ACS Biomaterials Science & Engineering

Bacterial biofilms on indwelling medical devices is a major driver of healthcare-associated infection despite significant advances in antifouling surface engineering, suggesting that laboratory antibacterial performance does not fully capture the determinants of clinical colonization. Here we show that adherent immune cells constitute a previously underappreciated conditioning layer that promotes biofilm formation on otherwise antifouling biomaterials. Pre-exposure of clinically used substrates to macrophages, monocytes, neutrophils or human peripheral blood cells markedly increased Staphylococcus aureus and Escherichia coli adhesion and aggregation. These studies also reveal that immune cells promote biofilms even after cell death with cellular debris acting as a conditioning agent. We demonstrate that reactive-oxygen-species amplification by incorporating bismuth telluride into a silicone composite converts adherent immune cells from passive conditioning agents into active bactericidal effectors. We note that this antimicrobial composite confers durable antibacterial protection across early, delayed and late infection time points in a murine implantation model. Together, these findings introduce a class of immune-coupled antibacterial materials as an alternative to the current antifouling paradigm.

BackgroundProtein fibrillation represents a critical challenge in therapeutic insulin delivery, yet the structural determinants and immunological consequences of insulin-derived fibrils (IDFs) formed in the presence of phenolic preservatives remain poorly characterized. ObjectiveThis study investigated the structural characteristics of IDFs formed with (IDF (+)) and without (IDF (-)) phenolic preservatives and elucidated their differential immunomodulatory mechanisms in bone marrow-derived macrophages (BMDMs). MethodsIDF structural properties were characterized using Thioflavin T fluorescence and nanoparticle tracking analysis (Spectradyne nCS1). BMDMs were treated with serial dilutions of IDF (+), IDF (-), or m-cresol. Cytotoxicity, reactive oxygen species (ROS) production, MIP-1 levels, and expression of signaling pathways were quantified. ResultsStructural analysis revealed similar aggregation states between IDF (+) and IDF (-). However, IDF (+) induced greater cytotoxicity and ROS production than IDF (-), which produced minimal ROS. Both fibrils increased MIP-1 chemokine levels. Additionally, IDF (-) upregulated NRF2 whereas m-cresol downregulated STAT6 compared to control. Together, these results support the existence of distinct mechanisms of macrophage activation and suggest that protein aggregates can directly induce macrophage responses independent of ROS production. ConclusionsInsulin fibrils activate macrophage inflammatory pathways through ROS-independent mechanisms. Phenolic preservatives enhance fibril cytotoxicity and likely ROS production while differentially modulating inflammatory signaling. These findings suggest that strategies to remove or reduce the effects of IDFs in insulin infusion therapy may increase longevity and biocompatibility of these devices.

Curcumin is a naturally occurring polyphenol that demonstrates considerable anti-cancer activity, however the aqueous insolubility, rapid metabolism and relatively low bioavailability are limiting to its clinical application. As such, a curcumin-magnesium (Cur-Mg) coordination complex was synthesized and subsequently encapsulated within DNA hydrogels (Cur-Mg-Hgel). The Cur-Mg complex was fully characterized using UV-Vis spectroscopy, FTIR and X-ray diffraction (XRD). UV-Vis, FTIR and XRD all support the formation of a coordination complex and suggest a decreased level of crystallinity compared to free curcumin. DNA hydrogels were formed and characterized using atomic force microscopy, rheology and swelling kinetic studies. In vitro cytotoxicity studies utilizing an MTT assay demonstrate dose dependent inhibition of HeLa cell proliferation and a slightly better retention of RPE-1 viability at low concentrations (suggesting some difference in sensitivity) though significant cell death is seen at higher concentrations and both cells. Intracellular production of ROS was measured using the DCFH-DA assay and is seen to increase when HeLa cells are treated with Cur-Mg-Hgel in comparison to un-treated controls. Annexin V/PI staining demonstrates primarily late or early apoptotic activity with minimal necrosis following treatment with Cur-Mg-Hgel. The evidence presented strongly supports the notion that Cur-Mg-Hgel is a ROS-modulating, pro-apoptotic Hydrogel suitable for cancer treatment. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=102 SRC="FIGDIR/small/724072v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@18727aeorg.highwire.dtl.DTLVardef@3e20adorg.highwire.dtl.DTLVardef@d3703eorg.highwire.dtl.DTLVardef@16e260e_HPS_FORMAT_FIGEXP M_FIG C_FIG

