Signal-On Detection of Dopamine and Tyrosinase Using Tris(hydroxypropyl)phosphine as a New Lucigenin Chemiluminescence Coreactant

Dopamine (DA) is a very imperative neurotransmitter in our body, since it contributes to several physiological processes in our body, for example, memory, feeling, cognition, cardiovascular diseases, and hormone secretion. Meanwhile, tyrosinase is a critical biomarker for several dangerous skin diseases, including vitiligo and melanoma cancer. Most of the reported chemiluminescent (CL) methods for monitoring DA and tyrosinase are signal-off biosensors. Herein, we introduce a new chemiluminescent "signal-on" system, lucigenin-tris(hydroxypropyl)phosphine (THPP), for the selective determination of DA and tyrosinase. THPP is well known as a versatile and highly water-soluble sulfhydryl-reducing compound that is more highly stable against air oxidation than common disulfide reductants. By employing THPP for the first time as an efficient lucigenin coreactant, the lucigenin-THPP system has shown a high CL response (approximately 16-fold) compared to the lucigenin-H₂O₂ classical CL system. Surprisingly, DA can remarkably boost the CL intensity of the lucigenin-THPP CL system. Additionally, tyrosinase can efficiently catalyze the conversion of tyramine to DA. Therefore, lucigenin-THPP was employed as an ultrasensitive and selective signal-on CL system for the quantification of DA, tyrosinase, and THPP. The linear ranges for the quantification of DA, tyrosinase, and THPP were 50-1000 nM, 0.2-50 μg/mL, and 0.1-800 μM, respectively. LODs for DA and tyrosinase were estimated to be 24 nM and 0.18 μg/mL, respectively. Additionally, the CL system has been successfully employed for the detection of tyrosinase in human serum samples and the assay of DA in human serum samples as well as in dopamine injection ampules with excellent obtained recoveries.