Title

Identification Of Molecular-Mimicry-Based Ligands For Cholera Diagnostics Using Magnetic Relaxation

Abstract

When covalently bound to an appropriate ligand, iron oxide nanoparticles can bind to a specific target of interest. This interaction can be detected through changes in the solution's spin-spin relaxation times (T2) via magnetic relaxation measurements. In this report, a strategy of molecular mimicry was used in order to identify targeting ligands that bind to the cholera toxin B subunit (CTB). The cellular CTB-receptor, ganglioside GM1, contains a pentasaccharide moiety consisting in part of galactose and glucose units. We therefore predicted that CTB would recognize carbohydrate-conjugated iron oxide nanoparticles as GM1 mimics, thus producing a detectable change in the T2 relaxation times. Magnetic relaxation experiments demonstrated that CTB interacted with the galactose-conjugated nanoparticles. This interaction was confirmed via surface plasmon resonance studies using either the free or nanoparticle-conjugated galactose molecule. The galactose-conjugated nanoparticles were then used as CTB sensors achieving a detection limit of 40 pM. Via magnetic relaxation studies, we found that CTB also interacted with dextran-coated nanoparticles, and surface plasmon resonance studies also confirmed this interaction. Additional experiments demonstrated that the dextran-coated nanoparticle can also be used as CTB sensors and that dextran can prevent the internalization of CTB into GM1-expressing cells. Our work indicates that magnetic nanoparticle conjugates and magnetic relaxation detection can be used as a simple and fast method to identify targeting ligands via molecular mimicry. Furthermore, our results show that the dextran-coated nanoparticles represent a low-cost approach for CTB detection. © 2011 American Chemical Society.

Publication Date

2-16-2011

Publication Title

Bioconjugate Chemistry

Volume

22

Issue

2

Number of Pages

307-314

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1021/bc100442q

Socpus ID

79951686103 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/79951686103

This document is currently not available here.

Share

COinS