Optimization of Surface-Enhanced Raman Spectroscopy Conditions for Implementation into a Microfluidic Device for Drug Detection

Abstract

A microfluidic device is being developed by University of California-Santa Barbara as part of a joint effort with the United States Army to develop a portable, rapid drug detection device. Surface-enhanced Raman spectroscopy (SERS) is used to provide a sensitive, selective detection technique within the microfluidic platform employing metallic nanoparticles as the SERS medium. Using several illicit drugs as analytes, the work presented here describes the efforts of the Edgewood Chemical Biological Center to optimize the microfluidic platform by investigating the role of nanoparticle material, nanoparticle size, excitation wavelength, and capping agents on the performance, and drug concentration detection limits achievable with Ag and Au nanoparticles that will ultimately be incorporated into the final design. This study is particularly important as it lays out a systematic comparison of limits of detection and potential interferences from working with several nanoparticle capping agents-such as tannate, citrate, and borate-which does not seem to have been done previously as the majority of studies only concentrate on citrate as the capping agent. Morphine, cocaine, and methamphetamine were chosen as test analytes for this study and were observed to have limits of detection (LOD) in the range of (1.5-4.7) × 10 M (4.5-13 ng/mL), with the borate capping agent having the best performance.

3D ZnO/Ag Surface-Enhanced Raman Scattering on Disposable and Flexible Cardboard Platforms

“…This localized enhancement effect allows the detecting of extremely small amounts of analytes, making SERS an efficient tool for the detection of a variety of problems, including corrosion, detection of chemical warfare agents, bacteria on food, trace evidence in forensic science, and blood glucose, among others [ 49 , 50 , 51 , 52 ].…”

Review of SERS Substrates for Chemical Sensing

“…Microfluidics have been explored as a means of mixing Ag NPs and samples [65,66]. A schematic of such a device is shown in Figure 3a [65].…”

“…Two approaches have been taken to make single-use, diposable substrates that can be dispersed through a sample. One approach is to immobilize Ag or Au nanpoparticles on either solid [66] or hollow [158,159,160] aminated silica beads, the latter referred to as ‘lab-on-a-bubble’. The other approach immobilizes Ag or Au nanoparticles on the surface of aminated magnetic beads to create capture matrices [9,23,24,161].…”

New advances in microfluidic flow cytometry

“…There are many other optical‐based detection techniques used in microfluidic devices including chemiluminescence , TL detection , surface plasma resonance detection , and surface‐enhanced Raman scattering (SERS) detection . Although these techniques are sensitive, they are not suitable to be used in the microfluidic flow cytometry due to their detection mechanism.…”