Interfacial Interactions between Neural Tracing Lectin–Gold Nanoparticle Conjugate and Cell Membrane Glycoproteins

The use of neural
tracers as targeting molecules for drug delivery
has been previously established as a novel and efficient method of
neural drug delivery. The wheat germ agglutinin–horseradish
peroxidase conjugate (WGAHRP) is a common neural tracer, which has
been used extensively to decipher neural pathways in vertebrates.
It has been widely reported to bind to cell surfaces and be transported
in a retrograde fashion (from synapses toward the cell body) via dynein
motors along microtubules within axons and transynaptically between
neurons. Here we report on the differential binding between WGAHRP
and gold-conjugated WGAHRP (AuNP-WGAHRP) to the glycoprotein profiles
extracted from two neuronal cell lines and one skeletal muscle cell
line, as well as the binding kinetics to heparin. From proteomic analysis
of the extracted glycoproteins, we suggest the identity of cell surface
glycoproteins involved in the retrograde transport of WGAHRP. This
study illuminates the interfacial and molecular interactions of protein–gold
conjugates with native ligands and opens the door for the identification
of new targets for neural tracing and nervous system-related drug
delivery.