Engineering of Removing Sacrificial Materials in 3D-Printed Microfluidics

Abstract

Three-dimensional (3D) printing will create a revolution in the field of microfluidics due to fabricating truly three-dimensional channels in a single step. During the 3D-printing process, sacrificial materials are usually needed to fulfill channels inside and support the printed chip outside. Removing sacrificial materials after printing is obviously crucial for applying these 3D printed chips to microfluidics. However, there are few standard methods to address this issue. In this paper, engineering techniques of removing outer and inner sacrificial materials were studied. Meanwhile, quantification methods of removal efficiency for outer and inner sacrificial materials were proposed, respectively. For outer sacrificial materials, a hot bath in vegetable oil can remove 89.9% ± 0.1% of sacrificial materials, which is better than mechanics removal, hot oven heating, and an ethanol bath. For inner sacrificial materials, injecting 70 °C vegetable oil for 720 min is an optimized approach because of the uniformly high transmittance (93.8% ± 6.8%) and no obvious deformation. For the industrialization of microfluidics, the cost-effective removing time is around 10 min, which considers the balance between time cost and chip transmittance. The optimized approach and quantification methods presented in this paper show general engineering sacrificial materials removal techniques, which promote removing sacrificial materials from 3D-printed microfluidics chips and take 3D printing a step further in microfluidic applications.

3D-Printed Concentration-Controlled Microfluidic Chip with Diffusion Mixing Pattern for the Synthesis of Alginate Drug Delivery Microgels

“…The outer sacrificial materials of microfluidic chips were removed by heating in 70 °C for 10 min. The inner sacrificial materials was removed successively by vegetable oil of 70 °C for 30–60 min, and deionized water for 1 h. A constant flow pump (Shanghai QiTi analytic instrument Inc., Shanghai, China) was used to pump removers (vegetable oil) into the inner chip channels with the rate of 0.1–0.3 mL/min [33,34].…”

Recent Developments in 3D Printing of Droplet-Based Microfluidics

“…This system has attracted many who do not have the skill to fabricate microfluidics devices using photo-and soft-lithography. While this technique suffers some limitations, as discussed earlier, some recent improvements in resolution, the biocompatibility of materials, and other properties have shown that 3D printing still holds the key to application in droplet-based microfluidics [209,[228][229][230]. For instance, traditional methods are difficult to fabricate complex structures; however, this can be achieved now with the potential of producing multifunctional microfluidics devices for biomedical applications.…”

Applying extrusion-based 3D printing technique accelerates fabricating complex biphasic calcium phosphate-based scaffolds for bone tissue regeneration

“…To manufacture the scaffolds with complicated structures, an admitted printing method, which uses sacrificial materials, is suggested [155] . Sacrificial materials act as supporting structures in the printing process, at the first, and should be removed after printing [156] . Pluronic® F-127 (BASF Corporation, USA) is a salient example of these materials commonly used in BCP robocasting for the temporary support [157] .…”