Journal of Materials Chemistry B最新文献

Mesenchymal stromal cell-derived artificial microvesicles (MSC-MVs) hold significant promise as a cell-free alternative to traditional stem cell therapy for the treatment of lower limb ischemia. However, their fragile plasma membrane is highly susceptible to oxidative damage, environmental fluctuations, and long-term storage, often leading to membrane rupture, vesicle disintegration, and leakage of bioactive cargoes. Additionally, MSC-MVs can be contaminated by nuclear genes, limiting their safety and therapeutic applicability. In this study, we developed gelated microvesicles (gel-MVs) derived from enucleated MSCs by incorporating a polyethylene glycol diacrylate (PEGDA) polymer network within the vesicular lumen. This intravesicular gelation process stabilized the structure of MSC-MVs, effectively preventing vesicle degradation and content leakage. In vitro experiments demonstrated that gelation preserved the integrity of bioactive components and maintained their functional activity. In a murine lower limb ischemia model, gel-MVs significantly enhanced angiogenesis, restored blood perfusion, reduced apoptosis, and promoted tissue regeneration in ischemic limbs. This study introduces a novel strategy that integrates artificial polymer networks with natural microvesicles, providing a promising platform for engineering robust and functional MSC-MVs with enhanced therapeutic potential for clinical translation.

This study reports an approach of using a molecularly imprinted polymer (MIP) combined with Bi-doped cobalt ferrite (Bi_xCoFe₂O₄) nanoparticles (NPs) for detecting C-reactive protein (CRP), a marker associated with cardiovascular diseases (CVDs). Sudden cardiac arrest is a growing concern in India, where CVDs have become the leading cause of mortality. MIPs have recently drawn increasing interest over time; consequently, the objective of this study is to engineer an MIP-based electrochemical sensor due to their reliability, ease of electrochemical control for template removal, and cavity renewal. MIPs are selective polymers that can bind target molecules and are synthesised using a ratio of 1 : 4 : 20 of a novel functional monomer (4-nitrophenyl methacrylate), a template (CRP), and a crosslinker (EGDMA) via the bulk polymerisation method, along with Bi_xCoFe₂O₄ NPs (Bi = 0.05, 0.10, 0.15, and 0.20 M). These NPs and MIPs were characterised using powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray (EDX) analysis, dynamic light scattering (DLS), ultraviolet-visible (UV) spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and the Brunauer–Emmett–Teller (BET) method. The synthesised NPs and MIP were fabricated onto an indium tin oxide (ITO) electrode using the electrophoretic deposition (EPD) process. Moreover, an electrochemical analysis was conducted using voltammetry and electrochemical impedance sensing (EIS) techniques for CRP detection across two linear ranges: a lower range of 0.5–80 ng mL⁻¹ with a limit of detection (LOD) of 0.1609 ng mL⁻¹ and a sensitivity of 0.740 Ω ng⁻¹ cm⁻², and a higher range of 90–400 ng mL⁻¹, in which the LOD was 0.3262 ng mL⁻¹, sensitivity was 0.0631 Ω ng⁻¹ cm⁻² and the response time of the fabricated sensor was observed to be 10 seconds.

A ubiquitous global threat of emerging multi-drug resistant (MDR) strains causing outbreaks of biofilm-mediated hospital-acquired infections (HAIs) has resulted in severe nosocomial contagious diseases, chronic wound inflammation, and lethal sepsis. Surface contamination of medical devices, implants and community transmission have further worsened the persistently high rate of morbidity and mortality spawned by epidemic resistant strains of opportunistic pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). Herein, a disulphide bridge containing an amphiphilic cationic peptide (AP1) has been designed, synthesised, characterised and studied for antibacterial activity against several multi-drug resistant strains. Notably, the lipopeptide AP1 spontaneously self-assembled to form an injectable hydrogel in Tris–HCl buffer (within a pH range of 7.2–8.0). Field emission gun transmission electron microscopic data showed an intertwined nanofibrillar morphology. Several spectroscopic techniques, including Fourier-transform infrared spectroscopy, X-ray diffraction, UV-visible spectroscopy, and circular dichroism, have been utilised to characterize the self-assembly of the synthesized AP1. Interestingly, this self-assembled peptide is found to exhibit potent antimicrobial activities against Gram-positive (MRSA and Bacillus subtilis) as well as Gram-negative (Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli) bacterial strains. Detailed mechanistic studies have illustrated the antibacterial efficacy against MRSA and MDR Pseudomonas aeruginosa via membrane disruption along with reactive oxygen species (ROS) generation. The biofilm inhibition and mature biofilm destruction capabilities of self-assembled AP1 were observed against MRSA due to the combined effect of the reduction competency of extracellular polymeric substances (EPS) and planktonic cytolysis. This subsequently corroborated the hydrogel's application as an anti-infective surface-coating biomaterial. The MTT assay with eukaryotic mammalian cells (HEK-293, NKE, HaCaT) and haemolytic assay convincingly substantiated the biocompatibility of the self-assembled amphiphilic peptide, emphasizing its therapeutic potential as an antibacterial agent in biomedicine.

