Matrix Degradation Research Articles

Ring‐Opening Metathesis Polymerization of 1,2‐Dihydroazete Derivatives

AbstractFischer carbenes have recently found great utility in the construction of degradable metathesis materials, but investigations have been limited to oxygen‐containing enol ether monomers. Here, the ring‐opening metathesis polymerization of 1,2‐dihydroazetes is reported. The polymerization proceeds regioselectively, and the resulting molecular weights are targetable by adjusting the Grubbs initiator loading. Under acidic conditions, the resulting polymers degrade into 3‐aminopropanal derivatives through hydrolysis of the recurring enamide motifs in the polymer backbone. Additionally, the underlying kinetics and thermodynamics of the polymerization were studied through DFT calculations to elucidate the origins of metathesis regioselectivity. This work further expands the suite of monomers available to generate degradable metathesis materials and provides a flexible platform for target applications.

Biodegradable Janus sonozyme with continuous reactive oxygen species regulation for treating infected critical-sized bone defects

Critical-sized bone defects are usually accompanied by bacterial infection leading to inflammation and bone nonunion. However, existing biodegradable materials lack long-term therapeutical effect because of their gradual degradation. Here, a degradable material with continuous ROS modulation is proposed, defined as a sonozyme due to its functions as a sonosensitizer and a nanoenzyme. Before degradation, the sonozyme can exert an effective sonodynamic antimicrobial effect through the dual active sites of MnN4 and Cu2O8. Furthermore, it can promote anti-inflammation by superoxide dismutase- and catalase-like activities. Following degradation, quercetin-metal chelation exhibits a sustaining antioxidant effect through ligand-metal charge transfer, while the released ions and quercetin also have great self-antimicrobial, osteogenic, and angiogenic effects. A rat model of infected cranial defects demonstrates the sonozyme can rapidly eliminate bacteria and promote bone regeneration. This work presents a promising approach to engineer biodegradable materials with long-time effects for infectious bone defects.

FSTL1 protects against acute aortic dissection by suppressing vascular smooth muscle cell phenotypic switching and degradation of the extracellular matrix

Acute aortic dissection (AAD) is a life-threatening cardiovascular emergency, which is closely related to the vascular smooth muscle cells (VSMCs) phenotypic switching and extracellular matrix (ECM) degradation. Previous studies have found that the secreted extracellular glycoprotein Follistatin-like 1 (FSTL1) is demonstrated as a protective factor for cardiovascular diseases. However, the role of FSTL1 in AAD remains elusive. We aimed to investigate whether FSTL1 could regulate VSMCs phenotypic switching and ECM degradation in AAD. Firstly, we found that FSTL1 expression in aorta was significantly decreased in human AAD examined by western blot and immunohistochemical staining. Then we established a mouse AAD model by administering β-aminopropionitrile (BAPN) dissolved in drinking water for 28 days. We found that FSTL1 expression in aorta was also decreased in mouse AAD. Exogenous supplement with recombinant human FSTL1 protein could rescue VSMCs phenotypic switching and ECM degradation to reduce the occurrence and progression of mouse AAD. In vitro, FSTL1 protein and adenovirus overexpressing FSTL1 (ad-FSTL1) reversed the primary VSMCs phenotypic switching and decreased the expression of MMP2 induced by PDGF-BB. Knocking down FSTL1 initiates VSMCs phenotypic switching and increases the expression of MMP2. In terms of mechanisms, AMPK phosphorylation was decreased and could be improved by FSTL1 protein in mouse AAD. FSTL1 protein and ad-FSTL1 reversed the decreased AMPK phosphorylation induced by PDGF-BB in primary VSMCs. These findings indicate that FSTL1 protects against VSMCs phenotypic switching and ECM degradation in AAD, and targeting FSTL1 may be a potential new strategy for prevention and treatment of AAD.

