Au/PPy Actuators for Active Micromixing and Mass Transport Enhancement, 2009, Vol: 1(1) Pp. 2-11
X. Casadevall, R.A. Lambert, L. Kulinsky, R.H. Rangel and M.J. Madou
[Abstract] [Full Text Article]


A Stepper Micropump for Ferrofluid Driven Microfluidic Systems, 2009, Vol: 1(1) Pp. 17-21
N.-T. Nguyen and M.-F. Chai
[Abstract] [Full Text Article]


Modeling, Design and Experimental Characterization of Bending Resonant Circular Nano Cantilevers, 2009, Vol: 1(1) Pp. 22-29
N. Lobontiu, B. Ilic, T. Reissman, E. Garcia, Y. Nam and H.G. Craighead
[Abstract] [Full Text Article]


Lab-on-Chip for Pharmacogenomics: An Embedded System Organization, 2009, Vol: 1(1) Pp. 30-40
G. Kornaros, A. Demiris and S. Blionas
[Abstract] [Full Text Article]


Editorial, 2009, Vol: 1(1) Pp.1


Microfluidic System Based on Thermoexpandable Polymer for on Chip Blood Coagulation Testing, 2009, Vol: 1(1) Pp. 41-45
L. Metref, F. Bianchi, V. Vallet, N. Blanc, R. Goetschmann and P. Renaud
[Abstract] [Full Text Article]


Preparation and Photocatalytic Activity of Mesoporous TiO₂ Microspheres, 2009, Vol: 1(1) Pp. 12-16
J. Mao-Xiang, J. Xue-Qin, L. Wang-Xing, L. Dong-Hong and W. Zhou
[Abstract] [Full Text Article]


A Highly Accurate Closed-Form Model for Pull-in Voltage of Circular Diaphragms under Large Deflection, 2009, Vol: 1(2) Pp. 139-146
M. Rahman and S. Chowdhury
[Abstract] [Purchase Article]


Numerical Simulation of Electrocapillary Driven Flows, 2009, Vol: 1(1) Pp. 57-62
P. Zhou and C.W. Wu
[Abstract] [Full Text Article]


Highly-Sensitive Nanostructured Sensor System Based on RuO₂ Sensing Electrode for Water Quality Monitoring, 2009, Vol: 1(2) Pp. 123-132
S. Zhuiykov
[Abstract] [Purchase Article]




Abstracts


[Back to top] [Full Text Article]
Au/PPy Actuators for Active Micromixing and Mass Transport Enhancement, 2009, Vol: 1(1)
X. Casadevall, R.A. Lambert, L. Kulinsky, R.H. Rangel and M.J. Madou

This study documents our efforts towards a novel design of an active micromixing device that employs Gold/Polypyrrole (Au/PPy) actuators. The devices were manufactured by the sequential deposition of a polyimide layer, a thermal evaporation of gold, and electrodeposition of PPy layer on top of the gold electrodes. Several types of mixers ranging in size from 10 by 1 mm to 380 by 38 μm were successfully actuated at frequencies up to 3 Hz. Mass transport in the solution was studied in a series of chronoamperometric experiments with a Redox sensor placed in close proximity to the actuators. Differential mass transport effects with and without the actuation of micromixers were recorded for several system configurations. In addition, numerical simulations of a biological surface-microreaction (i.e., DNA hybridization) were carried out. Simulation results indicate that compared to passive diffusion-limited transport active micromixing is capable of increasing reaction rates by 30% for sub-mm size actuators and by 100% for mm-size actuators.


[Back to top] [Full Text Article]
A Stepper Micropump for Ferrofluid Driven Microfluidic Systems, 2009, Vol: 1(1)
N.-T. Nguyen and M.-F. Chai

We demonstrate a novel stepper micropump for ferrofluid driven microfluidic systems. The rotor is a ferrofluid plug that works as a piston pushing another liquid in a circular microchannel. The actuation concept is similar to that of a stepper motor, where the angular velocity can be precisely controlled by a series of actuating solenoids. The actuation force is adjusted by the driving voltage or current. Thus fluids with different viscosities can be handled in the pump. The pump can be used for a circular ferrofluid driven microchip for rapid polymerase chain reaction (PCR), where the sample is continuously pumped in a closed loop over three temperature zones to realize thermal cycling.


