Advanced Materials Interfaces

Detection of micro- and nanoplastics (MNPs) in human tissues has raised growing concern about their biological effects on tissue and cell function. While previous studies have examined MNP-cell interaction, most focused on limited cell and plastic types. Here, we present a comprehensive, quantitative investigation into how different types of nanoplastics (NPs) associate with and affect diverse cell types under physiologically relevant conditions. Using microfluidic-calibrated fluorescence microscopy, we quantify NP accumulation in cells in vitro and match cellular NP concentrations to levels reported in human tissues. While cell-associated NPs could be gradually released in vitro, they persist in vivo for over one month without detectable reduction in a mouse model. We discover that NP exposure at these levels broadly impairs cell proliferation across epithelial, endothelial, fibroblast, and immune cells, with cell type-dependent sensitivity. NP exposure also reduces motility in T cells and fibroblasts, with more complex effects observed in macrophages. Mechanistically, NP-cell association and trans-epithelial transport involved not only classical endocytic regulators but also pathways related to ion and water transport. Notably, NP association and release were highly sensitive to the extracellular fluid environment within the physiological range. By testing inhibitors of these pathways, we identified molecules that reduce NP-cell association and promote release. We further compared common NPs found in human samples and widely used in research: polystyrene (PS), polyethylene (PE), and polypropylene (PP). Although these NPs similarly impaired proliferation and motility, they showed markedly different cellular association and release dynamics. These findings reveal the impact of NPs on tissue cell functions and uncover novel regulatory pathways, establishing a quantitative framework for studying NP-cell interactions in biologically relevant conditions.

Extracellular matrix (ECM) proteins assemble to form a heterogeneous connective scaffold that supports cells. Physical interactions between cells and the matrix regulate cellular behaviors and influence subsequent tissue construction. However, there is a lack of fundamental understanding regarding the contributions of individual native ECM proteins to the matrix. This gap arises from the need for nanoscopic characterization, which operates on a much smaller length scale than typical assessments in cell and tissue cultures, as well as in tissue reconstruction and clinical implantation. This study aims to systematically investigate how individual ECM proteins affect lipid membranes structurally and mechanically, and how these influences regulate cell migration. Results from Langmuir isotherm analysis, X-ray reflectivity measurements, and cell scratch assays demonstrate that strong collagen adsorption on the membrane surface disrupts lipid packing. However, its rigid network provides a sturdy scaffold for cell adhesion, thereby enhancing cell attachment and promoting cell migration. In contrast, elastin has a minimal structural or mechanical impact on the membrane during both adsorption and compression, but it benefits cells by facilitating migration and reducing the risk of infection. Fibronectin, on the other hand, exhibits complex mechanical responses to compression, characterized by significant structural rearrangements that occur during adsorption. This strong interaction with the membrane can result in excessively high adhesion forces, ultimately limiting cell motility. These findings lay the foundation for the design of artificial scaffolds that can manipulate cellular responses, a critical step toward advancing regenerative medicine and tissue engineering. SignificanceFabricating extracellular matrix (ECM) scaffolds from cells offers advantages over traditional approaches, such as decellularized tissues, which face donor limitations, and artificial scaffolds, which may hinder cellular communication. However, the slow harvesting process of cell-derived ECM has limited its clinical applications. This research is part of a larger mission to engineer ECM prescaffolds on lipid carriers tailored to cell requirements, enhancing ECM production and regulating cell behavior. The first step involves systematically analyzing the structural and mechanical effects of ECM on lipid membranes and how these effects regulate cellular behavior. This work confirms distinct characteristics of ECM proteins, advancing fundamental understanding of cell-matrix interactions and paving the way for scaffold engineering.

Silver (Ag+) ions are known to be toxic to bacteria, cells, organisms and living systems; yet its impacts on the locomotion of surface-crawling organisms remain poorly quantified. Here we investigated the short-term (0-6 hours) effects of Ag+ ions on the locomotion of Drosophila melanogaster larvae on flat agarose surfaces containing Ag+ ions at different concentrations (0, 1, 10, and 100 mM). By quantifying their locomotion, we found that Drosophila larvae showed shorter accumulated distances and reduced crawling speed. Additionally, we quantified the go/stop dynamics and peristalsis of the larvae and observed that Ag+ ions disrupted the normal, rhythmic, peristaltic contraction of the larvae and "trapped" them in the stop phase. Such toxic effects were dependent on Ag+ concentration and exposure duration.

