Surface enhanced Raman spectroscopic direct determination of low molecular weight biothiols in umbilical cord whole blood

Abstract

Biothiols play an essential role in a number of biological processes in living organisms including detoxification and metabolism. Fetal to neonatal transition poses a pro-oxidant threat for newborn infants, especially those born prematurely. A reliable and rapid tool for the direct determination of thiols in small volume whole blood (WB) samples would be desirable for its application in clinical practice. This study shows the feasibility of Surface Enhanced Raman Spectroscopy (SERS) using a silver colloid prepared by reduction of silver nitrate using hydroxylamine, as the SERS substrate for the quantification of thiols in WB samples after a simple precipitation step for protein removal. Bands originating from biothiols (790, 714 and 642 cm(-1)) were enhanced by the employed SERS substrate and the specificity of the detected SERS signal was tested for molecules presenting -SH functional groups. A statistically significant correlation between the obtained SERS signals and the thiol concentration measured using a chromatographic reference method in umbilical cord WB samples could be demonstrated. Using WB GSH concentrations obtained from the chromatographic reference procedure, a Partial Least Squares (PLS) regression model covering GSH concentrations from 13 to 2200 μM was calculated obtaining a root mean square error of prediction (RMSEP) of 381 μM when applied to an external test set. The developed approach uses small blood sample volumes (50 μL), which is important for clinical applications, especially in the field of neonatology. This feasibility study shows that the present approach combines all the necessary characteristics for its potential application in clinical practice.

Oxygen and oxidative stress in the perinatal period

“…The most relevant hindrance to the popularization of these techniques resides fundamentally in the complexity, cost and difficulty in driving of the laboratory equipment only available in academic setting with research facilities. Hopefully, the development of new machines with greater clinical applicability and new techniques such as surface enhanced Raman spectroscopy (SERS) can render excellent results at the cot side and may perhaps in the coming future allow to perform serial determinations of oxidative stress biomarkers with very little volume of sample and immediate results [83].…”

A Localized Surface Plasmon Resonance Sensing Method for Simultaneous Determination of Atenolol and Amiloride in Pharmaceutical Dosage Forms and Urine Samples

“…Moreover, LSPR is responsible for enhancing the surface sensitivity of different spectroscopic methods including fluorescence [ 20 ] and Raman scattering [ 21 , 22 ]. The reported applications of LSPR found in literature are based on the optical detection and its enhancement such as in surface enhanced Raman spectroscopy (SERS) which is applied for molecule detection using the extinction of metal nanoparticles [ 23 – 25 ].…”

Simultaneous quantification of multiple endogenous biothiols in single living cells by plasmonic Raman probes

“…Over the past few decades, a number of techniques have been exploited to detect biothiols, including high performance liquid chromatography (HPLC), 9 , 10 mass spectrometry (MS), 11 , 12 capillary electrophoresis, 13 , 14 electrochemistry assay, 15 , 16 UV-vis absorption spectrometry, 17 , 18 surface-enhanced Raman scattering (SERS), 19 – 21 and fluorescence methods. 8 , 22 – 25 Among these methods, fluorescence based imaging methods are the most available techniques for the detection of biothiols in cell samples.…”

“…1–2 nm) and a wealth of fingerprint information can provide much more molecular structural information. 29 , 30 Thus far, only a few Raman-based biothiol detection methods have been reported, 19 – 21 and two main challenges still remain unaddressed: discriminating different constituents within a multicomponent cellular system and quantifying the concentration of each constituent. Herein, we solved these two challenges by designing a Raman probe that could react with Cys, Hcy and GSH, and chemical reaction kinetics and quantitative principal component analysis (qPCA) allowed us to discriminate and quantify these three biothiols at the single cell level simultaneously via the one probe platform.…”