Assembling of anisotropic plasmonic sheet-core-satellites for simultaneous ultrasensitive detection of MC-LR toxin

Surface-enhanced Raman scattering nanotag of tunable ZIF-8 shell-encapsulated magnetic core-plasmonic satellites for disentangling chemical enhancement from electromagnetic enhancement

To enhance the stability of Raman reporters, these reporters were trapped in a metal organic framework (MOF) exoskeleton that was grown and compressed on Fe3O4@Au core-satellites, producing recyclable surface-enhanced Raman scattering (SERS) nanotags. Furthermore, encapsulation of Raman reporters in the assembled MOF-based nanocomposites was divided into two types of patterns, pre-enrichment and post-enrichment, in order to disentangle chemical enhancement of charge transfer (CT) from electromagnetic enhancement (EM) in SERS. Hence, to demonstrate the effect of encapsulation, a typical non-thiolated Raman reporter, for example crystal violet (CV) trapped in a core-satellite nanoassembly-based zeolitic imidazolate framework (ZIF-8) shell, was selected. The results suggest that stability and Raman intensity are remarkably improved. Moreover, the pattern of incorporation of CV into the ZIF-8 shell with tunable shell thickness can contribute to the disentangling of CT effects from EM effects.

SERS-based microdevices for use as in vitro diagnostic biosensors

Advances in surface-enhanced Raman scattering (SERS) detection have helped to overcome the limitations of traditional in vitro diagnostic methods, such as fluorescence and chemiluminescence, owing to its high sensitivity and multiplex detection capability. However, for the implementation of SERS detection technology in disease diagnosis, a SERS-based assay platform capable of analyzing clinical samples is essential. Moreover, infectious diseases like COVID-19 require the development of point-of-care (POC) diagnostic technologies that can rapidly and accurately determine infection status. As an effective assay platform, SERS-based bioassays utilize SERS nanotags labeled with protein or DNA receptors on Au or Ag nanoparticles, serving as highly sensitive optical probes. Additionally, a microdevice is necessary as an interface between the target biomolecules and SERS nanotags. This review aims to introduce various microdevices developed for SERS detection, available for POC diagnostics, including LFA strips, microfluidic chips, and microarray chips. Furthermore, the article presents research findings reported in the last 20 years for the SERS-based bioassay of various diseases, such as cancer, cardiovascular diseases, and infectious diseases. Finally, the prospects of SERS bioassays are discussed concerning the integration of SERS-based microdevices and portable Raman readers into POC systems, along with the utilization of artificial intelligence technology.

Progress on aptamer-based SERS sensors for food safety and quality assessment: methodology, current applications and future trends

It is well known that food safety has aroused extensive attentions from governments to researchers and to food industries. As a versatile technology based on molecular interactions, aptamer sensors which could specifically identify a wide range of food contaminants have been extensively studied in recent years. Surface-enhanced Raman spectroscopy integrated aptamer combines the advantages of both technologies, not only in the ability to specifically identify a wide range of food contaminants, but also in the ultra-high sensitivity, simplicity, portable and speed. To provide beneficial insights into the evaluation techniques in the field of food safety, we offer a comprehensive review on the design strategies for aptamer-SERS sensors in different scenarios, including non-nucleic acid amplification methods ("on/off" mode, sandwich mode, competition model and catalytic model) and nucleic acid amplification methods (hybridization chain reaction, rolling circle amplification, catalytic hairpin assembly). Meanwhile, a special attention is paid to the application of aptamer-SERS sensors in biological (foodborne pathogenic, bacteria and mycotoxins) and chemical contamination (drug residues, metal ions, and food additives) of food matrix. Finally, the challenges and prospects of developing reliable aptamer-SERS sensors for food safety were discussed, which are expected to offer a strong guidance for further development and extended applications.