pH-responsive Adsorption and Dissociation of Sialic Acid Expressed Protein on Boronic Acid Immobilized Surface

Detection and isolation of sialic acid (SA) over-expressed biomolecules is of continuous interest in cancer-related research. Boronic acid-based SA-recognition chemistry provides a synthetic molecular basis for such techniques. 5-Boronopicolinic acid, a derivative with the reportedly highest SA-binding strength, was immobilized to a gold surface and studied for its interaction with fetuin, a blood-circulating glycoprotein implicated in cancers. A submicron-molar level sensitivity was achievable, while the sample could be readily dissociated by modulating the pH. Boronic acid-based sialic acid recognition chemistry provides a molecular basis for detection of sialic acid (SA) over-expressed biomolecules. 5-boronopicolinic acid, a derivative with the reportedly highest SA-binding strength, was immobilized to a gold surface and studied for its interaction with fetuin. A submicron-molar level sensitivity was achievable along with the capability of sample recovery simply by modulating the pH.