ACS Biomaterials Science & Engineering最新文献

Affinity-controlled release provides a versatile approach for the delivery of proteins from hydrogel systems by harnessing noncovalent interactions between a molecule of interest and a binding ligand. We present a strategy for the controlled release of native antibodies by leveraging affinity interactions with peptide ligands specific to the fragment crystallizable (Fc) region. Two Fc-binding ligands (FcLs) were engineered using distinct spacers, yielding different degrees of equilibrium dissociation constants (K_D) for the Fc region of human IgG₁: 2.54 ± 0.03 × 10^-8 M (HWRGWV-GAKSKG; FcL1) and 3.01 ± 0.09 × 10^-7 M (HWRGWV-K(PEG); FcLPEG). These ligands were immobilized within a chemically cross-linked hyaluronan-oxime hydrogel, where controlled release of bioactive bevacizumab was observed with FcL1 but not with the lower-affinity FcLPEG. To further explore the versatility of this approach, FcL1 was incorporated into a physically cross-linked hyaluronan-methylcellulose hydrogel, demonstrating tunable release of multiple IgG₁ antibodies, including bevacizumab and adalimumab, each over a 7-day period. Together, this work demonstrates a broadly applicable strategy to tune antibody release.

Human enamel is a hierarchically organized hydroxyapatite biomineral, but it lacks regenerative capacity, motivating interfacial engineering strategies that control mineral growth at the enamel surface. This work examines an electric-field-assisted biomimetic mineralization approach that forms organized organo-mineral coatings composed of nanocrystalline carbonate-substituted hydroxyapatite (ncHAp), amino acids (AAs), and polydopamine (PDA). The method utilizes isolated electrodes to apply an electrostatic field, eliminating direct current through the substrate and directing the assembly at the interface. Crucially, this configuration with fully insulated electrodes prevents Faradaic current flow-through biological tissue, establishing a safe foundation for this in vitro proof-of-concept study. Grazing-incidence X-ray diffraction confirms the hydroxyapatite phase and shows a strong preferred orientation, which is reflected in a markedly increased crystallinity index due to the formation of a textured, highly oriented architecture. Electron microscopy, atomic force microscopy (AFM), and synchrotron nano-IR imaging (SINS) reveal densely packed ncHAp/AA/PDA nanoagglomerates with a core-shell architecture. Machine-learning clustering of SINS hyperspectral maps identifies nanoscale chemical heterogeneity and phosphate-rich oriented domains. Crucially, the coating exhibits enhanced mechanical properties: Vickers microhardness measurements and AFM-based nanoindentation show that the coating-substrate system exhibits a higher apparent surface hardness compared to that of native enamel under the tested indentation conditions, demonstrating the reinforcing effect of the textured, electric field-assisted composite layer. This enhancement in the composite coating-substrate system is attributed to the textured assembly of ncHAp nanocrystals reinforced by a PDA/AA interphase. The work elucidates the mechanism of electric-field-guided assembly, establishing a route for fabricating structurally organized, hard biomimetic coatings on enamel. This study establishes fundamental principles of electric-field-guided mineral assembly on enamel surfaces and provides a versatile platform for engineering high-performance biomimetic interfaces, with potential relevance to future noninvasive enamel restoration approaches.

