Acta biomaterialia最新文献

The escalating challenge of chemoresistance in breast cancer treatment severely limits clinical efficacy, necessitating the urgent development of innovative strategies that synergistically enhance tumor cell eradication and remodel the anti-tumor immune microenvironment. To address this, we developed a D-A structured theranostic probe, 1HA4CD, featuring a dihydroxanthene-fluorophore with diethylamino donor and acrylonitrile/pyridyl acceptors. Upon laser irradiation, 1HA4CD enables spatiotemporally controlled reactive oxygen species (ROS, primarily singlet oxygen, ¹O₂) generation. Crucially, its precise nuclear localization facilitates the induction of high-concentration ROS within the nucleus, causing irreversible oxidative genomic DNA damage. RNA sequencing analysis revealed that the transient nuclear ROS overload not only directly induces DNA double-strand breaks (DSBs) but also inhibits DNA repair pathways, creating a "dual-hit" effect that effectively overcomes the chemoresistance associated with traditional DNA-damaging agents through a nuclear-targeted photodynamic mechanism. DNA fragments released into the cytoplasm post-damage are recognized by the cytosolic DNA sensing machinery, subsequently activating the cGAS-STING signaling cascade, which leads to the systemic activation of both innate and adaptive immune responses. In vivo animal studies demonstrated that 1HA4CD-mediated photodynamic therapy exhibits significant therapeutic efficacy against breast cancer, coupled with a favorable biosafety profile. This research presents a nuclear-targeted molecular tool for photodynamic immune activation therapy and advances the development of combination therapies based on DNA damage-induced immune responses. STATEMENT OF SIGNIFICANCE: Photodynamic therapy (PDT) often suffers from limited efficacy due to insufficient subcellular targeting and the inability to induce systemic anti-tumor immunity, especially in chemoresistant cancers. This work presents 1HA4CD, a nuclear-targeting probe designed to enhance PDT by generating spatiotemporally controlled ROS directly within the nucleus. This approach causes direct DNA double-strand breaks while concurrently inhibiting DNA repair, and further activates the cGAS-STING pathway via damaged nuclear DNA fragments, thereby bridging localized photodamage with systemic immune activation. The resulting "dual-hit" mechanism effectively addresses chemoresistance in breast cancer. By integrating precise subcellular targeting with immunomodulation, this study provides a rational strategy for developing bioactive materials that combine PDT with immunotherap.

Dental caries is a multifactorial and dynamic disease primarily mediated by biofilm formation, resulting in a disruption of plaque microecological homeostasis and an imbalance in demineralization/remineralization of dental hard tissues. The development of antibacterial/remineralizing composite materials may help restore this balance. However, anticaries products that can mimic the amelogenesis process to achieve enamel remineralization and possess antimicrobial property are lacking. In this study, bovine serum albumin (BSA)-loaded ethylpyridinium chloride (CPC) was successfully used to form a BSA-CPC complex through H-bonding, van der Waals forces and electrostatic attraction. Subsequently, through fast amyloid-like aggregation, the phase-transitioned BSA (PTB)-CPC stabilized the amorphous calcium phosphate (ACP) to generate an ACP@PTB-CPC hydrogel. Next, 1% sodium hypochlorite (NaClO) was used to partly degrade this hydrogel and induce enamel remineralization. Herein, a biomimetic system of amelogenesis composed of the ACP@PTB-CPC hydrogel and NaClO was constructed, which mimics the gel-like microenvironment of amelogenesis, the amyloid-like structure of amelogenin, and the whole process of the three "key events" in the amelogenesis process. Compared with fluoride, this hydrogel has significant remineralization ability both in vitro and in vivo. Additionally, the application of the ACP@PTB-CPC hydrogel effectively inhibited the growth, adhesion and biofilm formation of Streptococcus mutans. In conclusion, the ACP@PTB-CPC hydrogel with remineralizing and antibacterial properties serves as an alternative therapy for preventing or arresting caries. STATEMENT OF SIGNIFICANCE: 1. Construction of An Amyloid-based Hydrogel: Using PTB as a fundamental framework, CPC was loaded and subsequently coassembled with ACP to obtain an amyloid-based hydrogel--ACP@PTB-CPC. 2. Biomimetic Amelogenesis Process: A biomimetic system of amelogenesis composed of ACP@PTB-CPC hydrogel and NaClO was constructed. 3. Potential for Clinical Application: A bifunctional anticaries material with remineralizing and antibacterial ability was developed, representing a promising alternative therapy of preventing and arresting enamel caries.

