Title :
On-chip integrated CMOS optical detection microsystem for spectrophotometric analyses in biological microfluidic systems
Author :
Minas, G. ; Ribeiro, J.C. ; Wolffenbuttel, R.F. ; Correia, J.H.
Author_Institution :
Dept. of Ind. Electron., Minho Univ., Portugal
Abstract :
An integrated optical detection microsystem, which includes photodetectors and a light-to-frequency converter for readout, is designed and fabricated in a standard CMOS process without extra masks. This detection microsystem is designed for use in biological microsystems for fluids analysis. The application is in the low-cost concentration measurement of biomolecules in biological fluids, by the optical absorption in a part of the visible spectrum defined by the specific molecule. Signals proportional to the intensity of the light transmitted through the biological fluid are available at the output in the form of bit streams, which allows simple computer interfacing. The quantitative measurement of uric acid in urine is successfully demonstrated. The photodiode responsivity is 224 mA/W at /spl lambda/= 495 nm (the wavelength at which the uric acid has its absorption maximum). The optical system sensitivity is 1 kHz/Wm/sup -2/ at /spl lambda/ =670 nm (using the TLS230 from Texas Instruments as reference).
Keywords :
CMOS integrated circuits; integrated optoelectronics; light absorption; microfluidics; photodiodes; spectrophotometry; 495 nm; 670 nm; biological microfluidic systems; fluids analysis; light-to-frequency converter; on-chip integrated CMOS optical detection microsystem; optical absorption; optical system sensitivity; photodetectors; photodiode responsivity; spectrophotometric analyses; standard CMOS process; uric acid measurement; urine; Biomedical optical imaging; CMOS process; Integrated optics; Microfluidics; Molecular biophysics; Optical design; Optical detectors; Optical sensors; Photodetectors; System-on-a-chip;
Conference_Titel :
Industrial Electronics, 2005. ISIE 2005. Proceedings of the IEEE International Symposium on
Conference_Location :
Dubrovnik, Croatia
Print_ISBN :
0-7803-8738-4
DOI :
10.1109/ISIE.2005.1529083