Inhibiting and reducing bacterial infections associated with biomedical implants and devices remains a significant challenge. In this study, we successfully grafted crosslinked antifouling and bactericidal coatings onto a polyurethane (PU) surface using sulfobetaine (SB) zwitterionic and quaternary ammonium cationic (QAC) copolymers through a combination of PDA-assisted co-deposition and amidation reactions. The successful formation and surface properties of the crosslinked coatings were characterized using Fourier transform infrared spectroscopy (FT-IR), water contact angle (WCA) measurements, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical corrosion tribometry (MFT-EC), and atomic force microscopy (AFM). The antifouling performance was evaluated via protein adsorption, platelet adhesion, whole blood adhesion, and cytotoxicity assays. Additionally, the antibacterial and bactericidal efficacy was evaluated using E. coli, P. aeruginosa and S. aureus as models. Our results indicate that the molar ratio of SB and QAC critically influences the antifouling and bactericidal properties, and a relatively high SB content (60 mol%) combined with a low QAC content (20 mol%) achieves an optimal balance between antifouling and bactericidal properties. This combination of zwitterionic and quaternary ammonium cationic copolymer modifications not only effectively kills bacteria upon contact but also prevents the adhesion of dead bacteria, demonstrating promising potential for applications in biomedical implants and devices.

The accumulation of Tau aggregates is commonly linked with various neurodegenerative diseases, such as Alzheimer's disease, Pick's disease, and corticobasal degeneration. Notwithstanding substantial investments in the development of clinical strategies for effective intervention, traditional design paradigms are predominantly confined to molecules featuring either a solitary function or single-dimensional mode of intervention, ignoring the necessity of personalized and precise medicine. Herein, we design and synthesize a dual-functional aggregation-induced emission-active agent to serve as both a fluorescent probe for the imaging of pathological Tau and a modulator for intervention. This amphiphilic theranostic agent, named TPE-P9, is prepared via a one-pot Michael reaction between hydrophobic maleimide-modified tetraphenylethylene (TPE-Mal) and a hydrophilic cysteine-modified Tau-targeting peptide (CKVQIINKK). Microscale thermophoresis measurement and in vitro fluorescence analysis demonstrate that TPE-P9 exhibits specific binding affinity (K_d = 4.46 µM) and high selectivity towards Tau fibrils, featuring a pronounced low background interference, which is superior to the classical amyloid protein probe thioflavin T (ThT). At the living cellular level, TPE-P9 is capable of readily imaging endogenic pathological Tau to distinguish normal neurons from the lesional neurons in situ, and the staining consequence is almost consistent with that of ThT. On the other hand, as a modulator, TPE-P9 can potently protect neurons from cytotoxic Tau-induced apoptosis both by inhibiting aberrant post-translational modification-induced Tau self-assembly and by blocking the produced pathological Tau propagation, enhancing cell viability by 35.4%. These findings offer valuable insights for the development of innovative image-guided therapeutic strategies for targeted tauopathies treatment.

Despite nanochitins showing favorable biological effects, the colloid stability of positively charged nanochitins by virtue of the amino group is limited to acidic pH, which is different from biological conditions. Here, we show that guanidinylated chitin nanocrystals (GChNCs) are dispersible at neutral pH. The GChNCs are prepared by guanidinylation of partially deacetylated chitin nanocrystals (ChNCs) with 1-amidinopyrazole hydrochloride. The degrees of guanidinylation and acetylation of the GChNCs are 4.6% and 75.7%, respectively. A 1.0 wt% GChNC dispersion is prepared with 0.5 wt% acetic acid solution by sonication treatment. Although slight white turbidity is observed due to scattering, no visible macroscopic precipitates are observed. The average diameter of the GChNCs estimated by DLS analysis is 327.2 nm. When the GChNC dispersion is neutralized by adding 0.1 M NaOH solution, the transmittance of the GChNC dispersion is decreased by aggregation. However, the transmittance of the GChNC dispersion is higher than that of the ChNC dispersion, suggesting that the GChNC particles are less aggregated than the ChNC particles due to the positive charge by virtue of the high basicity of the guanidino group. Interestingly, we find that the GChNCs homogeneously disperse in 0.1 M HEPES buffer (pH 7.4) up to 0.5 wt% by sonication treatment, even though the average diameter of the GChNCs in the solution is 3.4-fold higher (1115.1 nm) than that prepared at pH 3.0. We additionally find no observation of this improved dispersibility of guanidinylated chitin nanofibers due to the guanidino group. This result indicates that the guanidinylation is effective in improving the dispersion of nanochitins with smaller aspect ratios, like ChNCs. Furthermore, we demonstrate that the dispersibility of GChNCs at neutral pH can be utilized for material development, where a gelatin–GChNF composite hydrogel displaying enhanced mechanical properties is successfully prepared by adding 10% (w/w) GChNCs.

