Advanced Materials

Wound and device-associated infections remain difficult to eradicate because biofilms block host immunity and antibiotics, accelerating chronicity and resistance. Here, we present a portable, low-cost dual-syringe spray that deposits an ultra-thin, self-assembling antimicrobial film directly on wounds and implant surfaces. The device co-delivers oppositely charged hyaluronic acid (HA) and a cationic antimicrobial peptide (polyarginine, PAR30), which rapidly form a conformal nanometric polyelectrolyte complex at the tissue-material interface. Molecular dynamics simulation revealed pronounced positional heterogeneity within the PAR30/HA complex and identified an N-terminal arginine as a dominant interaction hotspot. The resulting coating adheres to diverse substrates, kills bacteria on contact, prevents biofilm formation, and sustains antimicrobial efficacy. Across vitro assays and murine wound infection models, treatment produced 4 to 5 log reductions in bacterial burden against methicillin-resistant Staphylococcus aureus and Gram-negative pathogens, including Pseudomonas aeruginosa and Escherichia coli. The formulation is biocompatible, did not increase cutaneous inflammation or IL-6 levels in vivo, and reduced post-surgical pain and motor deficits in a mouse incision model. To our knowledge, this is the first antimicrobial treatment system applicable to both tissues and medical devices. Developed under a safe-and-sustainable-by-design approach, this technology combines biocompatible components, nanometric coating for minimal material use, and a simple syringe-based delivery device, offering a scalable, antibiotic-free strategy for wound care and medical device infection prevention. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=173 HEIGHT=200 SRC="FIGDIR/small/717441v1_ufig1.gif" ALT="Figure 1"> View larger version (68K): org.highwire.dtl.DTLVardef@49381aorg.highwire.dtl.DTLVardef@1023e64org.highwire.dtl.DTLVardef@4e282aorg.highwire.dtl.DTLVardef@12eeae4_HPS_FORMAT_FIGEXP M_FIG C_FIG

The endothelialization of organ-on-chip platforms and vascular implants is often limited by slow cell attachment and unstable monolayer formation. This work presents a scalable workflow that imprints micro- and nano-gratings into elastin-like recombinamer (ELR)-based hydrogels, enabling rapid endothelial cell capture and accelerating monolayer formation within 14 days. Three gelatin-ELR formulations are engineered, with {superscript 1}H-NMR confirming incorporation of sequences designed to modulate bioactivity (ELR1: inert; ELR2: uPA-responsive; ELR3: RGD-adhesive). ELR incorporation generates fibrillar microstructures and enhances mechanical performance, yielding elastic-dominant networks suitable for high-fidelity pattern transfer and stable culture. Using this library, the combined effects of ELR bioactivity and groove geometry on human iPSC-derived endothelial cells (iPSC-ECs) are systematically evaluated. In a 15-minute attachment assay, patterned ELR composites markedly improve cell retention compared to gelatin, with ELR2 on [~]350 nm and [~]4 {micro}m grooves performing best, consistent with controlled, cell-mediated interfacial remodeling. This early advantage persists, as ELR2 and ELR3 hydrogels support rapid alignment and reach confluence by day 14, whereas gelatin remains sub-confluent. Cytoskeletal analysis confirms F-actin alignment. By combining enhanced early capture with protease-regulated remodeling, ELR2 identifies a favorable design window. These results establish a materials design framework linking programmable ELR chemistry with surface topography to engineer endothelial interfaces, providing a versatile platform for vascular biomaterials and microphysiological systems.

We present a proof-of-concept platform in which amyloids are displayed on the surface of engineered Bacillus subtilis spores for bioengineered materials. Amyloids possess high tensile strength, elasticity, and tunable assembly, but their use is limited by inaccessible native sources and low-yield or toxic heterologous expression. Here, spores were engineered to display the native amyloid TasA and Humboldt squid suckerins 9 and 10 as fusions to the spore coat protein CotY. Amyloid production and fibril formation were confirmed by Western blot and X-34 staining, and quantitative analysis indicated mg/L-level yields. Atomic force microscopy revealed altered stiffness and surface ultrastructure, and incorporation of amyloid-displaying spores into resin-based 3D printing modified tensile strength. These findings highlight spore-based amyloid display as a scalable, modular platform for materials applications, leveraging established industrial spore production.

