After having reviewed some aspects of microfluidic system preparation in the first part (1), in this second part of the review we will cover a number of standard operations (namely: sample preparation, sample injection, sample manipulation, reaction, separation, and detection) as well as some biological applications of micro total analysis systems (namely: cell culture, polymerase chain reaction, DNA separation, DNA sequencing, and clinical diagnostics). As previously, we will include papers issued from different scientific journals as well as useful abstracts from three conference proceedings: MEMS, Transducers, and μTAS. In this second part, we do not include the period covered by the history section (1975-1997) from part 1 but try to cover the relevant examples of the literature published between January 1998 and March 2002. We briefly describe articles that struck us as needing special attention, while more “standard” papers are dutifully reported in groups of interest. An article might be included in more than one section, depending on the ideas developed in it.

Micro total analysis systems. 2. Analytical standard operations and applications.

http://hg272.persiangig.com/che/Most%20Populare%20Papers/Micromixers%E2%80%94a%20review%20on%20passive%20and%20active%20mixing%20principles.pdf

Micromixers—a review on passive and active mixing principles

This paper describes the design, fabrication and evaluation of an active micromixer for continuous flow. Mixing occurs directly from ultrasonic vibration. The intended use of the device is for integrated microchemical synthesis systems or for micro total analysis systems. The patterns of inlets, outlet and mixing chamber were formed in glass. The entire flow path was encapsulated by anodic bonding of a Si wafer to the glass. A diaphragm ( 6 mm ×6 mm ×0.15 mm ) was etched on the Si side to prevent ultrasonic radiation from escaping to the other parts of the device. The ultrasonic vibration originated from a bulk piezoelectric lead–zirconate–titanate (PZT) ceramic ( 5 mm ×4 mm ×0.15 mm ). The PZT was adhered on the diaphragm and was excited by a 60 kHz square wave at 50 V (peak-to-peak). Liquids were mixed in a chamber ( 6 mm ×6 mm ×0.06 mm ) with the Si oscillating diaphragm driven by the PZT. A solution of uranine and water was used to evaluate the effectiveness of mixing. The entire process was recorded using a fluorescent microscope equipped with a digital camera. The laminar flows of the uranine solution (5 ml/min) and water (5 ml/min) were mixed continuously and effectively when the PZT was excited. The temperature rise of our device was 15°C due to the ultrasonic irradiation.

Ultrasonic micromixer for microfluidic systems

Ceramic integration technology requires downsizing and/or improvement of device performance in many applications, such as in the fabrication of microelectromechanical systems, display devises, fuel cells, optical devices, and RF components. For these applications, realization of high-speed deposition rate, low process temperature, and fine patterning in ceramic coating are very important. The aerosol deposition (AD) method has many advantages for above requirements in comparison with conventional thin-film method or thermal spray coating technology. In this article, advantages of the AD method are highlighted by realizing a comparison with conventional thin-film methods and thermal spray technology. Challenges associated with AD method are also highlighted. At the end, examples of integration of AD method in the fabrication of electronic components are also given to show the easiness in usage and in integration of this method in the device process flow.

Room Temperature Impact Consolidation (RTIC) of Fine Ceramic Powder by Aerosol Deposition Method and Applications to Microdevices

There has been a resurgence of complex oxides of late owing to their ferroelectric and ferromagnetic properties. Although these properties had been recognized decades ago, the renewed interest stems from modern deposition techniques that can produce high quality materials and attractive proposed device concepts. In addition to their use on their own, the interest is building on the use of these materials in a stack also. Ferroelectrics are dielectric materials that have spontaneous polarization in certain temperature range and show nonlinear polarization–electric field dependence called a hysteresis loop. The outstanding properties of the ferroelectrics are due to non-centro-symmetric crystal structure resulting from slight distortion of the cubic perovskite structure. The ferroelectric materials are ferroelastic also in that a change in shape results in a change in the electric polarization (thus electric field) developed in the crystal and vice versa. Therefore they can be used to transform acoustic wav...

