Can two-photon polymerization fabricate miniaturized chromatography columns whose flow architecture and interaction surfaces are controlled separately? The authors printed functionalized polymer monoliths with CAD-defined Schoen gyroid macropores and chemically generated finer pores, verified the structure by scanning electron microscopy and nano-computed tomography, and measured reversed-phase retention of naphthalene and fluoranthene in a 6 mm column assembled from two printed segments. Delaying the solvent gradient shifted the two nonpolar peaks while acetylsalicylic acid remained near the

Print the pathways. Build chemistry into the walls. Let the molecules reveal the difference.

This paper combines two-photon polymerization with porous, functionalized polymers to make miniature chromatography columns—with structure at two very different scales.

Tobias Drieschner et al. · A guided exploration of the paper

the printed gyroid unit cell

the estimated pores in its walls

the assembled column bed

A designed route for liquid. A functional surface for molecules.

Three molecules. One printed path.

All three enter together. Polar aspirin exits almost immediately. The two nonpolar molecules stay longer—until a stronger solvent carries them out. Try delaying the solvent gradient.

Illustrative traces; peak times and resolution measured in the paper. Later peaks tail and partly overlap.

Near the void time

Hydrophobic retention

Hydrophobic retention

Partly overlapping peaks

The measured setup · Two printed monoliths in an FEP sleeve · 20 µL/min flow · 50 nL injection · 218 nm UV detection. Water and acetonitrile each contain 0.1% formic acid.

Method 1: 10% acetonitrile from 0–1 min; 10 → 90% from 1–4 min; 90% from 4–6 min. Method 2: the initial hold extends to 2 min; the same gradient runs from 2–5 min, followed by a 90% hold to 7 min.

Retention times are average values from triplicate measurements. The virtual transport and curve shapes are conceptual; the peak locations and resolution values come from the paper. The aspirin peak is near the system void time. The result demonstrates reversed-phase retention, with no baseline separation of the later pair. Peak broadening reflects the complete fluidic setup, including its external volume.

Two scales. Two different jobs.

The laser writes the larger channels. Phase separation creates much smaller pores within the walls. Geometry controls the route; surface chemistry gives molecules a reason to linger.

A path with no dead ends.

The repeating 20 µm gyroid cell creates channels about 7.5 µm wide, with struts about 6.2 µm thick. The designed macroporosity is 70%; nano-CT measured 71%.

macroporosity measured by nano-computed tomography

The rotatable surface is a mathematical gyroid illustration. Dimensions refer to the paper's printed design.

Print structure. Include function.

Rather than adding a functional coating later, the authors incorporate hydrophobic chemistry and a pore-forming component into the printing resin.

Write the gyroid.

Focused laser light initiates two-photon polymerization only near its focal volume, turning a digital gyroid design into a polymer monolith.

A Nanoscribe Photonic Professional GT in dip-in mode prints 3 mm × 350 µm designs on ITO glass. A 25× objective, 85 mm/s scan speed, 1 µm slicing and 0.5 µm hatching give a print time of about 2 hours per monolith.

Make porous walls.

As the resin polymerizes, phase separation creates mesopores. Dodecyl methacrylate (DMA) contributes nonpolar alkyl groups within the polymer.

The monomer blend contains 95% pentaerythritol tetraacrylate (PETA) and 5% DMA. The resin combines 70% of this blend with 30% butyl benzoate porogen, plus photoinitiator at 1.5% relative to the monomers.

Wash. Join. Separate.

Washing removes residual resin and porogen. Two 3 mm monoliths are joined in an FEP sleeve and connected to fused-silica capillaries.

The printed structures are washed for 30 minutes in PGMEA, then 2 minutes in isopropanol. The measured diameter is 335 µm versus a 350 µm design—about 4% shrinkage. The two monoliths form a 6 mm column bed.

From design to measured evidence.

Microscopy reveals the two levels of porosity. Nano-CT checks the printed architecture. Chromatography shows that changing the solvent shifts molecular retention.

The hierarchy is visible.

The CAD model becomes a printed monolith. Scanning electron microscopy then reveals the larger channels and the much finer pores within the polymer walls.

Move from the whole structure to its struts, then to the texture within those struts. The two pore scales serve different purposes.

The supplement details the resin formulation, gyroid equation, printing parameters, microscopy and fluidic assembly. It also compares mesoporosity across resin formulations and describes system dispersion.

A column designed from the inside out.

The paper establishes a route to printing both architecture and functional porous material in one fabrication process. It points toward chromatography devices where shape, size and surface chemistry can be selected together.

Direct printing inside transparent microfluidic devices is a proposed next direction.

Science you can explore.

“Hierarchically Structured Functionalized Polymer Monoliths Via Two-Photon Polymerization for Miniaturized HPLC Separation Columns”

Tobias Drieschner, Tobias Werres, Martin Klassen, Björn Lang, Anita Lorenz, Marc Brecht, Günter Lorenz, Thorsten Teutenberg and Andreas Kandelbauer.

Analytical Chemistry 98 (30), 22009–22016 (2026). doi:10.1021/acs.analchem.6c02512 ↗

Paper figures © 2026 the authors, published by the American Chemical Society under CC BY 4.0. Figures are reproduced at a different size without content changes. Supporting information is linked at its repository under CC BY-NC 4.0.