Journal of materials chemistry. B最新文献

In this study, caprine forestomach native collagen (CFNC) isolated from rumen tissues is reported for the first time with subsequent surface modifications with varying concentrations of silver nanowires (AgNWs). Accordingly, CFNC/AgNWs scaffolds were prepared to be used as suitable wound healing dressing materials through a sequential isolation and decellularization process, followed by step-wise AgNW surface modification and ultraviolet (UV) crosslinking. The significant outcomes of this research highlight that CFNC/AgNWs scaffolds exhibit a highly porous three-dimensional (3D) network structure with favourable physicochemical characteristics. Also, the comprehensive tensile testing demonstrated that there were changes in mechanical properties based on the AgNW content. The CFNC/AgNWs scaffolds also exhibited strong antibacterial action against E. coli and S. aureus in a dose-dependent manner. The release of Ag⁺ ions from CFNC/AgNWs scaffolds exhibited a slow and sustained release pattern over an extended period of time. The cell-biomaterial interaction studies on CFNC/AgNWs scaffolds using L929 fibroblast cells showed dose-dependent and time-dependent toxicity when the concentration exceeded above 1 mg mL^-1. The cytotoxicity is mainly due to the higher concentration of Ag⁺ ions which initiates cell death through lipid peroxidation and causes cell membrane damage. The biocompatibility test results serve as a reference point to select the optimal dosage of AgNWs with balanced antibacterial and biocompatibility properties. Thus, the developed CFNC/AgNWs scaffolds will serve as a versatile wound dressing material similar to other metallic or conjugated reconstituted collagen systems with the added benefit of strong antimicrobial properties, and as a biomimetic xenograft for skin regeneration.

The self-organizable dendron (4-3,4-3,5)12G2X with X = -CO2CH3 and -CH2OH, an already classic dendron, facilitating the formation of a large diversity of columnar hexagonal phases including crystalline, with intracolumnar order, and liquid crystalline, and providing access for the first time to mimics of the transmembrane protein water channel Aquaporin was semifluorinated at eight of the sp³ hybridized carbons of its alkyl groups to provide (4-3,4-3,5)4F8G2X. The self-organization of (4-3,4-3,5)4F8G2X was analyzed by a combination of oriented fiber intermediate angle X-ray scattering, wide angle X-ray scattering, electron density maps, and reconstructed X-ray diffractograms by emplying molecular models. These experiments demonstrated that fluorophobic effect of (4-3,4-3,5)4F8G2X mediated mostly via the helical confiormation of the fluorinated fragments sharper miocrosegregation of the fluorinated fragments in the most ordered states of the resulting 12₄ helical porous columns. These results support the original model of self-organization of dendrons and provide access to new and simpler synthetic avenues for the construction of mimics of aquaporin channels which are of great interest for cell biology and for the next generation of membranes for water separation and water purification.

Intracortical microelectrode arrays (MEAs) can record neuronal activity and advance brain-computer interface (BCI) devices. Implantation of the invasive MEA kills local neurons, which has been documented using immunohistochemistry (IHC). Neuronal nuclear protein (NeuN), a protein that lines the nuclei of exclusively neuronal cells, has been used as a marker for neuronal health and survival for decades in neuroscience and neural engineering. NeuN staining is often used to describe the neuronal response to intracortical microelectrode array (MEA) implantation. However, IHC is semiquantitative, relying on intensity readings rather than directly counting expressed proteins. To supplement previous IHC studies, we evaluated the expression of proteins representing different aspects of neuronal structure or function: microtubule-associated protein 2 (MAP2), neurofilament light (NfL), synaptophysin (SYP), myelin basic protein (MBP), and oligodendrocyte transcription factor 2 (OLIG2) following a neural injury caused by intracortical MEA implantation. Together, these five proteins evaluate the cytoskeletal structure, neurotransmitter release, and myelination of neurons. To fully evaluate neuronal health in NeuN-positive (NeuN+) regions, we only quantified protein expression in NeuN+ regions, making this the first-ever cell-specific spatial profiling evaluation of targeted proteins by multiplex immunochemistry following MEA implantation. We performed our protein quantification along with NeuN IHC to compare the results of the two techniques directly. We found that NeuN immunohistochemical analysis does not show the same trends as MAP2, NfL, SYP, MBP, and OLIG2 expression. Further, we found that all five quantified proteins show a decreased expression pattern that aligns more with historic intracortical MEA recording performance.

