WHEN: Monday, February 5, 2018
WHERE: Duquesne University
RSVP BY: Wednesday, January 31, 2018
5:00 PM Social Hour: Power Center Ballroom
6:30 PM Dinner: Power Center Ballroom
Business Meeting: Power Center Ballroom
Technical Meeting: Power Center Ballroom
Student Affiliate Meeting: Shepperson Suite
Janusz Pawliszyn, University Professor and Canada Research Chair, University of of Waterloo
“In-vivo Application of SPME”
There is a growing interest in monitoring levels of biologically active compounds in living systems in their natural environments. These efforts are a significant departure from conventional ‘sampling’ techniques, where a portion of the system under study is removed from its natural environment, and the compounds of interest extracted and analyzed in a laboratory environment. There are two main motivations for exploring these types of investigations. The first one is the desire to study chemical processes in association with the normal biochemical milieu of a living system, and the second one is the lack of availability or impracticality of removing suitable samples from a living system, frequently because of size.
In the presentation, I will describe the use of solid-phase microextraction (SPME) for in vivo sampling of endogenous compounds, drugs and metabolites in the tissue of freely moving animals as well as humans, which eliminates the need for tissue withdrawal in order to obtain quantitative analytical information. In comparison to the established in-vivo technique of microdialysis, such chemical biopsy probe provides the advantages of reduced matrix effect improved spatial resolution, improved extraction of hydrophobic species and large molecular species and better compatibility with LC-MS because of elimination of salts and associated ionization suppression effects associated with large amounts of phospholipids extracted. In contrast, in-vivo microdialysis provides better temporal resolution and capability of semi-continuous monitoring in almost real-time.
The chemical biopsy in-vivo SPME method was evaluated in collaboration with medical staff at Center for Addiction and Mental Health, Toronto General and Toronto Western Hospitals. Up-to-date the technique was demonstrated useful during lung and liver transplantation, brain function monitoring during deep brain stimulation and drug administration, in vivo lung perfusion for local chemotherapy, and more recently, brain tumor metabolomic study. The study demonstrates feasibility of the method to extract wide range of metabolites, what allowed differentiating studied individuals and determining potential biomarkers of organ function. Also, the technique proved to be capable to monitor level and distribution of drugs over the time of surgery. The coated microfibre can be directly coupled to analytical instrumentation, such as mass spectrometer, permitting to obtain close to real-time results thus allowing for immediate action at the operation table. In the similar way to biopsy needle, chemical biopsy SPME device can be also placed in the organ through the skin by using guide cannula or via endoscope. Introduction of one of the available calibration approaches and reduced level of matrix effect characteristic to SPME makes the method fully quantitative.