Understanding how airborne particulates disrupt the alveolar barrier requires in vitro systems that recapitulate both the structure and transport properties of the lung air-blood interface. Here, we report a biodegradable lung alveoli-on-a-chip enabled by porous poly(lactic-co-glycolic acid)/polycaprolactone (PLGA/PCL) membranes with an interconnected porous architecture generated via porogen-assisted phase separation process. The membrane exhibits tunable degradation behavior, allowing progressive increases in surface porosity ([~]40%) and reduction in thickness ([~]3 {micro}m) during culture, while PCL maintains mechanical integrity under dynamic conditions. These degradation-driven structural changes regulate membrane transport properties, leading to enhanced permeability and supporting the formation of a functional epithelial-endothelial barrier under air-liquid interface (ALI) culture with breathing-mimetic cycling strain. Primary human alveolar epithelial and microvascular endothelial cells formed confluent, junctional monolayers on opposing membrane surfaces, exhibiting stable barrier function and high viability throughout the culture period. As a functional application, the platform was used to assess diesel particulate matter (DPM)-induced alveolar injury. Apical exposure to DPM induced dose-dependent cytotoxicity, increased barrier permeability, elevated reactive oxygen species, and DNA damage in both epithelial and endothelial layers, demonstrating trans-barrier propagation of particulate-induced injury. Pharmacological modulation with roflumilast-N-oxide (RNO), a phosphodiesterase-4 (PDE4) inhibitor, selectively attenuated oxidative stress and inflammatory responses, with limited effects on barrier integrity. Together, this work establishes degradable PLGA/PCL membranes as tunable interface materials for lung-on-a-chip systems, where structural evolution during degradation directly governs transport and barrier function. The resulting platform provides a physiologically relevant approach for studying particulate toxicity and therapeutic modulation at the alveolar interface.

Autologous cell suspension (ACS)-based therapies are an established strategy to enhance wound repair, yet limitations in preparation workflows and donor skin requirements remain barriers to wider clinical implementation. We have previously developed VeritaCell, a rapid enzymatic disaggregation-based approach that generates highly viable skin cell populations, including epidermal stem cell-enriched fractions, and demonstrated their pro-regenerative biological properties in vitro. Here, we have evaluated the in vivo efficacy of VeritaCell-derived ACS using a rat full-thickness excisional wound model. ACS preparations were applied at donor-to-wound area ratios of 1:1, 1:10, and 1:20, and wound progression was monitored through longitudinal image-based quantification alongside histological assessment of tissue architecture. ACS-treated wounds exhibited enhanced early wound closure dynamics, with significant within-group improvements evident by Day 6. Histological analysis demonstrated improved neo-epithelial organisation and reduced epidermal thickening in the 1:10 and 1:20 groups, with the 1:10 condition showing tissue architecture most closely resembling unwounded skin. Notably, beneficial effects were observed even at low estimated cell numbers, suggesting that cell viability and biological activity may be key determinants of therapeutic efficacy. Collectively, these findings provide in vivo validation of VeritaCell-derived ACS and support the use of biologically informed donor-to-wound coverage ratios. This approach may enable effective wound repair while minimising donor skin requirements, with potential relevance for the treatment of extensive injuries such as burns.

Understanding how airborne particulates disrupt the human alveolar barrier requires in vitro systems that accurately replicate its composition and function. We present a biodegradable lung alveoli-on-a-chip that reproduces the architecture and physiology of the human air-blood interface using a porous poly(lactic-co-glycolic acid) (PLGA) membrane positioned between epithelium and endothelium under air-liquid interface (ALI) culture. The membrane, fabricated by porogen-assisted nonsolvent-induced phase separation, exhibited >50 % porosity, [~]2 {micro}m thickness, and mechanical compliance over 100-fold higher than conventional Transwell inserts, closely resembling the native interstitium. During co-culture, gradual PLGA degradation was compensated by cell-secreted extracellular-matrix (ECM) proteins such as collagen IV and laminin, forming a self-remodeling barrier that maintained integrity for at least 11 days. The platform supported stable epithelial-endothelial co-culture, high transepithelial electrical resistance, and physiologically relevant permeability. To demonstrate its utility, the chip was used to assess pulmonary toxicity of four types of waste-combustion-derived particulates, including rubber, plastic bags, plastic bottles, and textile fibers, delivered apically under ALI conditions. All combustion products reduced cell viability, increased hydrogen-peroxide release, and elevated {gamma}-H2AX expression, indicating oxidative and genotoxic stress, while disrupting barrier permeability. Rubber combustion particles elicited the most severe toxicity, causing the greatest loss of viability, accumulation of reactive oxygen species, and formation of DNA double-strand breaks. Together, these results establish a biodegradable, ECM-remodeling lung alveoli-on-a-chip as a physiologically relevant platform for investigating source-specific particulate toxicity and alveolar-barrier pathophysiology. By bridging environmental exposure models with human-relevant lung biology, this system provides a quantitative and translatable tool for evaluating respiratory risks and therapeutic interventions.

