3D printing provides access to complex multilevel architectures, though the capability to routinely print and integrate structures of controlled porosity is limited. Herein, grayscale digital light projection 3D printing of a polymerization‐induced phase separation ink is introduced to directly 3D print functionally graded porous within a single layer from the same ink formulation. The structural properties of materials printed from a single ink are tuned from an effectively dense to a porous material with interconnected pores up to 250 nm. Heterostructures with the physically dense structure of porosity 0.8% and porous structures with up to 23% can be concurrently formed within a layer, with high spatial resolution inherent of this 3D printing technique. Materials with densities from 1.01 to 1.21 g cm⁻³ are 3D printed in a wicking device and show wicking rates (H₂O) from complete diffusion blockage up to 4.5 mm h⁻¹. Furthermore, a proof‐of‐concept membrane‐integrated fluidic device is used for the elemental metal sensing of iron in soil. The presented single‐step fabrication of functionally graded materials with pixel‐based control within a single layer holds potential for manufacturing and integrating membranes or sorbents for environmental, biotechnology, and healthcare applications.

Nucleic acid amplification testing facilitates the detection of disease through specific genomic sequences and is attractive for point-of-need testing (PONT); in particular, the early detection of microorganisms can alert early response systems to protect the public and ecosystems from widespread outbreaks of biological threats, including infectious diseases. Prior to nucleic acid amplification and detection, extensive sample preparation techniques are required to free nucleic acids and extract them from the sample matrix. Sample preparation is critical to maximize the sensitivity and reliability of testing. As the enzymatic amplification reactions can be sensitive to inhibitors from the sample, as well as from chemicals used for lysis and extraction, avoiding inhibition is a significant challenge, particularly when minimising liquid handling steps is also desirable for the translation of the assay to a portable format for PONT. The reagents used in sample preparation for nucleic acid testing, covering lysis and NA extraction (binding, washing, and elution), are reviewed with a focus on their suitability for use in PONT.

3D printing is established as an alternative microfabrication approach, and while printer resolution limits the direct 3D printing of pore features in the micron/submicron range, the use of nanoporous materials allows for the integration of porous membranes in 3D printed devices. Here, nanoporous membranes were formed by digital light projection (DLP) 3D printing using a polymerization-induced phase separation (PIPS) resin formulation. A functionally integrated device was fabricated using resin exchange following a simple, semi-automated manufacturing process. Printing of porous materials from a PIPS resin formulations based on polyethylene glycol diacrylate 250 as monomer was investigated by varying exposure time, photoinitiator concentration, and porogen content to yield materials with average pore size varying from 30–800 nm. Aiming for printing a size-mobility trap for electrophoretic extraction of deoxyribonucleic acid (DNA), conditions for printing materials with a mean pore size of 346 nm and 30 nm were selected for integration in a fluidic device using a resin exchange approach. Under optimized conditions (12.5 V for 20 min), cell concentrations as low as 10³ cells per mL were detected following amplification of the extract by quantitative polymerase chain reaction (qPCR) at a Cq of 29. The efficacy of the size/mobility trap formed by the two membranes is demonstrated by detecting DNA concentrations equivalent to the input detected in the extract while removing 73% of the protein in the lysate. The DNA extraction yield was not statistically different from that obtained using a spin column, but manual handling and equipment needs were significantly reduced. This study demonstrates that nanoporous membranes with tailored properties can be integrated into fluidic devices using a simple manufacturing process based on resin exchange DLP. The process was used to manufacture a size-mobility trap and applied for the electroextraction and purification of DNA from E. coli lysate with reduced processing time, manual handling, and equipment needs compared with a commercially sourced DNA extraction kit. Combining manufacturability and portability with ease of use, the approach has demonstrated potential for manufacturing and using devices used in point-of-need testing for diagnostic nucleic acid amplification testing.

3D printing of membrane-integrated devices for chemotaxis studies of aquatic animals.