Introducing specificity and sensitivity in imaging mass spectrometry

点击翻译按钮获取中文摘要

In this research proposal, we will leverage our expertise in Imaging Mass Spectrometry (IMS) to address important unmet needs in the field of biological imaging. Accordingly, this proposal will focus on the development of analytical methods to improve the specificity and sensitivity of IMS for the analysis of several classes of clinically relevant endogenous molecules. Sensitive and targeted methods must be developed to facilitate the identification of molecular targets that can be used in the diagnosis or prognosis of disease or as indicators of therapeutic response. Such targeted approaches can also be developed in the field of forensic science. Three main axes of research will be explored: 1) The development of chemically tailored surfaces to specifically enhance the detection of lipids and metabolites from thin tissue sections while maintaining their spatial integrity. The emergence of Surface-Assisted LDI IMS (SALDI IMS), fostered by the rapid development of nanomaterials, has created new prospects for the imaging of low molecular weight compounds. We propose to develop several gold and silicon-based SALDI surfaces precisely textured and treated with various chemistries to enhance desorption/ionization and analyte specificity. Further, a better control of surface hydrophobicity will greatly minimize analyte delocalization. 2) The development of in situ derivatization chemistries for the analysis of peptides, lipids and metabolites by desorption electrospray ionization (DESI) IMS from tissue sections is proposed. Peptides (and proteins) are more challenging biomolecules to analyze by DESI IMS from tissue sections. Peptide N or C-terminal derivatization novel chemistries using hydrophilic reactive groups containing a fix charge enhances peptide solubility and eliminates electrospray ionization ion suppression effects. Such reactive tags can be applied on tissue before or during (reactive DESI) the IMS process. 3) Innovative approaches will be developed to specifically detect and map genetic material contained within latent fingerprints with the goal of identifying the suspect gender. This aspect is of prime interest to the forensic community. To target gender specific genes, complementary DNA probes coupled to a charged reporter ion via a photocleavable group will be developed. After on-target spray deposition and probe incubation, the precise location of the photocleavable reporter ion within the latent fingerprint can then be mapped by LDI IMS. Through his research program, continued efforts in IMS method development will allow a deeper and unique analysis of molecules from forensic and biological samples complementary to those already developed and available in our laboratory. Overall, these new methods will be useful for a wide range and biological applications including human diseases and disorders as well as understanding normal development and functioning of cells, organs and whole organisms.