Facile, Ecofriendly, and Efficient Preparation of Flexible Gold Nanoparticles@Bacterial Nanocellulose Surface-Enhanced Raman Scattering Sensors by Magnetron Sputtering for Trace Detection of Hazardous Materials

Nanocellulose-based surface-enhanced Raman scattering (SERS) substrates have attracted extensive attention as sustainable, environmentally friendly, ultrasensitive sensing tools for trace detection of biological and chemical molecules. However, the development of a facile, ecofriendly, low-cost, and scalable fabrication method to prepare flexible nanocellulose-based SERS substrates remains a great challenge. Herein, the renewable and sustainable bacterial nanocellulose is used as a matrix material. The bacterial nanocellulose decorated with gold nanoparticles (AuNPs@BNC) SERS substrates are successfully constructed by a low-cost, efficient, and ecofriendly magnetron sputtering technology. The effect of sputtering times ranging from 25 to 200 s on the SERS performance of AuNPs@BNC substrates is systematically investigated. The Au nanoparticles with an average diameter of 18.5 nm are uniformly distributed on the surface of a nanocellulose matrix for an optimal AuNPs-150@BNC substrate. In addition, the optimal AuNPs-150@BNC substrate exhibits high sensitivity with a detection limit of 10–9 M for rhodamine 6G and excellent reproducibility as well as good stability. The 2D Raman mapping and finite-difference time-domain (FDTD) simulation also demonstrate the excellent SERS performances of AuNPs-150@BNC substrates. Further, the flexible AuNPs-150@BNC SERS sensor is successfully applied to detect pesticide residues on irregular fruit surfaces. The flexible SERS sensor enables the ultrasensitive detection of cypermethrin with high sensitivity down to 10–7 M. The flexible AuNPs@BNC sensor fabricated by magnetron sputtering technology shows promising applications as an ecofriendly and scalable SERS substrate for trace detection of hazardous materials.