digilib@itb.ac.id +62 812 2508 8800

Protein glycosylation is one of the most complicated but significant post-translational modifications. Minor alterations in glycan structure can considerably affect thebiology of a cell. Therefore, direct monitoring of glycan patterns of glycoproteins is closelyrelated to cancer progression as well as metastasis. In this study, a boronic acid (BA)-tosyl-directed strategy to selectively immobilize glycoproteins on glass slides was successfullydeveloped even in the presence of high-abundant nonglycosylated proteins. To enhance theimmobilization efficiency and reduce the undesired nonspecific absorption, the strain-promoted alkyne azide cycloaddition (SPAAC) conjugation chemistry and surface blockingconditions were carefully optimized for the collection of reliable data. The optimizedglycoprotein microarray platform describes specific lectin-recognition patterns ofglycoproteins of interest inE. coillysate and fetal bovine serum (FBS), which encouragesus for direct monitoring of glycan patterns from human sera without tedious samplepreparation. Three serum groups comprised of healthy controls and lung cancer andpancreatic cancer patients were analyzed by this new technique. Remarkably, thedistinguishable glycan patterns of the three groups make them a powerful platform for cancer screening and prediagnosis.