H3 (Hydrogel‐Based, High‐Sensitivity, Hybrid) Plasmonic Transducers for Biomolecular Interactions Monitoring

A hybrid plasmonic transducer made of a Poly‐(ethylene glycol) diacrylate (PEGDA) hydrogel and citrate gold nanoparticles detects the biotin‐streptavidin interaction at picomolar (× 10−12 m ) concentrations. The all‐solution fabrication strategy, herein proposed, is large‐scale, easily tunable, and low‐cost; nevertheless, this innovative device is highly reproducible and optically stable, and it can be used in dual‐optical mode. Indeed, both metal‐enhanced fluorescence and localized surface plasmon resonance signals can be exploited to quantify the biorecognition process in a 3D architecture. The large swelling capability of high molecular weight PEGDA is used to investigate the plasmon absorption variations resulting from the exposure to biological solutions containing high molecular weight molecules within the 3D network. The proposed transducer represents a low‐cost, flexible, and easy‐to‐use platform for sensing applications in biomedical or environmental diagnostics. Fabrication, characterization, and functionalization of a hybrid plasmonic transducer made of a high molecular weight hydrogel embedding spherical gold nanoparticles leads to a dual‐mode optical device capable of selectively and accurately quantifying high molecular weight proteins by simple absorption spectroscopy and metal‐enhanced fluorescence. The highly reproducible flexible platform can be a promising alternative to rigid sensors for biosensing purposes.