Characterization of Microchannel Replicability of Injection Molded Electrophoresis Microfluidic Chips

Abstract

Microfluidic chips have been widely applied in biochemical analysis, DNA sequencing, and disease diagnosis due to their advantages of miniaturization, low consumption, rapid analysis, and automation. Injection molded microfluidic chips have attracted great attention because of their short processing time, low cost, and mass production. The microchannel is the critical element of a microfluidic chip, and thus the microchannel replicability directly affects the performance of the microfluidic chip. In the current paper, a new method is proposed to evaluate the replicability of the microchannel profile via the root mean square value of the actual profile curve and the ideal profile curve of the microchannel. To investigate the effects of injection molding parameters (i.e., mold temperature, melting temperature, holding pressure, holding time, and injection rate) on microchannel replicability, a series of single-factor experiments were carried out. The results showed that, within the investigated experimental range, the increase of mold temperature, melt temperature, holding pressure, holding time, and injection rate could improve microchannel replicability accuracy. Specifically, the microchannels along the flow direction of the polymer melt were significantly affected by the mold temperature and melt temperature. Moreover, the replicability of the microchannel was influenced by the distance from the injection gate. The effect of microchannel replication on electrophoresis was demonstrated by a protein electrophoresis experiment.

Efficient and Precise Micro-Injection Molding of Micro-Structured Polymer Parts Using Micro-Machined Mold Core by WEDM

“…Due to its simple manufacturing process, high forming quality and low production cost, micro-injection molding is suitable for mass production and manufacturing of micro-structured polymers, and it is almost unlimited in the geometric shape of plastic parts. Therefore, it has become the main molding process of micro-structured polymer [5,6,7]. For instance, the disposable optical stretcher and microfluidic devices can be rapidly and precisely fabricated by micro-injection molding [8,9].…”

2D Spatially-Resolved Depth-Section Microfluidic Flow Velocimetry Using Dual Beam OCT

“…Although a commercially available microfluidic chip was used for this work, difficulties were encountered around the deviation from specification (there was additional narrowing from a specified 0.90 mm to 0.77 mm around the base of the slope, possibly due to PMMA flow during the injection moulding process) [23], which impacted the expected flow velocity. This emphasised the need for flow measurement even in cases where commercial microfluidic chips were utilised with known pump rates and for truly 3D flow measuring instruments to capture fully and directly the flow in such situations.…”

“…The sloped section rose from a (specified) full depth of 700 µm (measured to be accurate to ±15 µm) to 214 µm. The spanwise width narrowed from a (specified) width of 1.25 mm (measured to be 1.245 mm) at the top of the channel to 0.90 mm at the bottom (with additional narrowing to 0.77 mm around the base of the slope, possibly due to PMMA flow during the injection moulding process) [23]. Measurements were accurate to 15 µm.…”

“…The maximum measured ratio (2.5) was exceeded by the minimum area ratio (2.6), and it was speculated that two effects may contribute to explaining this. For the area, the spanwise-width constriction was not well modelled by the bottom trapezoidal shape, but instead had greater constriction at the base of the channel to support the mass resting above it [23]. For the peak velocities, the depth of the channel may cause the flow to vary differently in the spanwise-width direction, since in the shallow channel, the nearness of the top and bottom surface may dominate the forces, restraining the flow [32].…”

A new fuzzy rule based multi-objective optimization method for cross-scale injection molding of protein electrophoresis microfluidic chips

“…In addition, the replication fidelity of microchannel is represented by the mean square root of the ideal microchannel contour and the actual microchannel contour. The formula is as follows 41 : where represents the value of the mean square root, is the point of the actual microchannel contour, denotes the point of the ideal microchannel contour, i is the amount of the point for microchannel contour. Table 4 and Fig.…”