The human vasculature is a complex, multiscale system comprising hierarchical networks of macroscale to microscopic vessels. Existing in vitro fabrication techniques often fail to bridge these disparate scales, as high-resolution methods like multiphoton ablation are too slow for replicating larger vessels, while 3D printing lacks the resolution for fine microscale features. Here, we report a "twisted wire templating" strategy capable of generating perfusable bifurcating hydrogel networks that seamlessly transition from the macro- to the micro-scale (2.3 mm to 140 {micro}m) through seven orders of bifurcations. By optimizing wire-twisting geometries and polyurethane dip-coating, we overcame instability-driven bead formation to ensure replication fidelity across the networks. Fabrication rigs were reconfigured from existing 2D planar layouts to 3D reconfigurable architectures to better replicate 3D vessel geometries which simultaneously reducing the laboratory footprint and fabrication times by 47%. Using a Taguchi orthogonal array, we further optimized surface chemistry and hydrogel composition to inhibit structural failure during template extraction, resulting in fully patent, perfusable networks. This method provides a robust, low-cost, and scalable foundation for creating physiologically representative vascular models for investigating multiscale disease mechanisms and organ-level tissue engineering.

The ability to adhere to mucus-lined tissues underpins a range of biomedical devices and therapies. However, many existing strategies rely on covalent bonding chemistries and can be unstable, cytotoxic, or incompatible with therapeutics. Here, we present a bacteria-mimetic bioadhesion strategy inspired by Vibrio cholerae. A short Bap1-derived adhesion peptide is grafted onto chitosan to strengthen mucus interactions through multivalent, cooperative secondary bonding, while preserving pH-triggered interfacial bridging behavior. Bacterial peptide grafting significantly increases adhesion energy on porcine intestine, and when paired with a tough hydrogel matrix achieves adhesion energies >400 J/m2 without forming covalent bonds to tissue. Confocal imaging reveals deep tissue penetration ([~]80 m) with markedly enhanced mucin binding and no loss of cytocompatibility. Ex vivo intestinal delivery and in vitro drug release tests demonstrate improved drug transport and tissue exposure compared to carbodiimide-mediated covalent bonding strategy. These findings establish a bacteria-mimetic bioadhesion strategy for tissue repair and drug delivery. Novelty StatementBioadhesive designs have drawn inspiration from nature such as mussel-inspired catechol chemistry and gecko-inspired dry adhesion. In contrast, bacterial adhesion mechanisms, despite enabling robust colonization of mucus-lined tissues under demanding conditions, remain largely overlooked. This work introduces a bacteria-mimetic bioadhesion strategy that selectively repurposes a short, non-pathogenic peptide derived from a Vibrio cholerae adhesin to enhance bioadhesion through multivalent, cooperative physical interactions rather than covalent bonding. This strategy significantly toughens adhesion even on chitosan, a polymer already rich in adhesive functional groups. By decoupling bacterial adhesion function from pathogenic risk, this study establishes bacterial adhesion peptides as a safe, modular, and mechanistically distinct foundation for next generation bioadhesives with improved drug compatibility.

Over 200 monoclonal antibodies (mAbs) are approved for clinical use, yet their therapeutic potential is constrained by dependence on repeated injections or infusions that drive non-adherence, limit access in low-resource settings, and generate peak-trough pharmacokinetics linked to adverse effects and reduced efficacy. Here, we developed an immunomodulatory encapsulated cell-based biologics factory that overcomes mAb instability, immunogenicity, and the fibrotic foreign body response that have limited previous approaches, enabling continuous in situ production of therapeutic antibodies from a single administration. Screening chemically modified alginate biomaterials in immunocompetent mice identified a lead immunomodulatory alginate formulation that sustains stable serum titers of the HIV-neutralizing mAb 3BNC117 for one year. Single-cell RNA sequencing revealed that this formulation promotes a local anti-inflammatory, pro-resolving immune niche that attenuates fibrosis. The platforms versatility was demonstrated by production of thirteen diverse mAbs from an allogeneic cell chassis, with sustained in vivo delivery of a subset including ipilimumab, pembrolizumab, adalimumab, and PGT121. Integration into a retrievable macrodevice enabled on-demand therapeutic termination and re-implantation for dose-proportional tuning. In a non-human primates, subcutaneous implantation maintained stable ipilimumab titers for over six months with no detectable toxicity, anti-drug antibodies, or adverse events, and dose-dependent exposure was confirmed across a three-dose escalation. These results demonstrate a clinically translatable platform offering a practical strategy to replace frequent injections with single-administration therapy.

