Digital Light Processing 3D Printing for Microfluidic Chips with Enhanced-resolution via Dosing- and Zoning-controlled vat Photopolymerization

Abstract

Abstract Conventional manufacturing techniques to fabricate microfluidic chips like soft lithography and hot embossing processes show limitations including 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 3D printing of microfluidic chips, wherein, however, the fabrication resolution for microchannel is still limited to sub-100 microns at best. We hereby developed an innovative DLP printing strategy for high-resolution and scalable microchannel fabrication via 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 microchannel 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, therefore avoiding channel blockage due to UV over-exposure or compromised bonding stability owing to insufficient resin curing. Remarkably, this strategy can enable scalable and biocompatible fabrication of microfluidic drop-makers 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 the microfluidics-based techniques in biomedical fields.