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This paper proposes a hybrid actuation for long-term cell manipulation in a microfluidic channel. While a conventional actuation can manipulate a cell, it usually cannot last for a very long time (i.e. less than 10 minutes) due to unavoidable pressure leak or drifts. The hybrid actuation is composed of two actuations where one is a gravity-based pressure system for macro-scale pressure balancing and...
A high-resolution cell manipulation system is presented for investigating red blood cell deformation under long-standing load in this paper. Because the low Reynolds number in microfluidic system, cell position can be manipulated by controlling the flow in a microchannel. A high-speed vision system is embedded in the system for providing cell present position as the feedback signal for the controller...
A method for evaluating red blood cell (RBC) deformability by different channel width in a microfluidic device is proposed. While conventional methods usually have only one test channel to deform RBCs for the evaluation, a design including three test channels with different width is utilized in this work. The proposed design have the advantage of generating a wider range of deformation to each RBC,...
In tissue engineering, it is important to examine the hardness of cultivated tissues for evaluating their vitality. This paper proposes a new index, “Droplet Hardness”, defined by the representative plastic deformation in depth of tissue caused by collision with a droplet whose initial diameter and speed are 80 μm and 4m/s, respectively. To understand the nature of physical phenomena of single droplet...
A new concept of μ-cell fatigue test is proposed. By reciprocating a cell across the throat of a micro channel repeatedly, the dynamic deformation behavior of the cell is measured. We define a new index of fatigue characteristics of cells as the number of reciprocatory motion leading to a prescribed recovery ratio. The test system is composed of a piezoelectric (PZT) actuator, a high speed vision...
A novel method to achieve online measurements of cornea deformation during non-contact tonometry by use of an online camera system is presented. Kaneko et al. have shown that non-contact tonometry as a method of identifying the intraocular pressure can produce biased results due to differences in structural eye stiffness between individuals. By including deformation measurements of the cornea, results...
This paper proposes a high speed cell stiffness evaluation with high reliability. The procedure includes both online measurement and offline inspection. By using the property where the passing time of the cell in the micro channel is a function of the cell stiffness and its size, a real time vision system whose handling frequency is 6 kHz can capture the size as well as the passing time of each cell...
Cell stiffness could be an index for evaluating its activity. Although various systems measuring cell stiffness have been proposed so far, they are slow for adaptively connecting to cell sorters capable of handling more than 1000 [cells/sec]. This paper proposes a new approach that can indirectly evaluate the cell stiffness by measuring the passing time for a narrow channel. When a cell passes through...
This paper discusses the point-type non-contact active sensing for evaluating the stiffness of a soft tissue with coupling effect. The sensing system imparts a point force to a tissue and measures the displacement at the point of application of force. The benefit is that such point based information enables us to estimate two stiffness parameters constructing the 3D spring network tissue model. Through...
For the diagnosis and treatment of glaucoma, a reliable and non-invasive measurement method of the internal eye pressure, i.e. the intraocular pressure (IOP), is desired. The IOP resists a deformation of the eye and thus non-contact tonometers, which deform the eye by a short air pulse, are suitable to estimate the IOP. By monitoring the reflection of an incident infrared light, the tonometer measures...
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