At the core of Zoíray’s technology is label-free protein array sensing.  Antibodies or protein antigens that serve as capturing agents are spotted on an inexpensive slide with a SiO₂ surface.  The protein array is loaded in the instrument for incubation with a fluid sample.  Images of the array are taken every 45 seconds during incubation for obtaining real-time binding curves.  1024 spots (32 x 32 array) each 100 µm in diameter are imaged at once.  The mass bound at each spot is measured by optical interference using propriety technology for high sensitivity.  No labels or tags are necessary for the signal which makes the measurement much more quantitative and avoids other labeling challenges such as cost and cross-reactivity among secondary probes.  The system improves on alternative label-free detection in that it is highly multiplexed, highly sensitive, inexpensive to operate, temperature and solution invariant, and simple to use.

Advantages over fluorescent arrays:

• Quantitative (fluorescent dyes are sensitive to light, humidity, and storage conditions)
• Fewer steps (no need for a second labeling step)
• Real-time (can observe binding kinetics)

Advantages over imaging surface plasmon resonance (SPR):

• Quantitative (SPR is sensitive to temperature, buffer, and molecular orientation)
• Less expensive (instrumentation and slides at a fraction of the cost)
• Simple (quick to learn & easy to use)

E. Ozkumur et al. Biosensors & Bioelectronics (in press) 2010 abstract

A. Yalcin et al. Analytical Chemistry 81 2009 abstract

E. Ozkumur et al. Biosensors & Bioelectronics 25(1) 2009 abstract

A. Qavi et al. Analytical & Bioanalytical Chemistry 394 2009 abstract

S. Srivastava et al. Nature Biotechnology 26 2008 abstract
E. Ozkumur et al. PNAS 105(10) 2008 abstract
M. Cretich et al. Analytical Biochemistry 332 2004 abstract