Journal of Glycobiology
Open Access
ISSN: 2168-958X
+44 1478 350008
ISSN: 2168-958X
+44 1478 350008
Daniel Salem and Michael S Strano
Massachusetts Institute of Technology, USA
Scientific Tracks Abstracts: J Glycobiol
It is widely recognized that an array of addressable sensors can be multiplexed for the label-free detection of a library of analytes. However, such arrays have useful properties that emerge from the ensemble. As examples, we show that an array of near-infrared fluorescent single-walled carbon nanotube (SWNTs) sensors can estimate the mean and variance of the observed dissociation constant (KD), using three different examples of binding IgG with Protein A as the recognition site, including polyclonal human IgG, murine IgG and human IgG from CHO cells. In addition, we show that the observed dissociation constant is concentrationdependent, indicating multivalent interactions between the two binding partners. A bivalent binding mechanism is able to describe the concentration dependence of the effective dissociation constant, KD,eff, which varies from 100 pM to 1 �¼M for human IgG concentrations from 1 ng mL-1 to 100 �¼ g mL-1, respectively. We also demonstrate that an array of nanosensors can uniquely monitor weakly affined analyte interactions by monitoring the metabolically induced hypermannosylation of human IgG from CHO using PSA-lectin conjugated sensor arrays. In addition to our glycan profiling work using lectin-functionalized nanosensors, we have designed synthetic molecular recognition sites for carbohydrates using Corona Phase Molecular Recognition; a detection technology invented by our lab. Herein we synthesized 14 variants of well-defined water-soluble boronic acid copolymers through RAFT polymerization and created 14 distinct corona phases by adsorbing them onto the nanotube surface. We screened them against a panel of saccharides and sugar alcohols, revealing a corona phase that recognizes specific saccharides with high selectivity. In response to D-Arabinose binding, SWNT fluorescence decreases by >60% at saturation, while showing less than 20% response to all other aldopentoses including L-Arabinose. Binding selectivity was tuned by varying the location of boronic acid from para to meta and was also observed through cryogenic-TEM.
Daniel Salem has received his BS in Chemical Engineering from the University at Buffalo and a Master's degree in Chemical Engineering Practice from the Massachusetts Institute of Technology, USA. He is currently a National Science Foundation Graduate Research Fellow under the guidance of Professor Michael Strano in the Department of Chemical Engineering at MIT. His research involves the design of carbon nanotube-based optical sensors for biopharmaceutical characterization, diagnostics and food and water-borne contaminant detection.
Email: dpsalem@mit.edu