The study, published in Frontiers in Biomaterials Science, centers on a modified form of dextran, a sugar-based polymer with a long clinical history as a plasma expander and drug carrier. Dextran is built from glucose units linked predominantly through alpha-1,6 bonds, and each unit carries three hydroxyl groups that chemists can exploit. The Drexel team attached methacrylate groups to these hydroxyls by reacting dextran with glycidyl methacrylate, a base-driven esterification that proceeds uniformly in solution and allows the degree of substitution—the fraction of repeat units bearing a reactive methacrylate group—to be dialed anywhere from 5 to 95 percent. Nuclear magnetic resonance spectroscopy confirmed that this degree of substitution scaled linearly with the amount of glycidyl methacrylate used, giving the researchers a precise handle over how many light-reactive sites each polymer chain would carry.

The material’s defining trick lies in a two-stage photopolymerization scheme. In the first stage, the dissolved polymer and a water-soluble photoinitiator called lithium phenyl-2,4,6-trimethylbenzoylphosphinate, or LAP, are exposed to blue light (400 to 500 nanometers) just long enough—about 20 seconds—to form a solid, self-supporting hydrogel. Critically, this brief cure is deliberately incomplete: many methacrylate groups remain unreacted, held in reserve inside the swollen network. After the gel equilibrates overnight in salt solution, a second, much longer exposure of 60 to 600 seconds triggers a fresh wave of crosslink formation. Every new covalent bridge increases the network’s crosslink density, which squeezes water out of the gel. The hydrogel contracts, and any tube lined with the coating sees its inner diameter grow.

Rheological measurements traced the physics of this transformation in real time. Dissolved DexMA began as a weakly viscous fluid with a storage modulus below 1 kilopascal; within minutes of illumination, the storage modulus climbed steeply and then plateaued as available vinyl groups were consumed. Higher photoinitiator concentrations (3 and 5 millimolar) and higher light intensities (5 and 10 milliwatts per square centimeter) produced stiffer final gels—but they also exhausted the reactive pool too quickly, leaving nothing for the second act. The team therefore standardized on the mildest conditions, 1 millimolar LAP and 1 milliwatt per square centimeter, for the casting step. Under a 20-second initial cure, the gel reached roughly 1 kilopascal, and interestingly, crosslinking continued mildly after the lamp switched off, a sign that reactive radicals were diffusing through the network and extending growing polymer chains.

The parameter space governing how much the gel can shrink proved rich and, in places, counterintuitive. Volumetric changes rose with polymer concentration, from 2.5 up to 20 percent weight per volume, simply because denser solutions carry more methacrylate groups per unit volume. But the degree of substitution followed a more subtle pattern: gels made with intermediate modifications—25 to 50 percent—showed the largest volume changes and the widest mechanical tunability, while highly substituted polymers performed worse. The likely culprit is hydrophobicity. At high methacrylate densities, the modified dextran chain effectively collapses, reducing its hydrodynamic radius and the entanglements that support network formation, so final moduli actually fell for modifications exceeding 50 percent despite the abundance of reactive vinyl groups. Light dose also mattered temporally: significant differences appeared among 60-, 300-, and 600-second cures, though the response saturated between 300 and 600 seconds, meaning surgeons could dial in a specific degree of contraction simply by controlling exposure time.

Under optimized conditions—a 20-second casting at low initiator followed by a 300-second cure at 5 millimolar LAP—the hydrogels achieved volume reductions of 20.4 percent, plus or minus 0.79 percent. That number is not arbitrary. Earlier computational fluid dynamics work by the same group showed that a 20 percent volume change in a hydrogel lining translates to a 15 to 18 percent increase in shunt lumen diameter, which is precisely what models predict a child needs to accommodate the first two years of growth. A published case study of a dilatable shunt, whose lumen was expanded from 2.7 to 3.3 millimeters—an 18.2 percent expansion to correct inadequate blood perfusion—lends clinical corroboration to those targets. The team demonstrated feasibility in a benchtop model by loading a 50-percent-modified hydrogel into surface-treated quartz tubing with a 3.5-millimeter lumen and pulsing it with light in 10-second increments; the required 15 to 18 percent diameter increase arrived within 50 to 70 seconds of cumulative exposure.

