Decision Biomarkers has developed proprietary technology to adhere an ultra-thin film of nitrocellulose onto a glass substrate that provides a unique coating surface for binding proteins.

Our patent-pending product, the PATH® Protein Microarray Substrate, offers all of the features critical for protein microarrays: retained protein conformation, low background fluorescence, extended shelf life, excellent spot morphology and broad working range.

Our superior PATH® substrate delivers high signal-to-noise and low background fluorescence in multiplex immunoassay applications. It is the foundation of the biochip-based multiplex immunoassays that run on our AVANTRA™Q400 biomarker workstation.

<<< Background comparison. Comparison of PATH® substrate (left) and thick nitrocellulose membrane substrate (right). Both slides were scanned on an Affymetrix 418 laser scanner at 20 dB. The image setting is the same for both slides. Average background on the PATH® slide is 36 RFU. Average background on the thick membrane substrate is 324 RFU.

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The Historical Challenge with Protein Microarrays

Until now, immobilizing proteins successfully onto a solid substrate was a challenge that had not generally been met for microarray applications. Unlike DNA, proteins’ three-dimensional shapes play a critical role in their interactions with other molecules, and thus their function. Maintaining the functionality of proteins while keeping them immobilized had once presented a considerable challenge for scientists.

Historically, researchers and clinicians have used nitrocellulose membranes and polystyrene plates to immobilize and successfully preserve the functionality of a broad range of proteins. However, high background fluorescence has precluded their general use in microarrays, which used fluorescence detection systems. Because high background fluorescence obscures low-level signals, it obscures the weak fluorescence of low abundance proteins, limiting sensitivity and the range of proteins that can be detected.

Our Innovative Solution

Decision Biomarkers developed a method of adhering ultra-thin layers of nitrocellulose and polystyrene to microarray surfaces. By overcoming challenges in adhesion, thin-film coating and surface activation, our innovative approach enabled the use of traditional binding materials to develop a solid substrate that does not exhibit background fluorescence.

Our substrate’s thin-film — approximately one tenth of a micron thick — preserves the desirable binding characteristics of the material and all but eliminates the background fluorescence. Additionally, the opaque substrate also reduces background signal by eliminating the natural fluorescence of the glass slide.

Superior Performance

Testing to date demonstrates superior performance versus commercially available substrates. High binding capacity and low, uniform background signal are combined with excellent spot morphology. Visit the Library to download our poster comparing our PATH® substrate with other protein microarray substrates.

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