Background and ObjectivesCardiovascular cells differentiated from human induced pluripotent stem cells (iPSCs), including cardiomyocytes, are valuable for evaluating human cardiac pharmacology and toxicity. Early assessment of cardiotoxicity, especially for novel drugs like anticancer agents, is essential for improving drug development efficiency and reducing costs. This study aimed to develop a highly sensitive bioassay system capable of evaluating the physiological function of human cardiac tissue in vitro. MethodsHuman iPSCs were differentiated into cardiovascular cell types (cardiomyocytes, vascular endothelial cells, and vascular mural cells) and assembled into a cardiac tissue model on aligned fiber device. This tissue was cultured dynamically to induce the formation of vascular network-like structure. By combining the fiber device with our previously developed heart-on-a-chip microdevice (HMD), we created a new model of HMD (Aligned Fiber-based HMD; AF-HMD) with improved throughput and stability. Pulsatile force changes induced by drug exposure were quantified by tracking the displacement of fluorescent microbeads within the microchannels. ResultsAF-HMD demonstrated functional responses to known cardiac agonists and toxicants, such as doxorubicin. The device also replicated clinically relevant cardiotoxic events, including the synergistic effects of trastuzumab and doxorubicin, showing marked reductions in contractile force and beat rate, mirroring clinical observations. ConclusionsThe AF-HMD system provides a sensitive and reproducible platform for evaluating cardiotoxicity in drug development. It offers a promising tool for preclinical screening, with potential applications in personalized medicine and predicting cardiotoxic risk in cancer therapy.

Tissue regeneration using bioactive biomaterials has made great progress in the field of wound healing. Biopolymers play a cardinal role in regenerative medicine by providing safe, biocompatible and bioresorbable support. The electrospinning fabrication technique has been used in creating suitable wound care materials. PHBV and PLLA are FDA approved polymers having important applications in biomedical field. In this study, to increase the wound healing potential, PHBV was functionalized with -COOH group and electrospun nano-fibrous mat was produced using PHBV-COOH and PLLA blended solution. Antibiofilm peptide (IDR-1018) with immunomodulatory activity was incorporated into the blended solution to improve infected wound treatment by actively fighting against bacterial infections. Furthermore, in-vitro experiments including cell cytotoxicity assay and scratch wound healing assay were done to evaluate the potential of the synthesized bioactive nanofibrous mat as a potential wound management aid.

Hydrogels are widely used as three-dimensional cell culture systems to understand the impact of cellular mechanotransduction for tissue engineering applications. Photoinitiated thiol-ene click chemistry is a commonly utilized hydrogel crosslinking mechanism that provides spatial and temporal control over hydrogel network formation and resulting mesh size and compressive properties. Despite historically documented efficiency as step-growth reactions, these reactions do not always proceed as predicted. To understand the impact of cell confinement and microenvironmental mechanics on cellular function, thiol-ene network formation must be thoroughly characterized. To this end, the objective of this work was to investigate the crosslinking dynamics to determine hydrogel network formation as assessed via mesh size and mechanical properties using a pentenoate-functionalized hyaluronic acid thiol-ene reaction. Hydrogel parameters including polymer concentration and thiol:-ene crosslinker molar ratio were modulated (4, 6, or 8 polymer weight percent and 0.15:1, 0.5:1, or 1:1 molar ratio of thiol groups to reactive -ene groups) to tune network properties including shear storage modulus and relative mesh size. Molecular Dynamics (MD) simulations were used to simulate the thiol-ene crosslinking reaction and establish a method for predicting thiol-ene reaction efficiency. Lastly, the feasibility of this hydrogel system for in vitro modeling was confirmed via assessment of metabolic activity of encapsulated primary human meniscal cells.