The scalable fabrication of stable colloidosomes with controlled permeability and defined multicompartmental architecture remains a critical challenge, limiting their broader use in molecular delivery and environmental remediation. Here, we develop a hybrid lipid-metal-organic framework (lipid-MOF) colloidosome assembled through an interfacial emulsification strategy that integrates the structural rigidity of ZIF-8 particles with lipid-mediated membrane stabilization. During assembly, ZIF-8 particles accumulate at the oil-water interface to form a shell, producing hollow micron-sized spherical colloidosomes. The resulting colloidosomes exhibit excellent colloidal stability in aqueous media for over 30 days with a zeta potential of approximately -50 mV. Nitrogen adsorption measurements reveal a surface area of 45 m2g-1 and an average pore width of 4 nm. Fluorescence imaging shows that hydrophobic Nile red preferentially partitions into the colloidosomal membrane, whereas hydrophilic fluorescein isothiocyanate (FITC) localize predominantly within the aqueous interior, enabling simultaneous encapsulation of molecules with contrasting polarity with loading efficiencies approaching 90%. Furthermore, the colloidosomes demonstrate rapid removal of model pollutants from water, achieving >90% removal of methylene blue and metal ions without stirring. Together, these results introduce lipid-MOF colloidosomes as a new class of hybrid platforms that unify structural stability, multicompartmental encapsulation, and efficient adsorption behavior, opening pathways toward sustainable platforms for drug delivery and environmental bioremediation.

Maintaining a confluent, antithrombotic endothelium on cardiovascular biomaterial surfaces remains a major barrier to long-term hemocompatibility, as endothelial cells (ECs) rapidly denude under supraphysiological shear in prosthetic devices. Here, we hypothesized that mesoscale surface geometry ([~]100-200 {micro}m) could reorganize near-wall hemodynamics, preserving endothelial coverage and function under extreme shear. Engineered microtrenches were introduced onto an implant biomaterial to generate spatially defined shear environments. Under supraphysiological near-wall shear ([~]250 dyn/cm{superscript 2}), microtrenched geometries created attenuated shear and vorticity gradients. Endothelial monolayers were sustained in these flow domains for 120 hours, whereas flat controls rapidly denuded. Endothelial retention in 22.5{degrees} angled trenches increased dramatically, from an EC of 33 to 101 dyn/cm{superscript 2}. 45{degrees} angled trenches further increased endothelial shear resistance to an EC of 207 dyn/cm{superscript 2}. Endothelial monolayers demonstrated collective mechano-adaptation to ultra-high shear through VE-cadherin junction thickening and coordinated cytoskeletal and nuclear alignment. Mechanoadapted monolayers exhibited increased eNOS expression correlated with local shear and elevated nitrite production (45{degrees}: 50.4 {+/-} 6.1 {micro}M; 22.5{degrees}: 35.7 {+/-} 3.3 {micro}M; 0{degrees}: 28.4 {+/-} 6.8 {micro}M). In contrast, interfaces with abrupt shear transitions or elevated rotational flow exhibited reduced coverage, junctional thinning, and re-emergence of VCAM-1 and PAI-1, indicating inflammatory and pro-thrombotic activation. Structural, functional, and inflammatory readouts exhibited peak responses within a shared shear-vorticity regime. Multivariate regression identified shear-vorticity coupling as the dominant predictor of endothelial persistence, with optima clustering within a mechanical range ({approx}0.8-2.9 x 10 dyn{middle dot}cm-{superscript 2}{middle dot}s-{superscript 1}). These findings establish geometry-driven modulation of near-wall flow as a predictive, material-agnostic strategy for endothelialization and vasoprotection of high-shear cardiovascular implants.

