摘要
在生物医学工程中,微流控芯片用于细胞混合、培养和分选,其功能依赖于微流道的加工形貌和质量。因此,在皮秒绿光刻蚀过程中,利用激光振镜和动态聚焦系统确保材料去除位置,根据光斑直径设计激光扫描间距为5μm,在玻璃基板上加工出细胞分选用的微流控拓扑结构。分析了激光加工工艺及过程参数对微纳加工形貌的影响,进而探究了微流控流道分散和分选的自律流动性能。结果表明,减小激光功率和累计次数以及增大扫描速度会减小微流道深度和表面粗糙度,且当激光功率为8~10 W、扫描速度为1000~1400 mm/s、累积次数为6~9时,加工结构的形状完整,深度一致。在微流控的拓扑结构流动实验中发现,尺度为50~100μm、深宽比为1.16、粗糙度为500~600 nm的微阵列流池可以有效地分散直径为10μm和20μm的微粒子,且通过45°的夹流流道汇集将流速提高6.8倍,实现了这两种不同尺度的微粒子的加速分离。
Objective Microfluidic chips are an innovative technology used for the precise manipulation of small liquid samples and show great potential in fields such as medical diagnosis,biological research,drug screening,and environmental monitoring.Using glass as a material for microfluidic chips results in better thermochemical stability compared to using other materials.Owing to the high hardness,poor thermal conductivity,and fragility of glass materials,the traditional mechanical processing of glass flow channels is prone to edge breakage and cracking.Therefore,picosecond lasers are used for processing.Shortpulse laser etching technology has the advantages of high precision,noncontact,wide material adaptability,and fast processing speed,and can process glass channels with high aspect ratios.Compared with femtosecond lasers,picosecond lasers can be obtained from semiconductor lasers using gainswitching technology,with lower cost and easier access to high pulse energy and average power.However,the picosecond laser processing for glass microfluidic chips has not been widely reported,and the channel roughness is high,requiring further research on the processing technology and resulting performance.The results of this study provide guidance for the systematic processing of glass microfluidic chips using picosecond laser.Methods In this study,sodalime glass was employed,using an ultrafast laser with a pulse width of 7 ps and wavelength of 532 nm.Then,microfluidic chips for cell separation were fabricated on this glass.First,the influence of laser processing parameters on the depth and surface roughness of the flow channel was studied by controlling the variables,and the threedimensional morphology of the flow channel was measured using laser confocal microscopy.Subsequently,a set of orthogonal experiments with three factors and four levels were designed to obtain the optimal parameter combination for highquality processing of the flow channel and to further optimize the laser process parameters.Microfluidic chips were fabricated using the optimized parameters and packaging testing was performed.Finally,polystyrene microspheres were used on an independently built chip flow performance testing platform to test the flow performance of the chip channel,analyzing the dispersion,acceleration,and sorting functions of the chip.Results and Discussions The experimental results of direct laser etching of microchannels show that the depth of the processed microchannels increases with increasing laser power.Specifically,the increase in channel processing depth is most significant when the laser power increases from 6 W to 8 W.When the laser power is greater than 8 W,the increase in channel processing depth becomes slower(Fig.8).Increasing the scanning speed gradually reduces the depth of the flow channel(Fig.9),and increasing the number of scans increases the depth of the flow channel(Fig.10).Combining the significance analysis results for channel depth and channel roughness,we have the following conclusions.According to the results of the orthogonal experiment,when the repetition frequency f is 200 kHz,the laser power selection range is set to 8‒10 W,scanning speed is controlled at 1000‒1400 mm/s,and number of scans is 6‒9.The final processed channel has a depthtowidth ratio greater than 1,surface roughness of 500‒600 nm,and smooth channel edge without cracks(Fig.13).Conclusions In is study,an ultrafast laser processing technology was investigated for processing microfluidic chips on glass.By conducting experiments on direct laser etching of glass channels,the depth and roughness of the channels were studied as functions of the laser process parameters.After optimizing the process parameters through orthogonal experiments,highquality micronano channels were obtained without edge defects,with bottom roughness ranging from 500 nm to 600 nm.The material removal rate of the chip material was 5.64 mm3/min.Flow channel experiments showed that particles with diameters of 10μm and 20μm can be dispersed into different paths in the dispersion pool,and particles from different paths enter the main channel in 1.0,2.1,and 2.6 s respectively.After entering the intersection of the flow channel with an angle of 45°,particles can accelerate 6.8-fold under the action of the clamping flow and quickly pass through the sorting port.Particles with different scales can be sorted under the drive of the pressure.
作者
朱锡聪
陈绒
贺先送
谢晋
何姗姗
Zhu Xicong;Chen Rong;He Xiansong;Xie Jin;He Shanshan(College of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510640,Guangdong,China;Guangdong University of Science and Technology,Dongguan 523083,Guangdong,China)
出处
《中国激光》
北大核心
2025年第8期260-271,共12页
Chinese Journal of Lasers
基金
广东省基础与应用研究基金(2022A1515220053)
国家自然科学基金(52375493)
广东省教育厅普通高校认定类科研项目(2020KQNCX103)。
关键词
玻璃微流道
微流控芯片
激光刻蚀
快速分散分选
glass microchannels
microfluidic chip
laser etching
rapid dispersion and sorting
