Optical Tweezers in Human Cancers / 肿瘤防治研究

Optical tweezers are a means to manipulate objects with light. Optical tweezers can obtain a nanometer space, piconewton force, and a millisecond resolution; thus, they are excellently suited for studying biological processes from the single-cell to the single-molecule level. Optical tweezers can screen and manipulate tumor cells, study single molecule, and monitor cancer treatments. Thus, optical tweezers will promote the progress of cancer research and treatments.

Biomechanical and biochemical investigation of erythrocytes in late stage human leptospirosis

Leptospirosis is a zoonotic disease caused by bacteria of the genus Leptospira, which can cause lipid changes in the erythrocyte membrane. Optical tweezers were used to characterize rheological changes in erythrocytes from patients with leptospirosis in the late stage. Biochemical methods were also used for quantification of plasma lipid, erythrocyte membrane lipid, and evaluation of liver function. Our data showed that the mean elastic constant of erythrocytes from patients with leptospirosis was around 67% higher than the control (healthy individuals), indicating that patient's erythrocytes were less elastic. In individuals with leptospirosis, several alterations in relation to control were observed in the plasma lipids, however, in the erythrocyte membrane, only phosphatidylcholine showed a significant difference compared to control, increasing around 41%. With respect to the evaluation of liver function of individuals with leptospirosis, there was a significant increase in levels of alanine transaminase (154%) and aspartate transaminase (150%), whereas albumin was 43.8% lower than control (P<0.01). The lecithin-cholesterol acyltransferase fractional activity was 3.6 times lower in individuals with leptospirosis than in the healthy individuals (P<0.01). The decrease of the erythrocyte elasticity may be related to the changes of erythrocyte membrane phospholipids composition caused by disturbances that occur during human leptospirosis, with phosphatidylcholine being a strong candidate in the erythrocyte rheological changes.

Raman spectroscopy of bone marrow mesenchymal stem cells in medium-frequency pulsed electromagnetic fields / 中国组织工程研究

BACKGROUND:Studies about low-frequency pulsed electromagnetic fields interfering with bone marrow mesenchymal stem cells proliferation and differentiation are many, but the Raman spectra of single stem cells irradiated in electromagnetic fields analyzed by surface Raman spectroscopy analysis are rarely reported. OBJECTIVE:To compare the difference in Raman spectra of bone marrow mesenchymal stem cells with or with no irradiation of 3 000 Hz pulsed electromagnetic fields. METHODS:Bone marrow mesenchymal stem cells isolated from Sprague-Dawley rats were cultured and identified. Passage 3 cells were inoculated into 6-wel plates and divided into two groups:pulsed electromagnetic field irradiation group and blank control group. After cultured for 7 days, cells in the two groups were transferred to physiological saline, and 30 cells were randomly col ected from each group. Four Raman spectra were harvested from each celland the average relative intensity of Raman spectra was calculated and compared between two groups. RESULTS AND CONCLUSION:There were the same Raman peaks in the two groups, and the waveforms were basical y same in the two group based on the curve mapping by origin 7.0 software. The peak value in the irradiation group was decreased compared with the blank control group. Laser optical tweezers Raman spectroscopy can be applied to study the biochemical changes of a single stem cellat the molecular level. The Raman spectra of bone marrow mesenchymal stem cells irradiated by 3 000 Hz pulsed electromagnetic fields differ from those without irradiation, and the peak also lowered after irradiation.

Electrical properties of the red blood cell membrane and immunohematological investigation

Hemagglutination is widely used in transfusion medicine and depends on several factors including antigens, antibodies, electrical properties of red blood cells and the environment of the reaction. Intermolecular forces are involved in agglutination with cell clumping occurring when the aggregation force is greater than the force of repulsion. Repulsive force is generated by negative charges on the red blood cell surface that occur due to the presence of the carboxyl group of sialic acids in the cell membrane; these charges create a repulsive electric zeta potential between cells. In transfusion services, specific solutions are used to improve hemagglutination, including enzymes that reduce the negative charge of red blood cells, LISS which improves the binding of antibodies to antigens and macromolecules that decrease the distance between erythrocytes. The specificity and sensitivity of immunohematological reactions depend directly on the appropriate use of these solutions. Knowledge of the electrical properties of red blood cells and of the action of enhancement solutions can contribute to the immunohematology practice in transfusion services.

Raman Tweezers Techniques in Different Cells Research / 中国医学物理学杂志

Objective: To introduce the Raman spectrum, the optical tweezers physical principle and its working characteristics, unify the detail medical research work, summarize specific application situation of the Raman tweezers technology in the different cells domain. Methods: Use the optical tweezers to fix the living cells, simultaneously carry out Raman spectrometry on the living cell or the cell organ by using the laser Raman technology. By applying this technology, the samples will be captured in the suspending liquid. In an approximate physiological state, the single living specimens, such as the cells, the cell organs or the biological macro-molecules, will be studied and the real-time track to the research object physiological biochemistry process will be carried on, then the Raman spectrometry will be implemented to the living cells. Results: From the single cell level, Raman tweezers technology analyzes the oxygen ability and the deformability of red blood cells of normal persons and the Mediterranean Sea anemia patients, and implements the appraisal of blood red cell and the blood platelet of different species. The Raman tweezers technology reveals the differences between the organizational structure of the cancer cells and that of normal cells in the molecular level, providing important information and data for the cancer diagnosis and the mechanism analysis. The Raman tweezers technology has implemented the torsion and knotting of DNA molecules, and realizes the control and differentiation of human being's chromosome. Conclusion: The Raman tweezers technology is the prompt and effective tool for the real-time research of cell physiology and biochemistry changes, hopefully in the molecular level. It will become one of the most advanced tools to carry out examination and diagnosis of different kind of living cell. Surely it has a very bright prospect.