Flexible sers substrate fabricated from gold nanostar

Abstract

In this work, a one-pot protocol for the fabrication of surface-enhanced Raman scattering (SERS) substrate has been developed. It consists of quasi-spherical gold nanoparticles (AuQNPs) uniformly which is deposited on a disk paper substrate (5-mm in diameter). The disk of filter paper surface was coated by bacterial cellulose nanocrystal (BCNC). The BCNC smoothed the surface by forming thin nanopaper film upon drying while filling the gap between fibers. AuQNPs was directly synthesized on the surface of BCNC film via seed-growth method. The BCNC film with abundant hydroxyl groups became anchor points for AuNPs which help to create uniform distribution of AuQNP. The performance of the developed SERS substrate was evaluated by 4-aminothiophenol (4-ATP). The results indicated that the uniform distribution of AuQNP on BCNC/filter-paper SERS substrate leads to an increase of the SERS intensity at 1079 cm⁻¹ of 4-ATP from 1348 cps to 4600 cps while the relative standard deviation (RSD) was decreased from 30.3% to 8.9% compared to AuQNP/filter-paper SERS substrate. The lowest concentration of 4-ATP that can be detected was 1 nM. Furthermore, AuQNP/BCNC/filter-paper substrate can detect trace thiram pesticide with the limit of detection at 0.134 pM. The experiment would be an effective technique for preparing flexible SERS substrates that easily prepared in laboratory. This disposable, reproducible, highly stable, easy to use and low-cost SERS substrate, which affords high intensity and uniform SERS signal, has potential for trace chemical detection in practical application.