Dh. Charych et al., DIRECT COLORIMETRIC DETECTION OF A RECEPTOR-LIGAND INTERACTION BY A POLYMERIZED BILAYER ASSEMBLY, Science, 261(5121), 1993, pp. 585-588
Detection of receptor-ligand interactions is generally accomplished by
indirect assays such as enzyme-linked immunosorbent assay. A direct c
olorimetric detection method based on a polydiacetylene bilayer assemb
led on glass microscope slides has been developed. The bilayer is comp
osed of a self-assembled monolayer of octadecylsilane and a Langmuir-B
lodgett monolayer of polydiacetylene. The polydiacetylene layer is fun
ctionalized with an analog of sialic acid, the receptor-specific ligan
d for the influenza virus hemagglutinin. The sialic acid ligand serves
as a molecular recognition element and the conjugated polymer backbon
e signals binding at the surface by a chromatic transition. The color
transition is readily visible to the naked eye as a blue to red color
change and can be quantified by visible absorption spectroscopy. Direc
t colorimetric detection by polydiacetylene films offers new possibili
ties for diagnostic applications and screening for new drug candidates
or binding ligands.