The Raman tweezers spectroscopy is the combination of Raman spectroscopy combined with an Optical tweezers device. C.V. Raman was awarded Nobel Prize in the year 1930 for the discovery of the inelastic scattering of light called as Raman Effect, and Arthur Ashkin was awarded Nobel Prize in 2018 for the invention of Optical trapping of micron-sized particles in an aqueous medium to arrest them from Brownian motion.  The technique can trap individual cells and record Raman spectra to explore changes that occurred at cellular and molecular levels under physiological conditions.  This technique is widely applied to explore cell-drug, cell-cell, and cell-nanoparticle interactions.

Micro-Raman spectroscopy of storage lesions:

Blood components are stored in the blood bank for transfusion. Each blood component will be separately stored as packed red blood cells, platelet-rich plasma, and blood plasma. There is well established storing period for the blood components in blood banks. In the case of RBCs, the storage period is 42 days, and at the same time, the storage period of the platelet is five days. During the above said period, there will be a lot of biochemical changes occurring to the blood components. There is no proper method to probe these storage lesions. The Raman tweezers spectroscopy technique is the right choice to monitor the stored cells.

Raman tweezers spectroscopy to probe blood disorders:

Blood disorders include Anemia, Leukemia, Thalassemia, sickle cell disease, polycythemia, etc. These conditions are directly effecting the blood components (RBC, WBC, etc.). Raman tweezers spectroscopy technique can be used of these disease conditions. In the case of thalassemia, Iron deficiency anemia (IDA), and sickle cell anemia, all of these diseases are affecting RBCs. The IDA and thalassemia have microcytic RBCs, similarly, sickle cell anemia has cells in sickle shape, so using the Raman tweezers technique it is possible to trap a particular cell for recording the Raman spectra.

Micro-Raman spectroscopy for the analysis of blood components with external stressors (silver nanoparticles, gold nanoparticles, bisphenol, alcohol,  and IV fluids):

Interaction of Ag NPs with live red blood cells using single-beam Raman Tweezers spectroscopy was carried out. Our experiments reveal that AgNPs induce irreversible modifications within an RBC. In particular, the heme conformation in an RBC is observed to transform from the usual R-state (oxy-state) to the T-state (deoxy-state). We rationalize our observations by proposing a model for the nanoparticle cytotoxicity pathway when NP’s size is larger than the membrane pore size.  We propose that the interacting AgNPs with the cell surface induces cell damage due to the alteration of intracellular pH caused by the blockage of cell membrane transport. Gold nanoparticles of different sizes and shapes also induced oxidative stress on RBCs under certain concentrations.   

The interaction of several other external stressors such as bisphenol, alcohol, and different Intravenous fluids, and their interaction with RBCs were studied in detail using the Raman tweezers system to know the biochemical modification that takes place in RBCs.

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2. John RV, Devasia T, N M, Lukose J, Chidangil S. Micro-Raman spectroscopy study of blood samples from myocardial infarction patients. Lasers in Medical Science. 2022 Dec;37(9):3451-60.

3. Jacob SS, Lukose J, Bankapur A, Mithun N, Vani Lakshmi R, Acharya M, Rao P, Kamath A, Baby PM, Rao RK, Chidangil S. Micro-Raman spectroscopy study of optically trapped erythrocytes in malaria, dengue and leptospirosis infections. Frontiers in Medicine. 2022 Oct 6;9:858776.

4. Barik AK, Pavithran S, Mithun N, Pai MV, Upadhya R, Pai AK, Lukose J, Chidangil S. A micro-Raman spectroscopy study of inflammatory condition of human cervix: Probing of tissues and blood plasma samples. Photodiagnosis and Photodynamic Therapy. 2022 Sep 1;39:102948.

5. Mithun N, Lukose J, Mohan G, Shastry S, Chidangil S. Single cell spectroscopy of red blood cells in intravenous crystalloid fluids. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 2021 Aug 5;257:119726.