Biomimetic tubular scaffolds hold great promise for tackling unmet clinical needs thanks to their biocompatibility and recapitulation of cellular microenvironments, conferring the ability to promote regeneration. Potential applications include small-diameter vascular implants and grafts for airway repair, for which no viable off-the-shelf solutions currently exist. The tubular materials (4 and 8 mm internal and external diameters) presented here consist purely of type I collagen, contain no chemical crosslinkers, and reproduce the multi-scale architecture of the native tissue including the presence of collagen fibrils. A novel two-step protocol provides materials with distinct concentric layers. A porous external structure, obtained by means of ice templating combined with collagen topotactic fibrillogenesis, favours oriented cell colonization. A smooth and much less porous internal layer provides mechanical and water-tightness properties relevant for in vivo implantation and promotes the formation of an endothelial monolayer under both static and flow conditions. The compliance of the double-layered materials under physiological pressure is close to that of piglet carotid arteries. The materials are also determined to be sufficiently flexible to provide the ability to perform ex vivo anastomosis with bronchi, although the relatively low value of suture retention strength remains a limitation for in vivo suturing.

Scaffolded DNA origami has become a valuable nanoscale tool for applications in biomedical and physical sciences. Critical to leveraging the modular and programmable properties of DNA origami nanodevices is access to the scaffold strand, a long single-stranded DNA (ssDNA) of precise length and sequence, which is folded into a compact shape via piecewise base-pairing with many staple strands, short ssDNA oligonucleotides. Current methods to produce and manipulate long ssDNA scaffolds can be costly, time-consuming, and cumbersome. In contrast, methods to produce and manipulate the sequence of double-stranded DNA (dsDNA) are efficient and scalable. Here, we present a method for the rapid isolation of target ssDNA sequences from a variety of dsDNA sources using oligonucleotides as blocking strands that bind continuously to the undesired strand, thereby releasing the target scaffold strand. We report successful ssDNA isolation from linear and supercoiled dsDNAs of various sequences and lengths, ranging from 769 to 15,101 nucleotides. In addition to isolating ssDNA, we demonstrated this approach enables folding of DNA origami directly from dsDNA templates using both blocking and staple strands in a single-pot thermally controlled reaction. Furthermore, we explore multi-scaffold and gene-encoding DNA origami structures, expanding the framework for application-based designs. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/709872v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1cc75dcorg.highwire.dtl.DTLVardef@4df8e2org.highwire.dtl.DTLVardef@10ed113org.highwire.dtl.DTLVardef@1c05bdd_HPS_FORMAT_FIGEXP M_FIG C_FIG

Flexible and biocompatible piezoelectric materials are crucial for next-generation wearable and bio-integrated electronics. In this work, we report a sustainable bio-composite film by incorporating lysozyme, a naturally abundant protein, into a polyvinyl alcohol matrix to achieve efficient electromechanical conversion. The composite exploits the intrinsic molecular dipoles of lysozyme, which are effectively stabilized and aligned within the polymer network. Under applied bending strain and vertical pressure, the film exhibits a pronounced piezoelectric response, as evidenced by time-dependent electrical measurements under forward and reverse bias conditions. The deformation of -helices and other helical structures within lysozyme induces dipole reorientation and charge separation, generating a measurable electrical output. In contrast, pure polyvinyl alcohol films show no detectable response, confirming the essential role of lysozyme in the observed piezoelectricity. Furthermore, the device enables real-time human motion sensing, highlighting its potential for flexible, eco-friendly, and biocompatible electronic applications.

Nanoplastics generated from plastic waste in our ecosystems are becoming increasingly prevalent as bulk plastics exposed to natural factors like water and sunlight fragment to the nanoscale over time. These incidental nanoplastics span a wide range of physicochemical properties, which makes studying nanoplastic interactions in biological systems difficult. Here, we characterized the behavior of incidental nanoplastics generated through mechanical abrasion within coacervate droplets to probe the surface properties of the nanoplastics. We used elastin-like polypeptides (ELPs) to create hydrophobic or charged coacervate microenvironments. Using optical microscopy and fluorescence quantification, we observed that nanoplastics made from polyethylene terephthalate (nPET), nylon 6 (nPA), and polystyrene (nPS) exhibited distinct partitioning behavior with more favorable interactions with hydrophobic droplets. This indicated that the hydrophobic polymer backbone was the predominate surface feature despite exposed functional groups of the incidental nanoplastics, in contrast to findings with model carboxylated latex nanospheres (nPS-COOH). Furthermore, the selective partitioning of incidental nanoplastics into the hydrophobic droplets was able to capture over 80% of nPET in solution, and after recovery of the protein droplet, was able to cumulatively capture over 75% of the nPET feedstock across multiple cycles. This work explores the nuanced surface characteristics of incidental nanoplastics, expands the application of coacervates as chemical probes, and demonstrates a biopolymer approach for effective nanoplastic removal.