Cellular therapies involving the co-delivery of cells with complementary pro-regenerative functionality hold promise as a strategy to promote soft tissue augmentation and regeneration. In particular, the co-delivery of adipose-derived stromal cells (ASCs) and endothelial colony-forming cells (ECFCs) has shown promise for regenerating stable blood vessels in vivo. The current study developed "cell-assembled" scaffolds for co-delivering human ASCs and ECFCs within a supportive decellularized adipose tissue (DAT) matrix, with the objective of enhancing their localized retention and augmenting their capacity to stimulate adipose tissue regeneration. Human ASCs and ECFCs were seeded separately onto human-derived DAT microcarriers under cell-type specific conditions. The cell-seeded microcarriers were then combined and cultured for 8 days under conditions that promoted matrix remodeling to fuse the microcarriers into 3D engineered tissues containing ASCs+ECFCs, ASCs alone, or ECFCs alone. Co-culture with ECFCs within the scaffolds was shown to modulate ASC pro-angiogenic gene expression, with some ECFCs forming tubule-like structures in vitro in both the ASC+ECFC and ECFC alone groups. In vivo bioluminescence imaging using a dual luciferase reporter system showed that co-delivery with ASCs enhanced ECFC retention following subcutaneous implantation in athymic nu/nu mice, but co-delivery did not alter the localized retention of viable ASCs. Interestingly, while immunofluorescence staining for CD31 and microcomputed tomography angiography indicated that vascular regeneration was similar in the cell-assembled scaffolds containing ASC+ECFCs, ASCs alone, and ECFCs alone, histological staining revealed that extensive regions of the ECFC alone scaffolds had remodelled into adipose tissue at 29 days post-implantation. STATEMENT OF SIGNIFICANCE: Cellular therapies involving the co-delivery of complementary pro-regenerative cell types hold promise as a strategy to promote soft tissue regeneration. In particular, the co-delivery of adipose-derived stromal cells (ASCs) and endothelial colony forming cells (ECFCs) may enhance blood vessel regeneration in vivo, as well as promote ASC engraftment and adipogenic differentiation. The current study developed a modular bottom-up fabrication approach for generating "cell-assembled" scaffolds incorporating both human ASCs and ECFCs dispersed throughout a supportive human decellularized adipose tissue (DAT) matrix, which were compared to scaffolds incorporating ASCs alone or ECFCs alone. Co-delivery modulated ASC pro-angiogenic gene expression in vitro and enhanced viable ECFC retention in vivo, but interestingly, in vivo adipogenesis was augmented in the cell-assembled scaffolds incorporating ECFCs alone.

