Controllable Nanoparticle Aggregation through a Superhydrophobic Laser-Induced Graphene Dynamic System for Surface-Enhanced Raman Scattering Detection

Abstract

Surface-enhanced Raman scattering (SERS) is widely used for low-concentration molecular detection; however, challenges related to detection uniformity and repeatability are bottlenecks for practical application, especially as regards ultrasensitive detection. Here, through the coupling of bionics and fluid mechanics, a lotus-leaf effect and rose-petal effect (LLE–RPE)-integrated superhydrophobic chip is facilely developed using laser-induced graphene (LIG) fabricated on a polyimide film. Dense and uniform aggregation of gold nanoparticles (AuNPs) in droplets is realized through a constant contact angle (CCA) evaporation mode in the dynamic enrichment process, facilitating reliable ultrasensitive detection. The detection chip consists of two components: an LLE zone containing an ethanol-treated LIG superhydrophobic surface with a low-adhesive property, which functions as an AuNP-controllable aggregation zone, and an RPE zone containing an as-fabricated LIG superhydrophobic surface with water-solution pinning ability, which functions as a droplet solvent evaporation and a AuNP blending zone. AuNPs realize uniform aggregation during rolling on the LLE zone, and then get immobilized on the RPE zone to complete evaporation of the solvent, followed by Raman detection. Here, based on dense and uniform AuNP aggregation, the detection system achieves high-efficiency (242 s/18 μL) and ultralow-concentration (10–17 M) detection of a target analyte (rhodamine 6G). The proposed system constitutes a simple approach toward high-performance detection for chemical analysis, environmental monitoring, biological analysis, and medical diagnosis.

Ultrasensitive and Reliable SERS Chip Based on Facile Assembly of AgNPs on Porous LIG to Enhance the Local Electromagnetic Field

“…At present, there are few reports on SERS research of LIG integrated metal nanoparticles. Our team reported an extremely simple method to prepare the LIG SERS substrate with adjustable surface pinning performance . On this basis, we developed a SERS detection platform with controllable aggregation of gold nanoparticles (AuNPs), which achieved high efficiency and ultra-low concentration detection of a target analyte.…”

Flexible and Highly Sensitive Sandwich-Structured PDMS with Silver Nanowires and Laser-Induced Graphene for Rapid Residue Detection

“…However, current synthesis methods of graphene require either high-temperature processing or multistep chemical synthesis routes, lessening their widespread commercial potential. Laser-induced graphene (LIG), prepared by direct laser writing on some polymer materials, has the advantages of simple preparation, easy graphic design, low cost, and excellent physicochemical properties . Its potential as a potential material for SERS substrates has not yet been fully unlocked.…”

“…To further demonstrate the advantages of Ag NWs@LIG@PDMS, the SERS performances of three similar structures of silver nanowires with laser-induced graphene embedded in PDMS (Ag NWs/LIG@PDMS), silver nanowires embedded in PDMS Ag NWs/PDMS, and silver nanowire adhesive PDMS (Ag NWs@PDMS) were also compared. The results demonstrated that the LIG interlayer could promote the deposition and stabilization of Ag NWs, , and the sophisticated structural design of Ag NWs@LIG@PDMS enabled the substrate to have the combined effect of Ag electromagnetic enhancement and LIG chemical enhancement, showing highly sensitive SERS activity. Notably, the flexible and highly sensitive SERS substrate enabled detection of organic residues on noninvasive peel surfaces by in situ surface wiping.…”

3D Hot Spots Droplets on the MoS2/Al Hydrophobic Array Interface for SERS Quantitative and Multiplex Detection of Pesticide Residues

“…[19] On such a substrate, dense and uniform aggregation of nanoparticles in droplets is formed through a constant contact angle evaporation mode in the dynamic enrichment process. [20] Thus, the droplets of the mixed solution evaporate and concentrate on the tiny central area of the substrate, resulting in reliable ultrasensitive detection. [19] SERS signal reproducibility is another main factor for the ultimate SERS quantitative analysis, two-dimensional (2D) and three-dimensional (3D) nanostructure periodic arrays therefore are employed as reproducible SERS substrates, which are fabricated by particles self-assembly, [21,22] photolithography technique, [23] or template method, [24] etc.…”

“…[ 19 ] On such a substrate, dense and uniform aggregation of nanoparticles in droplets is formed through a constant contact angle evaporation mode in the dynamic enrichment process. [ 20 ] Thus, the droplets of the mixed solution evaporate and concentrate on the tiny central area of the substrate, resulting in reliable ultrasensitive detection. [ 19 ]…”