Reduction of non-specific adsorption in label-free assays via reversible surface blocking with amphiphilic sugars

We report a strategy to block non-specific binding of proteins in a label-free immunoassay using n-Dodecyl β-D-maltoside, an amphiphilic sugar that can be reversibly adsorbed on hydrophobic surfaces. Both the anti-fouling properties and reversibility of the blocker are documented using surface sensitive reflective interferometry. Reversible blocking is a potentially important approach to improving label-free assay technology. Because it enables the use of simple hydrophilic coatings, non-covalent probe binding chemistry is sufficient and greatly simplifies surface preparation. Specific detection of < 10 pg/mm2 antibody or antigen targets in the presence of a large excess of bovine serum albumin interferent is demonstrated.