[Back to top] [Full Text Article]
Modeling, Design and Experimental Characterization of Bending Resonant Circular Nano Cantilevers, 2009, Vol: 1(1)
N. Lobontiu, B. Ilic, T. Reissman, E. Garcia, Y. Nam and H.G. Craighead

This work reports on a new type of nano cantilever, the symmetric circular one, and provides results of its out-of-plane bending natural frequency by means of analytical modeling and experimental testing. The cantilever, with a 225 nm thickness and planar dimensions smaller than 10 μm, can be implemented in dynamic nano electromechanical applications such as atomic force microscopy, surface topology characterization or resonance-shift mass detection. An analytic model is proposed that considers the distributed stiffness and inertia properties through an accurate distribution function. The model also captures the short-beam character of this structure and the related shear effects. Several silicon nitride nano cantilevers have been surface-micromachined and tested by using in-vacuum laser excitation and interferometric measurement of the bending resonant response. The model predictions and the experimental results indicated minimal errors. Based on this agreement, the analytical model was utilized to further analyze the influence of the basic geometric parameters on the cantilever’s natural frequency.


[Back to top] [Full Text Article]
Lab-on-Chip for Pharmacogenomics: An Embedded System Organization, 2009, Vol: 1(1)
G. Kornaros, A. Demiris and S. Blionas

This paper presents the architecture of the electronic detection and data processing (analysis) part, of a Lab-on-Chip (LoC) device. The data processing part focuses on the analysis of signals captured from the sensors used to detect possible mutations in the sample under consideration. The LoC consists of a micro-fluidics part for the sample preparation and hybridization, a micro-system part including the sensors for the hybridization electronic detection and finally a processing part for the data analysis and an interface for results presentation. The use of such LoCs aims at identifying the appropriate cluster of patients for a pharmacogenomic medicine based on the gene analysis results and at optimizing the effectiveness of the drug or determining whether the affected patient belongs to a group of patients who would suffer severe side effects.


[Back to top]
Editorial, 2009, Vol: 1(1)

A mini revolution is taking place where developments in micro and nanosystems will lead to a whole range of new products that will have enhanced functionality and reliability with reduced cost. Micro and nanosystems will act as disruptive technologies for a variety of sectors. Innovations will, however, be required in a variety of areas to take the concepts to the market. Examples of such products include e-paper, portable displays and lab-on-chip systems that can provide chemical and biological information.

Micro and nanosystems are often required to integrate sensing, processing and actuating functions with a need to integrate mechanical, electrical and biological functions. As a consequence, the field is highly interdisciplinary, it combines amongst others physics, materials, chemistry, biology, engineering as well as micro and nanomanufacturing. We are witnessing a very significant growth in interest and research effort devoted to this field and we therefore believe that this journal is timely. Specifically, we hope that the journal will provide a space for conversations between the different disciplines to allow innovation and speed up the development of micro and nanosystems.

We can anticipate developments in a new generation of intelligent sensor and actuator systems as well as devices for energy management. The integration of chemical and biological components as part of micro and nanodevices will be used to meet the ever increasing demand for chemical and biological information in sectors such as health, environment, agriculture and food, security, and environmental. Examples include highly automated systems to provide high content information for drug discovery or easy to use point-of-care devices. Innovations in materials and the integration of organic electronics will lead to a range of new micro and nanodevices. The development of new manufacturing approaches, e.g. printable processes, for a variety of substrates, including polymers, will lead to reduction in cost of micro and nanosystems.

A high profile Editorial Board, with extensive experience of various disciplines, has been assembled to support the development of the Journal. I am very grateful for the guidance and support that they have already given. I would also very much welcome suggestions from you for improvements to the Journal and your support through submission of papers.


Editor-in-Chief
Zulfiqur Ali,
University of Teesside,
Middlesbrough,
UK
E-mail: z.ali@tees.ac.uk


[Back to top] [Full Text Article]
Microfluidic System Based on Thermoexpandable Polymer for on Chip Blood Coagulation Testing, 2009, Vol: 1(1)
L. Metref, F. Bianchi, V. Vallet, N. Blanc, R. Goetschmann and P. Renaud

This paper describes a simple system for the actuation of a biological fluid through micro-channels with a thermoactivated polymer actuator. This system is of interest for the development of single-use diagnostic test-strips since the actuation of the sample is integrated in the disposable test strip. On chip actuation has the advantage of reducing the size and the cost of the non disposable part of the measurement system and preventing any contamination of the sample since it is completely isolated from any non-disposable elements. The study of the developed system was done optically by monitoring the fluid progression in the channel. It has demonstrated typical flow range of 10 to 60 nl/min. A similar device was then used to prove its application to blood coagulation characterization based on an increase in blood viscosity. Such a system can find diverse applications in chemical analysis and diagnostics on chip where actuation by steps from nano to microliter range is required.