Crossing the blood-brain barrier (BBB) remains a major hurdle in neurotherapeutics delivery. However, adeno-associated virus serotype 9 (AAV9) variants can cross from the bloodstream to accumulate in brain tissue, with their tropism facilitated by surface peptide loops. In this work, we examined the feasibility of grafting AAV9-based peptides (AAV.PHP.eB, AAV.X1, and AAV.CPP.16) onto nanoparticles (NPs) to increase transport through brain endothelial cells. We also evaluated the effects of combining the cell-mediated transcytosis strategy with nanosecond pulsed electric fields (nsPEFs). To test the importance of the AAV9-mimetic peptide structural presentation, we chemically conjugated linear peptides or recombinantly inserted peptides into external loops of a protein NP delivery scaffold (E2). E2 shares similar size, symmetry, and nanostructure features to AAV9 but is based on a non-viral source. Computational modeling, particle sizes, and circular dichroism data showed that NPs were folded and intact, even after peptide insertion. NP uptake by brain endothelial cells was 6.2- and 3.4-fold greater (after 4 h) for designs that integrated AAV.X1 or AAV.CPP.16 loop peptides into the NP, relative to chemical conjugation of their respective linear peptides; this highlights the importance of retaining the structural context of the AAV9-derived peptide loops. Using a transwell BBB assay which was optimized to be conducted with nsPEF, we showed that the highest transcellular passage of NPs through the endothelial monolayer was obtained by combining the dual delivery strategies of AAV9 peptide loop incorporation and treatment with nsPEFs. This study also determined the AAV.CPP.16 loop to be the most effective peptide, with E2 NP transport to the basolateral side to be almost twice that of the AAV.X1 peptide in E2 (with nsPEFs). These results support the integration of AAV9-mimetic peptides into biomolecules and drug delivery carriers to facilitate their passage through the BBB.

Suitably functionalized polymer brush-modified micropatterned surfaces may enable precise control over interfacial interactions with multiple biomolecules, potentially leading to the creation of proteins/DNA microarrays, biosensors, diagnostics, tissue engineering, etc. Herein, we present a facile strategy to construct oppositely charged polymer brushes installed at their designated domains on the micropatterned biodegradable polymeric substrate PLA (polylactide) via SIATRP (surface-initiated atom transfer radical polymerization). Generally, it is challenging to graft polycationic and polyanionic brushes on a micropatterned surface with alternate domains of positive and negative charges. To avoid the inherent interactions between the opposite charges, this study demonstrates a unique strategy to fabricate micropatterned cationic (poly([2-(methacryloyloxy) ethyl] trimethylammonium chloride)) (PMETA) and anionic (poly(3-sulfopropyl methacrylate potassium)) (PSPMA) polymer brushes on the PLA surface. After grafting of the PSPMA brush on the desired region of the micropatterned surface (using the masking/demasking technique), tributylamine was employed to block the anionic sulfonate groups so that grafting of the cationic PMETA brush became feasible in the neighboring domain in the subsequent step. Following the polymerization of META, the anionic brushes were simply unblocked by reducing the pH of the medium, producing a micropatterned surface modified with oppositely charged polyelectrolyte brushes. As examples, oppositely charged brushes were employed to form proteins and DNA microarrays. Interestingly, while being cytocompatible and hemocompatible, the oppositely charged dual-brush-modified micropatterned surfaces were found to be highly antibacterial.

High-pressure arterial bleeding is a life-threatening condition that can rapidly lead to hemorrhagic shock or death. However, effective noncompressive hemostatic strategies for managing such bleeding remain a significant clinical challenge. To address this, we developed a Janus-structured silk fibroin-based sealant (designated SFM@STF) for rapid hemostasis. The SFM@STF sealant features a bilayer structure: an adhesive silk fibroin/tannic acid/fibrin (STF) layer and a supportive silk fibroin membrane (SFM) layer. The STF layer, designed to mimic the underwater adhesion of mussel proteins via a double-network hydrogel incorporating hydrophobic and catechol groups, ensures robust bonding to wet tissues. In contrast, the SM layer, comprising densely packed crystalline β-sheet structures, offers mechanical robustness. The resulting SFM@STF sealant demonstrated remarkable wet tissue adhesion strength (43.43 ± 8.42 kPa), coupled with superior structural stability, high burst pressure resistance, and a low swelling ratio. Excellent cytocompatibility and a low hemolysis rate were also confirmed. In arterial injury models, SFM@STF rapidly achieved hemostasis in high-pressure wounds. Furthermore, it continuously promoted endothelial regeneration without inducing thrombosis. This Janus-structured SFM@STF sealant, with its robust wet adhesion and rapid hemostatic performance, presents a promising strategy for managing high-pressure arterial bleeding in clinical settings.

