FIELD OF THE INVENTION

The present invention relates to improvements to substrates for the attachment of binding agents. In particular, the present invention is directed to an improved micro-array substrate. In another aspect there is provided an improved composition for use in coating a substrate for the attachment of binding agents and in particular for use in coating a substrate for a micro-array. In a further aspect of the invention there is provided an improved method for analysing a micro-array.

BACKGROUND OF THE INVENTION

Use of fabricated arrays of molecules in the detection and characterisation of analytes is well known. For example, fabricated arrays of polynucleotides are used widely in DNA sequencing procedures and in hybridisation studies for the detection of genetic variations in a patient. Immunoassays are also well known for detecting analytes, such as specific proteins or other binding agents, through their properties as antigens or antibodies.

Micro-array substrates typically comprise a supporting material comprising a plurality of reaction zones located in spatially distinct areas on the substrate. The provision of multiple reaction zones allows simultaneous testing of multiple analytes or biomarkers in a sample. Micro-arrays are important laboratory tools, not only allowing a more comprehensive analysis of a patient's condition but also saving the time and cost associated with laboratory tests. Typically, micro-arrays are manufactured by depositing or “spotting” molecules or molecular fragments onto the substrate to form an array of reaction zones. In order to obtain an acceptable quality of data, the spotting should be uniform so that the spots are of the same size and shape. However, the data obtained from currently available micro-arrays still has scope for improved accuracy and precision to be more effective in both research and clinical settings. Relatively little has been done to address this problem.

It would therefore be beneficial to provide a substrate that gives high quality data.

SUMMARY OF THE INVENTION

In accordance with an aspect of the invention, there is provided a substrate comprising a coating of a masking material, and a plurality of discrete reaction zones onto which one or more binding agents are intended to be covalently attached, wherein said zones are uncoated areas on the substrate.

It has surprisingly been found that the coated substrate of the present invention provides improved detection sensitivity and image quality, especially when using digital sensors. The coated areas of the substrate reduce non-specific binding and the cross-linking of the spots and so background noise is reduced resulting in an enhanced signal-to-noise ratio. This means that the signal obtained is proportional to the extent of the “true” binding that has occurred between the sample and the targets on the substrate. Increased spatial resolution is also achieved.

Furthermore, use of a coated substrate according to the present invention allows improved accuracy of deposition of binding agents. Internal calibration marks can be fabricated on the substrate to enable accurate identification of discrete reaction zones for accurate biomolecule deposition within the zones.

