Nanoparticle Tracers in Reservoir-On-A-chip by Surface-Enhanced Raman Scattering - Fluorescence SERS-SEF Imaging Technology

Nanoparticles or nanocomposite fluids are injected into oil reservoirs for reservoir tracing or to improve injectivity or recovery of oil. Effective application of nanoparticles in fluid flooding still needs to be investigated. Dual-mode surface-enhanced Raman scattering (SERS) - surface-enhanced fluorescence (SEF) composite nanoparticles have been developed as nanoparticle reservoir tracers. This presentation discusses their transport and detectability in porous media, providing valuable information for understanding the role of nanoparticles in EOR process. The dual-mode surface-enhanced Raman scattering (SERS) - surface-enhanced fluorescence (SEF) composite nanoparticles are synthesized composed of Ag or Au metal cores, specific dye molecules, and a SiO2 shell materials. To optimize maximum signal enhancement of both phenomena such as SERS and SEF, the distance between core metal nanoparticles and dye molecules are precisely controlled. The synthesized composite nanoparticles barcoded with dye molecules are detectable by both fluorescence and Raman spectroscopies due to the SERS-SEF phenomena. Both fluorescence and Raman microscopic images of dye embedded surfaceenhanced Raman scattering (SERS) surface-enhanced fluorescence (SEF) composite nanoparticles in water phase successfully were collected within microfluidic reservoir-on-a-chip. The reservoir-on-a-chip utilized in this study fabricated based on reservoir rock geometry and coated with calcium carbonate. The synthesized SERS-SEF composite nanoparticles in water solution have been flooded into the microfluidic reservoir-on-a-chip and imaged for probing interfacial behavior of fluids such as liquid-liquid interfaces and studying the behavior of nanoparticles at liquid-rock interfaces. The precise synthesis method to produce the composite nanoparticles has been developed for the embedded dye molecules to generate noticeably enhanced detectability due to the strong SERS phenomenon. In conclusion, SERS-SEF nanoparticles barcoded with the fingerprinted Raman and fluorescence signals can provide a possible pathway toward SERS-SEF nanoprobe as various barcoded tracers to understand fluid behavior in porous media. Composite nanoparticle synthesis and its detection in flow technologies have been developed for visualization of the fluid flow behavior in porous media representing reservoir rock geometry. The results of the high-resolution nanoparticle fluid imaging data in reservoir-on-a-chip can be applied to understand mechanism of nanoparticle fluid assisted chemical enhanced oil recovery.

Plasmonic Nanoparticles as Optical Sensing Probes for the Detection of Alzheimer’s Disease

Alzheimer’s disease (AD), considered a common type of dementia, is mainly characterized by a progressive loss of memory and cognitive functions. Although its cause is multifactorial, it has been associated with the accumulation of toxic aggregates of the amyloid-β peptide (Aβ) and neurofibrillary tangles (NFTs) of tau protein. At present, the development of highly sensitive, high cost-effective, and non-invasive diagnostic tools for AD remains a challenge. In the last decades, nanomaterials have emerged as an interesting and useful tool in nanomedicine for diagnostics and therapy. In particular, plasmonic nanoparticles are well-known to display unique optical properties derived from their localized surface plasmon resonance (LSPR), allowing their use as transducers in various sensing configurations and enhancing detection sensitivity. Herein, this review focuses on current advances in in vitro sensing techniques such as Surface-enhanced Raman scattering (SERS), Surface-enhanced fluorescence (SEF), colorimetric, and LSPR using plasmonic nanoparticles for improving the sensitivity in the detection of main biomarkers related to AD in body fluids. Additionally, we refer to the use of plasmonic nanoparticles for in vivo imaging studies in AD.

A comprehensive review on plasmonic-based biosensors used in viral diagnostics

The proliferation and transmission of viruses has become a threat to worldwide biosecurity, as exemplified by the current COVID-19 pandemic. Early diagnosis of viral infection and disease control have always been critical. Virus detection can be achieved based on various plasmonic phenomena, including propagating surface plasmon resonance (SPR), localized SPR, surface-enhanced Raman scattering, surface-enhanced fluorescence and surface-enhanced infrared absorption spectroscopy. The present review covers all available information on plasmonic-based virus detection, and collected data on these sensors based on several parameters. These data will assist the audience in advancing research and development of a new generation of versatile virus biosensors.

A straightforward and sensitive “ON–OFF” fluorescence immunoassay based on silicon-assisted surface enhanced fluorescence

A straightforward immunoassay based on silicon-assisted surface enhanced fluorescence (SEF) has been demonstrated using a silicon-based fluorescent immune substrate and silver-antibody nanoconjugate (SANC).