August 1, 2016.
Fibronectin is an important biomolecule due to its role in cell differentiation, growth, kinesis, and adhesion. Such biological responses are mediated through membrane recognition and signaling; where fibronectin is found. Studying the outer molecular surface of fibronectin allows deeper insight into the microbiological reactions that occur during these processes. In situ mass spectrometry analysis in aqueous solution accurately represents fibronectin’s chemical components, made possible by a vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface). SALVI was paired with the analytical tools: time-of-flight secondary ion mass spectrometer (ToF-SIMS), single photon ionization mass spectrometer (SPI-MS) and drop desorption electrospray ionization mass spectrometer (dropDESI-MS). ToF-SIMS employed a bismuth liquid metal ion beam. Positive and negative ion spectral plots were constructed and analyzed. The advanced light source (ALS) SPI-MS), using a synchrotron vacuum ultraviolet (VUV) light, elicited data depending on varying photoionization efficiencies (PIE). PIE plots were examined for the initial detection of photons of a mass to charge ratio (m/z), resulting in the determination of the ionization efficiency (IE) of a corresponding compound. Both ToF-SIMS and SPI-MS are surface tools, with ion beam impact no further than the second monolayer. DropDESI-MS, analyzed under ambient conditions, utilized a capillary connecting the electrode spray to the mass spectrometer. Charged microdroplets were used to introduce samples to the mass analyzer. Central masses (m/z) from all three apparatuses were identified to their most possible compounds or constituents, demonstrating complementary results. Mass identifications were based on literature survey and results from peer reviewed articles. Our results suggest the need for further research of organic compounds, like fibronectin, to understand their surface compositions in aqueous solution.
Analytical Chemistry | Biochemistry | Biophysics | Molecular Biology | Physical Chemistry
Pacific Northwest National Laboratory (PNNL)
This material is based upon work supported by the National Science Foundation through the Robert Noyce Teacher Scholarship Program under grant#1300012. Any opinions, finding, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. The research was made possible by the California State University STEM Teacher Researcher Program in partnership with Pacific Northwest National Laboratory and National Science Foundation.