Lectins are proteins that specifically bind various carbohydrates. Currently, we are attempting to use nanoporous gold (np-Au) modified with thiolated a-D-mannopyranoside or thiolated �-D-galactopyranoside to separate a mixture of the two lectins mannose-binding concanvalin A (ConA) and galactose-binding peanut agglutinin (PNA) by selective capture, followed by exposure to free ligand to elute the target lectin. In a preliminary investigation, comparison of significant mass losses reported by TGA analysis evaluated the formation of self-assembled monolayers (SAM) and subsequent immobilization of lectin on np-Au. Mass loss data were normalized to surface area of the np-Au surface as estimated from BET gas adsorption data. Loading onto np-Au was represented by the increase in mass loss, thus, mass loss was expectedly to decrease after the elution of lectins. Capture of protein was also confirmed by the decrease in protein concentration after flowing the solution across the modified np-Au surface using the BCA assay. Detection of proteins targeted for elution was also confirmed by analyzing the proteins in the solution of free ligand after the elution flow. Recognition of the target protein being eluted from the mixture was verified using SDS-PAGE on Polyacrylamide gel (12%), which showed distinct band profiles for each lectin, which enabled us to verify the presence of target lectin in the eluted sample. The current investigation aims to confirm the potential for utilizing np-Au in the separation and purification of lectins and of glycoproteins.

Selective capture and selective elution of lectins using nanoporous gold substrates

246th National Meeting (2013)

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