New near-infrared sensors


Shane McDonnell and Donal F O'Shea, Centre for Synthesis and Chemical Biology, Department of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
The development of fluorescent biosensors, which can be used for in vivo applications remain a challenge due to the lack of a synthetically versatile fluorophore platform with optimal photophysical properties from which the sensors can be constructed. For in vivo applications the reporter portion of the sensor must be able to absorb and emit within the 650-900 nm spectral region to avoid interference by endogenous chromophores. The principal platforms for sensors operating in this spectra region are based upon either cyanines or phthalocyanines. Recently we have reported the synthetically amenable BF2 chelated tetraarylazadipyrromethenes (1) as a new class of near infrared chromophore and now describe their adaptation for use as fluorescence based sensors. The design, syntheses and spectroscopic evaluation of a range of sensors based upon (1) are described. The receptor portion of the sensor when located on the aryl rings gives rise to dramatic spectroscopic changes upon analyte recognition.