by ToF-SIMS analysis.

Lipidomics has been an expanding field since researchers began to recognize the signaling functions of lipids and their involvement in disease. Time-of-flight secondary ion mass spectrometry is a valuable tool for studying the distribution of a wide range of lipids in multiple brain regions, but in order to make valuable scientific contributions, one has to be aware of the influence that sample treatment can have on the results. In this article, the authors discuss different sample treatment protocols for rodent brain sections focusing on signal from the hippocampus and surrounding areas.

Laser Desorption Ionization Mass Spectrometry Imaging of Drosophila Brain Using Matrix Sublimation versus Modification with Nanoparticles.

Laser desorption ionization mass spectrometry (LDI-MS) is used to image brain lipids in the fruit fly, Drosophila, a common invertebrate model organism in biological and neurological studies. Three different sample preparation methods, including sublimation with two common organic matrixes for matrix-assisted laser desorption ionization (MALDI) and surface-assisted laser desorption ionization (SALDI) using gold nanoparticles, are examined for sample profiling and imaging the fly brain. Recrystallization with trifluoroacetic acid following matrix deposition in MALDI is shown to increase the incorporation of biomolecules with one matrix, resulting in more efficient ionization, but not for the other matrix.

Development of an organic lateral resolution test device for imaging mass spectrometry.

An organic lateral resolution test device has been developed to measure the performance of imaging mass spectrometry (IMS) systems. The device contains periodic gratings of polyethylene glycol (PEG) and lipid bars covering a wide range of spatial frequencies. Microfabrication technologies were employed to produce well-defined chemical interfaces, which allow lateral resolution to be assessed using the edge-spread function (ESF).

Controlling and monitoring orientation of DNA nanoconstructs on lipid surfaces.

Its extraordinary self-assembly property, with potential to form nonperiodic structures with unique addressability, makes DNA ideal for fabrication of advanced nanostructures. We here demonstrate the controllable tethering of a hexagonal DNA nanostructure in two distinct orientations at the lipid bilayer of a liposome functioning as a soft-matter support. With polarized light (linear dichroism) applied to the flow-aligned liposomes, we show that the construct is preferentially in a parallel alignment with the lipid surface when two anchors are attached while with one anchor only a perpendicular orientation is observed.