J-aggregates are stable fluorescent structures formed by a number of small molecules noncovalently. These structures can be formed not only in solution but also on biological objects that act as templates. As association of these small molecules leads to drastic changes in their spectral properties, this phenomenon can in principle be used for the detection of biological structures that induce the aggregation. Here, the photophysical properties of J-aggregates formed in different media and, particularly on attachment to the objects of biological origin, such as nucleic acids, proteins, and biomembranes, are discussed.
Graphical Abstract
Schematic representation of characteristic absorption (A, blue) and fluorescence (F, red) spectra of monomers and J-aggregates (marked as M and J, respectively)