An implantable material must also survive the body, and here the results were reassuring. Over three months of incubation at physiological temperature and pH, every formulation degraded by less than 10 percent cumulatively, swelled or shrank by less than 5 percent in volume, and lost minimal mass—with only the softest, 2.5-percent gels showing moderate losses approaching 25 percent. Neither the dextran molecular weight (75 versus 500 kilodaltons) nor the degree of substitution materially altered this hydrolytic resilience, which the authors attribute to the stability of dextran’s glycosidic bonds and the dense crosslinked network. Because the geometry of the gel remains essentially locked in place for months, a light-induced adjustment would be expected to persist rather than drift back.

Biological testing spanned the cell types an implanted shunt would actually meet. NIH 3T3 fibroblasts proliferated normally for three days in direct contact with 25- and 50-percent-modified gels and in their extracts, with population doubling times matching the roughly 20 hours typically reported, though the 95-percent formulation depressed metabolic activity—likely because hydrophobic, highly substituted soluble polymer leached into the medium at concentrations exceeding anything a pre-polymerized gel could realistically release. RAW-Blue macrophages, a reporter line for innate immune activation, adhered poorly to DexMA surfaces compared with polystyrene and showed minimal inflammatory signaling after 24 hours across all formulations, casting and curing alike. Most importantly for a blood-contacting device, ASTM-compliant hemolysis testing with citrated whole rabbit blood returned hemolytic indices below 3 percent for every gel tested—comparable to the inert low-density polyethylene negative control, far below the Buna-N rubber positive control, and safely under the 5 percent threshold the standard recommends.

The implications reach beyond pediatric cardiology. A hemocompatible gel whose volume can be sculpted after fabrication, on a timescale of seconds to minutes, could serve in dynamically adaptable cell-culture platforms, size-changing implants, or any blood-interface construct where geometry must evolve. The authors are candid about remaining hurdles: LAP is a small, water-soluble molecule whose retention inside a gel under active blood flow cannot be assumed, so clinical implementation would likely require delivering fresh photoinitiator locally through a catheter before irradiation—conveniently, the same blue-light-emitting catheter envisioned for the adjustment itself. Even so, by mapping the full parameter space of polymer concentration, methacrylate density, initiator loading, and light dose, the Drexel team has transformed a clever proof-of-concept into an engineering manual. For the youngest cardiac patients, that could one day mean their implant grows up with them, one carefully metered pulse of light at a time.

Subject of Research: Photoresponsive, hemocompatible dextran hydrogels with tunable volumetric contraction for pediatric blood shunts

Article Title: Hemocompatible polymeric hydrogels with tunable photoresponsive volumetric properties

Article References: Seiner, A. J., Mishin, V., Soni, S. S., Posthill, E., Sarkar, B., Spiller, K. L., Throckmorton, A. L., & Rodell, C. B. (2026). Hemocompatible polymeric hydrogels with tunable photoresponsive volumetric properties. Frontiers in Biomaterials Science, 5, Article 1924191. https://doi.org/10.3389/fbiom.2026.1924191

Image Credits: AI Generated

DOI: 10.3389/fbiom.2026.1924191

Keywords: hydrogels, dextran, photopolymerization, pediatric cardiology, blood shunts, hemocompatibility, biomaterials, congenital heart defects, photoresponsive materials, crosslink density, medical devices, tunable implants

A new computational study published in the Annals of Biomedical Engineering by Yuval Gabso, Moshe Rosenfeld, and Idit Avrahami, researchers at Tel Aviv University and Ariel University in Israel, has now exposed a counterintuitive design paradox at the heart of these devices. The team used high-resolution computational fluid dynamics to compare four different micro-axial p-LVAD architectures across twenty distinct operating conditions, and their findings challenge a long-standing assumption in pump design. The results suggest that making a pump more hydraulically efficient can, under certain architectures, actually make it more dangerous to the blood it moves. The work was conducted at the Ariel Biomechanics Center and funded by the Israeli Ministry of Science and Technology.