The transplantation of stem cell-derived extracellular vesicles (EVs) holds promise for tissue repair and regeneration, but scalable production and effective delivery to target tissue remain major challenges. Here, we present a biomaterial platform that combines high-yield, scalable nanovesicles (NVs) - EV mimetics derived from human induced pluripotent stem cells - with an adhesive silk hydrogel patch for localized and sustained delivery. We show that this platform enables efficient NV encapsulation via visible light crosslinking and supports controlled release over short (2 days), intermediate (7 days), and extended (up to 28 days) periods, while maintaining adhesion to heart tissue. Importantly, the sustained delivery of NVs for 3 days in vitro results in promoting anti-fibrotic cell remodeling and significant functional recovery of primary myofibroblast activation, modulating integrin signaling, actomyosin organization, and cell-matrix adhesion networks. Finally, we demonstrate biocompatibility, retention, and anti-fibrotic function of the patch in a murine ischemia-reperfusion injury model. Thus, we establish the proof-of-principle that di-tyrosine silk hydrogels can be used as a strategy to encapsulate and deliver NVs to the heart, thus offering an innovative delivery platform for NVs. Statement of significanceExtracellular vesicles (EVs) represent an emerging frontier in tissue engineering. Their cell-specific cargo contains biological information capable of repairing and regenerating injured tissues. However, their clinical translation is hindered by limited manufacturing scalability, undefined dosing and modes of administration, and low organ retention, particularly in the heart. This study addresses these challenges by combining stem cell-derived nanovesicles (NVs), which mimic biological EVs, with an adhesive hydrogel patch for localized and sustained delivery to the heart. We provide proof-of-principle that di-tyrosine photo-crosslinked silk hydrogels are a suitable delivery platform for cell-derived NVs, preserving NV bioactivity and their ability to remodel recipient cells following delivery both in vitro and in vivo. This study integrates three key advantages: (i) the use of scalable iPSC-derived nanovesicles as an EV-mimetic platform, addressing limitations in EV manufacturing; (ii) a mechanically robust and tunable silk fibroin hydrogel formed via visible light-induced di-tyrosine crosslinking without chemical modification; and (iii) an injection-free, adhesive patch-based delivery strategy enabling localized and sustained therapeutic administration to the heart. This innovative platform represents a significant advancement in the fields of nanomedicine and biomedical engineering. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/722555v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@fed253org.highwire.dtl.DTLVardef@1a270b0org.highwire.dtl.DTLVardef@19437c1org.highwire.dtl.DTLVardef@1d863ca_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO C_FIG

Autonomous soft materials that can actuate, perform a function, and then self-terminate without external intervention remain difficult to realize. Here, a bilayer hydrogel actuator fabricated by digital light processing-based 3D bioprinter is introduced that couples rapid thermoresponsive deformation with slower enzyme-programmed mechanical feedback to achieve self-regulated shape transformation and autonomous recovery. The system integrates a poly(N-isopropylacrylamide) actuation layer with a bovine serum albumin-poly(ethylene glycol) diacrylate enzyme-programmed layer loaded with trypsin. Above the lower critical solution temperature, deswelling of the actuation layer generates a strain mismatch across the bilayer and drives rapid closure. In parallel, proteolytic cleavage of albumin domains progressively softens the enzyme-programmed layer, reduces interlayer constraint, and acts as an intrinsic mechanical off-switch that relaxes curvature and restores the open state. This materials logic enables sustained enzyme release, time-dependent modulus loss, and autonomous shape recovery without staged external triggers. As a proof-of-concept, this platform is implemented as a gastrointestinal-retentive hydrogel gripper for localized intestinal enzyme delivery, where it exhibits thermally triggered gripping, millinewton-scale gripping force, autonomous reopening, and robust ex vivo retention on porcine small intestine under dynamic motion. These findings establish enzyme-programmed mechanical feedback as a general design strategy for self-regulated soft actuators and therapeutic materials with built-in functional lifetimes.