[Back to top] [Full Text Article]
Preparation and Photocatalytic Activity of Mesoporous TiO₂ Microspheres, 2009, Vol: 1(1)
J. Mao-Xiang, J. Xue-Qin, L. Wang-Xing, L. Dong-Hong and W. Zhou

Mesoporous TiO₂ microspherical photocatalyst was prepared through a novel continuous precipitation method using Titanous sulphate and ammonium bicarbonate as raw materials. After calcination at 700 °C, the as-prepared TiO₂ sample showed anatase with spherical or spheroidal morphologies,large particle size of 5 to 30μm,crystallite size of 9.4nm, specific surface area ~138m²/g, and narrow pore size distribution with pore radius in the range of 2 to 5nm.In addition, this sample shows excellent photocatalytic activity to degrade phenol solution and good sedimentation to recover TiO₂. The mesoporous TiO₂ microspheres can be widely used as a photocatalyst in moving or fluidized bed reactors to treat organic waste waters.


[Back to top] [Purchase Article]
A Highly Accurate Closed-Form Model for Pull-in Voltage of Circular Diaphragms under Large Deflection, 2009, Vol: 1(2)
M. Rahman and S. Chowdhury

A simple easy to use highly accurate closed-form model to determine the pull-in voltage of electrostatically actuated circular diaphragms subject to large deflection has been developed. The model takes account of the nonlinear stretching of the diaphragm during large deflection, effects of residual stress, bending stress, and the effects of fringing field capacitances. At first a linearized uniform model of the nonlinear non-uniform electrostatic force has been derived that includes the effects of the fringing field capacitances. This model is then used in conjunction with the load-deflection model of a circular diaphragm subject to large deflection to derive the closed-form model for the pull-in voltage based on the condition that at unstable equilibrium, the electrostatic force is just balanced by elastic restoring force. The model has been verified by extensive 3-D electromechanical finite element analysis (FEA) using IntelliSuite. The model is in excellent agreement with 3-D electromechanical FEA with a maximum deviation of 1.6% for a wide range of residual stress and pull-in voltage values. The model leads to an integrated design strategy to optimize the electrical and mechanical design variables for MEMS-based capacitive type sensors having circular diaphragms. The model can be used to determine pull-in voltages of MEMS capacitive type pressure sensors, capacitive micromachined ultrasound transducers (CMUT) for medical diagnostic imaging, MEMS based microphones, touch mode pressure sensors, and other application areas where electrostatically actuated circular diaphragms are used.


[Back to top] [Full Text Article]
Numerical Simulation of Electrocapillary Driven Flows, 2009, Vol: 1(1)
P. Zhou and C.W. Wu

The developed single-component multiphase lattice Boltzmann model (LBM) is used for studying an electrocapillary driven flow. The basic principle of the electrocapillary driven flow is to control the interface tension with electric potential. In the present paper, two pseudo-effective mass of the solid wall are adopted to control the interfacial tension of gas-solid and liquid-solid respectively. This method can independently control the liquid-solid interfacial tensions which is in turn controlled by the applied electric voltage in the electrocapillary driven flow. The numerical results show that the method can simulate the contact angle saturation phenomenon in electrowetting and the capillary flow considering the dynamic contact angle (DCA). We also find here the cosine of the DCA is proportional to the capillary number and the prediction error of the liquid level (in single capillary tube) is close to the inverse of the adopted density ratio.


[Back to top] [Purchase Article]
Highly-Sensitive Nanostructured Sensor System Based on RuO₂ Sensing Electrode for Water Quality Monitoring, 2009, Vol: 1(2)
S. Zhuiykov

Sensor system based on nanostructured RuO₂ sensing electrode (SE) was fabricated and examined for pH and dissolved oxygen (DO) detection in water at a temperature range of 9-35°C. The electromotive force (emf) response at these temperatures was linear to the logarithm of pH (from 2.0 to 13.0 pH) and DO concentrations in the range from 0.6 to 8.0 ppm (log[O₂], -4.71 to -3.59) at a neutral pH. In was also found that the response/recovery time of the sensor to DO changes is sluggish as the water temperature cools down. Sensor response time, T₉₀, to the different DO increased from 8 min at a temperature of 23°C to about 30 min at a temperature of 9°C. The slope was -41 mV per decade for the RuO₂-SE at 8.0 pH and it was closely followed the Nernst equation. However, it was found that in strong alkaline solutions sensor emf is a mixed-potential of fast and slow electrochemical reactions involving O₂^-, RuO₄^2- and OH^- ions. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX) and impedance spectroscopy techniques were used to examine the morphology, crystalline structure and electrochemical behaviour of the nanostructured RuO_2-SEs, respectively. Characterization analysis revealed that RuO_2-SE consist of RuO₂ nano-particles in the range of 100-650 nm homogeneously distributed across SE.