Degradation, Intrinsic Microstrains, and Phase Structure Engineering in Lithium-Rich Oxide Cathode Materials

Degradation, Intrinsic Microstrains, and Phase Structure Engineering in Lithium-Rich Oxide Cathode Materials

Snake venom weakens neurovascular integrity and promotes vulnerability to neuroinflammation

Snake envenomation poses significant medical challenges, particularly in subtropical and tropical regions, with long-term impacts on neurovascular integrity and neuroinflammation remaining underexplored. This study investigates the effects of venom from four species of venomous snakes in southern China—Zhoushan Cobra (Naja atra, NA), Many-banded Krait (Bungarus multicinctus, BM), Five-paced Pit Viper (Deinagkistrodon acutus, DA), and Chinese Moccasin (Protobothrops mucrosquamatus, PM) — on the blood–brain barrier (BBB) and chronic neuroinflammation. Using mass spectrometry, we analyzed venom protein compositions, while cytotoxic effects on mouse brain endothelial cells (bEND.3) were evaluated to determine IC50 values. In vitro BBB models and in vivo experiments in C57BL/6J mice revealed that NA venom, in particular, significantly compromised BBB integrity without inducing large-scale apoptosis, leading to persistent BBB disruption characterized by increased permeability and selective degradation of extracellular matrix and tight junction proteins. Moreover, to simulate secondary infections that often occur following snakebites, we combined venom exposure with lipopolysaccharide (LPS) treatment, which exacerbated neuroinflammatory responses by intensifying microglial activation and promoting a pro-inflammatory phenotype. These findings highlight the role of snake venom in compromising neurovascular integrity and promoting vulnerability to chronic neuroinflammation, emphasizing the need for further research into venom-induced neuroinflammatory pathways and their potential as therapeutic targets.

Biodegradation of commercial polyester polyurethane by a soil-borne bacterium Bacillus velezensis MB01B: Efficiency, degradation pathway, and in-situ remediation in landfill soil

Polyurethane (PU), a widely used and durable plastic, persists in the environment, resulting in significant waste management challenges. Therefore, developing eco-friendly degradation technologies, such as screening for efficient biodegrading microorganism strains, is urgently needed to address this issue. Bacillus velezensis MB01B, an efficient polyester PU-degrading bacterium, was isolated from landfill soil and demonstrated the ability to degrade 91.4% of 0.75% Impranil DLN within 24 h under the optimal conditions (30.5 °C and initial pH 6.5). To assess the degradation capability of MB01B, three PU substrates of increasing complexity—Impranil DLN film, polyester thermoplastic polyurethane (TPU) film, and commercial PU desk mat—were tested; after 30 days, weight losses of 24.8%, 18.3%, and 5.4% were observed, respectively. In addition, SEM images showed significant morphological changes on the surface of these PU materials after treatment with MB01B. FTIR analysis of Impranil DLN films following degradation showed reductions in key functional groups (ester and urethane); and the identification of neopentyl glycol and 1,6-hexanediol as degradation intermediates suggested MB01B possesses the capability to hydrolyze ester and urethane bonds. Concurrently, genome sequencing combined with RT-qPCR identified several enzymes, including urethanases and esterases/lipases, involved in PU degradation. Based on these results, the pathway for MB01B to degrade Impranil DLN was inferred. Finally, MB01B was successfully formulated into a solid microbial inoculum with favorable storage properties and used for in-situ degradation of the commercial PU materials (Impranil DLN films, TPU films and PU desk mat) in landfill soil, underscoring its potential for the in-situ biological treatment of PU plastic wastes.

Facile preparation of soybean protein-based oil-resistant paper for food packaging

The use of plastic packaging is harmful to the environment. Due to the advantages of degradability, renewability, and safety of paper packaging materials, replacing plastic with paper has received much attention. However, the poor oil resistance of traditional paper constrains its application. In this research, oil-resistant agent is prepared using soy protein isolate and montmorillonite through physical blending. This oil-resistant agent has advantages of low cost and food safety. Subsequently, food packaging oil-proof paper is obtained by coating the above-mentioned coating on paper. This oil-proof paper has good heat resistance, oil resistance (kit rating is 8/12) and mechanical properties. In addition, it is found that the optimal storage environment for the oil-proof paper. This study provides a feasible method for producing, biodegradable, and eco-friendly food packaging oil-proof paper.