Biomaterials-based tissue engineering aims to recapitulate native tissue architecture and function for both clinical repair and advanced in vitro models. While improvements in biomaterials have been made, including granular hydrogels and ECM-derived scaffolds, current biomaterials lack intentional design choices for effective translation, including regulatory considerations, practical extrusion delivery, and biomimetic characteristics. Here, we develop and characterize a library of granular ECM (gECM) biomaterials for five key tissues (cartilage, bone, skin, liver, and kidney), in which ECM particles are densely packed within a hyaluronic acid hydrogel. We optimize tissue processing methods that preserve proteomic content and structure while also aligning with scale-up manufacturing and regulatory guidelines. We show that gECM hydrogels can be molded, extruded, and 3D-printed while retaining their shape, and they stabilize at physiological temperature and pH. Lastly, we demonstrate that bulk gECM mechanics are driven by tissue type, and gECM hydrogels support viability, proliferation, and tissue-specific cellular activity. Together, these findings establish gECM hydrogels as a translational and biomimetic platform for clinical tissue repair and complex in vitro models.

Critical-sized bone defects and implant-associated complications are often exacerbated by chronic inflammation, which compromises tissue repair and implant integration. Mesenchymal stromal cell (MSC)-derived extracellular vesicles have emerged as promising immunomodulatory nanotherapeutics; however, their clinical translation remains constrained by low yield, heterogeneity, and poor scalability. Here we present a bioengineered MSC-derived nanoghosts platform designed to overcome these translational barriers while enabling tunable osteoimmunomodulatory function. By coupling high-yield nanoghost fabrication with biomimetic MSC conditioning, we demonstrate that oxygen tension (5 or 21% O2) and 3D culture substrates (5 or 15 wt-% GelMA) can reprogram MSC immunophenotype. Nanoghosts generated under hypoxic and 3D conditions displayed enriched anti-inflammatory cargo, preserved MSC viability under inflammatory stress, and partially rescued osteogenic mineralization in the presence of pro-inflammatory cytokines. Together, these findings showcase MSC nanoghosts as scalable and bioactive immunoregulatory nanotherapeutic capable of modulating immune-bone crosstalk, providing a translational strategy to mitigate inflammation-driven impairment of bone regeneration and implant integration. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=90 SRC="FIGDIR/small/724218v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@1551655org.highwire.dtl.DTLVardef@12d3371org.highwire.dtl.DTLVardef@8c50bborg.highwire.dtl.DTLVardef@834a8_HPS_FORMAT_FIGEXP M_FIG C_FIG

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.

Virus-like particles represent an emerging and promising vaccine platform. However, these particles are inherently mechanically soft and have limited control over particle surface architecture, thereby constraining their immunological control. Herein, we report the rational design of bioinspired virus-like porous silica (VLPSi) nanoparticles (NPs) with tunable and mechanically rigid spike architectures that function dually as antigen delivery carriers and immune adjuvants. Using ovalbumin (OVA) as a model antigen, we systematically elucidate the spiky structure-function relationship in antigen delivery and immune response. VLPSi NPs exhibit good biocompatibility, sustained antigen release, and markedly enhanced cellular uptake and endosomal escape compared with soft spike and spherical counterparts. Mechanistic investigations combining molecular dynamics simulations and proteomic analyses reveal that rigid spike architectures reduce the energetic barrier for cellular internalization and concurrently activate dual pathways involving endosomal Toll like receptors and calcium signaling. Consequently, VLPSi with long spikes elicit significantly enhanced humoral and cellular immune responses, outperforming the particles with shorter spikes, spherical shape as well as clinically used alum adjuvant. To demonstrate translational potential, bioinspired antibacterial vaccines were produced by loading Staphylococcus aureus surface protein rEsxB. The VLPSi-based vaccine elicited robust protective immunity to achieve complete (100%) survival following lethal challenge without detectable adverse effects, whereas traditional Alum-adjuvanted formulation conferred only minimal protection, with a survival rate of 10%. Collectively, this work establishes VLPSi with tunable spikes as a mechanistically controlled platform for next generation vaccines. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=145 SRC="FIGDIR/small/720861v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@1f6c13eorg.highwire.dtl.DTLVardef@1090d07org.highwire.dtl.DTLVardef@1364926org.highwire.dtl.DTLVardef@fc68ab_HPS_FORMAT_FIGEXP M_FIG C_FIG