Curvature provides essential mechanical cues for epithelial cells, playing a key role in cell differentiation and morphology. Repeatable manufacture of precisely controlled curvature in soft hydrogel materials is therefore essential to study epithelial mechanobiology and function. Multiphoton (MP) based biofabrication holds promise due to its high resolution and three-dimensional design flexibility. Here, we leverage MPs advantages while increasing print speed to develop two complementary tools based on replica molding and multiphoton ablation. These can provide scalable hydrogel curvatures with tunable surface properties relevant for epithelial tissue engineering. In replica molding, MP prints are transferred into PDMS used to pattern centimeter scale arrays in hydrogels. In multiphoton ablation, hydrogels are locally degraded to generate precisely controlled curvatures and surface topography. With both methods, we repeatably guide epithelial cells into alveolar and duct-like shapes. Concave alveolar-like surfaces are shown to enhance the formation of thicker epithelial layers. We observe that surface properties, controlled by both tools, could enhance cytoskeletal organization. Using these biofabrication techniques, individual effects of curvature, surface properties, hydrogel composition, and bulk stiffness on epithelial cells can be studied. Both approaches offer high curvature control and throughput, providing a viable alternative to traditional 3D culture and other printing methods.

Controlled delivery of growth factors and viable cells remains a significant challenge in bone tissue engineering. In this study, a 3D-printed hydrogel scaffold system was developed for the co-delivery of bone morphogenetic protein-9 (BMP-9) and preosteoblasts to enhance bone regeneration. The system consisted of a 3D-printed base scaffold containing BMP-9-coated calcium sulfate (CaS) microparticles and a photocurable hydrogel coating layer encapsulating viable cells. The scaffold design exploited electrostatic interactions between BMP-9 and gelatin matrices by incorporating gelatin type B in the base scaffold and gelatin type A in the coating layer. Differences in the isoelectric points of these gelatin types were utilized to regulate protein binding and release. Release studies demonstrated that CaS microparticles alone exhibited rapid burst release, with nearly 80% of BMP-9 released within 24 h. Encapsulation of BMP-9 coated CaS particles in the 3D-printed scaffolds reduced the release rate, while the addition of the coating layer significantly improved sustained release, limiting BMP-9 release to approximately 50-60% by day 5. Bioactivity studies showed enhanced cell attachment in BMP-9 containing scaffolds compared with controls. Live/Dead cytotoxicity assays demonstrated high cell viability (>80%) within the coating layer over the culture period, confirming that the encapsulation and photocuring processes did not adversely affect cell survival. Cell proliferation and differentiation were further evaluated using WST-1 and alkaline phosphatase assays. The results demonstrate that electrostatic interactions governed by gelatin type selection can regulate BMP-9 release while maintaining high cell viability, providing a promising platform for growth factors and cell delivery in bone tissue engineering.

