Achievement

Novel biosensors allow detection of increasingly low levels of analyte. However, a universal surface coating with specific characteristics is needed to employ these devices in real world applications, such as cancer diagnostics. This coating must prevent non-specific adsorption of proteins to eliminate background noise, have abundant functionalizable groups for efficient immobilization of molecular recognition elements for improved sensitivity, and express convenient attachment to numerous sensor platforms. IGERT trainee Norman Brault linked the ultra-low-fouling and functionalizable poly(carboxy-betaine) bifunctional polymer to the adhesive molecule DOPA for convenient attachment to a variety of surfaces. This enabled detection of the cancer biomarker ALCAM at pico-molar concentrations in undiluted human blood, outperforming the commonly used poly-ethylene glycol. This coating has since been successfully used at MIT, Northwestern, and Oakridge National Laboratory.