The fabrication and use of sustainable and biocompatible wound-healing materials represent a newer approach to wound regeneration. An eggshell membrane (ESM), a naturally derived biomaterial, has a thin but permeable structure, making it suitable to be used for tissue engineering, as it can mimic the native extracellular matrix. In this study, bioactive glass (BAG) and ion-doped BAG (Mn, Ce, and Mn + Ce) were coated onto the ESM films to build four composite scaffolds: EgB, EgBMn, EgBCe, and EgBMnCe. These scaffolds were characterized by using FTIR, X-ray diffraction (XRD), scanning electron microscopy (SEM), and EDAX to confirm the successful incorporation of BAG and dopants onto the ESM films. In vitro biocompatibility assays using the L929 fibroblast cell line showed that all scaffolds supported cell viability, with ion-doped variants showing enhanced proliferation. Fluorescein diacetate (FDA), DAPI, and SEM studies further revealed superior cell adhesion, vitality, and intact nuclear morphology in doped scaffolds. In vivo wound healing studies in animal models exhibited accelerated wound contraction and increased collagen deposition at the wound site, particularly in EgBMn and EgBMnCe groups. These results point to the synergistic effect of ion release, and the ESM matrix creates a suitable environment conducive to tissue regeneration. Overall, ion-doped BAG-coated ESM scaffolds offer a promising and sustainable solution for advanced wound care by combining natural biomaterials with therapeutic bioactive agents.

Bone defect repair remains a major clinical challenge. This study presents a novel strategy using a 3D-printed piezoelectric hydrogel scaffold─composed of gelatin methacrylate (GelMA, Gel), hydroxyapatite (HA), and barium titanate (BTO)─for functional bone tissue engineering. The GelMA/HA/BTO scaffold exhibited a well-defined porous structure, enhanced mechanical stability, and, crucially, reliable piezoelectric responsiveness. This key feature enables the material to convert external mechanical stimuli, such as low-intensity pulsed ultrasound (LIPUS), into endogenous electrical signals. In vitro, the scaffold promoted BMSC adhesion, proliferation, and osteogenic differentiation, with the performance significantly enhanced under LIPUS stimulation. Mechanistic insights revealed that the piezoelectric microenvironment remodeled the cellular miRNA expression profile, particularly upregulating osteogenesis-related miR-29b-3p and activating the AMPK signaling pathway. Collectively, this ultrasound-responsive, gene-regulating scaffold represents a promising approach for treating bone defects by leveraging piezoelectricity to actively stimulate bone regeneration.

Titanium (Ti) and its alloys have evolved through multiple generations to possess enhanced biomedical performance. However, challenges such as stress shielding, low yield strength, and inadequate corrosion resistance persist in conventional Ti-based alloys. In this study, we explore the complex concentrated alloy (CCA) approach to develop two novel Ti-Zr-Nb alloys: Ti₅₀Zr₃₅Nb₁₅ and Zr₅₀Ti₃₅Nb₁₅. These compositions were designed using CALPHAD-based phase stability predictions based on nontoxic lightweight approach and fabricated via vacuum arc melting, yielding a single-phase body-centered cubic (BCC) structure with large equiaxed grains. The CCAs exhibit higher hardness (∼1.95 GPa) and lower elastic modulus (∼99-102 GPa) than traditional Ti alloys, making them more compatible with human bone. Electrochemical analyses, performed under simulated physiological conditions (Hanks' solution and at 37 °C) confirm superior corrosion resistance for both the CCAs. Tribological studies (performed in Hanks' solution and at 37 °C) reveal improved wear behavior, with the formation of smeared patches reducing material loss and enhancing surface stability. The combination of high hardness, low modulus, excellent corrosion resistance, and favorable wear characteristics under simulated physiological conditions, makes these CCAs promising candidates for next-generation orthopedic and dental implant applications.

