Label-free trace detection of bio-molecules by liquid-interface assisted surface-enhanced Raman scattering using a microfluidic chip

Abstract

Surface-enhanced Raman scattering (SERS), owing to its high sensitivity based on localized surface plasmon resonance of nanostructured metals, is recently attracting much attention to be used for biotechnology, such as cell imaging and tumor therapy. On the other hand, the trace detection of bio-molecules with large molecular weight is still challenging because the troublesome treatment of SERS substrate using coupling or cross-linking agents is required. In this paper, we apply liquid interface assisted SERS (LI-SERS) method, which provides unique features of collection and self-immobilization of analyte molecules on the SERS substrate, to realize the label-free trace detection of bio-molecules with detection limits of pM ~ fM. Specifically, deoxyribonucleic acid (DNA) discrimination and quantitative detection of β-Amyloid (Aβ) in trace-concentration are demonstrated to illustrate the ultrahigh sensitivity and versatility of the LI-SERS method. The results suggest LI-SERS is promising for the early-stage diagnosis of diseases such as virus infection and Alzheimer's disease.

Hybrid metal-dielectric gratings (HMDGs) as an alternative UV-SERS substrate

“…Surface-enhanced Raman scattering (SERS) spectroscopy has attracted great interest as a promising analytical technique for bimolecular detection due to its capability of label-free detection and high sensitivity. [1][2][3][4] Fleischmann et al first observed the Raman scattering signal of pyridine adsorbed onto the surface of roughened silver electrodes in 1974. 5 Further, with the development of processing techniques, SERS has acquired great strides and has been applied in numerous fields, such as surface science, electrochemistry, biomolecule detection, medical science, environmental monitoring, and food safety.…”

Single‐platform, Attomolar Detection of Multiple Biomarkers by a Flexible SERS Sensor

“…There have been significant efforts to produce stable and uniform substrates with maximum number of effective hotspots to engender better SERS sensitivity [14] . Various plasmonic nanomaterials have been explored on rigid SERS substrates with limited onsite detection capabilities.…”

“…There have been significant efforts to produce stable and uniform substrates with maximum number of effective hotspots to engender better SERS sensitivity. [14] Various plasmonic nanomaterials have been explored on rigid SERS substrates with limited onsite detection capabilities. Conversely, flexible SERS substrates offer easy sampling, scalability through printing and electrospinning, are low costing, making them ideal for translational sensing applications, especially when integrated as wearable SERS devices.…”

Interfacial Self-Assembly of Surfactant-Free Au Nanoparticles as a Clean Surface-Enhanced Raman Scattering Substrate for Quantitative Detection of As5+ in Combination with Convolutional Neural Networks

“…In recent years, surface-enhanced Raman scattering (SERS) spectroscopy is considered as a promising technique for the determination of trace heavy metal ions because of its special fingerprinting ability, high sensitivity, fast detection speed, and simple operation. − The bottom-up approach is a simple and cost-effective strategy for fabricating SERS substrates, which mainly relies on the assembly of nanoparticle (NP) suspensions at the interface. ,− To date, using strong adsorbent surfactants to guide particle growth has produced a variety of noble metal NPs with different sizes, morphologies, compositions, or structures. On the other hand, the surfactants facilitate the separation of nanoparticles and ensure the stability of the NPs. − Although the morphology of the synthesized NPs can be easily manipulated using surfactant molecules, their presence is problematic for the application of plasmonic sensing. − Surfactant molecules bound to the surface of NPs act as physical and chemical barriers that restrict access of the analyte to the hot spot region, resulting in reduced Raman intensity of the analyte. , However, it remains a significant challenge to avoid the influence of surfactants on the adsorption of detection molecules by converting surfactant-free NPs to stable and reliable SERS substrates.…”