Processing, Structure, Properties, and Applications of PZT Thin Films

We have developed a diaphragm piezoelectric microactuator. The diaphragm consists of a Pb(Zr, Ti)O3 (PZT) thin film, electrode layers, an isolation layer and a Si substrate. The diaphragm is deflected by transverse stress in the PZT thin film which is fabricated by a sputtering and annealing process. The PZT thin film has a piezoelectric coefficient d31 of -100 pC/N, which is comparable to that of bulk PZT. A diaphragm deflection of 3 µ m was obtained at an electric field of 16 V/µm.

https://iopscience.iop.org/article/10.1143/JJAP.35.5012/pdf

Static characteristics of piezoelectric thin film buckling actuator

The silicon micromachined optical scanner integrated with photo detectors and piezoresistor has been developed for highly miniaturized scanning type of optical sensors. The scanner is fabricated with silicon micromachining technologies including IC manufacturing methods. It is capable of scanning a light beam spot two dimensionally and photo detection with the information of where the light beam is being scanned. The scanning angle was over 40 deg. x 30 deg. and the photo sensitivity was 0.5 A/W at 680 nm wavelength.

Two Dimensional Silicon Micromachined Optical Scanner Integrated With Photo Detector And Piezoresistor

For achieving higher performance and for miniaturizing the size of an optical scanning sensor, raising the scanning angle response, increasing the accuracy of detection of the scanning location independent from the environmental temperature, and miniaturizing an optical-scanning sensor were considered. And the silicon micromachined 2D optical scanner integrated with a piezoresistor for scanning location detection and a photodiode for optical intensity detection was newly designed and fabricated. The obtained results with the fabricated scanner are following. The scanner is capable of scanning a light beam more than 40 degrees 2D. The scanning angle sensitivities are 4.8 deg/V for horizontal direction and 10.5 deg/V for vertical direction. The scanning location detection sensitivity for each horizontal and vertical directions are 21 mV/deg and 26 mV/deg., respectively. The decrease of detection accuracy of scanning location has been reduced to less than 1 percent within +/- 10 degrees C temperature shift. And the photodetector has a photosensitivity of 0.33 A/W which allows the optical-scanning sensor to detect the reflected light intensity from an object which is 200 mm away from the sensor.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Two-dimensional miniature optical-scanning sensor with silicon micromachined scanning mirror

Novel PZT thin film actuators for optical applications were proposed. Key issues for realizing the actuators such as PZT thin film processes, mechanical properties evaluation of thin films, and design for laminated structure were described. [1 1 1]-oriented PZT films were obtained by anneal/non-anneal sputtering process. Also for PZT dry etching, it was made clear low pressure and low temperature conditions were advantageous for high selectivity and etch rate. ECR etcher was used and etch rate of 1000 A/min and selectivity of 0.56 to photoresist mask were obtained. Young’s modulus and built-in stress of PZT film, measured by load-deflection method, were 72 GPa, −335 MPa respectively. Using these results, calculated deflection of each actuator was on the order of a few microns to 20 microns. It was confirmed that deflection of actuators would be enough for the application.

Pb-based ferroelectric thin film actuator for optical applications

Micro mixer using turbulence principle was first reported. The turbulence occurred from the work of valveless micropump. Liquids were mixed in a chamber with oscillating diaphragm driven by PZT at high frequency. The mixer had a layout of 2 pairs of diffusers on the inlet and outlet of the chamber, respectively. All those diffusers were in the size of 1.5 mm long and had an angle of 5°. The diaphragm was in the size of 6 mm x 6 mm x 0.15 mm. The mixing chamber was in the same length and width of diaphragm and had a depth of 0.04 mm. A piece of bulk PZT (5 mm × 4 mm × 0.2 mm) was glued onto the diaphragm. As a pump, it worked until 10 kHz when a square wave voltage (120V peak-to-peak) was used for the excitation. The maximum output was found to be 15.6 μl/min of the maximum flow rate and 2.16 kPa of the zero flow pressure using 870 Hz square excitation wave to drive ethanol. To test the properties of the mixer, different pigments were added into water, methanol and ethanol, respectively. The color changes were observed when water mixed with ethanol and methanol mixed with ethanol.

Tsuneji Yada

Papers

Static characteristics of piezoelectric thin film buckling actuator

Two Dimensional Silicon Micromachined Optical Scanner Integrated With Photo Detector And Piezoresistor

Two-dimensional miniature optical-scanning sensor with silicon micromachined scanning mirror

Pb-based ferroelectric thin film actuator for optical applications

Micro Mixer Incorporated with Piezoelectrially Driven Valveless Micropump