Masanobu Ogawa

High-speed separation system of randomly suspended single living cells by laser trap and dielectrophoresis

We developed a new system for random separation of a single microorganism, such as a living cell and a microbe, in the microfluidic device under the microscope by integrating the laser‐trapping force and dielectrophoretic (DEP) force. An arbitrarily selected single microbe could be isolated in a microchannel, despite the presence of a large number of microbes in solution. Once the target microbe is trapped at the focal point of the laser, we can easily realize exclusion of excess microbes around the target by controlling the electric field, while keeping the target trapped by the laser at the focal point. To realize an efficient separation system, we proposed a new separation cell and produced it by microfabrication. Flow speed in the microchannel is adjusted and balanced to realize high‐speed and high‐purity extraction of the target. Some preliminary experiments are conducted to show the effectiveness. The target is trapped by the laser, transported, and is taken out from the extraction port. Total separation time is less than 20 s. Our method is extremely useful in the pure cultivation of the cell and will be a promising method for biologists in screening useful microbes.

High speed random separation of microobject in microchip by laser manipulator and dielectrophoresis

We developed a new system for high speed random separation of a microobject, such as a microbe, in a microfluidic device by optical radiation pressure and dielectrophoretic force control under a microscope. An arbitrary single microbe can be isolated speedily in a microchannel, even though there are a large number of these microbes in solution. Once the target microbe is trapped at the focal point of the laser manipulator, we can easily realize exclusion of excess microbes by controlling the electric field, while keeping the target trapped at the focal point. To realize an efficient separation system, we made a new separation cell by microfabrication. We show experimental results on our system. We also propose indirect manipulation methods by the micro-tools to avoid direct laser radiation to the target. Some preliminary experiments are conducted to show the effectiveness. Our method is extremely useful in the pure cultivation of the targeted microbe and will be a promising method for biologists in discovering a new microbe or for bio-remediation.

3D micromanipulation system under microscope

It is important to be able to manipulate a biological small object, such as a cell and embryo. Three-dimensional high speed micromanipulation is needed as a fundamental technology for bio-science and bio engineering application. In this paper, we focus on the contact type micromanipulation in the liquid, and introduce new methods to improve operability and working efficiency.

Indirect manipulation and bilateral control of the microbe by the laser manipulated microtools

We proposed a new teleoperation method using the bilateral control to improve the operability of the laser scanning micromanipulation of the microobject. We propose indirect non-contact manipulation methods of the microbe. It has been reported that direct irradiation of the laser beam to the microbe may give some damage. This phenomenon depends on the target, wavelength, irradiation time and power of the laser. To avoid this problem, we proposed the indirect manipulation of the target by the laser trapped microtools. As a microtool, we tested a micro bead and Lactobacillus bulgaricus (LB) as a micro-chopsticks and a liposome as a micro capsule. Experimental results on indirect manipulation of the microbe are shown.

Teleoperated laser manipulator with dielectrophoretic assistance for selective separation of a microbe

We propose a new methodology for isolation of a microbe by the optical radiation pressure and dielectrophoretic force under the microscope. Our methodology is based on the fact that an arbitrary single microbe can be isolated speedily in a microchannel, even though there are a large number of these microbes in a solution. We show that once the target microbe is trapped at the focal point of the laser manipulator, we can easily realize the non-contact exclusion of a large number of excess microbes immediately by controlling the electric field, while keeping the target at the focal point. To improve the operability of the micromanipulation in solution and to realize high-speed separation, the technique of sequential, precise and non-invasive handling is necessary. We propose a new teleoperation method using bilateral control to improve the operability of micromanipulation. Our method can be extremely useful in the pure cultivation of the targeted microbe and will be a promising method for biologists in discovering a new microbe.

Separation of Target Microbe in Microchip by Flow Balancing and Visually Guided Laser Tele-Manipulator

We developed a new system for random separation of a microobject, such as a microbe, in the micro fluidic devise under the microscope by integrating the laser-trapping force and dielectrophoretic (DEP) force. An arbitrary selected single microbe was isolated in a microchannel, even though there are a large number of microbes in solution. To realize an efficient separation system, we proposed a new separation cell and made it by microfabrication. The flow speed in the micro channel is adjusted and balanced to realize high speed and high purity extraction of the target microbe. The target is trapped by the laser and transported by the vision based control system to be taken out from the extraction port.