Daniel Erenso

Direct laser trapping for measuring the behavior of transfused erythrocytes in a sickle cell anemia patient.

Using a laser trap, we have studied the properties of erythrocytes from a sickle cell anemia patient (SCA) after receiving an intravenous blood transfusion, and a normal adult individual carrying normal adult hemoglobin. The hemoglobin type and quantitation assessment was carried out by high performance liquid chromatography (HPLC). We conducted an analysis of the size distributions of the cells. By targeting those erythrocytes in the overlapping regions of size distributions, we have investigated their properties when the cells are trapped and released. The efficacy of the transfusion treatment is also studied by comparing the relative changes in deformation and the relaxation-time of the cells in the two samples.

Formation of synthetic structures with micron size silica beads using optical tweezer

We have demonstrated that micron-size silica beads can be arranged in desired synthetic structure using an optical tweezer in a saline buffered solution. In 3.1 µm silica and water solution we added the right proportion of antistick glycol and NaCl to form a solution in which silica beads brought close to one another can bind by an adhesive electrostatic force without drifting away due to their thermal energy. Then by trapping and dragging one bead at a time using an optical tweezer, we have arranged the silica beads in two-dimensional structures.

Single cell ionization by a laser trap: a preliminary study in measuring radiation dose and charge in BT20 breast carcinoma cells

In this work, a preliminary study in the application of a laser trap for ionization of living carcinoma cells is presented. The study was conducted using BT20 breast carcinoma cells cultured and harvested in our laboratory. Each cell, for a total of 50 cells, was trapped and ionized by a high intensity infrared laser at 1064 nm. The threshold radiation dose and the resultant charge from the ionization for each cell were determined. With the laser trap serving as a radiation source, the cell underwent dielectric breakdown of the membrane. When this process occurs, the cell becomes highly charged and its dielectric susceptibility changes. The charge creates an increasing electrostatic force while the changing dielectric susceptibility diminishes the strength of the trapping force. Consequently, at some instant of time the cell gets ejected from the trap. The time inside the trap while the cell is being ionized, the intensity of the radiation, and the post ionization trajectory of the cell were used to determine the threshold radiation dose and the charge for each cell. The measurement of the charge vs ionization radiation dose at single cell level could be useful in the accuracy of radiotherapy as the individual charges can collectively create a strong enough electrical interaction to cause dielectric breakdown in other cells in a tumor.

Application of a laser trap as a viscometer

A laser tweezer (LT) along with advanced imaging techniques has been widely applied to manipulate and study living as well as nonliving microscopic objects. In this study we present yet another novel application of LTs for a precise measurement of the viscosities of fluids in a micro-volume flow. We have demonstrated this novel application by measuring the viscosity of a fetal bovine serum (FBS) using a LT constructed from a single intensity gradient laser trap. By calibrating the LT using dielectric silica micro-beads in a fluid with a known viscosity, specifically water, and by suspending same size of silica beads in the FBS and trapping with the same trap, we have determined the viscosity of the FBS at different temperatures. We have used the relationship between the trapping and Stoke’s drag force for a constant drag speed to determine the viscosity. We have also analyzed the viscosities determined in comparison with corresponding viscosities measured using an Ostwald viscometer.

Cancerous Lung Cells Treatment by Herbal Medicines Measured by the Response to Compressional Force Induced by a Laser Trap

We have studied human lung carcinoma cells (A549) treated by Chinese Herbal medicine (Paeonia suffruticosa), widely used as anti-tumor agent. We used a comparative analysis of the treated vs untreated cell response to laser trapping.

Response of Human Breast Carcinoma (BT20) Cell Lines to Compressional Force Induced by a Laser Trap

In BT20 human breast cancer cells we have studied the physical changes resulting from compressional stress. We used optical tweezers to directly induce compressional stress on individual cells and measure the resulting elastic deformations.

Laser Trapping for Single Red Blood Cell (RBC) Ionization and Measurement of Charge

Application of high intensity gradient laser trap for charging a single cell is demonstrated. We used RBCs from normal person (AA hemoglobin) and an individual with sickle cell trait (AC hemoglobin).

Polarization encrypted quantum teleportation using two type-II Parametric Down Converters

A Physical scheme for quantum teleportation that uses photons emitted by two type-II spontaneous parametric down converters (SPDC) is proposed and studied. We have analyzed the delity in comparison with photons emitted by single SPDC.

Semiclassical entanglement analyses in a non-degenerate parametric oscillator (NDPO)

The entanglement of the intracavity photons in subthreshold NDPO coupled to a squeezed vacuum is studied using the von-neumann entropy (VNE). The VNE is calculated in terms of the Q-function representation for the density operator.

Heterozygotes and homozygotes genotypes human red blood cells response to trap and drag Force

We have studied the relative difference in the deformability of human red blood cells (RBCs) with heterozygotes (sickle cell trait) and homozygotes (sickle cell anemia) genotypes using infrared laser trap and drag shear force