Myocardial infarction (MI), a leading cause of global cardiovascular mortality, is characterized by a vicious cycle of oxidative stress and inflammatory responses, resulting in irreversible myocardial damage and ventricular remodeling. To address the limitations of current therapies in comprehensively targeting the post-MI pathological microenvironment, this study developed an injectable hydrogel system, termed CPH (DS/CMCS), through the rational integration of carboxymethyl chitosan (CMCS), dextran sulfate (DS), and oxidized dextran (ODex) as a dynamic crosslinker. The CPH hydrogel not only mimicked the mechanical properties of the native myocardial extracellular matrix but also integrated multifunctional capabilities, including antioxidant activity, anti-inflammatory effects, pro-angiogenic potential, and enhanced electrical signal conduction. Through both cellular and animal studies, it was conclusively shown that the CPH hydrogel effectively scavenged reactive oxygen species (ROS), protected cardiomyocytes from oxidative damage, modulated macrophage polarization to mitigate inflammatory cascades, and promoted vascular regeneration and myocardial remodeling. In the rat MI model, the CPH hydrogel significantly improved cardiac function and achieved comprehensive structural restoration of infarcted myocardium. This study introduces an innovative acellular spatiotemporal approach for the treatment of MI and advances the rational design of cardiac tissue-engineered biomaterials, highlighting its substantial clinical translation potential for regenerative medicine.

Zeolitic imidazolate frameworks (ZIFs) have garnered significant attention in immunotherapy and anti-inflammatory therapy due to their tunable porosity, high drug-loading capacity, pH responsiveness, and biocompatibility. This review systematically summarizes recent advancements in ZIF-based composites for immunotherapy and anti-inflammatory therapy, emphasizing their dual roles in enhancing therapeutic efficacy and minimizing adverse effects. In immunotherapy, ZIFs serve as versatile platforms for targeted drug delivery, immune checkpoint modulation, and synergistic cancer therapies (photodynamic/chemodynamic therapy), demonstrating remarkable potential in reversing immunosuppressive tumor microenvironments and activating anti-tumor immunity. For anti-inflammatory applications, ZIFs enable sustained release of therapeutic agents, mitigate oxidative stress, and promote tissue regeneration, particularly in osteoarthritis management and wound healing. In addition, the performance optimization of AI-assisted synthesis of ZIFs, as well as AI-assisted disease detection and treatment, was also discussed. It is hoped to provide ideas for the synthesis and application of ZIFs in immunotherapy and anti-inflammatory therapy.

Pathogenic infections, which accompany the process of biological evolution, represent a primary risk factor threatening human life and health. The fabrication of heterostructures is an efficient strategy against pathogens. Typical heterostructures consist of inorganic materials. Investigating heterostructures composed of organic components provides strong groundwork for advancing heterostructural systems. Herein, the Ag₂S/IEICO-4F heterostructure is proposed and established. It possesses a favorable reactive oxide species (ROS) yield under NIR irradiation, including ¹O₂/˙O₂⁻ and ˙OH, which originates from the enhanced electron–hole separation, resulting in an obviously higher ROS yield compared to the Ag₂S and IEICO-4F groups. Its antibacterial properties and the subsequent wound regeneration capability have been verified using in vivo S. aureus-infected skin defects on rats. This work provides a rational materials design platform based on an organic–inorganic heterostructure and its application in photo-induced anti-bacterial activity.

As a group of natural nanocarriers, exosomes have become a hotspot for drug delivery research due to their biocompatibility, targeting, and ability to cross biological barriers. In this paper, we systematically review the biological properties, drug-carrying strategies, and delivery mechanisms of exosomes as delivery carriers. Studies have shown that exosomes have a unique double-layer membrane structure and abundant biological activities, which can realize efficient drug delivery by physical, chemical, and biological methods. Genetic engineering and chemical modifications can further optimize their targeting and delivery efficiency. Exosomes deliver bioactive molecules (e.g., proteins, nucleic acids) to recipient cells via mechanisms such as surface ligand–receptor recognition, membrane fusion, or endocytosis. This precise delivery system regulates cellular functions, evades immune clearance, and holds immense promise for disease treatment, showcasing broad clinical application prospects. However, this field still faces key technological bottlenecks such as large-scale production and quality control. To address these challenges, emerging technologies such as the EXODUS system and microfluidic chips, which have demonstrated significant advantages in enhancing extraction efficiency and purity, have been utilized, offering potential solutions for scalable and standardized production. Future research should focus on addressing issues related to production process standardization and clinical translation to promote the practical application of this novel delivery system.