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The capillary force is always used as the driving force of microfluidic chips. In this study, the capillary force of blood smart diagnostic microfluidic chip which fabricated by micro-injection molding (μ-IM) is offered by the structure of micro pillar array. And the detection effect of blood smart diagnostic microfluidic chips is affected by the replication and height distribution of large scale micro pillar array. So the effect of process parameters on the micro-structure and the height distribution of micro pillar is studied. The mold design is also an important factor affecting micro parts properties. In this study, a steel mold insert with almost 15,500 micro blind cavities was fabricated by milling, electrical discharge machine and Femtosecond Laser process. Polymethyl methacrylate -Polystyrene copolymer (SMMA NAS 30) was used as the molding material. The single factor trail and orthogonal experiment approach were adopted to investigate the effect of several process parameters and the significant effect factors affecting the replication of micro pillar. And the height distribution of micro pillar array was investigated by scanning electron microscope (SEM) and universal tool-measuring microscope to measure the replication quality. The results reveal that the replication of micro pillar is sensitive to the flow direction of the polymer melt. The height of micro pillar increases with the increase of mold temperature and injection speed. Moreover, the height distribution of micro pillar along and against flow direction was tightly related to the thermomechanical history of material during the molding process. [ABSTRACT FROM AUTHOR]

In this work, a thermal bonding method based on O plasma and water treatment was proposed to address the high dimension loss and low bonding strength issue during plastic planar nanofluidic device fabrication process. By this method, the PET (polyethylene terephthalate) planar nanofluidic device could be bonded at low temperature of 60 °C, force of 100 N and time of 15 min. To decrease the dimension loss and increase the bonding strength, thermal bonding parameters were optimized. The tensile test showed that the bonding strength of the PET planar nanofluidic device could be as high as 288.1 N. The fluorescence dye filling test indicated that there was no leakage and block in the PET planar nanofluidic device. [ABSTRACT FROM AUTHOR]

A novel hot embossing method is developed to fabricate polymer nanochannels. The pattern on the silicon nanomould is transferred to polymethylmethacrylate (PMMA) plates, and then polyethylene terephthalate (PET) nanochannels are embossed by using the PMMA mould. The use of the PMMA intermediate mould can extremely increase the device yield of the expensive silicon nanomould. To avoid the use of nanolithography, a method based on UV-lithography techniques for fabricating silicon nanomoulds with sub-micrometer width was put forward. 1 PMMA mould can be used to repeatedly emboss at least 30 PET substrates without damage and obvious deformation. Good pattern fidelity of PET nanochannels was obtained at the optimized embossing temperature of 90 °C. For an 808 nm-wide and 195 nm-deep nanochannel, the variations in width and depth between PET nanochannels and PMMA moulds were 1.8 and 2.5 %, respectively. The reproducibility was also evaluated, and the relative standard deviations in width and depth of 5 PET nanochannels were 5.1 and 7.3 %, respectively. [ABSTRACT FROM AUTHOR]

A microfluidic chip for the chemiluminescence detection of cobalt (II) in water samples, based on the measurement of light emitted from the cobalt (II) catalysed oxidation of luminol by hydrogen peroxide in basic aqueous solution, is presented. The microfluidic chip was designed and fabricated from polydimethylsiloxane using micro-molding method. Optimized reagents conditions were found to be 5.0 × 10 mol/L luminol, 1.0 × 10 mol/L hydrogen peroxide, and 8.0 × 10 mol/L sodium hydroxide. The system can perform fully automated detection with a reagent consumption of only 2.4 μL each time. The linear range of the cobalt (II) ions concentration was 1.0 × 10-1.0 × 10 mol/L and the detection limit was 5.6 × 10 mol/L with the S/N ratio of 3. The relative standard deviation was 4.6 % for 1.0 × 10 mol/L cobalt (II) ions ( n = 10). [ABSTRACT FROM AUTHOR]