ABSTRACT
When considering new sensory technologies, one should look to nature for the most favorable solution.
The evolution of living organisms has developed the ultimate chemical sensors. The astonishing sensory
performance of biological systems does not originate from a single element. Their optimal performance
is mostly derived from a completely interactive system wherein the selectivity is derived from receptors,
and sensitivity is the result of analyte-triggered biochemical cascades. Clearly, optimal artificial sensory
systems should also display all of these features. In this regard, conjugated polymers are a diverse sensor
platform, and can be used in a wide range of biomolecular recognition schemes to obtain sensory
responses. Biosensors based on conjugated polymers are sensitive to very minor perturbations, due to
amplification by a collective system response and offer a key advantage compared to small molecules-
based sensors [1-4]. The physical properties of conjugated polymers can be utilized for a wide range of
biosensors [5] based on the mechanisms related to charge or energy transfer in its widest scope. The
nature of conjugated polymers suggests biosensors based on charge transfer and transport, and electro-
chemical methods where the analyte controls the condition for charge transfer at electrodes have been
studied [6-9]. We will leave these mechanisms out of discussion and here limit the coverage to the use of
conjugated polymers as optical probes, and colorimetric biosensors and biosensors utilizing fluorescence
will be discussed. The long history of such biosensors based on small molecules, either covalently
attached to biological macromolecules or bound to them in solution, testifies to the need for sensors
of this kind. The possibility to develop the staining of biomolecular structures, in order to follow
morphology and dynamics with new probes, could lead to novel tools for biological research [10].
