RESUMEN
Extracellular tonicity has a significant influence on human red blood cell deformation capability. Advancements in the area of laser physics and optical trapping have opened up a plethora of applications for understanding cell structure and dynamics. Here, Raman Tweezers technique was employed to investigate the impact of extracellular tonicity by exposing human red blood cells to both hypertonic and hypotonic intravenous fluids. Heme aggregation was observed in hypertonic saline solution, accompanied with damage in membrane protein. Loss of intracellular hemoglobin in hypotonic solution was evident from the decrease in porphyrin breathing mode present at 752 cm-1. Oxygen binding to the central iron in the red blood cell heme was also affected under both hyper/hypo tonicity conditions. Morphological deviation of discocytes to echinocytes/spherocytes were also evident from quantitative phase imaging. Principal component analysis have showed clear differentiation of samples in order to classify the control erythrocytes and the tonicity stressed erythrocytes. Present study has also demonstrated the application of Raman Tweezers spectroscopy as a potential tool for probing red blood cell under different stress conditions.
Asunto(s)
Deformación Eritrocítica , Eritrocitos/química , Hemoglobinas/análisis , Soluciones Hipertónicas/administración & dosificación , Soluciones Hipotónicas/administración & dosificación , Pinzas Ópticas/estadística & datos numéricos , Espectrometría Raman/métodos , Eritrocitos/efectos de los fármacos , Humanos , Análisis de Componente PrincipalRESUMEN
BACKGROUND: Arteriovenous malformation surgery is particularly demanding owing to the need to control bleeding of small, deep white matter vessels during and after removal of the nidus; this is probably one of the most critical moments of arteriovenous malformation surgery. The aim of this article is to describe a useful technique based on the use of tweezers to temporarily stop the blood flow followed by coagulation with the thulium laser. METHODS: Surgery was performed in 20 patients with unruptured cerebral arteriovenous malformations. In each case, the superficial feeder vessels were easily coagulated with nonstick bipolar tips. The finer and deeper feeder vessels were coagulated with use of tweezers and thulium laser. RESULTS: All patients were treated successfully. Optimal intraoperative hemostasis was achieved. CONCLUSIONS: Results were good with no postoperative complications. Our results could encourage a more standardized use of the described technique.
Asunto(s)
Fístula Arteriovenosa/cirugía , Malformaciones Arteriovenosas Intracraneales/cirugía , Terapia por Láser/métodos , Pinzas Ópticas/estadística & datos numéricos , Adolescente , Adulto , Anciano , Fístula Arteriovenosa/diagnóstico , Niño , Femenino , Humanos , Malformaciones Arteriovenosas Intracraneales/diagnóstico , Terapia por Láser/instrumentación , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Optoelectronic tweezers (OET) has advanced within the past decade to become a promising tool for cell and microparticle manipulation. Its incompatibility with high conductivity media and limited throughput remain two major technical challenges. Here a novel manipulation concept and corresponding platform called Self-Locking Optoelectronic Tweezers (SLOT) are proposed and demonstrated to tackle these challenges concurrently. The SLOT platform comprises a periodic array of optically tunable phototransistor traps above which randomly dispersed single cells and microparticles are self-aligned to and retained without light illumination. Light beam illumination on a phototransistor turns off the trap and releases the trapped cell, which is then transported downstream via a background flow. The cell trapping and releasing functions in SLOT are decoupled, which is a unique feature that enables SLOT's stepper-mode function to overcome the small field-of-view issue that all prior OET technologies encountered in manipulation with single-cell resolution across a large area. Massively parallel trapping of more than 100,000 microparticles has been demonstrated in high conductivity media. Even larger scale trapping and manipulation can be achieved by linearly scaling up the number of phototransistors and device area. Cells after manipulation on the SLOT platform maintain high cell viability and normal multi-day divisibility.
Asunto(s)
Micropartículas Derivadas de Células , Microfluídica , Micromanipulación/instrumentación , Pinzas Ópticas/estadística & datos numéricos , Análisis de la Célula Individual , Medios de Cultivo , Conductividad Eléctrica , Electroforesis/métodos , Diseño de Equipo , HumanosRESUMEN
Laser trapping by optical tweezers makes possible the spectroscopic analysis of single cells. Use of optical tweezers in conjunction with Raman spectroscopy has allowed cells to be identified as either healthy or cancerous. This combined technique is known as laser tweezers Raman spectroscopy (LTRS), or Raman tweezers. The Raman spectra of cells are complex, since the technique probes nucleic acids, proteins, and lipids; but statistical analysis of these spectra makes possible differentiation of different classes of cells. In this article the recent development of LTRS is described along with two illustrative examples for potential application in cancer diagnostics. Techniques to expand the uses of LTRS and to improve the speed of LTRS are also suggested.
Asunto(s)
Células/química , Técnicas y Procedimientos Diagnósticos/instrumentación , Neoplasias/diagnóstico , Pinzas Ópticas/estadística & datos numéricos , Análisis de la Célula Individual/métodos , Espectrometría Raman/métodos , Humanos , Rayos Láser , Espectrometría Raman/instrumentaciónRESUMEN
Microtubule (MT) polymerization dynamics, which are crucial to eukaryotic life and are the target of important anticancer agents, result from the addition and loss of 8-nm-long tubulin-dimer subunits. Addition and loss of one or a few subunits cannot be observed at the spatiotemporal resolution of conventional microscopy, and requires development of approaches with higher resolution. Here we describe an assay in which one end of an MT abuts a barrier, and MT length changes are coupled to the movement of an optically trapped bead, the motion of which is tracked with high resolution. We detail assay execution, including preparation of the experimental chamber and orientation of the MT against the barrier. We describe design requirements for the experimental apparatus and barriers, and preparation of materials including stable, biotinylated MT seeds from which growth is initiated and NeutrAvidin-coated beads. Finally, we discuss advantages of moving the optical trap such that it applies a constant force (force clamping), detection limits, the importance of high temporal resolution, data analysis, and potential sources of experimental artifacts.
Asunto(s)
Microtecnología/instrumentación , Microtecnología/métodos , Microtúbulos/química , Microtúbulos/metabolismo , Pinzas Ópticas , Multimerización de Proteína , Animales , Técnicas de Laboratorio Clínico , Diseño de Equipo/instrumentación , Diseño de Equipo/métodos , Falla de Equipo , Humanos , Límite de Detección , Nanoestructuras/análisis , Nanoestructuras/química , Pinzas Ópticas/estadística & datos numéricosRESUMEN
Resonance Raman spectra of single red-cell from human blood are presented by different laser sources. It is reported that there is 1002 cm(-1) line of insensitive conformation of phenylalanine aromatic ring stretching and 1620 cm(-1) line of C-N breathing stretching band of pyrrole ring, which cause strong and sharp resonance lines when excited by 782 nm laser source. They are weaker and the intensity of other lines of high wave number is large and clear when excited by 514 nm laser source. But the intensity of lines of low wave number is strong and clear when excited by 782 nm laser source. At the same time, the authors got Raman spectra lines at different times after taking blood under the same laser source. When using 782 nm laser source, there is no difference except for 1601 cm(-1). There are a lot of weakened lines and lines shifting about 4-10 cm(-1) toward low wave number. The results indicate that Raman spectra may offer the experimental basis for studying structure, function and variability of single red-cell.