4.

3D Printing techniques in the fabrication of VF-μPADs for POCT. (A) FDM approach for VF-μPAD fabrication using PLA and wax filaments: (i) Illustration of an FDM 3D printer depositing PLA and wax filaments onto Whatman chromatography paper to create hydrophobic barriers; (ii) view of the VF-μPAD layers produced by FDM, including the sample inlet, reaction zones, and absorbent pad; and (iii) VF-μPADs for dengue virus serotype detection using cell-free reactions. Reproduced with permission from ref (). Copyright 2021 Elsevier B.V. (B) DLP 3D printing approach for VF-μPAD fabrication with integrated plasma separation functionality: (i) Schematic of DLP printing setup showing the integration of a parylene C-coated PSM within a photocurable polymer matrix and (ii) illustration of the wetting of the plasma separation membrane (PSM) and the corresponding color generation in the detection zone using 10, 30, and 100 μL of whole blood containing 5 mM glucose. Reproduced with permission from ref (). Copyright 2019, American Chemical Society.