Toward Levofloxacin Monitoring in Human Urine Samples by Employing the LoC-SERS Technique

Abstract

The pharmacokinetics of antibiotics such as levofloxacin exhibits large interindividual differences, questioning the value of fixed dose regimens and warranting individual dosing based on therapeutic drug monitoring. Here, in a proof of principal study, it is shown that levofloxacin can be detected in human urine samples by employing lab-on-a-chip surface enhanced Raman spectroscopy (LoC-SERS). First, artificial urine is used as a matrix in order to get insights into the influence of different parameters such as matrix complexity, aggregation time, and matrix dilution on the overall SERS signal. Second, three anonymized individual and three pooled urine samples originating from patients undergoing either no or unknown medical treatments have been spiked with the target analyte. Measurements were performed with a benchtop and a portable Raman setup. In all six samples urinary levofloxacin concentrations between 0.45 mM (162.6 μg/mL) and 1.8 mM (650.5 μg/mL) have been successfully detected. According to the literature, the normal levofloxacin concentration in urine is 1.38 mM ± 0.68 mM with a minimum measured concentration of 0.45 mM after 4 h from the administration of a 500 mg dose. The presented results therefore show that LoC-SERS is a promising bioanalytical tool for urine analysis.

Plasmonics in Sensing: From Colorimetry to SERS Analytics

“…Lab-on-a-chip (LOC) SERS is an approach that is particularly well-suited for diagnostic applications. Figure 8D depicts a droplet-based microfluidic setup for LOC SERS measurements [104]. For measurements, equal amounts of Ag colloids and buffer/analyte solutions were mixed and, finally, 1 M KCl was added for inducing the aggregation in a controlled and reproducible manner [105].…”

Evaluation and Optimization of Paper-Based SERS Substrate for Potential Label-Free Raman Analysis of Seminal Plasma

“…Insufficient chloride ions would not overcome electrostatic repulsion between AgNPs effectively to achieve more hotspots; while excessive chloride ions could induce excessive aggregation and precipitation of AgNPs, both are not preferred for SERS measurement. Moreover, the SERS spectra of analytes are time dependent between the induction of the aggregation and the measurement [19,20]. However, to our knowledge, there are no systematic or comprehensive studies that aim at evaluating the effect of NaCl concentrations and the time of incubating paper substrate in colloidal AgNPs to paper SERS performance.…”

Functionalization of nanostructured gold substrates with chiral chromophores for SERS applications: The case of 5‐Aza[5]helicene

“…Raman spectroscopy is a powerful molecular probe, and the detection threshold characteristic of biomedical applications can be conveniently achieved by surface enhanced Raman scattering (SERS) spectroscopy. SERS conditions can be achieved at nanostructured metal surfaces with favorable plasmonic properties, and even low concentrations of drugs can be measured, as reported in literature …”

“…SERS conditions can be achieved at nanostructured metal surfaces with favorable plasmonic properties, and even low concentrations of drugs can be measured, as reported in literature. [11][12][13][14][15][16][17][18][19] [This article is part of the Special Issue: Proceedings 16th International Conference on Chiroptical Spectroscopy, Rennes France 2017. See the first articles for this special issue previously published in Volumes 30:4, 30:5, and 30:6.…”