Integration of NanoMIPs With Gold-Patterned Plasmonic Surfaces as Synthetic Protein A

In modern bioanalytical sensing, the integration of biorecognition elements with transducer platforms represents an established strategy for achieving selective detection. Among the available bioreceptors, proteins have been widely used for their ability to mediate highly specific interactions. However, proteins often present limitations such as instability, high production costs, animal-derived manufacturing, and strict storage protocols. A promising alternative is molecularly imprinted polymeric nanoparticles (nanoMIPs), which have shown potential due to features such as greater stability, durability, and potentially lower costs. This study introduces, for the first time, the use of nanoMIPs imprinted for IgG on a silicon surface functionalised with gold nanoparticles. These nanoMIPs are designed to bind IgG in an oriented manner by targeting Fc-specific epitopes selected through a novel epitope-mapping technique. Detection is based on metal-enhanced fluorescence (MEF), which significantly amplifies the signal. The sensor showed high specificity for IgG, with no cross-reactivity toward IgA, reaching a detection limit of 10 ng mL^-1. Compared with protein A, the natural binder of IgG, nanoMIPs achieved superior performance by 20.6% and 17.8% for the two epitopes tested.