A Multi-Center, Double-Blind, Randomized, Comparator Controlled Trial Evaluating Topical Formulations for Skin Fragility of the Arms.

Skin atrophy and fragility associated with Dermatoporosis result from chronic extracellular matrix (ECM) degradation. A current marketed product, ReFORM & RePAIR COMPLEX with TriHex Technology® (R&R, Alastin Skincare, Inc.), contains actives that aid in recycling the ECM with new matrix components that have been found to be deficient in patients with DP.1 This study evaluates the efficacy of R&R compared to a ceramide moisturizer for reducing acute episodic purpura events and improving atrophic skin associated with this condition over a 24-week period. Participants were evaluated in a double-blind, 24-week split-arm study. Each participant applied R&R to one arm and a ceramide moisturizer on the opposite arm twice daily for 24 weeks. Participants’ arms were evaluated at screening/baseline and follow-up visits at weeks 4, 8, 12, 16, and 24. At all visits, different assessment parameters were evaluated at selected clinical trial centers including standardized photography, skin biopsies, skin barrier function, hydration/transepidermal water loss (TEWL) measurements, line-field confocal optical coherence tomography imaging (LC-OCT), and ultrasound imaging. Efficacy assessments were performed by blinded investigators, and participants completed global improvement questionnaires for each arm. Pre- and post-treatment biopsies were collected for histological evaluation in randomly selected consenting participants. Thirty-eight (38) participants completed the study, and statistically significant improvements were seen across all arm skin parameters evaluated after 24 weeks of treatment. The R&R treatment arm achieved greater mean improvements and showed substantially better TEWL recovery compared to the ceramide moisturizer treatment arm. Ultrasound analysis revealed improvement in rete pegs and dermoepidermal junction (DEJ) undulation associated with the R&R-treated arm in 83% of study participants compared to the ceramide moisturizer-treated arm (17%). Significantly improved DEJ undulation and strengthening was seen in the R&R-treated arm, which was confirmed by LC-OCT imaging. Histology revealed improved collagen formation in the majority of R&R-treated arm case biopsies, as opposed to the comparator arms, which showed minimal improvements with early changes in elastin formation only evident in the R&R group. In addition, the R&R arms demonstrated more skin resilience and less bruising and skin fragility than the comparator arms. Dermatoporosis is a condition that takes years to evolve, and recovery is expected to take time. That noted, this study revealed that the DEJ is the first anatomic area to demonstrate improvement in DP status. This was evident in the R&R-treated arms. In addition, skin functionality related to TEWL measurements, overall texture, crepiness, and biopsy changes were all improved to a larger extent in the R&R-treated arms compared to the comparator arms, demonstrating the logical use of R&R for DP management. J Drugs Dermatol. 2024;23(12):1064-1071. doi:10.36849/JDD.8177.

Long Non-coding RNA DLEU1 Promotes Progression of Osteoarthritis via miR-492/TLR8 Axis.

Long non-coding RNAs (LncRNAs) are generally reported to participate in the development of Osteoarthritis (OA) by acting as competing endogenous RNAs (ceRNAs). However, the molecular mechanism is largely unknown. This study aimed to investigate the possible mechanisms contributing to osteoarthritis (OA). Four gene expression profiles from patients with OA were downloaded from a public database and integrated to screen important RNAs associated with OA. Differentially expressed (DE) lncRNAs, microRNAs (miRNAs), and mRNAs were filtered, and a ceRNA network was constructed. An in vitro OA model was established by treating chondrocytes with IL-1β. The expression levels of MMP-13, COL2A1, aggrecan, and RUNX2 were detected by qRT-PCR and western blot. Cell proliferation ability was detected by CCK-8 assay. Flow cytometry was used for apoptosis assay. A dual luciferase reporter gene was used to confirm the relationship between DLEU1, miR-492, and TLR8. An OA-related ceRNA network, including 11 pathways, 3 miRNAs, 7 lncRNAs, and 16 mRNAs, was constructed. DLEU1 and TLR8 were upregulated, and miR-492 was downregulated in IL-1β-induced chondrocytes. Overexpression of DLEU1 suppressed viability and promoted apoptosis and extracellular matrix (ECM) degradation in IL-1β induced chondrocytes. Luciferase reporter assay validated the regulatory relations among DLEU1, miR-492, and TLR8. Further study revealed that the effects of DLEU1 on chondrocytes could be reversed by miR-492. DLEU1 may be responsible for the viability, apoptosis, and ECM degradation in OA via miR-492/TLR8 axis.