Acquired drug resistance in hepatocellular carcinoma (HCC) hinders the clinical therapeutic efficacy of various drugs, but efficient intervention strategies remain scarce. In this study, we reported a coacervate-fusion strategy for inhibiting membraneless organelle stress granules (SGs) via stimuli-induced peptide droplets to reverse sorafenib resistance (SFR) in HCC. SGs are coacervated from translation-stalled mRNAs and RNA-binding proteins, including Ras-GAP SH3 domain-binding proteins (G3BPs), and play a critical role in SFR. The peptide droplets YsF-L^SG are formed by liquid-liquid separation (LLPS) of the sulfatase-responsive peptides YsF and YsF-FGDF containing the G3BP ligand. Characterizations in solution reveal that, upon exposure to arylsulfatase A (ARSA), the peptides YsF and YsF-FGDF undergo LLPS and form agglomerate droplets YsF-L^SG. Investigations of HCC-SFR cells confirm that the YsF-L^SG mixtures are efficiently internalized via clathrin-mediated endocytosis, experience ARSA-responsive hydrolysis in lysosomes and lysosomal escape, and undergo in situ LLPS into droplets. Notably, in situ-formed coacervates YsF-L^SG recruit G3BP2 and target SGs with high tumor permeability. YsF-L^SG coacervates enhance sorafenib-triggered apoptosis by relieving SGs-mediated inhibition of p38-Caspase-3 signaling and thus reversing SFR of HCC cells. Further investigations in HCC cell-derived xenograft (CDX) models confirm that YsF-L^SG peptide coacervates significantly reverse SFR through SGs-targeting and apoptosis-restoring mechanisms. Critically, the combination of the YsF-L^SG peptide coacervates with sorafenib more effectively inhibits HCC-SFR growth and has a stronger antitumor effect accompanied by good biosafety. This study highlights the reversal of HCC-SFR via fusion between internal and external coacervates, offering a new approach for overcoming cancer drug resistance. STATEMENT OF SIGNIFICANCE: Design and application of peptide-based coacervates targeting SGs to overcome drug resistance have rarely been studied. Combining the advantages of in situ formulation of coacervate peptide droplets with SGs-targeting property, we developed YsF-L^SG peptide mixtures that target SGs through in situ sulfatase-responsive LLPS into droplets for reversing the SFR of HCC. YsF-L^SG peptide mixtures present high tumor-permeability and SGs-coalescence potential, undergo CME-involved uptake, experience ARSA sulfatase-responsivity and lysosomal escape, and exhibit potent tumor-killing advantage in HCC-SFR cells and CDX mice model. YsF-L^SG peptide mixtures reverse SFR of HCC through G3BP2-recruited, SGs-targeting and apoptosis-restored mechanisms. This provides a new strategy for developing enzyme-induced LLPS peptide coacervates with drug resistance-reversal capacity.

Gasdermin-mediated pyroptosis has emerged as a promising mechanism in cancer immunotherapy, however, its efficacy is often limited by inefficient activation within the immunosuppressive tumor environment. Herein, we generated an acid-regulating biomimetic liposomal nanovesicle (L-P-Cn-U) for the co-delivery of a photosensitizer prodrug (P-Cn) and a carbonic anhydrase IX (CAIX) inhibitor (U-104). By conducting efficacy screening of various P-Cn prodrugs within the L-P-Cn-U system, we identified L-P-C16-U with identical lipid tail structures, as the optimal candidate due to its strong colloidal stability and reactive oxygen species (ROS) generation efficiency. Our cellular and murine model studies demonstrated that L-P-Cn-U-mediated pyroptosis and immunogenic cell death could convert immunologically cold tumors into hot tumors, thereby enhancing antitumor immunity and concurrently inhibiting tumor cell migration. Mechanistic investigation revealed that the acid-triggered U-104 release from L-P-Cn-U augmented intracellular acidity through CAIX inhibition, which subsequently attenuated PI3K-Akt/mTOR signaling. This result enhances O₂-dependent ROS production and establishes a negative feedback loop for CAIX expression. Collectively, our findings provide a combinatorial strategy that integrates pyroptosis-focused therapy with metabolic regulation, offering a broadly applicable conception to augment cancer immunotherapy. STATEMENT OF SIGNIFICANCE: Herein, we report the rational design and synthesis of a new class of biomimetic liposome by integrating chemically engineered pH-responsive lipids (L-pH) with lipid-like photosensitizer prodrugs (P-Cn). Characterization studies demonstrated an optimal construct (L-P-C16) with identical lipid tails, showing robust stability and reactive oxygen species production. This optimized nanovesicle was subsequently co-loaded with the carbonic anhydrase inhibitor U-104. The resulting L-P-C16-U system was adequately investigated and shown to effectively synergize photodynamic therapy and immunotherapy. Our work provides new insights into liposome engineering strategies for combination tumor therapy.

