A low-light CMOS contact imager with an emission filter for biosensing applications

Marianna Beiderman, Terence Tam, Aalexander Fish, Graham A. Jullien, Orly Yadid-Pecht

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


In this paper, a fully functional low light 128 × 128 contact image sensor for cell detection in biosensing applications is presented. The imager, fabricated in 0.18 μ CMOS technology, provides low-noise operation by employing both a modified version of the active reset (AR) technique and a modified version of the active column sensor (ACS) readout method. High-sensitivity, low noise performance of the presented sensor is well-suited for fluorescence imaging. For this purpose, an emission filter was fabricated and integrated with the sensor. The filter was fabricated using PDMS and Sudan II Blue dye mix, spin-coated and deposited in a class 1000 clean room. The designed filter is suitable for excitation at wavelengths below 340 nm and emission at 450 nm and above. The fabricated imager architecture and operation are described, noise analysis is presented and measurements from a test chip are shown. Experimental results using live neurons from the pond snail, Lymnaea stagnalis, and fluorescence polystyrene micro-beads prove the functionality of the fabricated system and indicate its biocompatibility.

Original languageEnglish
Pages (from-to)193-203
Number of pages11
JournalIEEE Transactions on Biomedical Circuits and Systems
Issue number3
StatePublished - 24 Nov 2008


  • Ab-on-a-chip (LOAC)
  • Active column sensor
  • Active reset
  • Biosensor
  • CMOS imaging
  • Contact imaging
  • Fluorescence imaging
  • Low light


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