A new Nature Materials study from good Prof. Alqvist’s team turns a wonderfully simple biological observation into a potentially powerful wound-care platform: repairing cells pull, and the material responds.
What if a wound dressing did not simply dump a drug into a wound, but waited for repairing cells to tug on it – and only then opened the local medicine cabinet?
That is the elegant idea behind traction-force-activated payloads, or TrAPs, reported by Magdalene Ho, Ben Almquist and colleagues in Nature Materials. It is part biomaterial, part molecular mousetrap and part lesson in listening to the body.
The wound pulls the trigger
Cells do not sit quietly inside tissue. They grip, migrate, push and pull on the extracellular matrix around them. The Almquist team uses those traction forces as an intrinsic trigger.
Each TrAP is built from an aptamer – a short synthetic strand of DNA folded to bind a specific protein – tethered to a scaffold at one end and fitted with a cell-adhesive handle at the other. The aptamer captures a growth factor and holds it inactive. When a cell grabs the handle and pulls, the aptamer unfolds and releases that signal at the cell-material interface.
In other words: the cell provides both the request and the release mechanism. No light source, magnet or external device is needed. The signal is delivered where a cell is actively engaging the material, rather than diffusing indiscriminately through the wound.
From a clever switch to repairing tissue
The group first introduced this force-responsive concept in 2019. The new paper makes the important leap from elegant in-vitro engineering to complex, enzyme-rich repair environments.
The investigators created TrAPs for four familiar growth factors – VEGF-A, HGF, FGF-2 and PDGF-BB – and incorporated them into collagen scaffolds. Across a series of experiments, the system captured, concentrated and redelivered growth factors produced by cells or harvested from human platelet lysate.
- In human cell models, force-activated delivery increased endothelial sprouting and migration and supported dermal fibroblast growth compared with non-activating control constructs.
- In a rat femoral-defect model, VEGF-TrAP scaffolds promoted more and larger blood vessels after three weeks. As expected for a pro-angiogenic rather than pro-osteogenic treatment, they did not increase bone growth.
- In wounded human skin maintained ex vivo, collagen sponges carrying three platelet-lysate-loaded TrAPs showed greater tissue-sponge integration by day eight. This experiment used skin from three independent donors; it was human tissue, but it was not a treatment study in living patients.
- In a pilot mouse wound model, four-factor TrAP sponges reduced normalized wound diameter at day ten compared with both the non-activating TrAP control and the plain scaffold control.
There is another intriguing result beneath the headline. The unmodified DNA aptamers remained functional long enough to influence repair despite the enzyme-rich wound environment. Their matrix-bound configuration may protect them more effectively than we would expect from free oligonucleotides in solution.
Why this matters to wound care
Growth factors have always been biologically attractive and practically difficult. Proteins can be unstable. Passive delivery is inefficient. Recombinant products may require high doses, repeated application and cold-chain logistics. Combining several factors adds still more complexity.
TrAPs invert that model. Instead of manufacturing and broadly releasing large quantities of active protein, the scaffold can harvest endogenous signals, keep them quiet and let engaged cells activate them locally. The authors calculate that the platform’s maximum loaded doses are orders of magnitude below common clinical and experimental growth-factor delivery levels. That is an encouraging engineering comparison – not yet a human dose-finding result.
The modularity may be just as important. In principle, different aptamers could be paired with different scaffolds and cell-binding handles, creating combinatorial materials that respond to the cells actually doing the work. This is less like coating a wound with a message and more like giving the wound a responsive switchboard.
The caveat is the compass
This is outstanding translational science, but it is still preclinical science. The study did not treat diabetic foot ulcers, and it did not test the platform in people. The animal wounds were not diabetic, ischemic, infected, neuropathic or repeatedly loaded. Human skin was studied ex vivo. Toxicity and immunogenicity were not primary endpoints, long-term remodeled skin function remains unknown, and scaffold stiffness, degradation and matrix remodeling may all change TrAP activation over time.
The authors also disclose that Ben Almquist is an inventor on a TrAP patent, and Magdalene Ho and Almquist are founders of Traxion Biotech, a spin-out developing the technology.
Ben’s own note to me struck exactly the right tone: there are still several stops before first-in-human testing. But this paper clears an important one. It shows that cellular traction can function as a reliable delivery trigger in living repair environments, not only in a dish.
For those of us who spend our days thinking about wounds that have stopped listening to the normal choreography of repair, that is a compelling idea. The future dressing may do more than cover, carry or release. It may wait for the right cell to pull – and then answer.
Primary reference
Ho MY, Oliva N, Basu C, et al. Force-responsive biomaterials drive tissue repair by harnessing endogenous growth factors. Nature Materials. Published July 27, 2026.
Foundational TrAP study
Stejskalová A, Oliva N, England FJ, Almquist BD. Biologically inspired, cell-selective release of aptamer-trapped growth factors by traction forces. Advanced Materials. 2019;31:1806380.
#WoundHealing #Biomaterials #RegenerativeMedicine #DiabeticFoot #LimbPreservation #ActAgainstAmputation
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