Molecularly imprinted polymer-based reusable biosensing device on stainless steel for spatially localized detection of cytokine IL-1β

Abstract

A molecularly imprinted polymer (MIP) based biosensing device on stainless steel (SS) for detection of locally variable concentration of cytokine interleukin-1β (IL-1β) was successfully developed using a sandwich assay scheme. The SS surface was firstly modified with a layer of polydopamine (PDA) followed by the attachment of a layer of poly(ethyleneimine) (PEI) by electrostatic adsorption. Subsequently, the template protein IL-1β was adsorbed on the PEI terminated SS surface due to electrostatic adsorption. A PDA imprinting film was then in-situ synthesized on the surface of the modified SS substrate with incorporated template cytokine. Finally, the template was washed off the SS substrate leaving behind cavities with specific shape and capable of capturing cytokines thus forming a MIP biosensing interface. After exposure to the analyte IL-1β, the MIP biosensing device was incubated with IL-1β detection antibody-modified fluorescent polystyrene beads allowing to determine the amount of captured IL-1β based on fluorescence intensity. The device has been demonstrated to detect IL-1β with low detection limit of 10.2 pg mL−1, and a linear detection range of 25–400 pg mL−1. This MIP biosensing device can be regenerated more than three times with coefficient of variation 2.08%. The device was applied for the detection of IL-1β secreted by rat macrophages, where the good specificity and selectivity were achieved. MIP serves in this device as a superior substitute of antibody with exceptional stability and reusability. The MIP based biosensing technology presented in our work paves a new way for developing a universal and robust sensing platform for the detection of spatially localised small proteins with low physical concentration.