Synergistic approach: Peridynamics and machine learning regression for efficient pitting corrosion simulation

Corrosion-induced material deterioration poses a pervasive threat to structural integrity, necessitating an in-depth understanding of its intricate behaviors. Pitting corrosion, a critical concern in this context, accelerates the degradation of materials. The limitations of conventional models arise from their neglect of the subsurface electrode boundary layer dynamics during the dissolution process. In this study, we present a novel approach that combines Peridynamics (PD) diffusion framework with machine learning (ML) techniques to develop an efficient predictive model and computational efficiency. The proposed hybrid PD-ML model leverages the non-local effects inherent to Peridynamics and the pattern recognition capabilities of machine learning. It establishes an analytical connection between the concentration value at a specific material point and the concentrations exhibited by related constituents within its spatial horizon, considering the external mass flux applied. The adaptability of the model is achieved through the utilization of weighted regression coefficients, determined via multivariate linear regression. Validation against experiments and conventional PD model demonstrates the model's precision and efficiency using diverse micro-diffusivity scenarios. For 1D uniform and 2D pitting corrosion cases, our hybrid model yields precise concentration predictions while showcasing a remarkable improvement in computational speed compared to conventional approaches. Specifically, the hybrid model achieves an impressive speedup, approximately 4 times faster per time step and 2.5 times faster overall simulation. The study presents a promising tool for predicting corrosion-induced material deterioration in practical systems, offering accuracy, efficiency, and potential for broader applications.

Anti-inflammatory and antioxidant succinyl-chitosan oligosaccharide protects human epidermal cell and mouse skin against ultraviolet B-induced photodamage

Ultraviolet B (UVB) irradiation from sunlight is one of the primary environmental factors that causes photodamage to the skin. The aim of this study was to prepare succinyl-chitosan oligosaccharide (SU-COS) and evaluate its protective effects and related molecular mechanisms against UVB-induced photodamage for the first time. SU-COS (substitution degree: 69.26 %, molecular weight: 6400 Da) was shown to have excellent biocompatibility and to effectively promote the migration of human epidermal HaCaT cells. UVB irradiation was used to develop photodamage models in HaCaT cells and murine skin. In vitro, treatment with SU-COS significantly increased the cell survival ratio by >11 % while concurrently reducing reactive oxygen species formation, preserving normal cytoskeletal morphology, stabilizing the cell cycle, and decreasing the apoptosis ratio. The SU-COS intervention also demonstrated a reparative effect on UVB-damaged mouse skin by reducing skin erythema and water loss, relieving crusting, and maintaining the epidermis thickness of the skin and the stability of collagen fibers. The observed changes in both in vitro and in vivo results were accompanied by significant modulation of gene and protein expression associated with the cellular cycle, collagen synthesis, extracellular matrix degradation, antioxidant defense, and inflammation. Overall, SU-COS holds immense promise for applications in repairing photodamage.

