We have tried using different concentrations and batches of the antibodies but nothing works. The error shown is "pre concentration binding is too slow".
What matters is the charge on the antibody? If you prepare it in a buffer of acidic pH it shall have net positive change and if you prepare in alkaline buffer say sodium carbonate-bicarbonate buffer it shall have net negative charge. The binding you desire on biochip is adsorption or covalent for the antibody?