Fluorescence-lifetime-based phase-sensitive sensor array with LED or diode laser excitation for chemical- and biosensing

摘要

Fluorescence lifetime-based sensors are well-suited for chemical and biological applications since they are relatively insensitive to background light intensity, fluctuations and bleaching of fluorophores. Examples of applications include biosensing strategies where binding or a target analyte to an immobilized biological receptor molecule results in a change in the fluorescence lifetime of a fluorescent reporter group. It is desirable in many instances to have a sensor array to monitor the simultaneous binding of several analytes. We have designed a multichannel system using LEDs (or laser diodes) to excite fluorescence, multiple photodetectors, and a multichannel computer algorithm-based phase meter. The multichannel phase meter utilizes a PC and multichannel digital acquisition board. The resolution of each channel in the multichannel phase meter has been estimated at approximately 0.05 degrees. The eigen-phase fluctuations for each channel of the system are approximately 0.15 degrees, which allow us to estimate the lifetime resolution as better than 10 ps. We estimate the processing time of phase measurements for each channel as less than 200 ms. The usefulness of the system has been demonstrated in several operational examples, including a multichannnel pH meter and a fluoresphore competitive immunoassay-based chemical sensor.