Raman spectroscopic screening of high and low molecular weight fractions of human serum

Abstract

This study explores the suitability of Raman spectroscopy as a bioanalytical tool, when coupled with ultra-filtration and multivariate analysis, to detect imbalances in both high molecular weight and low molecular weight fractions of the same samples of human patient serum, in the native liquid form.

Potential of Raman spectroscopy for the analysis of plasma/serum in the liquid state: recent advances

“…In several studies of human serum, β-carotene has been observed as a string contributor to the spectrum, particularly when using 532nm or lower as source, as the scattering from the conjugated antioxidant species are resonantly enhanced [29,50,83]. The LMWF species are not easily removed by centrifugal separation [69], but their contributions can be effectively "digitally" removed using the adapted EMSC protocol.…”

“…In order to advance the studies of Berger et al, [86] and Rohleder et al, [36,37] using the improved inverted microscopy modality, Parachalil et al [69] also used the EMSC correction, ultrafiltration protocols and PLSR analysis to construct models for the quantitation of the whole serum (total protein, γ globulin), serum concentrate (albumin) and serum filtrate (urea and glucose) of patient samples, resulting in higher accuracy and sensitivity of analysis. The strategy demonstrated in this study enables the simultaneous estimation of total protein level and detection of imbalance in γ globulin concentration accurately from whole serum, without the use of any reagents and without destroying the sample being studied.…”

“…Parachalil et al [69] using this analytical set up combined with chemometric techniques such as EMSC to measure concentrations of HMWF, LMWF and drugs in human serum strongly indicates a highly significant correlation between predicted and reference concentrations.…”

“….2 mg/dL, and the technique was demonstrated to be at least as accurate as ATR-FTIR of similar patient samples[69], measured in the dried state and closer to the accuracy of colorimetric methods, 1.4 mg/dL urea[99] and 2 mg/dL glucose[100]. Similarly, higher prediction accuracy (RMSECV=1.14 mg/dL) was attained when PLSR analysis was performed on a reduced range for urea from patient samples over the concentration range 2.52-78.99 mg/dL, compared to the full range (RMSECV=1.73 mg/dL).…”

“…LOD of glucose[44], busulfan[101], methotrexate[101], cholesterol, urea[69] and vitamin B12 calculated from the PLSR prediction plot of these analytes, compared to the maximum Raman intensity of maximum peak per unit acquisition time, per unit concentration Vibrational spectroscopic techniques have attracted a lot of attention as analytical methods of choice for analysing biological samples. The promise of the techniques is based on the abilities to objectively fingerprint the biochemical profile underlying early onset of disease in cells, tissues or bodilyfluids[3,6,9].…”