Ag Nanoparticles for the Direct Detection of Oxaprozin in the Blood Using Surface-Enhanced Raman Spectroscopy

Abstract

Direct detection of drugs in the blood contributes to the study of pharmacokinetics, whereas the low-concentration blood drug makes this goal challenging. Here, silver nanoparticles (AgNPs) are used for direct detection in the blood environment. The finite element method is used to study the electric field enhancement of AgNPs in the blood environment. We study the Raman enhancement factors associated with AgNPs and study the effects of parameters such as the wavelength, medium environment, and nanoparticle distribution on near-field enhancement. The method for directly detecting oxaprozin (OXA) drug in the blood of mice is reported, which is based on surface-enhanced Raman scattering (SERS) detection. We prepare AgNPs with a diameter of 15 nm and further concentrated them as a SERS substrate to achieve low-concentration OXA solution detection in blood and aqueous environments. The minimum detection limit in the aqueous environment is 10 −6 M, and the detection limit in the blood is 10 −4 M (29.32 μg/mL), which is less than the peak blood drug concentration in clinical applications. Further analysis shows that OXA in the blood can be directly detected by SERS because of the characteristic peak of 1025 cm −1 , and the corresponding attribution is the C−C−C plane vibration. The numerical simulation of AgNPs and the detection of OXA solution in the blood environment indicate that SERS has a good application prospect in low-concentration blood drug detection.

Enhanced Superhydrophobic Substrate-Based 3D SERS Platform for a Portable Raman Spectrometer-Assisted Drug Detection in Plasma

“…PFT could rapidly adsorb onto Ag NPs, reducing the energy barrier on the particle surface and facilitating the rapid assembly of Ag NPs into a monolayer film on a water–hexane interface. This film could then be transferred to a silicon wafer and dried to form a uniform solid silver film with superhydrophobic property, as PFT provided an abundant superhydrophobic structure (−CF 3 ) to achieve an ultralow adsorption barrier Figure b displays the shiny Ag NPs film self-assembled on the liquid interface in a beaker that formed quickly in less than 1 min after the addition of PFT.…”

“…This film could then be transferred to a silicon wafer and dried to form a uniform solid silver film with superhydrophobic property, as PFT provided an abundant superhydrophobic structure (−CF 3 ) to achieve an ultralow adsorption barrier. 36 Figure 1b displays the shiny Ag NPs film self-assembled on the liquid interface in a beaker that formed quickly in less than 1 min after the addition of PFT. This film could be compactly transferred to a silicon wafer and dried to a solid film with yellow color (Figure 1c).…”

“…In this paper, a superhydrophobic silver-film-assisted 3D SERS platform was proposed for the simple and sensitive detection of drugs in plasma (Scheme 1). The highlighted advantages include the following: (1) The most rapid strategy NP self-assembly method until now was introduced to produce a homogeneous superhydrophobic SERS substrate; 36 (2) Raman-reporter-embedded, core−shell-structured Au@Ag NPs were mixed with plasma, whose "internal standard (IS)" SERS signal could calibrate the signal of the analyte adsorbed on the outer surface and alleviate the adverse effects of nonuniform NPs distribution, benefitting by gaining reliable quantitative analysis results. 37 Ag NPs of the superhydrophobic silver film, together with the Au@Ag NPs, generated 3D hotspots for drug sensing.…”