Engineering functional bone scaffolds can be enhanced by integrating biologically instructive nanoscale surface features (e.g., nanotopography and nanoroughness), micro-scale geometric cues (e.g., curvature and porosity), and macro-scale mechanical properties (e.g., bulk stiffness); however, these length scales are often optimized independently. Here, we present a multiscale design framework combining additive manufacturing of triply periodic minimal surface (TPMS) gyroid scaffolds with plasma-assisted nanoscale surface engineering to regulate osteogenesis. Controlled variation in strut thickness generates distinct architectural regimes with coupled changes in curvature, porosity, and compressive modulus, recapitulating key aspects of trabecular bone mechanics. Micro-computed tomography confirms trabecular bone-like features, while finite element modeling and compression testing reveal that thinner architectures (0.6 mm) exhibit curvature-preserving geometry and distributed stress profiles favorable for cellular interaction. A low-temperature plasma electroless reduction (PER) strategy enables controlled silver nanoparticle deposition, while polydopamine-mediated adhesion ensures uniform and cytocompatible coatings. Notably, PDA-AgNP-functionalized 0.6 mm scaffolds significantly outperform unmodified and AgNP-only groups, exhibiting enhanced cytoskeletal organization, stress fiber formation, matrix mineralization, and osteogenic gene expression. These findings demonstrate that coupling nanoscale biointerface features with micro- and macro-scale architecture produces a synergistic enhancement in osteogenesis, providing a design framework for functional bone scaffolds. Table of Content GraphicsA plasma-enabled strategy integrates 3D-printed scaffold architecture with nanoscale surface engineering to enhance bone formation. By combining tunable structural design with uniform nanoparticle coating, the study shows that optimal biological responses occur only when mechanical and surface cues act together, highlighting a synergistic multiscale approach for designing advanced biomaterials for bone regeneration. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/718992v1_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@1d29685org.highwire.dtl.DTLVardef@983752org.highwire.dtl.DTLVardef@15816f5org.highwire.dtl.DTLVardef@4b4f50_HPS_FORMAT_FIGEXP M_FIG C_FIG

Ingestible electronics enable the tracking and treatment of gastrointestinal and systemic diseases. However, bulky batteries and circuit boards require large capsules that can result in bowel obstruction, a medical emergency. Here, we engineered a 9 x 26 mm electronic pill capable of triggered severing into tiny pieces with sizes clinically proven to reduce obstruction risk. Our capsule enables multicomponent circuit boards to connect with separately encapsulated powering elements via conductive, interlocking connections. Heat induced softening of polyethylene glycol/polycaprolactone channels activates a spring to separate encapsulated components into inert 9 x 15 mm segments, facilitating intestinal passage. Separation triggers included closed-loop sensors and time-delay circuits. In vivo swine studies demonstrate the ability of our capsules to sense luminal oxygen changes via an optoelectronic sensor, locally trigger upadacitinib delivery, and facilitate safe excretion.

