An innovative in-plane passive micromixer using modified Tesla structures, which are used as passive valves, has been designed, simulated, fabricated and successfully characterized in this paper. Simulation and experimental results of the developed novel micromixer have shown excellent mixing performance over a wide range of flow conditions in the micro scale. The micromixer realized in this work has achieved even better mixing performance at a higher flow rate, and its pressure drop is less than 10 KPa at the flow rate of 100 microl min(-1). This micromixer shows characteristics similar to Taylor dispersion, with contributions from both diffusion and convection. The mixer has a diffusion domain region at low flow rate, but it moves to a convection domain region at high flow rate. Due to the simple in-plane structure of the novel micromixer explored in this work, the mixer can be easily realized and integrated with on-chip microfluidic devices and micro total analysis systems (micro-TAS).

This paper presents a functional on-chip pressure generator that utilizes chemical energy from a solid chemical propellant to perform fluidic delivery in applications of plastic-based disposable biochips or lab-on-a-chip systems. In this functional on-chip pressure generator, azobis-isobutyronitrile (AIBN) as the solid chemical propellant is deposited on a microheater using a screen-printing technique, which can heat the AIBN at 70 degrees C to produce nitrogen gas. The output pressure of nitrogen gas, generated from the solid chemical propellant, is adjustable to a desired pressure by controlling the input power of the heater. Using this chemical energy source, the generated pressure depends on the deposited amount of the solid chemical propellant and the temperature of the microheater. Experimental measurements show that this functional on-chip pressure generator can achieve around 3 000 Pa pressure when 189 mJ of energy is applied to heat the 100 microg of AIBN. This pressure can drive 50 nl of water through a microfluidic channel of 70 mm and cross-sectional area of 100 microm x 50 microm. Due to its compact size, ease of fabrication and integration, high reliability (no moving parts), biologically inert gas output along with functionality of gas generation, this pressure generator will be an excellent pressure source for handling the fluids of disposable lab-on-a-chip, biochemical analysis systems or drug delivery systems.

This paper presents the development of an easy-to-handle and disposable clinical diagnostic lab-on-a-chip using fully integrated plastic microfluidic components, which has the sampling/identifying capability to make fast and reliable measurements of metabolic parameters from human whole blood. A smart and functional lab-on-a-chip cartridge, which incorporates a full on-chip auto-calibration function for in the field applications, has been developed, and then fully characterized using a portable analyzer (3 (1/4)''x 5''x 1'') with multi-analyte detection capability. In addition, several new approaches in realizing smart and functional lab-on-a-chips on polymer have been adopted, which include the pinch valve for automatic fluidic sealing, a by-pass channel as the sampling indicator, and a robust connector design for long analyzer lifetimes. Metabolic parameters such as glucose, lactate, and partial oxygen from human whole blood have been successfully measured using the functional polymer lab-on-a-chips and the portable analyzer developed in this work.

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