Accurate assessment of inflammatory bowel disease (IBD) severity is crucial for optimizing treatment decisions and improving prognosis. However, conventional assessment methods are time-consuming and primarily detect anatomical changes at moderate or late stages, limiting timely intervention. Here, we report an HClO‑responsive NIR‑IIb ratiometric nanosensor (CSSS@PMH‑mPEG2000) that combines down‑conversion core-shell nanoparticles with strong NIR‑IIb emission under 808/980 nm excitation and an HClO‑responsive IR780MA dye. By means of dye sensitizing mechanism, the sensor enables dynamic ratiometric quantification of HClO and supports real-time assessment of IBD progression and severity. Comprehensive in vitro and in vivo studies validate CSSS@PMH‑mPEG2000 as a highly sensitive and reliable platform for real-time, quantitative HClO monitoring of IBD in a mouse model. Moreover, ratiometric NIR‑IIb fluorescence imaging effectively captures changes in disease severity, highlighting its potential for assessing treatment efficacy. Together, these findings underscore the translational value of CSSS@PMH‑mPEG2000 for advancing IBD diagnosis and management, while also demonstrating its broader applicability to in situ HClO detection across a range of inflammatory diseases. STATEMENT OF SIGNIFICANCE: Accurate IBD severity assessment is vital for optimizing treatment and prognosis, but conventional methods are time‑consuming and detect mainly mid‑to‑late anatomical changes, delaying intervention. We present an HClO‑responsive NIR‑IIb ratiometric nanosensor (CSSS@PMH‑mPEG2000) combining down‑conversion core-shell nanoparticles with an HClO‑responsive IR780MA dye. Using dye sensitizing mechanism, it enables dynamic ratiometric HClO quantification and real‑time evaluation of IBD progression and severity. In vitro and in vivo studies in a mouse IBD model demonstrate high sensitivity and reliability for real‑time, quantitative HClO monitoring. Ratiometric NIR‑IIb imaging captures disease‑severity changes and supports treatment‑efficacy assessment, underscoring the platform's translational value for IBD management and broader in situ HClO detection in inflammatory diseases.

Recent research has demonstrated that the accumulation of excessive mitochondrial double-stranded RNA (mt-dsRNA) plays a significant role in inflammatory processes. Although interventions targeting mt-dsRNA release have shown efficacy in treating various inflammatory diseases, their therapeutic potential in osteoarthritis (OA) remains unclear. This study elucidates the pivotal role of mt-dsRNA in the pathogenesis of OA. Advancing beyond traditional mt-dsRNA suppression methods, we have developed cerium-integrated dendritic mesoporous silica nanoparticles (Ce@DMSN) designed to deliver the mt-dsRNA release inhibitor IMT1, referred to as Ce@DMSN-IMT1 nanoparticles. These biocompatible nanoparticles possess dual functionalities: a robust mt-dsRNA degradation capability and effective inhibition of dsRNA release, leading to substantial anti-inflammatory effects. Intra-articular administration of Ce@DMSN-IMT1 nanoparticles significantly reduced cartilage degradation and synovitis in rat models with destabilized medial meniscus by specifically targeting the mt-dsRNA pathway. This study presents the first instance of nanozyme-mediated mt-dsRNA hydrolysis for the control of inflammation, with the multifunctional Ce@DMSN-IMT1 system offering a synergistic therapeutic approach that holds promise as a disease-modifying strategy for OA. STATEMENT OF SIGNIFICANCE: Therapeutic targeting of mitochondrial double-stranded RNA (mt-dsRNA) to mitigate osteoarthritis (OA) progression has not been previously reported. The utilization of cerium for RNA degradation as an anti-inflammatory strategy remains undocumented. The application of mt-dsRNA release inhibitor to attenuate OA progression has not been previously documented. The dual mechanism combining mt-dsRNA degradation and release inhibition enhances anti-inflammatory effects, conferring superior therapeutic outcomes compared to traditional single-target approaches. This nanoplatform attenuates mitochondrial dysfunction and suppresses retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5) signaling pathway activation. The Drug-Cerium nanozyme represents a synergistic and disease-modifying therapeutic strategy for osteoarthritis.