Stimulus-responsive nanomedicines promise spatiotemporally controlled therapy, yet most systems rely on passive delivery and lack precise, externally programmable activation while maintaining clinical compatibility. Here we engineer sub-200 nm, perfluorocarbon (PFC)-core nanodroplets (NDs) that integrate efficient core drug loading, physiological stability, and acoustically programmable activation within a single nanoscale agent. These NDs are fabricated using microfluidic nanoassembly to achieve controlled size and composition, and are designed to encapsulate fluorinated payloads directly within the liquid core. Upon exposure to a sequential dual-frequency ultrasound (US) paradigm, the NDs undergo acoustic droplet vaporization followed by low-frequency cavitation, enabling spatially confined mechanical disruption and on-demand payload release within clinically relevant acoustic limits. These properties are engineered to overcome physicochemical barriers in solid tumors, including dense extracellular matrix and restricted drug penetration. This approach achieves enhanced payload release and induces potent mechanochemical cytotoxicity in vitro. In vivo, NDs exhibit prolonged circulation and tumor accumulation, while US activation drives substantial tissue fractionation, control drug release, and increases subsequent nanoparticle uptake. When applied to a solid tumor model, this combined mechanochemical strategy improves tumor control and significantly extends survival compared to either modality alone. These acoustically activatable NDs provide a versatile system for stimulus-responsive, site-targeted drug delivery and mechanical tumor disruption, with strong potential for clinical translation. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=99 SRC="FIGDIR/small/719550v1_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@9c07f8org.highwire.dtl.DTLVardef@1cf355aorg.highwire.dtl.DTLVardef@b7afd1org.highwire.dtl.DTLVardef@177fa1a_HPS_FORMAT_FIGEXP M_FIG C_FIG

Spatiotemporal control over cell fate and behaviour within bioprinted constructs remains a key challenge in tissue engineering. Optogenetics offers versatile potential for non-invasive regulation of biological processes. Yet, its integration within large-scale, cell-laden bioprinted materials is still limited, especially considering spatial constraints of existing light delivery methods. In this study, we introduce a novel approach that repurposes tomographic volumetric bioprinting to enable post-printing stimulation of photosensitive protein-switches and optogenetic circuits in cells deep within hydrogel constructs. By converging different bioprinting approaches, computer vision, context-aware model generation, and synthetic biology and cell engineering, we demonstrated selective activation of a fluorescent, light-responsive protein probe within multi-material centimeter-scale constructs. Moreover, leveraging a multi-wavelength volumetric bioprinter, we further demonstrate this concept by selectively stimulating cells expressing a near-infrared optogenetic system that triggers gene expression and the induction of pancreas-specific transcription factors. The described methods provide platforms for remote, repeatable, and localized control of biological events in volumetric constructs, opening new possibilities for advanced tissue models, and dynamic tuning of cell-mediated protein production in engineered living systems.

Nanoclay-based biomaterials offer promise for localised growth factor presentation, yet their in vivo degradation, clearance, and systemic fate remain poorly defined. Here, we investigate the fate of a synthetic nanoclay-BMP-2 gel during ectopic bone induction using a combination of in vivo imaging, histology, and component-resolved elemental analysis. Fluorescent tracking confirmed prolonged localisation of BMP-2 within the nanoclay gel and robust bone induction despite negligible growth-factor release. Inductively coupled plasma mass spectrometry (ICP-MS) revealed divergent clearance kinetics for lithium and silicon, structurally distinct components of the clay crystalline lattice, indicating decoupled ionic and particulate degradation pathways. Early clearance was dominated by cell-mediated fragmentation and the transport of clay particulates, while later stages involved preferential lithium release associated with local clay dissolution as well as integration within newly formed bone. Systemic biodistribution analysis demonstrated rapid, transient lithium release into circulation with renal clearance, contrasted with initial hepatic and then later-phase renal handling of silicon species. Together, these findings define a multiphasic in vivo clearance model for nanoclay biomaterials consistent with progressive remodelling, localised BMP-2 activity and, importantly, safe systemic handling. This work provides mechanistic insight into the activity and clearance of nanoclay-based regenerative therapies and establishes the importance of component-resolved tracking for evaluating the biodistribution of degradable inorganic biomaterials.