Cells dynamically integrate biochemical and mechanical signals arising from their surrounding microenvironment to regulate morphology and behavior. Mechanical cues like matrix stiffness, surface topography, and other physical perturbations modify biophysical signals. Surface topography, particularly curvature regime acts as any important mediator of mechanotransduction by coordinating cytoskeletal organization, focal adhesion dynamics, and nuclear architecture. Curvature response has been demonstrated at broader length scales and influences nucleus shape change, chromatin organization, and gene regulation, positioning the nucleus as an active mechanosensitive hub. Bone tissue consists of a curvature-rich microenvironment defined by a trabecular architecture at tissue scale and by resorption cavities such as Howships lacunae at cellular scale. While these geometries are essential for homeostasis, their role in pathological context remains poorly understood. Osteosarcoma develops within this mechanically complex multiscale architecture, but how bone-inspired curvature regulates nuclear behavior and signaling in osteosarcoma cells remains unclear. Here, we engineered three-dimensional (3D) concave hemispherical substrates that recapitulate nucleus-scale bone micro-curvature and assessed their effects on human SaOS-2 osteosarcoma cells. In comparison with flat surfaces, concave confinement resulted in pronounced nuclear rounding and softening, accompanied by Lamin A/C reorganization and increased heterochromatin compaction marked by H3K9me3. Curvature-driven nuclear remodeling selectively modulated Hippo pathway main effectors YAP/TAZ without activating NF-{kappa}B mediated canonical inflammatory responses. Furthermore, cells maintained overall viability without elevated pathological DNA damage or apoptotic signaling, suggesting an adaptive, damage-tolerant nuclear response. Overall, these findings indicate nucleus-scale curvature as a critical regulator within the bone microenvironment that governs nuclear modelling and mechanosensitive signaling in osteosarcoma cells. Incorporating physiologically relevant geometry into in vitro models establishes new insight into cancer microenvironment crosstalk and highlights nuclear interior and outer architecture as a key regulator of tumor cell behavior.

Direct ink writing is compatible with an expansive materials palette. While enabling diverse applications, this materials versatility brings significant bottlenecks in ink formulation, often requiring the mixing, printing, and testing of dozens to hundreds of ink compositions over the course of a project. To accelerate ink-space exploration, we introduce gradient embedded multinozzle (GEM) printheads that combine the high-throughput parallelized printing of multinozzles with combinatorial ink mixing. These printheads allow simultaneous mixing of two-, three-, and four-input inks which are distributed to printer nozzles to create complex 3D structures with graded compositions of inks. Using a two-way GEM printhead, we vali-date cell compatibility by printing scaffolds containing various concentrations of fibroblasts and observing non-linear compaction behaviours. We next test a three-way GEM multinozzle to print ten compositions of di- and multi-functionalized poly(ethylene-glycol) diacrylate hydrogel tri-leaflet valves, optimizing for stiffness, swelling ratio, and toughness. Our GEM multinozzles are compatible with open-source printers and either pressure- or volume-driven extrusion systems and promise to accelerate iterative ink design and testing.

BackgroundPlatelet-derived Growth factors play key roles in tissue repair and regeneration, yet conventional platelet-rich plasma (PRP) formulations release these mediators inconsistently in vivo due to variability in platelet yield and activation dynamics. To overcome this limitation, direct administration of concentrated platelet-derived growth factor preparations has gained interest, though current manufacturing approaches for human platelet lysate (hPL), growth factor concentrates (GFC), and conditioned serum remain constrained by batch variability, incomplete platelet degranulation, and reliance on anticoagulants. Here, we examine alternative platelet activation workflows to establish a standardized, efficient, and reproducible method for high-yield growth factor recovery suitable for translational and clinical applications. MethodsNine GFC production protocols were compared, employing different combinations of freeze-thaw (FT) cycling, glass bead (GB) agitation, calcium (Ca2) activation, and a novel Enriched Growth Factor (Enriched-GF) method. The objective was to identify a protocol capable of maximizing growth factor yield within a three-hour workflow. Optimal Ca2 concentrations and GB conditions were determined from prior optimization studies and integrated into the Enriched-GF processing scheme. Platelet concentrates (n = 10 per protocol) were processed under each condition, and growth factor levels were quantified using ELISA. ResultsGrowth factor yields differed significantly across protocols. The greatest and most consistent increases in growth factor release were observed with the Enriched-GF method combining GB activation, FT cycling, and Ca2 stimulation. This approach resulted in markedly elevated concentrations of key regenerative mediators, including enhanced EGF release, a 4.5-fold increase in PDGF, maximal TGF-{beta} liberation, and a four-fold increase in FGF2 relative to conventional platelet lysate or conditioned serum preparations. These results were reproducible across independent donor pools, demonstrating robustness and batch-to-batch consistency. ConclusionWe describe a rapid and reproducible method for producing highly concentrated platelet-derived growth factors using a combined GB-FT-Ca2 activation strategy. The Enriched-GF protocol consistently outperformed existing platelet lysate, conditioned serum, and conventional GFC preparation methods, yielding a standardized product with enhanced growth factor content. This Enriched-GF approach offers a clinically practicable solution for applications in regenerative medicine requiring reliable and high-yield growth factor delivery. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/712883v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@1f059d9org.highwire.dtl.DTLVardef@9aeffforg.highwire.dtl.DTLVardef@27cd1org.highwire.dtl.DTLVardef@150b7d1_HPS_FORMAT_FIGEXP M_FIG C_FIG Schematic overview of platelet concentrate preparation from whole blood and the generation of different platelet lysates and growth factor-enriched serum using freeze-thaw, calcium gluconate, and glass bead activation methods.

