A Stable Dicationic Salt in Reactive DESI-MS Imaging in Positive Ion Mode to Analyze Biological Samples

A dicationic salt was applied for imaging in reactive desorption electrospray ionization mass spectrometry (DESI-MS) on biological samples. The samples interrogated in this experiment were whole body zebrafish tissues and rat brain tissue. The stable dictation salt forms a stable bond with biological tissue fatty acids and lipids and allows detection in positive ion mode. Reactive DESI-MS imaging in positive ion mode of rat brain and zebrafish tissues allowed enhanced detection of certain compounds commonly observed in negative ion mode. Variance in intensity between negative and positive mode indicate that the ionization process could be affected by matrix effects of various tissues, leading to different overall intensity which could provide new information on the same compounds when compared between negative ion mode images and reactive DESI positive ion mode images

Tunnel Magnetoresistance-Based Sensor for Biomedical Application: Proof-of-Concept

The aim of this work was to investigate and prove the possibility of the real-time detection of magnetic nanoparticles (MNPs) distributed in solid material by using a tunnel magnetoresistance-based (TMR) sensor. Following the detection tests of FeCrNbB magnetic nanoparticles distributed in transparent epoxy resin (EPON 812) and measuring the sensor output voltage changes at different particle concentrations, the detection ability of the sensor was demonstrated. For the proposed TMR sensor, we measured a maximum magnetoresistance ratio of about 53% and a sensitivity of 1.24%/Oe. This type of sensor could facilitate a new path of research in the field of magnetic hyperthermia by locating cancer cells

Reactive DESI-MS imaging of biological tissues with dicationic ion-pairing compounds

This work illustrates reactive desorption electrospray ionization mass spectrometry (DESI-MS) with a stable dication on biological tissues. Rat brain and zebra fish tissues were investigated with reactive DESI-MS in which the dictation forms a stable bond with biological tissue fatty acids and lipids. Tandem mass spectrometry (MS/MS) was used to characterize the dication (DC9) and to identify linked lipid-dication compounds formed. The fragment m/z 85 common to both DC9 fragmentation and DC9-lipid fragmentation was used to confirm that DC9 is indeed bonded with the lipids. Lipid signals in the range of m/z 250–350 and phosphoethanolamines (PE) m/z 700–800 observed in negative ion mode were also detected in positive ion mode with reactive DESI-MS with enhanced signal intensity. Reactive DESI-MS imaging in positive ion mode of rat brain and zebra fish tissues allowed enhanced detection of compounds commonly observed in the negative ion mode