Foreign body response is a common yet serious challenge for biomedical implants. It can trigger inflammation and eventually lead to the formation of a fibrotic capsule, which compromises device function. Although significant efforts have been made to develop antifibrotic surface coatings for implantable materials, developing broadly applicable solutions remains challenging due to the diversity of materials used in biomedical implants. Here, we propose a simple and versatile strategy to develop antifibrotic coatings for biomedical implants. Photoreactive benzophenone groups are incorporated into designer polymers to enable covalent attachment to various substrates. The effect of benzophenone group density within polymer chains on surface coating efficiency was investigated, and an optimal BP incorporation ratio was identified. Polymers incorporating varying ratios of an anti-fibrotic small molecule and anti-fouling zwitterionic moieties were synthesized and successfully attached to silicone implants. In vivo evaluation of these implants in C57BL/6 mice identified an optimized polymer composition that reduced fibrotic capsule thickness by around 60%. Coating of commercial medical catheters with this optimized polymer reduced collagen deposition by over 3.5-fold following 4 weeks of implantation in the peritoneal space of C57BL/6 mice. Finally, we demonstrated that the optimized polymer coating can be readily applied to a variety of commonly used biomedical materials using this straightforward method, highlighting the versatility of the approach. This work provides a facile and broadly applicable strategy for developing antifibrotic coatings, which has the potential to expand the design of surface modifications aimed at improving the performance of biomedical implants.

Stroke remains a leading cause of adult disability, driven in part by the formation of a non-permissive extracellular matrix environment that limits endogenous repair. Injectable biomaterials that can modulate this microenvironment while enabling localised therapeutic delivery, represent a promising strategy for post-stroke brain regeneration. Here, we report the development of a thermoresponsive hybrid hydrogel composed of chitosan, {beta}-glycerophosphate, silk fibroin, polyvinyl alcohol and polyvinyl pyrrolidone, engineered to provide a tuneable physicochemical properties and enhanced biological functionalities for intracerebral delivery. Systemic optimisation identified a formulation (F6) that exhibited rapid gelation at physiological temperature, appropriate viscoelastic properties, a microporous architecture, and controlled biodegradation, conducive to cellular infiltration and molecular transport. In a mouse model of photothrombotic stroke, intracerebral delivery of the F6 hydrogel attenuated reactive astrogliosis and microglial activation in the peri-infarct region, while enhancing neurogenesis in the subventricular zone. Notably, incorporation of brain-derived neurotrophic factor within the hydrogel significantly improved functional recovery over 8 weeks, demonstrating the capacity of this system to act as a localised delivery platform for neuro-regenerative therapeutics. Together, this study establishes a tuneable thermoresponsive hydrogel platform that integrates structural support with controlled therapeutic delivery, highlighting its potential as a minimally invasive strategy for modulating the post-stroke microenvironment and promoting functional recovery.

Over the past decade, the integration of microgel-based granular hydrogels in biomedical technologies has experienced substantial growth due to the numerous benefits microgels offer. However, the inability to easily adopt uniform microgel fabrication workflows at scale constitutes a major bottleneck, or in some cases, a barrier-to-entry that stunts further growth of the field. The gold-standard technique for emulsion-based microgel production is through microfluidic droplet-generating devices that produce liquid gel precursor droplets that gel post-production. However, traditional microfluidic workflows often require multiple independent flows and controlled pressure sources, along with a steep learning curve in using microfluidics to achieve uniform droplet sizes reproducibly and repeatedly. This difficulty in adopting microgel fabrication is further compounded by low throughput and the extensive flow rate calibration required when switching to new formulations (e.g., material type, droplet size). In this work, we present a step-emulsion system that bridges the gap by providing a robust and simple setup. We experimentally characterize and evaluate how flow and outlet channel dimension contribute to the generation of uniform droplet populations at specific sizes. With our large dataset consisting of various outlet channel dimensions, we evaluated outlet channel geometrical impacts (height, width, cross-sectional area, aspect-ratio, etc.) on gel precursor droplet size and generation throughput. We demonstrate robust, highly compatible, and repeatably uniform droplet generation from various gel precursor polymer backbones, users with varying microfluidics experience, and a wide viscosity range, including alginate solutions with 650 times the viscosity of water. Furthermore, we confirmed consistent gel precursor droplet generation outcomes driven by a constant flow source (syringe pump) and by direct manual injection as a simple and highly adoptable option for the generation of gel precursor droplets. This platform is ideal for researchers seeking rapid and easy microgel fabrication, regardless of microfluidics experience.

