A chromo- and fluorogenic sensor for probing the cancer biomarker lysophosphatidic acid

A novel chromo- and fluorogenic sensor, 4-(4-dimethylaminostyryl)-1-hexadecylpyridinium (DSHP) for lysophosphatidic acid (LPA) was successfully developed by incorporating a long alkyl chain into the cyanine molecule. DSHP shows excellent selectivity and high sensitivity towards LPA with a detection limit of about 7.09 x 10(-7) M based on electrostatic and hydrophobic interactions between the sensor and LPA. Upon addition of LPA ranging from 0 to 7.5 x 10(-4) M, DSHP displays an 'on-off-on' fluorescence response and obvious colour change. Good linear relationships between the fluorescence intensity and LPA concentrations were achieved in the fluorescence quenching ranges of 0-28 mu M and 34-52 mu M, which could be attributed to the combined effects of the photoinduced electron transfer and LPA-induced aggregation of the sensor molecules.