Luo Zhiming, Zhang Haoyue, Chen Runze, Li Hanting, Cheng Fang, Zhang Lijun, Liu Jia, Kong Tiantian, Zhang Yang, Wang Huanan
School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen, 518000 P. R. China.
State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, School of Bioengineering, Dalian University of Technology, Dalian, 116024 P. R. China.
Microsyst Nanoeng. 2023 Aug 15;9:103. doi: 10.1038/s41378-023-00542-y. eCollection 2023.
Conventional manufacturing techniques to fabricate microfluidic chips, such as soft lithography and hot embossing process, have limitations that include difficulty in preparing multiple-layered structures, cost- and labor-consuming fabrication process, and low productivity. Digital light processing (DLP) technology has recently emerged as a cost-efficient microfabrication approach for the 3D printing of microfluidic chips; however, the fabrication resolution for microchannels is still limited to sub-100 microns at best. Here, we developed an innovative DLP printing strategy for high resolution and scalable microchannel fabrication by dosing- and zoning-controlled vat photopolymerization (DZC-VPP). Specifically, we proposed a modified mathematical model to precisely predict the accumulated UV irradiance for resin photopolymerization, thereby providing guidance for the fabrication of microchannels with enhanced resolution. By fine-tuning the printing parameters, including optical irradiance, exposure time, projection region, and step distance, we can precisely tailor the penetration irradiance stemming from the photopolymerization of the neighboring resin layers, thereby preventing channel blockage due to UV overexposure or compromised bonding stability owing to insufficient resin curing. Remarkably, this strategy can allow the preparation of microchannels with cross-sectional dimensions of 20 μm × 20 μm using a commercial printer with a pixel size of 10 μm × 10 μm; this is significantly higher resolution than previous reports. In addition, this method can enable the scalable and biocompatible fabrication of microfluidic drop-maker units that can be used for cell encapsulation. In general, the current DZC-VPP method can enable major advances in precise and scalable microchannel fabrication and represents a significant step forward for widespread applications of microfluidics-based techniques in biomedical fields.
制造微流控芯片的传统制造技术，如软光刻和热压印工艺，存在一些局限性，包括制备多层结构困难、制造过程成本高且耗费人力以及生产率低。数字光处理（DLP）技术最近作为一种用于微流控芯片3D打印的经济高效的微制造方法出现；然而，微通道的制造分辨率目前最高仍局限于亚100微米。在此，我们通过剂量和分区控制的光致聚合（DZC-VPP）开发了一种用于高分辨率和可扩展微通道制造的创新DLP打印策略。具体而言，我们提出了一种改进的数学模型来精确预测树脂光致聚合的累积紫外线辐照度，从而为制造具有更高分辨率的微通道提供指导。通过微调打印参数，包括光辐照度、曝光时间、投影区域和步距，我们可以精确调整相邻树脂层光致聚合产生的穿透辐照度，从而防止因紫外线过度曝光导致的通道堵塞或因树脂固化不足而导致的粘结稳定性受损。值得注意的是，该策略能够使用像素尺寸为10μm×10μm的商用打印机制备横截面尺寸为20μm×20μm的微通道；这一分辨率显著高于先前的报道。此外，该方法能够实现可扩展且具有生物相容性的微流控滴液制造单元的制造，该单元可用于细胞封装。总体而言，当前的DZC-VPP方法能够在精确和可扩展的微通道制造方面取得重大进展，代表了基于微流控技术在生物医学领域广泛应用向前迈出的重要一步。