The central question the researchers tackled is one of the most stubborn in biomedical engineering: how do you predict, reliably and early in the design process, how much mechanical damage a pump will inflict on blood? The classical approach relies on so-called Eulerian indices, which evaluate the flow field at fixed points in space and estimate blood damage from local stress levels, often using turbulence-based models. These methods are computationally fast and attractive for screening many design candidates. The alternative is Lagrangian particle tracking, in which thousands of virtual blood cells are released into the simulated flow and followed along their entire trajectories, accumulating stress exposure minute by minute as they travel through the pump. Lagrangian methods are far more faithful to the physics of blood trauma, because real cells do experience their damage cumulatively along a path, but they demand much more computational effort.

Whether the cheaper Eulerian approach can be trusted in the tight, fast, complex geometry of a micro-axial pump has been an open question, and it is precisely the gap this study set out to close. The team evaluated two Eulerian turbulence-based hemolysis indices, labeled HI1 and HI2, against two Lagrangian metrics: the median stress accumulation experienced by tracked particles, and the mean supra-threshold exposure time, which measures how long cells spend above damaging stress levels. Four pump configurations were modeled, three of them using a discharge-type architecture and one using a suction-type configuration featuring an expanding hub, a design element intended to smooth the flow and prevent separation from the impeller surfaces.

The paradox emerged from the suction-type design. The expanding hub did exactly what it was engineered to do: it improved hydraulic efficiency by preventing flow separation, meaning the pump could deliver the required pressure and flow with less wasted energy. But the same geometric feature created a high-velocity bottleneck inside the pump, a narrow passage through which blood had to accelerate dramatically. That acceleration drove up the bulk shear stress throughout the device, and shear stress is the primary mechanism by which mechanical pumps destroy red blood cells. In other words, the more efficient the suction-type pump became, the more it stressed the blood passing through it. Efficiency and hemocompatibility, two goals designers usually pursue together, turned out to pull in opposite directions in this architecture.

Just as striking was the failure of the Eulerian indices to detect any of this. When the researchers examined how the two turbulence-based indices behaved across the twenty operating conditions, they found that both functioned essentially as RPM trackers. Their values correlated almost perfectly with the Womersley number, a dimensionless parameter related to the pulsatile operating conditions, with correlation coefficients exceeding 0.94. But that near-perfect correlation was a symptom of a deeper problem: the indices were responding almost entirely to how fast the pump was spinning, not to the intricate geometry inside it. They completely missed the geometry-induced stress peaks created by the expanding hub, the very feature that distinguished the suction design from its discharge-type siblings and drove the paradoxical blood damage.

The Lagrangian metrics told a fundamentally different and richer story. By following virtual cells along their actual paths, the median stress accumulation and mean supra-threshold exposure time captured the multivariate reality of mechanical loading inside the pump, sensitive to both operating conditions and architectural details. A cell that lingers in a high-shear bottleneck accumulates far more damage than one that flashes through a brief stress zone, and only a trajectory-based method can register that distinction. The authors conclude that for micro-axial pumps, where bulk shear stress is the dominant damage mechanism, Eulerian turbulence models are simply insufficient, and that Lagrangian particle tracking must remain the high-fidelity standard for evaluating and optimizing these devices.

Beyond its methodological verdict, the study carries a practical design message. The three discharge-type architectures consistently offered a more favorable fluid dynamic profile, mitigating the high-shear stress exposure that plagued the suction configuration. For engineers developing the next generation of percutaneous heart pumps, this suggests a compelling strategy: favor architectures in which the flow is decelerated and discharged in a controlled manner rather than squeezed through accelerating bottlenecks, even if the raw hydraulic efficiency numbers look less impressive on a datasheet. The finding resonates with clinical observations that hemolysis, the destruction of red blood cells, remains a recognized complication of micro-axial support, and with prior work from the same group showing that impeller hub design significantly influences both pump performance and predicted blood damage.

The stakes extend beyond red blood cells. Mechanical stress inside these pumps also unfolds von Willebrand factor, a large protein essential for normal clotting, and activates platelets, the cellular fragments that initiate thrombosis. Shear-mediated platelet activation is a well-documented pathway to device-induced thrombosis, while the loss of functional clotting proteins paradoxically increases bleeding risk, so a single design flaw can simultaneously promote clots and hemorrhage. Understanding exactly where and how long cells are stressed inside a pump is therefore not an academic exercise; it directly shapes the safety profile that patients experience in the intensive care unit, where these devices are often deployed as a bridge during the most critical hours of cardiac illness.

