Quantitative Detection of Pharmaceuticals Using a Combination of Paper Microfluidics and Wavelength Modulated Raman Spectroscopy

Abstract

Raman spectroscopy has proven to be an indispensable technique for the identification of various types of analytes due to the fingerprint vibration spectrum obtained. Paper microfluidics has also emerged as a low cost, easy to fabricate and portable approach for point of care testing. However, due to inherent background fluorescence, combining Raman spectroscopy with paper microfluidics is to date an unmet challenge in the absence of using surface enhanced mechanisms. We describe the first use of wavelength modulated Raman spectroscopy (WMRS) for analysis on a paper microfluidics platform. This study demonstrates the ability to suppress the background fluorescence of the paper using WMRS and the subsequent implementation of this technique for pharmaceutical analysis. The results of this study demonstrate that it is possible to discriminate between both paracetamol and ibuprofen, whilst, also being able to detect the presence of each analyte quantitatively at nanomolar concentrations.

Modulated Raman Spectroscopy for Enhanced Cancer Diagnosis at the Cellular Level

“…Wavelength-modulated Raman spectroscopy (WMRS) for analysis on a paper microfluidics platform allows us to suppress the background fluorescence of the paper and explore pharmaceutical analysis. Our data show that it is possible to discriminate between both paracetamol and ibuprofen and record nanomolar concentrations of each analyte [ 69 ].…”

“…Further, by optimising the modulation parameters, we can achieve a complete discrimination between cancer/non-cancer bladder cells with a total acquisition time of only a few seconds [ 67 ]. Finally, we demonstrate that this modulated Raman method can robustly improve the performance, not only of bulk free-space systems, but can be applied to portable approaches (wave guide-confined Raman spectroscopy and paper microfluidics) [ 68 , 69 ], opening new opportunities to develop portable microfluidic devices for higher throughput Raman analysis.…”

Recent applications of paper‐based point‐of‐care devices for biomarker detection

“…Presently, 2D‐ and 3D‐PADs have been invented and applied to different applications ranging from biological testing , clinical diagnosis to education tools in developing countries . Furthermore, PADs have gained popularity in pharmaceutical development and analysis for quality assessment of pharmaceutical dosage forms , determination of drug levels in biofluids , and detection of counterfeit drugs .…”

Assessment of shifted excitation Raman difference spectroscopy in highly fluorescent biological samples

“…Several approaches exist to correct spectra with high spectral backgrounds, which can be broadly classified into instrumental and computational methods. 12 The instrumental methods can be separated into time-gated, 13,14 wavelength and frequency modulated [15][16][17][18] methods. Examples for computational baseline correction methods are the sensitive nonlinear iterative peak (SNIP) algorithm, 19,20 multiplicative signal correction (MSC), 21 extended multiplicative signal correction (EMSC), 22,23 polynomial fitting, 24 rubberband method 25,26 etc.…”