Matrix-bound nanovesicles (MBVs) are a recently discovered subclass of small extracellular vesicles (EVs) that reside within the extracellular matrix of non-mineralized tissues throughout the body. Functionally, MBVs exhibit unique immunomodulatory properties that have been leveraged therapeutically to treat various tissue pathologies, including periprosthetic osteolysis, rheumatoid arthritis, and skeletal muscle injury. However, like other EVs, the therapeutic efficacy of MBV applications is limited by delivery methods, namely bolus injections, that offer poor control of EV persistence and bioavailability at the site of administration. We hypothesized that a superior MBV delivery platform could be developed by entrapping MBVs in a tunable, engineered alginate matrix to control retention and release of MBVs on therapeutically relevant timescales. To this end, we encapsulated dermal fibroblast MBVs in bioinert alginate hydrogels of varying stiffness and stress relaxation rates to determine the impact of matrix mechanical properties on MBV release and retention over a 14-day period. We found that stiffer matrices increased MBV release compared to their softer counterparts. Additionally, fast-relaxing matrices exhibited release of MBVs in the first four days of release experiments, in contrast with slow-relaxing matrices, which promoted long-term sequestration of nearly all encapsulated MBVs regardless of differences in matrix stiffness. Our results offer promise that alginate hydrogels can be utilized for more precise control of MBV delivery in the body and may overcome limitations associated with current EV administration methods.

Ex vivo airway engineering approaches such as 3D bioprinting offer a promising strategy for generating functional airway replacements, but the fabrication of hollow, patient-specific proximal airway constructs using translationally relevant bioinks remains challenging. This study describes the development of biocompatible, polymer-blended human airway-derived decellularized extracellular matrix (AW-dECM) bioinks for engineering structurally and mechanically relevant airway tissues. An optimal formulation consisting of 30 mg/mL AW-dECM and nanofibrillar cellulose alginate conjugated to RGD supported the bioprinting of simple and complex hollow airway structures with mechanical properties comparable to native airways ([~]8-10 kPa). The bioinks also promoted primary human airway epithelial cell viability, adhesion, and differentiation into mucociliary and secretory phenotypes during 28 days of air-liquid interface culture. Furthermore, subcutaneous implantation in immunocompetent rats demonstrated excellent biodegradative stability and overall biocompatibility over 30 days. Collectively, these findings establish a foundation for improved physiological airway models and future tissue-engineered airway replacements.

Potent antineoplastics, such as afatinib and freebase doxorubicin, are associated with systemic toxicity. To address this issue, we developed a carrier that releases drugs, including afatinib and doxorubicin, specifically at the focus of low-intensity ultrasound. This remotely triggered and focal approach enables the release of drugs specifically at the ultrasound focus, thus mitigating undesirable off-target effects, and at concentrations governed by the duration of the applied ultrasound. We produced ultrasound-sensitive microdroplets with high encapsulation efficiencies (39.6% for afatinib and 46.6% for doxorubicin). The microdroplets consist of an ultrasound-sensitive drug delivery system based on a methoxy poly(ethylene glycol)-poly(D, L-lactide) diblock copolymer (mPEG-PDLLA) and perfluorooctyl bromide (PFOB). Antineoplastic agents were encapsulated within these microdroplets via co-evaporation during particle synthesis. The microdroplets released doxorubicin and afatinib in an ultrasound-pressure-dependent manner, with fitted half-maximal release pressures (P50) of 0.61 MPa and 0.72 MPa, respectively. Together, the effective encapsulation of hydrophobic antineoplastic agents and the dose-dependent ultrasound-triggered release provide a new method for targeted drug delivery and a foundation for future targeted chemotherapies.

