A novel enhanced dynamic range camera (EDRaC) is proposed for greatly improved fluorescence detection in proteomics. In the longer term the EDRaC can improve the performance of a wide range of biomedical applications using fluorescent microwell plate reading and/or microscopy. The initial emphasis will be to develop, demonstrate, and apply the technology to multicolor fluorescent 2D gel imaging. The system will use a Digital Micro-mirror Device (DMD) and digital feedback to selectively attenuate bright pixels before imaging onto a CCD focal plane array, thereby greatly reducing stray light in the camera and enabling simultaneous measurements of very bright and very dim regions in samples. In the limit of perfect imaging and no scattered light, the resulting dynamic range of this system would be the product of the DMD dynamic range (~13 bits) and the CCD dynamic range (typically 12-14 bits in practice due to stray light) for a maximum system dynamic range of approximately 25-27 bits. In practice, we expect that this approach will add between two and four orders of magnitude (100-10,000x) of dynamic range to fluorescent detection. This improvement will be extremely valuable for fluorescent 2D gel imaging, which currently suffers from dynamic range limitations, with the most advanced multicolor fluorescent detection dyes. A work plan has been developed to design, assemble, and demonstrate the technology. The design effort will include detailed ray-trace optical modeling, stray-light analysis, and mechanical design. Prototype testing of a bench scale system will include measurements of the system Modulation Transfer Function, stray-light measurements, and measurements of the dynamic range for various scenes. Following system characterization the system dynamic range will be demonstrated on gels. High dynamic range plasma protein patterns will be investigated on 2D zoom gels, using samples from selected disease states that are depleted of the most abundant proteins, using the EDRaC prototype to seek candidate protein pattern correlations with health and disease. Optical signal strengths from biomedical samples can vary by factors of over a billion (the dynamic range), whereas conventional cameras can measure signals that vary by factors of about ten-thousand. This is a common disparity for proteomics and other biomedical applications and it greatly limits the information that can be obtained. The proposed system will greatly decrease this disparity, thereby enabling more accurate and easier measurements for numerous biomedical applications.
