A DNA Nanosyringe Opened a Synthetic Cell, Delivered Cargo, Then Let It Reseal

A nanodevice built mainly with DNA origami has done something unusually mechanical: it anchored to a synthetic cell membrane, pushed a needle through it, carried molecular cargo across, then withdrew so the membrane could close again. The result is a controllable laboratory interface, not a medical injection system.

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The needle moved in two 14-nanometre steps, giving it a maximum programmed travel of 28 nanometres.

Why a retractable pore is different

Cell membranes are selective barriers. Existing DNA nanopores can create passages through them, but many designs stay embedded after insertion. A fuller guide to DNA origami nanomachines explains how folded strands become moving structures and why laboratory motion is not the same as medical readiness. The new device adds a separate mechanical cycle: anchor, puncture, transport, retract.

That reversibility is the important result. Electrical recordings returned to baseline after the researchers commanded the needle upward, while fluorescence tests indicated that lipid vesicles regained their barrier after retraction. This does not make the device ready for drug delivery, but it gives synthetic-cell researchers a way to control when and where a membrane opens.

What the team actually built

The structure contains two DNA origami bundles, each about 70 nanometres long, linked by a gold nanoparticle roughly 10 nanometres across. One bundle forms a base with 12 cholesterol anchors that attach it to a lipid membrane. The other acts as a movable needle with three central channels, each about 2 nanometres wide, plus sites for attaching cargo at its tip.

Short DNA “fuel” strands change which footholds bind the gold connector. This DNA strand-displacement mechanism slides the bundles relative to one another. Downward motion forces the needle across the membrane; a different set of strands drives the reverse movement.

In current measurements on free-standing lipid bilayers, the anchored device produced no conductive path until the fuel strands moved the needle. The resulting pore remained conductive for more than an hour. In a separate experiment, a dye about 0.7 nanometres across entered giant lipid vesicles after penetration, while a roughly 3-nanometre dextran molecule remained outside, consistent with transport through the narrow channels rather than uncontrolled rupture.

Cargo did more than cross the membrane

The researchers then attached larger molecules to the needle tip and used the motion to place them inside synthetic compartments. Delivered DNA initiated a localized chain reaction at the membrane. Another cargo activated RNA transcription, and a catalytic DNA molecule cut a selected RNA target.

Those three demonstrations make the work more substantial than a pore-opening experiment. The nanosyringe did not merely change permeability; it started chosen biochemical events on command. The open-access Nature Nanotechnology paper reports the device architecture, controls and quantitative measurements. The University of Stuttgart research report explains the intended synthetic-biology context, while Phys.org’s reviewed report provides a concise account of the publication and its visual material.

What has to happen next

The immediate test is not a human trial. Researchers first need to show repeatable operation on increasingly realistic membranes and living cells, then measure whether insertion damages those cells or triggers unwanted responses. They also need to determine how many devices reach a target membrane and how reliably each one completes the full cycle.

The paper establishes a programmable membrane tool whose needle can move, carry cargo and retreat. Its unresolved boundary is equally specific: the demonstrated target was a synthetic lipid compartment, and crossing that boundary in living biology remains a separate experiment.