Fluorescent Platforms Based on Organic Molecules for Chemical and Biological Detection

Abstract

Fluorescent platforms based on organic molecules have attracted great attention in the field of chemical and biological detection because of their high detection efficiency and sensitivity. Strategies in fluorescent platform design with controlled luminescence properties based on Förster resonance energy transfer, excimer/exciplex formation, and metal‐enhanced fluorescence mechanisms are reviewed herein. Attention is focused on the photophysical processes of fluorescent molecules in their interactions with other components as well as with the target. Color‐ and intensity‐tunable luminescence from energy or electron transfer and the electronic structures of fluorescent molecules are discussed. On the basis of the photophysical properties of fluorescent molecules, their responsive fluorescence signals, which reflect specific inter‐ and intra‐molecular interactions, are particularly effective for chemical and biological detection.

Fluorescent Ensemble Sensors and Arrays Based on Surfactant Aggregates Encapsulating Pyrene-Derived Fluorophores for Differentiation Applications

“…Pyrene is well-known to exhibit structured monomer emission with peaks at short wavelengths and broad excimer emission band at long wavelengths (Figure ). − Moreover, the formation of excimer is not only dependent on the concentration, but also highly sensitive to the microenvironment. Another particular characteristic about pyrene derivatives is the excimer formation can be dynamic or static.…”

Conjugated Polymer-Functionalized Stretchable Supramolecular Hydrogels to Monitor and Control Cellular Behavior

“…Owing to the high temporal and spatial resolutions, the fluorescence technique well suits the detection dimension of molecular interaction. − The matrix–cell connection accompanies with a distance variation. In a typical Förster resonance energy transfer (FRET) process, an excited fluorescent donor transfers energy to a fluorescent acceptor in a space. − In most cases, the shorter the donor–acceptor distance, the higher the FRET efficiency . Organic fluorescent molecules, inorganic metal nanoclusters, or quantum dots with a high emission efficiency can act as energy donors. − Among them, conjugated molecules possess π-conjugated backbones that allow large absorption coefficients. , Relying on an effective energy transfer from conjugated molecules, amplified signals of the acceptor can be gained for detection .…”

Different Surface Interactions between Fluorescent Conjugated Polymers and Biological Targets

“…The occurrence of MEF effect strongly depends on the distance between fluorophores and metal nanostructures, which is limited in 5−90 nm. 16 Therefore, by introducing the metal nanostructures, the interaction between CPs and biological targets can be transduced into the distance change between CPs and metal. The MEF effect fluctuation caused by the distance change can realize a fluorescent signal response, which is corresponding to different interaction of CPs with different biological targets.…”

“…During the process of bioapplications, it is necessary to modify CPs with functional groups to establish connection with biological targets. The ionic side chains, hydrogen-bonding chemistries, amphiphilic coating, targeting moieties, and reactive groups decorated on CPs will induce electrostatic interaction, hydrogen bond, hydrophobic interaction, ligand–receptor recognition, and covalent bond. − These driven forces can organize CPs on the surface of biological targets that have a great bearing on producing reliable optical signals. Most biological targets, such as nucleic acids, proteins, human cells, and microorganisms, exhibit a charged surface. − The electrostatic interaction is the origin of ionic CPs’ attraction on the biological targets .…”

“…Surface plasmon resonance originated from a coherent oscillation of the excited free electrons of metal nanostructures, which can enhance the fluorescence of adjacent CPs. The occurrence of MEF effect strongly depends on the distance between fluorophores and metal nanostructures, which is limited in 5–90 nm . Therefore, by introducing the metal nanostructures, the interaction between CPs and biological targets can be transduced into the distance change between CPs and metal.…”