MSCs-derived ECM functionalized hydrogel regulates macrophage reprogramming for osteoarthritis treatment by improving mitochondrial function and energy metabolism

Osteoarthritis (OA) is a degenerative disease that affects the entire joint, with synovial inflammation being a major pathological feature. Macrophages, as the most abundant immune cells in the synovium, have an M1/M2 imbalance that is closely related to the occurrence and development of OA. Mesenchymal stem cells (MSCs) have been shown to effectively suppress inflammation in the treatment of OA, but they still pose issues such as immune rejection and tumorigenicity. The extracellular matrix (ECM), as a major mediator of MSCs' immunoregulatory effects, offers a cell-free therapy to circumvent these risks. In this study, we developed an ECM-functionalized hydrogel by combining MSC-derived ECM with gelatin methacryloyl (GelMA). To enhance the immunomodulatory potential of MSCs, we pre-stimulated MSCs with the inflammatory factor interleukin-6 (IL-6) present in OA. In vitro results showed that the ECM-functionalized hydrogel promoted M2 macrophage polarization and inhibited the expression of various inflammatory genes, strongly indicating the hydrogel's powerful immunoregulatory capabilities. In an in vivo rat OA model, the ECM-functionalized hydrogel significantly reduced synovial inflammation and cartilage matrix degradation, alleviating the progression of OA. Furthermore, we utilized proteomics and transcriptomics analysis to reveal that the hydrogel accomplished macrophage metabolic reprogramming by regulating mitochondrial function and energy metabolism, thereby reducing inflammation. These findings suggest that the ECM-functionalized hydrogel is a promising biomaterial-based strategy for treating OA by targeting key pathological mechanisms.

Study of fretting wear behavior of 690TT heat exchanger tube under three fretting regimes in high temperature pressurized water

Fretting wear behavior of the 690TT tube under three fretting regimes in high temperature pressurized (HTP, 288 °C and 8.4 MPa) water was studied based on fretting maps. The running condition fretting map was established in the ranges of 10 ∼ 100 N and 10 ∼ 100 μm. Fretting regime in this map can be divided into gross slip regime (GSR), mixed stick-slip regime (MSSR) and stick regime (SR). The GSR and MSSR ranges increase in HTP water compared to room temperature water, while the SR range decreases. According to the material response fretting map, the severe material degradation of 690TT tube under GSR is mainly caused by substrate delamination, whereas under MSSR can be attributed to the rapid corrosion. For SR, adhesive wear cannot cause material loss to 690TT tube.

Environmental stress cracking of silver‐coated polycarbonate

AbstractThis study investigates the effect of silver coating on the environmental stress crack resistance (ESCR) of Lexan EXL9330 polycarbonate under exposure to anti‐corrosion oil and mechanical strain. Polycarbonates, known for their durability and versatility, are susceptible to environmental stress cracking (ESC) when exposed to aggressive chemicals under mechanical stress. In this research, eight groups of test specimens were evaluated, with variations including coated and uncoated surfaces, and exposure to anti‐corrosion oil under controlled strain conditions. The specimens were fabricated using Sabic EXL9330 resin, subjected to tensile testing, and analyzed for surface defects using optical microscopy and Fourier transform infrared (FTIR) spectroscopy. Results showed that anti‐corrosion oil significantly exacerbates ESC, leading to considerable surface defects such as crazes and pores, particularly in uncoated specimens under strain. In contrast, silver‐coated specimens demonstrated enhanced ESCR, with a notable reduction in surface defects and only a modest decrease in ductility (approximately 9.5%) compared to the control group. FTIR analysis confirmed that chemical composition remained unchanged, reinforcing the role of ESC in the observed material degradation. This study underscores the effectiveness of silver coating in improving the resistance of polycarbonate materials to environmental stress cracking, highlighting its potential for applications where chemical exposure and mechanical stress are prevalent.Highlights Silver coating improves environmental stress crack resistance (ESCR) in polycarbonate. Anti‐corrosion oil exposure significantly exacerbates stress cracking in polycarbonate. Coated specimens show reduced surface defects and minimal loss in ductility (9.5%). Uncoated specimens exposed to oil and strain exhibit severe crazes and pores. FTIR analysis confirms no chemical degradation in tested polycarbonate samples.

Restraining Planar Gliding in Single-Crystalline LiNi0.9Co0.05Mn0.05O2 Cathodes by Combining Bulk and Surface Modification Strategies.

