Co-assembly of Ag nanowires and nanocubes mediated by adhesive tape in hydrophilic and hydrophobic pattern for SERS-based determination of gefitinib and ritonavir in serum

Controlled aggregation of noble metal nanoparticles is incredibly crucial for obtaining reliable surface-enhanced Raman scattering (SERS) properties. Here, a rational agglomeration of large Ag nanowires (NWs) and small Ag nanocubes (NCs) was readily facilitated by simply utilizing the intrinsic viscosity of adhesive tape, leading to the generation of abundant electromagnetic "hotspots" around the numerous crossed nanotips and ultra-small nanogaps. After the molecular enrichment efficiency was further promoted by exploiting a hydrophilichydrophobic strategy, an ultra-low limit of detection as 8.8 x 10-11 M was demonstrated for rhodamine 6 G. Benefiting from the high sensitivity of the SERS chip, its application in the determination of clinical sample containing mixed gefitinib and ritonavir was finally proved, facilitating impressive specificity and accuracy. Considering the simplicity and reliability, our strategy has great potentials to be applied in clinical blood drug identification and concentration monitoring.