Spectroscopic fiber probes for chemical sensing based on LbL self assembled ultra-thin films

Electrostatic Layer-by-Layer self-assembly (LbL) is an attractive method for depositing films, composed of charged molecules, on a wide variety of charged substrates. This report describes progress toward development of LbL as a platform for fabrication of fluorescent sensors based on nanocomposite multilayer ultra-thin films. Two types of fiber probes have been fabricated to demonstrate this concept: oxygen sensing Ruthenium-based multilayer films with additional reference fluorophore allowing ratiometric measurements, and multilayer films containing a pH-sensitive fluorophore assembled on imaging fiber bundles. This work provides a basis for development of sensors for numerous biomedical sensing applications, including fiber-optic probes for research and clinical measurements and implantable micro/nanoparticle based sensors for in vitro or in vivo monitoring.