Tissue engineered constructs are increasingly used for both modeling organs and disease in vitro as well as for therapeutic intervention. In addition to collagen, these constructs commonly include native extracellular matrix proteins (ECM), such as fibronectin and laminin. Given the critical role of inflammatory pathways in disease and in response to implanted materials, it is important to understand the role these proteins play in regulating the inflammatory environment. Fibronectin and laminin influence neutrophil function and endothelial activation in 2D, but their regulation of the inflammatory environment in 3D engineered constructs is not clear. For this study, we used an inflammation-on-a-chip device that includes a model blood vessel surrounded by a collagen I hydrogel with fibronectin and/or laminin. We investigated the additive effects of both proteins and a range of concentrations for each protein to determine concentration dependence. Both fibronectin and laminin have concertation dependent effects on neutrophils and the endothelium. High concentrations (50 {micro}g/mL) of fibronectin reduced neutrophil migration, while 20 {micro}g/mL laminin reduced neutrophil extravasation and migration, potentially due to lower ICAM-1 expression by the endothelium. Interestingly, 50 {micro}g/mL of laminin significantly disrupted endothelial vessel formation and reduced ICAM-1 and VE-cadherin expression, likely due to significant changes in the collagen architecture. The inclusion of fibronectin and laminin, even at physiological levels, results in significant effects on neutrophil behavior, endothelial vessel formation, and collagen architecture. These proteins impact the inflammatory environment and thus need to be considered when modeling diseases and designing therapeutics, especially when neutrophils or an endothelium are involved. Translational Impact StatementThis work uses an inflammation-on-a-chip device to study how fibronectin and laminin impact neutrophil behavior and vascular inflammation as these proteins are commonly used in engineered constructs. We found that fibronectin impairs neutrophil migration, while laminin decreases neutrophil extravasation and migration and at higher concentrations also prevents endothelial vessel formation. Therefore, researchers should be aware that these proteins will alter the inflammatory environment when including them in engineered constructs.

Most antimicrobial drug candidates currently in development are derivatives of established antibiotic classes. In contrast, antimicrobial heteroatom-doped carbon quantum dot (CQD) nanoparticles vastly differ from their chemical antibiotic counterparts and exhibit potent antibacterial activity and favourable biocompatibility, representing a promising alternative strategy, particularly for topical applications. Here, we report the incorporation of cobalt-doped carbon quantum dots (Co-CQDs) into injectable, biocompatible hydrogels capable of both sensing pH and eliminating bacteria. Ultrasmall Co-CQDs demonstrated broad-spectrum activity against gram-positive Methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative Pseudomonas aeruginosa (PAO1), mediated by membrane hyperpolarisation and reactive oxygen species (ROS) induced membrane damage. The particles showed negligible effect on primary fibroblast and endothelial cell viability at concentrations that were bactericidal to MRSA. Polymeric hydrogels were fabricated via electrospinning of chitosan, polyvinylpyrrolidone (PVP), and polyvinyl alcohol (PVA) polymer blends incorporating Co-CQD and pH-responsive HPTS particles. This approach provided accurate measurement of environmental pH within the physiological range observed across healthy and chronic wounds. In vivo, the injectable hydrogels exhibited robust antimicrobial efficacy against MRSA without impairing wound closure relative to untreated controls, while also reducing inflammatory immune responses in infected tissues. Collectively, these findings demonstrate the potential of ultrasmall metal-doped CQDs for infection control and their integration into 3D matrices as multifunctional theragnostic platforms.

