Nanopillar-Assisted SERS Chromatography

Abstract

Practical implementation of surfaced enhanced Raman spectroscopy (SERS) sensing is hindered by complexity of real-life samples, which often requires long and costly pretreatment and purification. Here, we present a novel nanopillar-assisted SERS chromatography (NPC-SERS) method for simultaneous quantitation of target molecules and analysis of complex, multicomponent fluids, e.g., human urine spiked with a model drug paracetamol (PAR). Gold-coated silicon nanopillar (AuNP) SERS substrates and a centrifugal microfluidic platform are tactfully combined, which allows (i) a precise and fully automated sample manipulation and (ii) spatial separation of different molecular species on the AuNP substrate. The NPC-SERS technique provides a novel approach for wetting the stationary phase (AuNP) using the “wicking effect”, and thus minimizes dilution of analytes. Separation of PAR and the main human urine components (urea, uric acid, and creatinine) has been demonstrated. Quantitative detection of PAR with ultrawide linear dynamic range (0–500 ppm) is achieved by analyzing the spreading profiles of PAR on the AuNP surface. NPC-SERS transforms SERS into a sensing technique with general applicability, facilitating rapid and quantitative detection of analytes in complex biofluids, such as saliva, blood, and urine.

Wide Line Surface‐Enhanced Raman Scattering Mapping

“…Samples with different concentrations were placed into different positions on a SERS disk and centrifuged according to the rotation algorithm described in our previous work. [ 11,39 ]…”

Wafer‐Scale Polymer‐Based Transparent Nanocorals with Excellent Nanoplasmonic Photothermal Stability for High‐Power and Superfast SERS Imaging

“…Gold is chosen due to its stability which extends shelf life of the WTNC SERS substrates. During gold deposition, a shadow mask with a specific pattern can be employed on the wafer to render bare SU‐8 areas, facilitating further processes to be performed, such as laser dicing and microfluidic integration by ultrasonic wielding . A photograph of a WTNC SERS substrate taken from its backside is shown in Figure f.…”

Recent progress of microfluidics in surface‐enhanced Raman spectroscopic analysis

“…In another example, AgNPs were formed on Si wafer through metal magnetron sputtering [24]. To further improve the signal in SERS detection, micro-/nanostructures of microneedle [37], micro pyramidal [38] and nanopillar [25,[39][40][41][42] were constructed before metal deposition. To prevent delamination, on the other hand, a thin Ti adhesion layer was deposited onto Si/SiO 2 before Au layer in many cases [37,43,44].…”