Ambient DESI and LESA-MS analysis of proteins adsorbed to a biomaterial surface using in-situ surface tryptic digestion.
The detection and identification of proteins adsorbed onto biomaterial surfaces under ambient conditions has significant experimental advantages but has proven to be difficult to achieve with conventional measuring technologies. In this study, we present an adaptation of desorption electrospray ionization (DESI) and liquid extraction surface analysis (LESA) mass spectrometry (MS) coupled with in-situ surface tryptic digestion to identify protein species from a biomaterial surface. Cytochrome c, myoglobin, and BSA in a combination of single and mixture spots were printed in an array format onto Permanox slides, followed by in-situ surface digestion and detection via MS. Automated tandem MS performed on surface peptides was able to identify the proteins via MASCOT. Limits of detection were determined for DESI-MS and a comparison of DESI and LESA-MS peptide spectra characteristics and sensitivity was made. DESI-MS images of the arrays were produced and analyzed with imaging multivariate analysis to automatically separate peptide peaks for each of the proteins within a mixture into distinct components. This is the first time that DESI and LESA-MS have been used for the in-situ detection of surface digested proteins on biomaterial surfaces and presents a promising proof of concept for the use of ambient MS in the rapid and automated analysis of surface proteins.
Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, NG7 2RD, UK.
Wei
W
Rao
Adam D
AD
Celiz
David J
DJ
Scurr
Morgan R
MR
Alexander
David A
DA
Barrett
D000327:Adsorption; D000818:Animals; D002417:Cattle; D045304:Cytochromes c / Q000032:analysis* / Q000378:metabolism; D004867:Equipment Design; D057230:Limit of Detection; D009211:Myoglobin / Q000032:analysis* / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000032:analysis* / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation*; D014357:Trypsin / Q000378:metabolism
D009211:Myoglobin; D012710:Serum Albumin, Bovine; D045304:Cytochromes c; D014357:Trypsin