Detection of Sugar-Lectin Interactions by Multivalent Dendritic Sugar Functionalized Single-Walled Carbon Nanotubes

TL;DR

This study demonstrates that sugar-functionalized single-walled carbon nanotubes can be used as a sensitive platform to detect and quantify lectin interactions through electrical conductance changes, highlighting high specificity and affinity.

Contribution

It introduces a novel nanotube-based sensor platform utilizing dendritic sugar functionalization for specific detection of carbohydrate-lectin interactions.

Findings

Conductance changes follow Langmuir isotherm.

Affinity constant for Con A-mannose is 8.5 x 10^6 M^-1.

High specificity demonstrated by conductance and Raman shifts.

Abstract

We show that single walled carbon nanotubes (SWNT) decorated with sugar functionalized poly (propyl ether imine) (PETIM) dendrimer is a very sensitive platform to quantitatively detect carbohydrate recognizing proteins, namely, lectins. The changes in electrical conductivity of SWNT in field effect transistor device due to carbohydrate - protein interactions form the basis of present study. The mannose sugar attached PETIM dendrimers undergo charge - transfer interactions with the SWNT. The changes in the conductance of the dendritic sugar functionalized SWNT after addition of lectins in varying concentrations were found to follow the Langmuir type isotherm, giving the concanavalin A (Con A) - mannose affinity constant to be 8.5 x 106 M-1. The increase in the device conductance observed after adding 10 nM of Con A is same as after adding 20 \muM of a non - specific lectin peanut agglutinin, showing the high specificity of the Con A - mannose interactions. The specificity of sugar-lectin interactions was characterized further by observing significant shifts in Raman modes of the SWNT.