The mechanical properties of the cellular microenvironment are key regulators of cellular physiology. Although the field of cancer mechanobiology has attracted attention, the availability of matrix systems with independently and precisely tunable mechanical properties remains limited. Our group previously developed a collagen gel with enhanced mechanical strength by cross-linking collagen molecules using a platinum complex. In this study, we investigated the tunability of the mechanical properties of the platinum cross-linked collagen gel (PCG) and demonstrated that mechanical parameters can be controlled by varying the amount of the platinum complex. In addition, we examined how matrix mechanical properties modulate the phenotypes of lung adenocarcinoma A549 cells using the collagen matrix. Although A549 cells exhibited significant morphological alterations on stiffer matrices, these changes were not accompanied by classical epithelial-to-mesenchymal transition (EMT). Instead, they were associated with the upregulation of diverse gene expression related to cancer malignancy. We focused on maternal embryonic leucine zipper kinase (MELK) whose gene expression increased on stiffer matrices. Consistently, A549 cells cultured on stiffer matrices displayed enhanced sensitivity to a MELK-targeting anticancer drug. These findings highlight the potential of the matrices with tunable mechanical parameters not only to provide variety of physiological microenvironment but also to advance anticancer drug screening when combined with gene expression analysis. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC="FIGDIR/small/720034v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@419074org.highwire.dtl.DTLVardef@72ef67org.highwire.dtl.DTLVardef@1c36e17org.highwire.dtl.DTLVardef@170dc33_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIPlatinum cross-linked collagen gel enables independent tuning of compressive and shear elasticities. C_LIO_LICellular functions may be regulated by matrix mechanical parameters through distinct mechanisms. C_LIO_LICorrelation analysis between matrix mechanical parameters and cancer cell gene expression provides a rational strategy for therapeutic drug screening. C_LI

Heparin, a naturally derived glycosaminoglycan, is the most commonly used anti-thromboembolic in the world. However, the biological origin of heparin inherently results in batch-to-batch variability, large dispersity indexes, and potential contamination, leading to inconsistent activity and patient-dependent dose-response. As such, new synthetic anticoagulants are of keen interest, particularly those that mimic heparin while being amenable to alterations in polymer structure and composition for performance optimization. Herein, we report the strategy, synthesis, and evaluation of well-defined, regioselectively functionalized di-sulfated polyamidosaccharides (disulPASs) including exploration of the structure-function relationship of molecular weight and sulfation density on anticoagulant activity. Polymerization of an orthogonally protected beta-lactam monomer via anionic ring-opening, followed by selective deprotection and sulfation reactions affords disulPAS. Similar to heparin, disulPASs elongate clotting time through the intrinsic and extrinsic pathways, showing molecular weight and dose-dependent responses in clotting time; are non-cytotoxic and non-hemolytic, partially neutralized by protamine sulfate, and unlike heparin, are not degraded by heparinases. As compared to less sulfated and randomly sulfated iterations of PAS, disulPAS performs superiorly, with in vitro and in vivo clotting activity most similar to native heparin.

Fibrosis is a progressive and often fatal pathological process characterized by excessive extracellular matrix deposition, tissue stiffening, and irreversible organ dysfunction. Effective antifibrotic therapies remain limited by the lack of in vitro models that recapitulate the full spectrum of fibrotic disease progression. Here, we leverage tyramine-modified silk fibroin (SF-TA) hydrogels to investigate normal human lung fibroblasts (NHLF) responses to progressively stiffening environments relevant to pulmonary fibrosis. Two hydrogel formulations with distinct stiffening profiles over 14 days were prepared: a gradual-stiffening 0% SF-TA formulation reaching [~]20 kPa, and a rapidly stiffening 50% SF-TA formulation reaching [~]60 kPa. NHLFs were cultured on both formulations, with and without TGF{beta} (5 ng/mL), for 14 days and assessed for viability, metabolic activity, cytokine and collagen secretion, cytoskeletal organization, and mechanotransductive gene expression. The 0% SF-TA hydrogels drove sustained fibroblast proliferation and elevated secretion of IL-6, IL-8, and MCP-1, consistent with early inflammatory fibrosis. The 50% SF-TA hydrogels induced a metabolic plateau without senescence, suppressed inflammatory cytokine secretion, and, in the presence of TGF{beta}, led to significant upregulation of ACTA2 and CTGF, alongside -SMA stress fiber incorporation, consistent with established myofibroblast persistence. Both conditions produced comparable secreted collagen output by day 14. Together, these findings establish dynamically stiffening SF-TA hydrogels as a tunable platform for investigating stage-dependent fibroblast activation and mechanobiological progression in fibrosis.

