Hybridizing Silver Nanoparticles in Hydrogel for High-Performance Flexible SERS Chips

An ideal surface-enhanced Raman scattering (SERB) substrate should have high sensitivity, long-term stability, excellent repeatability, and strong antiinterference. In the present work, single-layer carbon-based dot (CD)-capped Ag nanoparticle aggregates (a-AgNPs/CDs) with high SERS activity are synthesized and hybridized with a hydrogel to prepare novel hydrogel SERS chips. Benefiting from the unique properties of a-AgNPs/CDs and the hydrogel, the constructed hydrogel SERS chips show excellent performances. Taking crystal violet detection as an example, the hydrogel SERS chips show a detection limit of around 1 x 10(-16) mol/L (high sensitivity), maintain above 96.40% of SERS activity even after 14 weeks of storage (long-term stability), and display point-to-point relative standard deviation (RSD) in one chip as low as 1.43% (outstanding repeatability) and RSD in different chips as low as 2.75% (excellent reproducibility). Furthermore, the self-extraction effect of the hydrogel enables the flexible hydrogel SERS chips to be used for analyzing various real samples including soybean milk, juices, and fruits without any complex pretreatment. For instance, the hydrogel SERS chips are able to detect trace thiram and 2-(4-thiazolyl)benzimidazole with the detection limits of 1 and 5 ppb in liquid samples, respectively, and of 1 and 2.5 ng/cm(2) on the peel of fruits, respectively. The self-extraction functional flexible SERS chips offer a reliable and convenient platform for the quick detection and on-site monitoring of chemical contaminants.

Automated summary

By synthesizing carbon-based dot-capped silver nanoparticle aggregates and hybridizing them with a hydrogel, novel hydrogel SERS chips with excellent performance were constructed. These flexible chips showed high sensitivity, long-term stability, outstanding repeatability, and excellent reproducibility, making them reliable and convenient for the detection and on-site monitoring of chemical contaminants in various real samples.