1 Water Soluble Poly(fluorene) Homopolymers and Copolymers for Chemical and Biological Sensors 1.1 Introduction 1.2 General Structures and Properties 1.2.1 Design, Synthesis, and Structural Properties 1.2.2 Optical Properties 1.3 Signal Transduction Mechanisms in Sensors 1.4 Chemo- and Biosensor Applications 1.4.1DNA Sensors 1.4.2RNA Sensors 1.4.3 Protein Detection 1.4.4Glucose Sensors 1.4.5Detection of Other Small Molecules 1.5 Heterogeneous Platforms 1.6 Summary and Outlook References 2 Polyelectrolyte-Based Fluorescent Sensors 2.1 General Introduction 2.1.1Amplified Fluorescence Quenching 2.1.2 General Sensor Schemes: Bioassays Based on Quench/Unquench 2.2 Enzyme Activity Assays 2.2.1Assay Formats and Types 2.2.2 Proteolytic Enzyme Assays Using Conjugated Polyelectrolytes 2.2.3 Phospholipase Assays Using Conjugated Polyelectrolytes 2.2.4 Assays Based on “Frustrated Super-Quenching” 2.2.5 Supramolecular Self-Assembly and Scaffold Disruption/Destr ……