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.