采用价格便宜的聚甲基丙烯酸甲酯(PMMA)代替价格昂贵的硅或者玻璃作为聚合酶链式反应(PCR)微流控芯片的基片材料,采用柔性大、自动化程度高的准分子激光微加工方法代替加工工艺复杂的光刻化学腐蚀方法。通过对聚甲基丙烯酸甲酯准分子激光加工规律的研究,在19 kV和18 mm/min的优化加工参量下,在40 mm×63 mm的聚甲基丙烯酸甲酯基片上制备出了20个循环的聚合酶链式反应微流控芯片。芯片微通道横截面呈倒梯形,底面粗糙度小于0.5 μm。微通道宽104 μm,深56 μm,长1040 mm,加工耗时57 min。该芯片和相同尺寸的盖片在160 N和105 ℃条件下经过20 min热压键合在一起,键合强度为0.85 MPa。通过进样实验发现键合后的芯片具有良好的密封性。键合后的芯片和温控系统集成在一起,采用比例积分微分(PID)方法得到的控温精度为±0.2 ℃,采用红外热像仪得到的相邻温区间的温度梯度分别为16.5 ℃和22.2 ℃,即该芯片可以实现聚合酶链式反应扩增。

A cheap PMMA was chosen as the substrate instead of expensive silicon or glass, and a 248-nm excimer laser with flexible and auto character replaced complex lithography as a new fabrication technique. After studying the PMMA ablation principle fabricated by 248-nm excimer laser, a PMMA (40 mm×63 mm) based micro-flow through polymerace chain reaction (PCR) chip with 20 cycles was fabricated at 19 kV and 18 mm/min parameters. The cross section of the chip microchannel was inverse trapezoid, and its bottom surface roughness was less than 0.5 μm. The microchannel had a width of 104 μm, a depth of 56 μm, and a length of 1040 mm. It cost 57 minutes to finish the total length. Then the chip was bonded together with another cover chip at 105 ℃, 160 N for 20 min. It could endure 0.85 MPa pressure and seal micro fluid well after sample injection experiment. In the end, it was integrated with the temperature control system. Three micro temperature controllers were chosen to control the temperature and gained ±0.2 ℃ temperature control precision. The temperature gradients between the three temperature zones were 16.5 ℃ and 22.2 ℃ respectively. This chip could realize PCR reaction.