The pulmonary alveolus is a highly specialized microenvironment where epithelial, interstitial, and immune components interact to maintain gas exchange and tissue homeostasis. In vivo, the air-blood barrier consists of an epithelial layer and a capillary endothelium separated by an ultrathin interstitium composed of extracellular matrix (ECM) and lung fibroblasts. However, most existing lung-on-a-chip platforms rely on permanent synthetic membranes, which fail to recapitulate the dynamic biological and mechanical properties of the native interstitium. Here, we present a membrane-free human alveoli-on-a-chip enabled by a biodegradable poly(lactic-co-glycolic acid) (PLGA) scaffold that is progressively replaced by fibroblast-derived ECM. This process reconstructs a biologically formed interstitial layer while preserving an alveolus-like dome architecture. The resulting system supports multicellular organization under air-liquid interface conditions, enabling epithelial barrier formation and surfactant-related phenotypes. Additionally, direct epithelial-fibroblast interactions enhanced surfactant-related phenotypes, as evidenced by increased SPC and LAMP3 expression. Importantly, we demonstrate that conventional rigid substrates promote fibroblast-to-myofibroblast differentiation, leading to elevated reactive oxygen species (ROS) production, increased epithelial cell death, and compromised barrier integrity. In contrast, the membrane-free PLGA system mitigates stiffness-driven myofibroblast activation, preserving epithelial viability and maintaining barrier function. These findings highlight the critical role of interstitial mechanics in regulating alveolar homeostasis and reveal limitations of conventional membrane-based platforms. The platform further enables chemokine-driven monocyte migration across the alveolar barrier, recapitulating key immune trafficking processes observed in vivo. In addition, aerosolized metal-organic framework (MOF) nanoparticles efficiently mediated mRNA delivery to epithelial and interstitial cells with minimal cytotoxicity and modest inflammatory responses. Together, this membrane-free alveoli-on-a-chip reconstructs essential structural, mechanical, and functional features of the human alveolar microenvironment and provides a physiologically relevant platform for studying pulmonary biology, fibrosis-related mechanisms, immune cell trafficking, and inhaled nanomedicine delivery.

The dynamics of the tumor microenvironment (TME) are a key determinant of cancer progression and therapeutic resistance through complex interactions between tumor, stromal and immune cell populations. Among these, tumor-associated macrophages (TAMs) play a central role in promoting tumor growth and immune suppression. However, the specific contributions of TAMs remain poorly understood due to the lack of tools enabling selective genetic manipulation in three-dimensional (3D) tumor models. Here, we present a gold nanoparticle-assisted optoporation approach that enables spatially selective plasmid-based gene delivery to TAMs within intact heterocellular 3D pancreatic ductal adenocarcinoma (PDAC) spheroids, thereby modulating the TME. In two-dimensional (2D) TAM cultures, conventional transfection of IRF5- and IKBKB-encoding plasmids validated their capacity to induce TAM repolarization, as evidenced by activation of interferon signaling. Extending this approach to 3D PDAC spheroids, nanoparticle-assisted optoporation achieved selective transfection of TAMs with IRF5- and IKBKB-encoding plasmids by transiently generating nanoscale membrane pores in illuminated cells. TAMs transfection elicited a robust interferon response, marked by transcriptional upregulation of IFNA, IFNB1, and CXCL10, and increased protein levels of IFNB1, IFNL1, and CXCL13, together with downregulation of pro-tumorigenic markers CEACAM5, IL19, and IL32. These coordinated changes indicate a shift towards an anti-tumorigenic TME. By enabling minimally invasive, TAM-specific gene delivery in complex multicellular 3D spheroids, this strategy allows precise modulation of the TME and opens new avenues for modeling its dynamics in cancer progression and therapeutic response.

Small-diameter vascular grafts that can grow with pediatric patients and resist thrombosis remain an unmet need, primarily due to slow and unstable endothelialization. Here, we engineer a tri-layer, human induced pluripotent stem cell (hiPSC)-derived vascular graft featuring a soft, patterned lumen. We introduce a scalable soft-lithography method to imprint longitudinal micro-grooves directly into the lumen of compliant hydrogel tubes, a key advance for cell-laden constructs. Computational fluid dynamics reveals that these grooves redistribute wall shear stress into protective low-shear valleys and aligning high-shear ridges without increasing the mean load. This engineered shear landscape, combined with a bioactive elastin-like recombinamer (ELR) hydrogel matrix, synergistically enhances hiPSC-endothelial cell (hiPSC-EC) capture and retention under perfusion. Patterned grafts accelerate the formation of confluent, axially aligned endothelial monolayers with mature VE-cadherin junctions, outperforming non-patterned controls. Concurrently, smooth muscle cells within the graft wall deposit extracellular matrix, driving time-dependent mechanical maturation. This platform provides a physiologically relevant model for vascular disease and a promising strategy for engineering growth-competent pediatric grafts.