The study also arrives at a moment when the use of percutaneous ventricular assist devices is expanding rapidly, with growing clinical evidence and debate about their outcomes in cardiogenic shock and high-risk interventions. As devices shrink and operating speeds climb, the margin for fluid dynamic error narrows, and the tools used to vet new designs matter more than ever. By demonstrating that fast, turbulence-based screening indices can be blind to the very geometric features that determine blood damage, the Israeli team has issued a caution to the field: computational shortcuts that work for large pumps may quietly mislead designers of micro-axial machines. The paradox they documented, in which a smarter-looking geometry trades efficiency for blood trauma, is a vivid reminder that in the miniature world of catheter-mounted heart pumps, the fluid that keeps us alive is also the most delicate component in the machine.

Subject of Research: Computational fluid dynamics analysis of blood damage in percutaneous micro-axial left ventricular assist device designs

Article Title: The Efficiency-Hemocompatibility Paradox: A Comparative Lagrangian and Eulerian Analysis of Micro-axial p-LVAD Architectures

Article References: Gabso, Y., Rosenfeld, M., & Avrahami, I. (2026). The Efficiency-Hemocompatibility Paradox: A Comparative Lagrangian and Eulerian Analysis of Micro-axial p-LVAD Architectures. Annals of Biomedical Engineering. https://doi.org/10.1007/s10439-026-04406-0

Image Credits: AI Generated

DOI: 10.1007/s10439-026-04406-0

Keywords: p-LVAD, micro-axial pump, hemocompatibility, hemolysis, computational fluid dynamics, Lagrangian particle tracking, Eulerian indices, shear stress, platelet activation, cardiogenic shock, mechanical circulatory support, pump design

The core of the innovation lies in a manufacturing technique called electrospinning, which has become one of the most versatile tools in biomedical materials science. In electrospinning, a polymer solution is loaded into a syringe and subjected to a high electric field. As the charge builds at the tip of the needle, it overcomes the surface tension of the liquid and ejects a fine jet that whips violently through the air, stretching and drying until it lands as a fiber hundreds of times thinner than a human hair. Layer upon layer of these fibers accumulate into a soft, porous mat whose architecture closely mimics the fibrous structure of the extracellular matrix that cells naturally inhabit. For wound care, this architecture is highly desirable: the tiny interconnections between fibers allow oxygen exchange and fluid handling while presenting an enormous surface area for therapeutic action.

The polymer chosen as the carrier was polylactic acid, or PLA, a biodegradable polyester derived from plant sugars such as corn starch. PLA is already a familiar material in medicine, appearing in dissolvable sutures, screws, and drug delivery systems, because it breaks down in the body into lactic acid, a naturally occurring metabolite. The researchers’ idea was to use electrospun PLA as a structural scaffold and to load it with grape pomace oil, abbreviated GPO, which they had previously characterized as a source of lipophilic bioactive compounds from Mexican Cabernet Sauvignon pomace. The oil carries fatty acids and antioxidant species that, in principle, could protect wounded tissue from oxidative stress while discouraging bacterial colonization.

To test the concept, the team fabricated PLA mats containing grape pomace oil at four different concentrations: zero, five, ten, and twenty percent by weight per volume of the spinning solution. Scanning electron microscopy of the resulting mats revealed fibers with diameters ranging from roughly 401 to 911 nanometers, squarely within the nanofiber regime that wound dressing researchers prize. The oil concentration had a clear and systematic effect on morphology. As the GPO content increased, the fibers became thicker, rougher, and more prone to fusing together at their contact points, a sign that the oil was altering the conductivity and evaporation dynamics of the spinning jet. This kind of morphological tuning matters, because fiber diameter and surface texture influence how a dressing interacts with cells, exudate, and bacteria.

Confirming that the oil was genuinely encapsulated rather than simply smeared on the surface required a battery of analytical techniques. Fourier transform infrared spectroscopy detected the characteristic vibrational fingerprints of the oil’s fatty acid chains within the composite mats. Ultraviolet-visible spectroscopy and color measurement showed changes consistent with the presence of the oil’s chromophores, and differential scanning calorimetry revealed shifts in the polymer’s thermal transitions, indicating that the embedded oil was interacting with the PLA matrix at the molecular level. Together, these measurements established that electrospinning had successfully locked the bioactive oil inside the fibers, a nontrivial achievement given that volatile and oily additives often migrate or are lost during solvent evaporation.