The delamination cracking from planar gliding along the (003) facets and anisotropic lattice strain perpendicular to the (003) facets inevitable lead to degradation of Ni-rich single-crystal cathode materials, adversely affecting their cyclability. Herein, we rationally design a single-crystal LiNi0.9Co0.05Mn0.05O2 (SC90) cathode with robust chemo-mechanical properties, in which coherently grown MgO6 octahedra and BO4 tetrahedra are incorporated into the lattice, and a stabilizing Mg3(BO3)2 layer is concurrently formed on the particle surface. Multiscale in/ex situ characterizations and theoretical calculations indicate that introducing the MgO6 and BO4 units leads to a "pinning effect" within the layered structure. This in turn strongly mitigates mechanical degradation by reducing planar gliding and delamination cracking over extended cycling. Moreover, the Mg3(BO3)2 coating maintains fast lithium diffusion by suppressing parasitic reactions at the cathode|electrolyte interface. The tailored SC90 cathode exhibits a capacity retention of ~88% after 300 cycles at 5C rate, significantly outperforming the pristine counterpart (~60%). Additionally, a pouch-type full cell with a graphite anode sustains a specific discharge capacity of 177 mAh g-1 after 500 cycles, with 90% capacity retention. This work highlights the "pining effect" in preventing unfavorable slab sliding and structural deterioration, offering new insights for designing advanced ultrahigh Ni single-crystal cathodes.

Structural Assessment Material and Fire Induced Strength Degradation Material of Multistory Building

This paper presents a detailed case study of a multistory building near Bombay Motors in Jodhpur that suffered severe fire damage, with temperatures reaching up to 900°C. The fire brigade arrived 30 minutes after the incident. Under the guidance of MBM University, research scholars conducted site investigations to analyze the impact of the fire on the building's materials, particularly concrete and reinforcement. The study reveals how the fire weakened these materials, leading to a significant reduction in the building's strength, especially in the columns. Notably, Floor 4 retained more strength than Floor 3, with strength differences ranging from +26.67% in one column to -20% in another. This highlights the variation in damage, indicating that while some columns on Floor 4 remained stronger, others experienced considerable strength loss. The findings emphasize the vulnerabilities exposed by fire and suggest ways to enhance building resilience. The research advocates for updates to building codes to incorporate better fire safety measures and provides valuable insights for improving firefighting and evacuation plans during emergencies. While the study is focused on this particular building, its results can also inform urban planning and fire risk management in other high-risk areas. By identifying weaknesses in design and materials, the study offers guidance for architects, engineers, and policymakers. Overall, the case study contributes to the goal of creating safer, stronger buildings in similar environments, promoting better construction practices and fostering safer cities. Additionally, the evaluation of residual strength was conducted using ISO 834 and Euro Code standards, and simulations performed through Abaqus software yielded results closely aligned with experimental techniques.

Molten carbonate electrolyzer for synthetic fuel generation

In the transition to a CO2-neutral circular economy, innovative solutions for e-fuels production are imperative. This study delineates the potential of molten carbonate electrolysis, utilizing a reversible molten carbonate fuel cell technology, recognized for its efficacy in large-scale electrical power generation and CO2 capture, to steer a groundbreaking pathway to e-fuels production through molten carbon electrolyzer modality. By meticulously scrutinizing the rMCFC's electrochemical behavior under assorted thermal-flow parameters, we offer an incisive analysis of its operation in the electrolysis mode, thereby unveiling a promising avenue for high-efficiency gaseous fuel production through electrochemical reactions. The experimental study includes current-voltage assessments and electrochemical impedance spectroscopy analysis, providing an elucidative view of the cell's performance landscape. Moreover, SEM microscopy was employed in both pre- and post-mortem stages, facilitating a deep understanding of material degradation mechanisms. Our results not only enhance the contemporary comprehension of reversible cell operations but also delineate the pivotal operating parameters that are conducive to optimizing both fuel cell and electrolysis modes, signposting a highly promising route to efficient and sustainable e-fuels production for the future circular economy. This study stands as a critical milestone in harnessing the molten carbonate electrolysis technology as a corner stone on the roadmap towards achieving a high-efficiency e-fuels production ecosystem.

