Compact phase-sensitive multichannel detection system with array measurements of biosensor chips

Tn many medical, biological, chemical and environmental applications it is desirable not only to monitor one specific chemical or biological species, but several simultaneously. Thus, we have focussed our efforts on development of a detection system for multi-analyte sensor arrays (MASAs) that is able to monitor the changes in fluorophore lifetimes (via the detection of phase shifts) corresponding to the presence of many analytes of interest in near-real time. We describe a phase-sensitive electronic detection system employing a multianode photomultiplier tube (PMT). This system utilizes the frequency-domain method of time-resolved spectroscopy and is also suitable for lifetime-based imaging. The sixteen-channel prototype is inexpensive, compact, assembled from off-the-shelf components, and may use several different kinds of light excitation sources (including light emitting diodes (LEDs), laser diodes (LDs), as well as Ar+ and He-Ne lasers with an external electro-optical modulator) and light delivery systems (including fiber optical light delivery). We present some examples of its applications and demonstrate the monitoring of sixteen sectors of a biosensor chip surface created with fluorophore-labeled anti-body molecules immobilized on a mixed monolayer of hapten and hydroxy-terminated thiolates. The basic design is scalable; future versions may accommodate up to 63 channels or more with currently available PMTs.