Chapter 7: Cell-Mimicking Supramolecular Assemblies Based on Polydiacetylene Lipids: Recent Development as “Smart” Materials for Colorimetric and Electrochemical Biosensing Devices

Abstract

Abstract Design and synthesis of simplified models of cell membranes that mimic their self-organization and functions represent great technical challenge, yet have opened doors to innovative diagnostic and therapeutic methods. Functionalized supramolecular polydiacetylene (PDA) assemblies exhibit unique blue–red colorimetric transitions upon specific interactions with a variety of biological analytes in aqueous solutions. The chemical assemblies include conjugated PDA, responsible for the chromatic transitions, and the molecular recognition elements, which are either chemically or physically associated with the PDAs. The supramolecular assemblies therefore integrate both molecular recognition and signal transduction functions. Langmuir–Blodgett thin films and vesicle bilayers provide ideal configurations for precise delivery of the biological binding entity to the sensing interface, and for control of molecular orientation for effective biomolecular interaction. By incorporation of specific recognition elements, the systems based on PDAs have proved to be versatile and sensitive sensors for a wide range of biological analytes, including viruses, toxins, ions, antibacterial peptides, membrane penetration enhancers, interfacial enzymatic catalysis, and antibodies. The rapid and specific color transitions observed in the “smart” PDA systems will open wide-range of possibilities for biosensor, drug discovery, and diagnostic applications.