The physical behavior of the mats in aqueous environments is critical for any wound dressing, and here the team mapped out a nuanced picture. All of the formulations displayed hydrophobic surfaces, with water contact angles between 100 and 132 degrees, meaning droplets bead up rather than soak in immediately. Porosity, meanwhile, decreased from 89 percent in the pure PLA mat to 77 percent at the highest oil loading, reflecting the thicker, more fused fiber network. Interestingly, the intermediate formulation containing ten percent GPO showed the highest swelling capacity, absorbing water to reach 422 percent of its original mass. This balance of water repellency at the surface with substantial internal swelling suggests the mats can manage wound exudate without dissolving or collapsing, a combination that supports the moist wound healing environment clinicians favor.

The biological performance of the mats is where the study becomes genuinely exciting. In antioxidant assays using the ABTS radical, the GPO-loaded mats scavenged up to 69 percent of the radicals presented to them, a direct demonstration that the oil’s antioxidant compounds remained active after encapsulation and could, in principle, counteract the oxidative damage that accompanies inflammation in wounded tissue. Even more striking were the antibacterial results. The mats inhibited four clinically significant pathogens commonly found in infected wounds: Staphylococcus aureus, a notorious cause of skin and soft tissue infections; Enterococcus faecalis, a hardy survivor in chronic wounds; Klebsiella pneumoniae, an increasingly drug-resistant threat; and Proteus mirabilis, a frequent culprit in urinary and wound infections. Importantly, the researchers traced this activity to a contact-killing mechanism, meaning bacteria are destroyed when they touch the fiber surface rather than through the release of soluble antibiotics into the environment.

A contact-killing mechanism carries real clinical appeal. Because the antimicrobial action is localized to the dressing itself, there is less concern about systemic exposure, the selection of resistant strains elsewhere in the body, or the ecological disruption associated with broad-spectrum antibiotics. At the same time, the approach avoids the heavy-metal nanoparticles, such as silver, that dominate the antimicrobial dressing market but raise questions about cytotoxicity and environmental persistence. A plant-derived oil embedded in a biodegradable polymer offers a gentler profile, provided it does not harm the patient’s own cells. On that front, the study delivered one of its most reassuring findings: in hemocompatibility testing, all of the formulations caused hemolysis of less than 0.5 percent, far below the thresholds generally considered safe, indicating that the mats do not damage red blood cells.

The broader significance of the work extends beyond wound care into the economics of sustainability and the circular economy. Grape pomace is generated in enormous quantities by wineries worldwide, and its disposal represents both a cost and a lost opportunity. Previous studies have explored grape seed extracts and pomace-derived phenolics in electrospun fibers for food packaging, tissue scaffolds, and other dressings, but this study is notable for using the oil fraction specifically, valorizing a component that is often left behind after phenolic extraction. The researchers, led by Marcos Leon-Bejarano, had earlier demonstrated that Mexican Cabernet Sauvignon pomace is a viable source of oil and lipophilic bioactive compounds, and the new work closes the loop by converting that oil into a functional biomedical material. A waste product from one industry thus becomes raw material for another, with potential value multiplication at every step.

Considerable work remains before grape pomace oil-loaded PLA mats reach a clinic. The study was conducted entirely in vitro, without animal or human testing, and questions of long-term biodegradation behavior, controlled release kinetics, mechanical durability under real dressing conditions, and efficacy against mature bacterial biofilms will all need systematic answers. Regulatory pathways for plant-extract-loaded medical devices add further complexity. Yet the foundational results are compelling: a simple, scalable electrospinning process yields mats that combine the structural virtues of nanofibrous scaffolds with measurable antioxidant power, broad antibacterial activity against four troublesome pathogens, and excellent blood compatibility, all from a material that would otherwise rot in a landfill. As antibiotic resistance tightens its grip and the demand for sustainable biomaterials grows, the image of a wound dressing spun from wine waste is exactly the kind of convergence of environmental and medical ingenuity that modern materials science promises.

