Electrochemical Synthesis of 3D Plasmonic‐Molecule Nanocomposite Materials for In Situ Label‐Free Molecular Detections

For several decades, the precise positioning of chemicals and biomolecules at nanosized electromagnetic hotspots has posed a challenge to achieving ultrasensitive and reliable label‐free molecular detection. Here, the authors report the rapid ultrasensitive direct detection of chemicals and biomacromolecules (i.e., enveloped virus) through the in situ electrochemical synthesis of a 3D plasmonic‐probe molecule composite skin layer on a 3D Au nanopillar array. The bottom‐up growth of plasmonic nanomaterials in the presence of target probe molecules provides intimate contact between the Au and the target molecules, thereby enhancing light–matter interactions in 3D spaces. These enhanced interactions result in highly sensitive and rapid direct detection of both small molecules and large influenza A virus (H1N1) with hierarchical complex structures. The virus serves as a structural motif for the formation of Au–virus nanocomposite structures through Au electrodeposition, which results in the in situ formation of hotspots for the surface‐enhanced Raman spectroscopy (SERS) detection of spike proteins. The proposed SERS detection system with fast composite plasmon‐molecule skin layer formation provides a general platform for highly sensitive and rapid label‐free direct detection for chemical and biomedical applications. Electrochemical bottom‐up growth of Au in the presence of target molecules provides intimate contact between Au and the target molecules and thereby enhances light–matter interactions in 3D spaces, which results in the highly sensitive and fast direct detection of molecules for both small chemical molecules and large influenza A (H1N1) virus with hierarchical complex structures.