Structure-adjustable colloidal silver nanoparticles on polymers grafted cellulose paper-based highly sensitive and selective SERS sensing platform with analyte enrichment function

Abstract Paper-based sensing platforms have become one of the hot topics in spectroscopic technique for chemical and biological detections. However, it has been still challenging to detect molecules at trace levels owing to its intrinsic interconnected porous structures related to the fibril structure of paper and hydrophilic characteristic. Herein, a cellulose paper combined molecular polymers and hybridized chain reaction that led to hydrophobic functionalization with static water contact angles>90° for surface-enhanced Raman scattering (SERS) was proposed. During the fabrication, the formation of the ultrasensitive SERS is supported by interconnection of silver nanoparticles (NPs) of varying diameters from 20 to 50 nm and concentration in the range of 2–6 mL on one side of the paper substrate to achieve excellent quantification capability based on hotspots engineering-based clusters and analyte enrichment system, particularly, AgNPs with diameter of 30 nm exhibit the highest Raman signals at 532 nm excitation. The resulting plasmonic arrays show SERS detection of CV molecules at a low concentration of 10–10 M with an enhancement factor of 1.2 × 108 and excellent reproducibility with RSD of Raman signal as low as 10.39%. An outstanding selectivity each probe molecule in an analyte mixture solution of R6G and CV at diluted concentration (10−8 M) of the platform was obtained. These outcomes could be designated to the more target molecules trapped in the hotspots and cluster of AgNPs after activated molecular enrichment mechanism underlying hydrophobic layer correlated with natural evaporation.