Subject of Research: Development of grape pomace oil-loaded electrospun PLA nanofiber mats as bioactive antibacterial wound dressings

Article Title: Grape pomace oil loaded PLA electrospun fibers: characterization and evaluation as promising novel bioactive wound dressing

Article References: Leon-Bejarano, M., Semidey, F., Del Toro-Sánchez, C. L., Ovando-Martínez, M., del Castillo-Castro, T., Castillo-Ortega, M. M., Simsek, S., & Encinas-Encinas, J. C. (2026). Grape pomace oil loaded PLA electrospun fibers: characterization and evaluation as promising novel bioactive wound dressing. Polymer Bulletin, 83(12), Article 658. https://doi.org/10.1007/s00289-026-06727-5

Image Credits: AI Generated

DOI: 10.1007/s00289-026-06727-5

Keywords: grape pomace oil, PLA, electrospinning, nanofibers, wound dressing, antibacterial, antioxidant, biomaterials, biodegradable polymers, winery byproducts, contact-killing, hemocompatibility

The work, published in Biomedical Microdevices, extends a long-running effort to build what the group calls an artificial placenta: a lung assist device assembled from arrays of single oxygenator units, each a microfluidic chip fabricated from polydimethylsiloxane, the transparent silicone elastomer beloved by microfluidics engineers. PDMS is easy to mold, gas-permeable and optically clear, but in contact with blood it is profoundly thrombogenic. When plasma proteins adsorb onto its hydrophobic surface, they undergo conformational changes that activate the coagulation factors, platelets and complement proteins that normally patrol the vasculature. In a device whose channels are measured in tens or hundreds of micrometers, even a small clot can occlude flow, degrade gas exchange and shed emboli into the patient’s circulation.

The McMaster strategy centers on a molecule with an unusual pedigree. Antithrombin is the body’s natural brake on coagulation, a serine protease inhibitor that neutralizes thrombin and factor Xa. Heparin accelerates this inhibition dramatically, but heparin immobilized on biomaterial surfaces has historically underperformed, because the pentasaccharide sequence that activates antithrombin must be presented in a specific orientation and because bound heparin alone cannot catalyze inhibition without recruiting antithrombin from plasma. To sidestep these limitations, Anthony Chan, John Brash and colleagues developed a covalent antithrombin-heparin complex in which the two molecules are permanently linked, preserving the catalytic machinery in a single, surface-tethered unit. Earlier studies showed that such complexes, when coated onto flat PDMS using polydopamine as an adhesive layer, could render the material blood-compatible.

Polydopamine itself is a piece of bioinspired chemistry borrowed from marine mussels, which anchor themselves to rocks in churning surf using adhesive proteins rich in the amino acid DOPA. When dopamine is oxidized under mildly alkaline conditions, it polymerizes into a thin, conformal film that adheres tenaciously to virtually any surface, from metals to polymers, through a combination of covalent and noncovalent interactions. In the new study, the team flowed a polydopamine solution through the microchannels of the oxygenator units, then introduced the antithrombin-heparin complex under flow as well, allowing the coating to build up uniformly inside the tortuous three-dimensional geometry that flat-surface experiments cannot fully replicate.

Quantifying what sticks to the inside of a sealed microfluidic device is a technical challenge in its own right. The researchers solved it by radiolabelling the antithrombin-heparin complex, which allowed them to measure surface density directly: the coated units carried 0.21 plus or minus 0.05 micrograms of the complex per square centimeter. More importantly, the coating proved durable. When the modified devices were perfused with flowing blood for two days, 76 percent of the bound complex remained on the surface, a stability figure that matters enormously for any device intended to support a neonate for days or weeks. A coating that leaches away within hours would offer only fleeting protection and might itself become a source of embolic debris.

Surface density alone does not guarantee function, so the team also measured whether the immobilized heparin retained its biological activity. Their assay exploited the fact that active heparin binds antithrombin from plasma with high affinity. Devices coated with the antithrombin-heparin complex captured 47.78 plus or minus 10.63 nanograms of antithrombin per square centimeter from plasma, roughly four times the 11.56 plus or minus 4.58 nanograms per square centimeter measured on devices coated with polydopamine alone. That fourfold difference demonstrates that the covalent complex presents heparin in a catalytically competent configuration, effectively turning the entire blood-contacting surface of the device into an anticoagulant reactor that continuously neutralizes thrombin as blood passes through.