Research Progress of Transcription Factor RUNX1 Mediating Inflammatory Response in the Pathogenesis of Aortic Dissection

Aortic dissection is a highly lethal condition of the major vessels of the heart, with its pathogenesis still not fully understood. This review explores the critical role of transcription factor Runx-related transcription factor-1 (RUNX1) in the pathogenesis of aortic dissection, particularly its involvement in mediating inflammatory responses through various signaling pathways such as nuclear factor kappa-B (NF-κB), interleukin-6 (IL-6), and matrix metalloproteinase-9 (MMP-9). The review covers studies detailing RUNX1's impact on endothelial cell damage, smooth muscle cell phenotypic changes, and extracellular matrix degradation. Potential therapeutic strategies targeting RUNX1 are discussed, highlighting the need for further research to translate these findings into clinical practice.

Harnessing the Engineered Probiotic-Nanosystem to Remodulate Tumor Extracellular Matrix and Regulate Tumor-Colonizing Bacteria for Improving Pancreatic Cancer Chemo-Immunotherapy.

Poor chemotherapy efficacy in pancreatic cancer is attributed to limited drug permeation caused by the dense extracellular matrix (ECM) and drug degradation induced by tumor-colonizing bacteria. Here, a tumor-targeting probiotic-nanosystem is elaborately designed to remodulate ECM and selectively regulate tumor-colonizing bacteria for improving chemo-immunotherapy against pancreatic cancer. Specifically, drug-loaded liposomes are conjugated with Clostridium Butyricum (CB) via matrix metalloproteinase-2 (MMP-2)-responsive peptide to construct a probiotic-nanosystem. Particularly, vactosertib (VAC, a transforming growth factor-β1 receptor inhibitor) is delivered by probiotic-nanosystem to silence the active pancreatic stellate cells (PSCs) for inhibiting the development of ECM, resulting in a loosened ECM and providing a golden opportunity for the deep penetration of chemotherapy drugs and immune cells. Subsequently, gemcitabine (GEM) is efficiently delivered into the core of tumors via probiotic-nanosystem, achieving an enhanced chemotherapy efficacy. Noteworthily, CB can alleviate γ-proteobacteria-mediated GEM degradation through competitively reducing the contents of γ-proteobacteria and promoting the amounts of tumor-inhibiting bacteria, thereby significantly potentiating the therapeutic effect of GEM. The engineered probiotic-nanosystem can not only enhance the GEM-induced immunogenic cell death (ICD) of a pancreatic tumor to activate antitumor immune responses but also markedly increase the tumor-infiltration of effector immune cells to heighten tumoricidal immunity, offering a promising strategy for chemo-immunotherapy of pancreatic cancer.

Analyzing Thermal Degradation Effects on Devulcanized GTR-Based NR/SBR/NBR Rubber Compounds Reinforced with SiO2 Particles

The large number of tires produced annually demands new recycling methods. A key challenge associated with recycling elastomers is their crosslinking structure that prevents fusion. It is possible to reverse crosslinking through a process called devulcanization. Devulcanized elastomers can be blended with fresh rubber and revulcanized for reuse. This paper examines samples made from natural rubber (NR), styrene–butadiene rubber (SBR), and nitrile butadiene rubber (NBR), blended with varying proportions of devulcanized ground tire rubber (dGTR) and newly revulcanized rubber. SiO2, commonly present in tire formulations, is also added. Samples of these materials, with 0, 10, 20, and 40 phr of dGTR are subjected to accelerated degradation for 0, 30, 60, 120, and 240 h. The effects of this treatment, the influence of SiO2, and the presence of a silane-based devulcanization agent (TESPT) that promotes the interaction between the rubber and silica, are analyzed at the microstructural level (FTIR, TGA, SEM) and through mechanical properties testing. The microstructural results of the spectroscopy and thermal analysis show that interactions between dGTR, silica, and silane compounds form aggregates that impact the material properties and degradation of the tires. Mechanically, when the sample contained up to 20 phr of dGTR, the compound presented a more brittle behavior, due to the crosslinking induced by the degradation.