Tuning the fabrication of knotted reactors via 3D printing techniques and materials

Although three-dimensional (3D) printing technologies can customize a diverse range of devices, cross-3D printing technique/material comparisons aimed at optimizing the fabrication of analytical devices have been rare. In this study, we evaluated the surface features of the channels in knotted reactors (KRs) fabricated using fused deposition modeling (FDM) 3D printing [with poly(lactic acid) (PLA), polyamide, and acrylonitrile butadiene styrene filaments], and digital light processing and stereolithography 3D printing with photocurable resins. Also, their ability to retain Mn, Co, Ni, Cu, Zn, Cd, and Pb ions was evaluated to achieve the maximal sensitivities of these metal ions. After optimizing the techniques and materials for 3D printing of the KRs, the retention conditions, and the automatic analytical system, we observed good correlations (R > 0.9793) for the three 3D printing techniques in terms of the surface roughnesses of their channel sidewalls with respect to the signal intensities of their retained metal ions. The FDM 3D-printed PLA KR provided the best analytical performance, with the retention efficiencies of the tested metal ions all being greater than 73.9% and with the detection limits of the method ranging from 0.1 to 5.6 ng L^-1. We used this analytical method to perform analyses of the tested metal ions in several reference materials (CASS-4, SLEW-3, 1643f, and 2670a). Spike analyses of complicated real samples verified the reliability and applicability of this analytical method, highlighting the possibility of tuning 3D printing techniques and materials to optimize the fabrication of mission-oriented analytical devices.