Cell encapsulation offers a promising strategy for sustained therapeutic protein delivery, obviating the need for repeated injections. Among potential implantation sites, the subcutaneous space is particularly attractive for its accessibility and amenability to minimally invasive procedures. However, performance of subcutaneous devices reported to date has been limited due to various challenges including foreign body response (FBR) and inadequate mass transfer. Moreover, typical encapsulation devices require surgeries for implantation and retrieval, limiting their potential use in resource-limited settings. Here we present a miniaturized cell encapsulation platform comprising cells engineered to produce therapeutic proteins and an FBR-mitigating zwitterionic polyurethane nanofibrous membrane, in a thin cylindrical form factor compatible with applicator-based minimally invasive implantation and retrieval. Clonal mesenchymal stromal cells engineered to produce PGT121, a broadly neutralizing anti-HIV-1 antibody, were encapsulated and inserted subcutaneously, achieving long-term cell survival and sustained serum PGT121 concentrations for up to 36 weeks across multiple murine models. Cell-loaded devices retained therapeutic function after cryopreservation, supporting their potential use as an off-the-shelf product that can be centrally manufactured and implanted on-site without specialized infrastructure. The custom-designed applicator-based implantation and minimally invasive retrieval procedures were demonstrated in a more clinically relevant minipig model. These mini-"cellular factories" represent a translatable strategy for sustained delivery of biologic drugs in resource-limited settings. One Sentence SummaryAn insertable and retrievable mini cellular construct enables sustained protein delivery, supporting its potential use in resource-limited settings.

Pulmonary delivery of lipid nanoparticles (LNPs) remains an area of significant interest, given the broad range of genetic disorders that could be addressed through localized administration of therapeutic nucleic acids to the lung. In this study, we investigated how incorporation of the clinically used lung surfactant cocktail Poractant alfa affects the in vitro and in vivo transfection performance of mRNA-loaded LNPs. The resulting lung surfactant-enhanced LNPs (Surf-LNPs) exhibited substantial improvements in particle assembly, yielding an order of magnitude higher particle concentration at equivalent input conditions compared to conventional (Onpattro-like) LNP formulations. In vitro, Surf-LNPs demonstrated several-fold increases in mRNA transfection efficiency and protein expression while maintaining excellent cytocompatibility. These enhancements are attributed to an elevated apparent pKa and the surface-active properties of surfactant protein B (SP-B), which promote more rapid and efficient endosomal escape relative to conventional LNPs. In vivo evaluation following intranasal administration further revealed enhanced mCherry expression in the lungs of mice treated with Surf-LNPs compared to conventional LNPs. Ultimately, these findings establish lung surfactant incorporation as a simple yet powerful formulation strategy to improve pulmonary gene delivery using LNPs, with the potential to significantly advance the translation of inhaled nucleic acid therapeutics.

Radiofrequency ablation is a mainstay of cardiac rhythm management despite high recurrence rates. Current radiofrequency ablation catheters are limited by poor contact with trabeculated cardiac tissue that promotes uneven heating with hot spots that cause collateral damage and regions of incomplete ablation that promote recurrence. Herein, we report on a conductive hydrogel coating of radiofrequency ablation catheters to improve tissue contact while promoting efficient energy transfer. A method was developed to graft a polyether urethane diacrylamide hydrogel to the distal tip of the catheter that maintained stable adhesion following drying, sterilization, and rehydration. The coating also remained intact after passage through an introducer sheath and 50 cycles of radiofrequency ablation at clinical power. The hydrogel-coated catheter demonstrated enhanced tissue contact that was dependent on hydrogel modulus. Hydrogel-mediated ablation prevented steam pop incidence and generated homogeneous lesions in an ex vivo ablation model; however, increased hydrogel conductivity is needed to achieve comparable lesion dimensions as the bare metal catheter and prevent coating damage at higher power. Collectively, these results establish a tunable hydrogel coating method that addresses limitations of conventional radiofrequency ablation and offers a promising approach to enhance the safety and efficacy of cardiac ablation therapies.