3D-Printed Paper Spray Ionization Cartridge with Fast Wetting and Continuous Solvent Supply Features

We report the development of a 3D-printed cartridge for paper spray ionization (PSI) that can be used almost immediately after solvent introduction in a dedicated reservoir and allows prolonged spray generation from a paper tip. The fast wetting feature described in this work is based on capillary action through paper and movement of fluid between paper and the cartridge material (polylactic acid, PLA). The influence of solvent composition, PLA conditioning of the cartridge with isopropanol, and solvent volume introduced into the reservoir have been investigated with relation to wetting time and the amount of solvent consumed for wetting. Spray has been demonstrated with this cartridge for tens of minutes, without any external pumping. It is shown that fast wetting and spray generation can easily be achieved using a number of solvent mixtures commonly used for PSI. The PSI cartridge was applied to the analysis of lidocaine from a paper tip using different solvent mixtures, and to the analysis of lidocaine from a serum sample. Finally, a demonstration of online paper chromatography–mass spectrometry is given

Fused Deposition Modeling 3D Printing for (Bio)analytical Device Fabrication: Procedures, Materials, and Applications

In this work, the use of fused deposition modeling (FDM) in a (bio)­analytical/lab-on-a-chip research laboratory is described. First, the specifications of this 3D printing method that are important for the fabrication of (micro)­devices were characterized for a benchtop FDM 3D printer. These include resolution, surface roughness, leakage, transparency, material deformation, and the possibilities for integration of other materials. Next, the autofluorescence, solvent compatibility, and biocompatibility of 12 representative FDM materials were tested and evaluated. Finally, we demonstrate the feasibility of FDM in a number of important applications. In particular, we consider the fabrication of fluidic channels, masters for polymer replication, and tools for the production of paper microfluidic devices. This work thus provides a guideline for (i) the use of FDM technology by addressing its possibilities and current limitations, (ii) material selection for FDM, based on solvent compatibility and biocompatibility, and (iii) application of FDM technology to (bio)­analytical research by demonstrating a broad range of illustrative examples