The study asks how to program liquid-crystal alignment throughout three-dimensional printed microactuators. Experiments use two-photon polymerization and diffusion-guided reorientation at the growing polymer interface to encode multiple alignment domains, enabling reversible contraction, bending and twisting, plus microsphere handling and scattering-triggered gripping. Reliable reorientation depends on printing geometry, dose and transport time; switching alignment in bulk builds requires an inter-layer interval exceeding about 3 seconds under the reported conditions.

TWO-PHOTON PRINTING · SOFT MICROACTUATORS

A printed object can remember how to move. This paper shows how the growth of a liquid-crystal material writes that instruction into its molecular alignment.

Hsu et al. · Nature Communications · 2026

Print in 3D A focused laser solidifies tiny volumes of a liquid-crystal precursor.

Encode alignment The growing interface guides mobile molecules into new orientations.

Add the fourth dimension After printing, light turns those orientations into reversible motion.

01 / THE MOTION LAB

One material. Many ways to move.

Choose an alignment pattern, then turn up the light. The shape changes because each domain responds differently to heat.

Ready to bend · turn up the light

1 Choose the molecular program

The upper layer contracts along the strip. The vertical director in the lower layer creates a different strain, so the bilayer bends upward.

The dye is introduced after printing . Heated liquid-crystal networks contract along their director and expand transversely. This model illustrates that mechanism; its light scale and deformation amplitudes are not a calibrated prediction.

02 / WRITE THE INSTRUCTION

The next layer learns from the last.

Polymerization consumes reactive monomers locally, creating a concentration gradient. Mobile precursor diffuses toward the growing network, reorients at its interface, and the next laser pass fixes that alignment.

The substrate sets the initial vertical alignment. Reorientation needs more transport time in the bulk network.

1 Choose the stacking direction

For switching away from the initial alignment in bulk structures, the paper reports an inter-layer interval greater than 3 seconds .

The interval includes scanning and the laser’s return path. It does not mean adding a pause before every written line.

A qualitative illustration of the reported bulk experiment. The director is drawn in two representative states; no exact angle is inferred from the interval.

Scan is not stack. The red spot scans along y. Layers accumulate along x or z, defining the growing interface.

Single layers have a different clock. At 2,200 µm/s scan and 500 µm/s return speeds, 20 µm and 100 µm lines give about 49 ms and 245 ms per line.

The interface sets the direction. Mobile mesogens diffuse toward the polymerized network and reorient perpendicular to its effective surface.

03 / THE MEASURED RESPONSE

A tiny strip. A clear contraction.

Explore the paper’s thermal measurements for a freestanding strip with nominal dimensions of 55 × 30 × 8 µm. Heating shortens it along its programmed longitudinal alignment.

22 mW writing power · n = 3 repeated measurements of the same sample

Mean strip length: 54.12 µm

Dots and error bars are reported measurements from the paper’s Source Data. The slider selects measured temperatures in 10 °C steps.

Thermal and optical experiments test the same programmed response. The 3D lab above slows the motion so you can explore it.

04 / FROM THE EXPERIMENT

Watch the material follow its program.

The flower turns local alignment into a collective movement. The microgripper turns controlled movement into a physical task.

A SEPARATE TARGET-TRIGGERED DESIGN

Can an object trigger its own grasp?

A bottom-up beam passes through the gap. A highly scattering target redirects light into the gripper, increases local heating and triggers closure. A transparent or weakly scattering target does not. Light off releases the object.

Hsu et al. (2026), Fig. 6c–d and Supplementary Movie 9 · CC BY 4.0. Excerpt; resized and compressed; original speed.

Figures 4–5: Hsu et al., Nature Communications (2026). CC BY 4.0. Reproduced; resized for display.

WHY THIS OPENS A NEW DESIGN SPACE

Shape and function, written together.

Two-photon polymerization gives the structure its form. Diffusion-guided alignment gives each region its mechanical instruction. Combining them allows free-standing, multi-axis actuators to be printed directly in three dimensions.

The paper also demonstrates a separate target-triggered gripper: a highly scattering object entering a 515 nm beam locally enhances heating and triggers closure. A transparent or weakly scattering target does not. Turning the light off releases the object.

These results point toward event-driven manipulation in microfluidics and cell handling, with material orientation designed as carefully as the object’s shape.

AT THE PRINTING SCALE

Fabrication and irradiation conditions vary by structure. The strip explored above was written at 22 mW.

Research, made explorable.

THE SOURCE PAPER

Wei-Ting Hsu, Po-An Tsou, Hsin-Jung Chou, Tsung-Kai Lin & Yu-Chieh Cheng Nature Communications 17 (2026) · DOI: 10.1038/s41467-026-73035-x