Intercalation of small molecules between DNA base pairs affects DNA conformation, disrupting essential cellular processes including replication, transcription, and repair. We investigated conformational changes in 18-mer DNA upon intercalation of doxorubicin, SYBR Gold and YOYO-1 using extensive MD simulations. Two main patterns for the intercalation were identified: RISE-type intercalation occurs between adjacent base pairs and extends the DNA helix with decreased twist angles, while OPEN-type intercalation proceeds through base-pair opening without significant DNA extension. Kinetic analysis revealed that association rates for intercalation followed the order: first YO-moiety (mono-intercalation) > SYBR Gold > doxorubicin > YOYO-1 (bis-intercalation). Free energy landscape showed that forces at DNA termini reached up to 117 pN during stretching. Notably, base pairs adjacent to intercalators were protected from strand separation, accompanied by additional helical unwinding. MM-PBSA/GBSA analysis revealed that the driving force for intercalation is the stacking energy, and the binding affinity was highest for minor groove binding. Persistence length decreased with single molecule binding but recovered with two molecules due to their electrostatic repulsion. Mechanical properties of intercalated DNA showed position-dependence, demonstrating that multiple intercalation modes coexist in solution. The heterogeneous nature of intercalation explains why experimental measurements reflect ensemble averages rather than single binding configurations.

Central nervous system (CNS) disease or injury might be treated by implanted devices, tissue regenerative scaffolds, or drug delivery platforms. However, inflammatory CNS responses limit these interventions and may worsen outcomes following damage to the CNS. Via the foreign body reaction (FBR), macrophages and glial cells trigger a "glial scar" around implants, reducing device performance, scaffold regenerative ability, or drug delivery potential. Previous studies have shown that stiffness of CNS implants significantly affects glial encapsulation, but few studies have investigated materials that truly match brain tissue stiffness. Porous precision-templated scaffolds (PTS) with uniform, interconnected, 40 {micro}m pores have shown favorable healing outcomes and a reduced FBR in numerous soft and hard tissue applications. To quantify the effects of both hydrogel compliance (stiffness) and pore size on glial encapsulation, we implanted poly(2-hydroxyethyl methacrylate-co-glycerol methacrylate) (pHEMA/GMA) PTS of varying stiffness and pore size for 4 weeks in rat brain. We observed reduced astrocyte encapsulation around PTS compared to solid hydrogel rods, reduced pro-inflammatory macrophage polarization for softer hydrogels versus stiffer hydrogels, and the presence of neuronal markers and neurogenesis within the pores. Utilizing soft, precision-porous hydrogels could provide a strategy for mitigating glial scarring and improving implant-based CNS treatments.

Engineering three-dimensional neuronal tissues with defined architecture and functional connectivity remains a critical challenge for applications in disease modeling, drug discovery, and regenerative medicine. Recently, a variety of fabrication methods have arisen, such as bioprinting or manual assembly of organoids, but often struggle with scalability, reproducibility, or maintaining cell viability. Here, two scaffold-free acoustic levitation bioreactors are introduced: one optimized for the culture of uniform neuronal spheroids, and another designed for the structuration of assembloids composed of distinct neuronal identities. Using acoustic standing waves, these platforms enable the contactless manipulation of cells and aggregates, facilitating the formation of highly viable functionally mature spheroids. This study shows that both striatal and cortical cell aggregates formed in acoustic levitation self-organize into spheroids within 24 hours and remain viable up to 10 days under these particular culture conditions without medium renewal. These neuro-spheroids demonstrate healthy development with increased growth and typical terminal differentiation and synaptic maturation. Moreover, concentric cortico-striatal assembloids were successfully structured and cultivated using optimized acoustofluidic chips. Offering versatile and scalable tools for engineering complex neuronal networks, acoustic levitation reveals itself as an innovative approach to 3D neuronal tissue modeling, with broad implications for bioengineering, regenerative medicine and fundamental neuroscience research.