Authors: A. Shah, V. Sachdev, A. Bharti
Affilation: Boston University Medical School, United States
Pages: 266 - 269
Keywords: cancer, serum, phosphopeptide, nanoparticles, enrichment, biomarker
The role of kinases in transformation and cancer progression is established. We hypothesize that The role the specific phosphoproteins/phosphopeptides will be present in cancer patient serum as leak proteins and their isolation and identification will bear diagnostic/prognostic value. MS based methods are efficient for identification and characterization of phosphopeptides. However, low abundance serum phosphoprotein isolation and characterization still remains a challenge. The existing technology (micro-columns) to isolate and enrich phosphopeptide from biological samples lacks the specificity, efficiency and flexibility necessary to analyze larger sample volumes. To overcome these problems we have used nanoparticles to enrich phosphopeptide from serum and then analyze by mass spectrometry (MS). Nanoparticles provide a very large surface area (at least 1000 fold), is specific (amenable to functionalization) and can analyze larger serum samples (up to 10 ml). We have developed and characterized Fe3O4-SiO2-TiO2 core shell nanoparticles to specifically enrich phosphopeptides. Silica was first coated on 12 nm Fe3O4 magnetic core and subsequently TiO2 was cross linked. The size of the Fe3O4-SiO2-TiO2 particles was determined to be 18nm and was uniform. Preliminary data indicates that particles bind specifically to phosphopeptides and these phosphopeptides bound to nanoparticles can also be analyzed directly by MALDI-MS. The ongoing work will determine the efficiency of phosphopeptide enrichment from serum.