We describe a two-chip micro-scale time-resolved fluorescence analyzer integrating excitation, detection, and filtering. A new 8×8 array of drivers realized in standard low-voltage 0.35-μm complementary metal-oxide semiconductor is bump-bonded to AlInGaN blue micro-pixellated light-emitting diodes (micro-LEDs). The array is capable of producing sample excitation pulses with a width of 777 ps (FWHM), enabling short lifetime fluorophores to be investigated. The fluorescence emission is detected by a second, vertically-opposed 16 × 4 array of single-photon avalanche diodes (SPADs) fabricated in 0.35-μm high-voltage CMOS technology with in-pixel time-gated photon counting circuitry. Captured chip data are transferred to a PC for further processing, including histogramming, lifetime extraction, calibration and background/noise compensation. This constitutes the smallest reported solid-state microsystem for fluorescence decay analysis, replacing lasers, photomultiplier tubes, bulk optics, and discrete electronics. The system is demonstrated with measurements of fluorescent colloidal quantum dot and Rhodamine samples.
- single-photon avalanche diodes
- GaN micro light emitting diodes
- complementary metal oxide semiconductor
- integrated circuits
- fluorescence lifetime
Rae, B. R., Yang, J., Mckendry, J., Gong, Z., Renshaw, D., Girkin, J. M., ... Henderson, R. K. (2010). A vertically integrated CMOS microsystem for time-resolved fluorescence analysis. IEEE Transactions on Biomedical Engineering, 4(6), 437-444. https://doi.org/10.1109/TBCAS.2010.2077290