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Shiojiri, Japan

Fujita S.,Japan National Institute of Advanced Industrial Science and Technology | Onuki-Nagasaki R.,Japan National Institute of Advanced Industrial Science and Technology | Fukuda J.,Japan National Institute of Advanced Industrial Science and Technology | Fukuda J.,University of Tsukuba | And 5 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2013

Super-dense transfected cell microarrays (TCMs) were created by a piezoelectric inkjet printer on a glass substrate that had been grafted with poly(ethylene glycol) (PEG). The micro-spots that contained plasmid and extra-cellular matrix (ECM) protein were separated from one another by a hydrophilic barrier generated by PEG. We successfully constructed the densest TCMs with spots of 50 μm in diameter and 150 μm in pitch. © The Royal Society of Chemistry.

Microjet Corporation | Date: 2013-04-24

A discharge system includes: a head unit including discharge heads that discharge a liquid material from nozzle openings that are communication with cavities onto a target by changing the internal pressure of the cavities using piezo elements; a viscosity estimating unit that estimates the viscosity of the liquid material by sucking the liquid material from first vessels that hold the liquid material into the cavities; and a waveform control unit that controls the voltage applied to the piezo elements according to the estimated viscosity of the liquid material.

Microjet Corporation | Date: 2011-02-09

A discharge device includes a discharge head that discharges a liquid material from a nozzle opening connected to the cavity by varying the internal pressure of a cavity using an actuator. The discharge head includes a monitoring portion provided between the cavity and the nozzle opening and the discharge device further includes a detection apparatus that detects the number and/or form of the particle-like bodies included in the liquid material in the monitoring portion of the discharge head and a control unit that drives the actuator according to the detection result of the detection unit to change the state of the particle-like bodies included in the liquid material of the monitoring portion.

Shinose M.,Shinshu University | Ueno A.,MICROJET Corporation | Yamaguchi S.,MICROJET Corporation | Akiyama Y.,Shinshu University
2015 International Symposium on Micro-NanoMechatronics and Human Science, MHS 2015 | Year: 2015

We examine cell cryopreservation method without cryoprotectant agent (CPA). In general, the CPA is supplemented to the freezing medium to inhibit the generation and growth of ice crystals inside and outside the cell because cell structures are destroyed by the ice crystals. On the other hand, we need to think about the cytotoxicity of CPA in the cell cryopreservation. The faster the cooling rate become, the more the generation and growth of ice crystals are inhibited inside and outside the cell. To freeze picolitter droplets at high cooling rate, we used inkjet technique and liquid nitrogen. Thereby, the damage to the cells was inhibited. The viability of the flash frozen cells at 20 pL improved about 60 times higher than the viability of frozen cells by slow-rate freezing without CPA. We confirmed that the cell viability of cryopreservation method without CPA increased in flash freezing. Moreover, the viability of the flashly frozen cells at 20 pL increased to more than twice the viability of the flash frozen cells at 200 pL. As the droplet size became small, the cell viability increased in the flash freezing method. We were able to find the possibility of the inkjet-based flash cell freezing toward cryopreservation without CPA. © 2015 IEEE.

Yamaguchi S.,Osaka University | Yamaguchi S.,Tokyo University of Agriculture and Technology | Yamaguchi S.,MICROJET Corporation | Ueno A.,MICROJET Corporation | And 2 more authors.
Journal of Micro-Nano Mechatronics | Year: 2012

The droplet ejection technology commonly used in inkjet printers has become the focus of numerous biofabrication research field including recent research that examined the ejection of cells through the jets. However, no studies have addressed clogging causes, or the trajectory errors that occur when ejecting particles several tens of micrometers in diameter. Nor have any studies investigated the specific conditions that permit stable ejection of liquid suspensions containing particles that are over 10 μm in diameter. In this study, one of our objectives was to experimentally establish the optimal conditions that gave stable ejection of suspensions containing particles at least 10 μm in size without trajectory errors. An inkjet head was fabricated from transparent glass to permit its interior to be observed. The behaviors of microparticles in the head were recorded using a high-speed camera, and a survey of the optimal conditions was conducted to determine conditions necessary for reliable ejection of particles over 10 μm in diameter. Furthermore, we also investigated the optimal dimensions of the print head nozzle required for stable ejection, the optimal waveform of the voltage pulse applied to a piezoelectric actuator mounted in the head, and the relation between the particle concentration and stable ejection. For stable particle ejection, the nozzle diameter must be at least three times the particle diameter and the voltage waveform driving the piezoelectric actuator generates droplets using the push-pull method. The upper limit of particle volume concentration that permits stable ejection depends on the nozzle diameter, the particle diameter, and the ejection waveform. © 2012 Springer-Verlag.

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