Retinal neovascularization is closely linked to retinal inflammation. Microglia, the resident immune cells of the retina and the primary responders to inflammatory stimuli, play a central role in pathological retinal vascular remodeling, including aberrant neovascularization and increased vascular tortuosity. High-mobility group box 1 (HMGB1), a ubiquitously expressed DNA-binding protein, functions as a damage-associated molecular pattern and has been shown to drive microglial polarization toward the pro-inflammatory M1 phenotype. Whereas M1 microglia exacerbate inflammatory responses, M2 microglia exhibit anti-inflammatory and tissue-repair functions. Accordingly, inhibition of HMGB1 to induce metabolic reprogramming of microglia may promote the transition from the M1 to the M2 phenotype. In this study, we adopted a targeted therapeutic strategy aimed at modulating the M1/M2 polarization balance of microglia to attenuate retinal inflammation and suppress pathological angiogenesis, thereby offering a potential treatment for retinal neovascularization. To achieve this, we engineered a self-assembled nanoparticle delivery system (H–H@MG1) designed to selectively target M1 microglia. These nanoparticles encapsulate the anti-inflammatory flavonoid hesperidin and are functionalized with an M1 microglia-targeting peptide (MG1). In vitro experiments demonstrated that H–H@MG1 efficiently targets M1 microglia, inhibits HMGB1-induced activation of resting microglia, and promotes their polarization toward the M2 phenotype. Furthermore, in vivo studies using an oxygen-induced retinopathy mouse model revealed that H–H@MG1 rebalances M1/M2 microglial polarization within the retina, remodels the retinal immune microenvironment, and significantly reduces the expression of pro-inflammatory cytokines, including IL-6 and TNF-α. Collectively, these effects suppress abnormal retinal vascular remodeling and pathological angiogenesis. Overall, this nanodelivery system effectively reshapes the retinal immune microenvironment and represents a promising therapeutic strategy for the treatment of retinal neovascularization.

Hydrogels have gained prominence in biomedical applications, including drug design, tissue engineering, and wound dressing, due to their versatile properties. In this study, we investigated the mechanical and biological properties of a photo-cross-linked hydrogel hybrid composed of methacrylated gelatin (GelMa) and methacrylated alginate (AlgMa). Leveraging the stable, cell-adhesive properties and delayed erosion of GelMa alongside the swelling behavior and negative charge of AlgMa, we developed a hybrid hydrogel that mimics native tissue mechanics and provides tailored viscoelastic properties with controlled remodeling. Rheological analysis revealed concentration-dependent changes in storage and loss moduli. GelMa exhibited a low loss modulus favorable for cell motility, while AlgMa demonstrated rapid swelling and increased stability modulus, emulating physiological tissue mechanics. Swelling and strain tests highlighted the dynamic remodeling capacity of the composite, with the 1:3 L-AlgGelMa hybrid exhibiting significant swelling. AlgMa acted as a sacrificial element, while the hybrid maintained mechanical properties conducive to cell attachment and migration over 21 days. Scanning electron microscopy revealed increased pore sizes due to swelling, enhancing infiltration. Cell viability assays demonstrated that L-GelMa exhibited significantly higher viability than collagen controls by day 14, while the 1:3 L-AlgGelMa Hybrid showed delayed but sustained cell proliferation with diminished fibronectin deposition and enhanced cell infiltration, confirming that AlgMa’s erosion creates a diminished need for ECM remodeling and transient porosity, facilitating migration. Additionally, the hydrogel’s tunable electrostatic environment, driven by AlgMa’s charge, suggests potential for improved growth factor retention and signaling. These findings demonstrate that the AlgGelMa hybrid hydrogel provides a bioactive, mechanically adaptable platform, combining structural integrity with dynamic remodeling for regenerative applications.