Normal saline-induced deoxygenation of red blood cells probed by optical tweezers combined with the micro-Raman technique

Abstract

The use of normal saline for washing red blood cells and treating critically ill patients is a regular medical practice in hospital settings. An optical tweezer in combination with Raman spectroscopy is an analytical tool employed for the investigation of single cell dynamics, thus providing molecular fingerprint of the cell by optically trapping the cell at a laser focus. In this study, the impact of normal saline on individual human red blood cell was compared with that of blood plasma using Raman tweezers spectroscopy.Major spectral variations in the marker frequencies at 1209 cm À1 , 1222 cm À1 , 1544 cm À1 , and 1561 cm À1 of the Raman spectrum of the treated cells imply that the transition of hemoglobin to the deoxygenated state occurs when 0.9% normal saline is used. This may result in serious implications in blood transfusion. The results obtained from the principal component analysis also displayed clear differentiation among the red blood cells diluted in normal saline and those diluted in plasma. In future studies, efforts will be made to correlate the deoxygenation status of red blood cells with various human disorders. Fig. 3 Average Raman spectra of RBCs diluted in normal saline and plasma where spectral variations are dominant (a), (b) the spin marker region, (c) the methine deformation region, (d) the FeO 2 stretch, and (e) the porphyrin breathing mode.This journal is

Optical tweezers combined with micro‐Raman investigation of alcohol‐induced changes on single, live red blood cells in blood plasma

“…The oxygenation markers in the Raman spectra show prominent intensity enhancement in plasma compared with normal saline. This observation is drawn by monitoring the peaks mainly at 565; 1,222; 1,561; and 1,636 cm ‐1 . To maintain the blood oxygenation conditions and to keep the cells intact for long time, all the alcohol experiments were further continued with blood plasma as the solvent medium.…”

“…This observation is drawn by monitoring the peaks mainly at 565; 1,222; 1,561; and 1,636 cm -1 . [27] To maintain the blood oxygenation conditions and to keep the cells intact for long time, all the alcohol experiments were further continued with blood plasma as the solvent medium. Because the cells in plasma are showing the oxygenation trend, any stress-induced deoxygenation effect can be clearly noted from the respective established spectral regions (methine deformation region, spin marker region, pyrrole deformation region, etc.…”

Micro-Raman Spectroscopy Analysis of Optically Trapped Erythrocytes in Jaundice

“…This specific band region comprises Raman signatures that were scattered from the C-C bonds in the porphyrin ring and rely on the spin-state of the iron atom ( Wood and McNaughton, 2002 ). It is an important spectral range to explore, as it describes the “oxygenation” (oxy) state of Hb ( Lukose et al, 2019 ). The Raman peaks at 1,524, 1,545, 1,563, 1,602, 1,617, and 1,636 cm –1 exhibited a decrease in their intensities in the jaundice samples when compared to their corresponding peaks from the healthy samples.…”

“…This indicated that RBCs in the "jaundice environment" produced heme-aggregates within themselves. There appeared to be a shift in the 1,370 cm −1 (oxy state) peak to 1,375 cm −1 (deoxy state) in jaundice, ascertaining lesser oxy states in jaundice (Lukose et al, 2019).…”

“…In jaundice, there was a shift of the Raman peak at 973 to 975 cm −1 with a significant increase in its intensity along with a shouldering of 675 cm −1 pyrrole-deformation band with a new peak at 663 cm −1 . These occurrences indicate heme-aggregation, as a consequence of protein denaturation, under "stressful" environments (Wood et al, 2005;Lukose et al, 2019). The 752 cm −1 porphyrin breathing mode peak, a crucial spectral-marker that confers the integrity of Hb (Deng et al, 2005), shows reduced intensity in the jaundice group.…”