Biodegradable zinc (Zn)-based implants have shown great potential for orthopedic applications. However, excessive Zn²⁺ release during the degradation of Zn-based implants results in compromised biocompatibility and suboptimal osteogenic activity. Layered double hydroxides (LDHs), known for the capability to regulate degradation behavior while also exhibiting remarkable biocompatibility and osteoinductive capacity, offer a promising solution. Herein, Zn-Al LDH coating was fabricated on Zn-0.8Mg alloy substrates via an in-situ growth method. Subsequently, the effect of solution pH on the degradation behavior, cytotoxicity and osteogenic capacity of the LDH coating was investigated. Benefiting from the distinctive characteristics of the constructed LDH coating, the Zn-0.8Mg alloy with LDH coating prepared at pH=11 exhibited uniformly distributed nanosheets and demonstrated favorable corrosion resistance. During degradation, the low concentration of Zn²⁺ released from LDH-modified Zn-0.8Mg alloy implants fabricated at pH=11 improved cytocompatibility, facilitated osteoblasts proliferation and osteogenic differentiation in vitro, and accelerated bone regeneration in vivo. Furthermore, the formation mechanism of the LDH coating on Zn-based alloy was elucidated. Transcriptomic analysis further revealed that the LDH coating promoted osteogenic differentiation by activating the Wnt/β-catenin and PI3K/Akt signaling pathways. Collectively, this work offered a feasible strategy to enhance the biocompatibility and bone regeneration capability of Zn-based alloys, broadening their biomedical application. STATEMENT OF SIGNIFICANCE: As highly promising biodegradable metals, Zn-based alloys have become a research hotspot in the fields of dentistry and orthopedics. However, the excessive Zn²⁺ release during initial degradation may cause adverse biological responses, limiting their clinical translation. In this study, we fabricated LDH-coated Zn-0.8Mg alloy by in-situ growth method at different pH values to regulate degradation behavior, improve biocompatibility and enhance osteogenic properties. This study demonstrated that LDH-coated Zn-0.8Mg alloy fabricated at pH=11 exhibited significantly optimized corrosion resistance, biocompatibility and osteogenic properties, thereby expanding its potential for implant applications.

Zinc (Zn) has emerged as a promising biodegradable metal for bone tissue engineering, yet fabricating porous scaffolds via laser-based additive manufacturing (AM) remains challenging due to Zn evaporation. This study presents the successful fabrication of porous Zn scaffolds via extrusion-based AM through systematic ink formulation and sintering optimization. Printability was optimized through rheological analysis of 50-56 vol % Zn-loaded inks, while sintering conditions were refined within a precise temperature window. SEM and micro-CT characterized sintering quality and quantified pore defects. Optimal scaffolds, printed with 53 vol % ink and sintered at 415 °C for 5 h, achieved 40 ± 3% absolute porosity with minimal evaporation, attributed to a hybrid solid-liquid phase sintering mechanism. The scaffolds exhibited trabecular bone-matching mechanical properties with compressive yield strength of 16.1 ± 1.3 MPa and elastic modulus of 1.4 ± 0.1 GPa. In vitro biodegradation in r-SBF showed a corrosion rate of 0.03 ± 0.01 mm/year after 28 days, with biodegradation products including ZnO, Ca₃(PO₄)₂, and Zn-phosphate/chloride hydrates. Electrochemical tests demonstrated increasing polarization resistance (21.1 ± 3.8 kΩ·cm²) and passivation behavior. Indirect cytocompatibility assays showed > 90% metabolic activity for MC3T3-E1 cells in ≤ 50% Zn extracts, while direct seeding confirmed cell adhesion. These results establish extrusion-based AM as a viable route for fabricating Zn scaffolds with tailored porosity, controlled biodegradation, bone-like properties, and acceptable cytocompatibility, advancing the development of Zn-based biodegradable implants. STATEMENT OF SIGNIFICANCE: Although laser-based additive manufacturing of pure zinc and its alloys is becoming increasingly mature, its inherent drawbacks, such as evaporation-driven composition loss and melt-pool instabilities, remain non-negligible and underscore the need to develop and apply alternative AM strategies for Zn-based bone scaffolds. We presented an extrusion-based route to fabricate porous Zn bone scaffolds and establish an end-to-end workflow spanning ink formulation, debinding, sintering, and multi-scale characterization. By tailoring the binder system and defining a robust thermal window, we achieved high-fidelity architectures with densified struts. The resulting scaffolds displayed bone-mimicking mechanical behavior together with predictable in-vitro degradation and cytocompatibility. Our work positions extrusion-based 3D printing as a practical manufacturing platform for Zn-based biodegradable bone substitutes.