The functional consequences were visible at the macroscopic scale. When plasma was perfused through the modified units for one hour, the devices resisted clotting, whereas unmodified or polydopamine-only controls showed the fibrin deposition and flow obstruction characteristic of biomaterial-triggered coagulation. Just as critically, the researchers verified that the coating did not compromise the device’s primary job. Oxygen permeability, the property that allows the thin PDMS membranes to transfer gas between an oxygen supply and the blood, was unchanged by the surface treatment. That dual requirement, anticoagulant function without degraded gas exchange, has been the stumbling block for many previous hemocompatibility strategies, including polyethylene glycol layers and zwitterionic coatings, which can delaminate or alter transport properties over time.

The clinical context gives the work its urgency. Neonatal extracorporeal membrane oxygenation, or ECMO, remains an anticoagulation enigma, as pediatric intensivists have described it, because the systemic heparin required to keep circuits patent exposes infants, whose hemostatic systems are immature, to serious bleeding risks including intracranial hemorrhage. Ventilator-induced lung injury adds another layer of harm for preterm babies, whose alveoli can be damaged by the very pressures meant to keep them alive. A lung assist device whose internal surfaces actively inhibit clot formation could reduce the systemic anticoagulation burden, and the artificial placenta concept envisions pumpless microfluidic oxygenator arrays that could support preterm neonates with far less trauma than conventional extracorporeal circuits.

What distinguishes the new study is the translation from flat substrates to functional devices under realistic flow conditions. Coating chemistry that works on a flat coupon frequently fails inside a microchannel, where flow profiles, channel aspect ratios and surface-to-volume ratios conspire to produce uneven films. By performing both the polydopamine deposition and the complex immobilization under flow, the team showed that the strategy scales to the device level, a prerequisite for assembling the single oxygenator units into the integrated arrays that would constitute a clinical lung assist device. The authors note that the results demonstrate a previously developed modification strategy can be translated from flat PDMS substrates to microfluidic units, providing device-level anticoagulant function without measurably compromising membrane oxygen permeability under the conditions tested.

Challenges remain before the technology reaches the neonatal intensive care unit. The one-hour plasma clotting resistance and two-day stability experiments, while encouraging, must be extended to longer durations, whole blood and ultimately animal models, and the group has already explored pairing the antithrombin-heparin coating with immobilized tissue plasminogen activator to add fibrinolytic activity to the anticoagulant function. Regulatory pathways for combination products that blend a device with a pharmacologically active surface will also demand careful scrutiny. Still, the study offers a compelling proof of concept: by borrowing the adhesive tenacity of a mussel and the catalytic elegance of a natural anticoagulant complex, the researchers have shown that the surfaces of life-supporting microdevices can be engineered to fight the clotting response they provoke, bringing the artificial placenta one step closer to the bedside of the tiniest patients.

Subject of Research: Covalent antithrombin-heparin surface modification of PDMS microfluidic oxygenator units for anticoagulant function in neonatal lung assist devices

Article Title: Surface modification of microfluidic oxygenator units with an antithrombin-heparin (ATH) covalent complex for enhanced anticoagulant function

Article References: Li, S., Sandejas, D., Saraei, N., Dabaghi, M., Atkinson, H. M., Fusch, G., Rochow, N., Fusch, C., Selvaganapathy, P. R., Chan, A. K. C., Brash, J. L., & Sask, K. N. (2026). Surface modification of microfluidic oxygenator units with an antithrombin-heparin (ATH) covalent complex for enhanced anticoagulant function. Biomedical Microdevices, 28(3), Article 60. https://doi.org/10.1007/s10544-026-00842-w

Image Credits: AI Generated

DOI: 10.1007/s10544-026-00842-w

Keywords: antithrombin-heparin complex, microfluidic oxygenator, polydopamine, PDMS surface modification, blood compatibility, neonatal respiratory distress, artificial placenta, lung assist device, anticoagulant coating, hemocompatibility, Biomedical Microdevices, ECMO