We constructed two novel boron-dipyrromethene (BODIPY)-based fluorescent probes, BOPD and BOBA, each equipped with the phosgene specific recognition units o-phenylenediamine (OPD) and o-aminobenzylamine (OBA) at the 2-position of the BODIPY core. BOPD and BOBA represent rare examples of BODIPY-based probes that operate by modulating an intramolecular charge transfer process (ICT), as validated by computational studies. We systematically compared the analytic performance of those recognition units while focusing on selectivity, fluorescence turn-on ratios and response times. Probe BOBA, equipped with OBA as the recognition unit, demonstrated a remarkably low detection limit (i.e., 1.40 nM) and a rapid response time (<10 s) for triphosgene. By comparison, BOPD, featuring an OPD unit, showed superior selectivity towards triphosgene, with a detection limit of 93 nM and a response time of up to 30 s. A portable sensing platform was developed by loading BOPD onto test strips made of TLC plates, nonwoven materials and small-headed cotton swabs, which were assessed for their effectiveness in detecting phosgene. We additionally performed the first successful application of a fluorescent probe, namely BOPD, for monitoring the accumulation of phosgene in plants.

Alzheimer's disease (AD) heavily impacts human lives and is becoming serious as societies age. Inhibiting and disaggregating β-amyloid aggregates is a possible solution for AD therapy. In this study, a novel type of nanozyme based on Ru³⁺-chelated nanoscale metal organic frameworks (Ru³⁺-NMOFs), displaying strong peroxidase-like activity, was proposed as an inhibitor and disaggregator of β-amyloid aggregates. As a high concentration of hydrogen peroxide is present at the sites of β-amyloid aggregates, Ru³⁺-NMOFs could catalyze the conversion of hydrogen peroxide to hydroxyl radicals. Thus, these hydroxyl radicals would attack the β-amyloid chain, oxidizing it to enhance its hydrophilicity, which results in a decreased hydrophobic interaction and reduced degree of aggregation. Ru³⁺-NMOFs could effectively inhibit as well as disaggregate β-amyloid fibrils both in vitro and in vivo. Additionally, the reduction of the β-amyloid aggregates and the attenuation of reactive oxygen species transfer led to lower levels of inflammatory factors, which could be beneficial in alleviating AD symptoms. In a typical treatment, Ru³⁺-NMOFs could mitigate the paralysis of C. elegans CL2120 and elevate survival rates. This study opens a new avenue for MOF-based nanozymes as potential treatment agents for AD therapy.

With the continuous progress of nanotechnology in the field of tumor vaccines, immunotherapy has been regarded as one of the most powerful approaches for cancer treatment. Currently, DNA vaccines are used to efficiently deliver plasmids encoding tumor-associated antigens to antigen-presenting cells (APCs) and enhance the activation of immune cells. In this work, a series of aromatic sulfonyl small-molecule-modified polymers R-P based on low-molecular-weight polyethylenimine (PEI) were prepared, and their structure-activity relationship was studied. Among them, Ns-P with high transfection efficiency and low toxicity was applied to deliver antigen ovalbumin (OVA)-encoded plasmid DNA to APCs for triggering the immune activation of dendritic cells (DCs). It was also found that Ns-P could be used as an immune adjuvant to activate the STING pathway in DCs, integrating innate stimulating activity into the carrier to enhance antitumor immunity. Moreover, the modification of Ns-P/pOVA complexes with oxidized mannan could not only improve the biocompatibility of the complex, but also enhance the uptake of DCs, further inducing OVA antigen presentation and immune stimulation. In vivo antitumor assays indicated that Ns-P/pOVA/Man immunization could inhibit the growth of OVA-expressing E.G7 tumors in C57BL/6 mice. These results demonstrated that Ns-P/pOVA/Man is promising for gene delivery and immunotherapy application.

Osteogenesis imperfecta (OI) is a hereditary skeletal disorder characterized by bone fragility and deformities, primarily attributed to defects in type I collagen, the most abundant structural protein in humans. Multiple phosphorylation sites have been detected within collagen, suggesting that phosphorylation may influence mineralization processes, thereby impacting the development of OI. In this study, we investigated the modulation of biomineralization morphology by phosphorylated collagen peptides mimicking Gly-Ser mutations in osteogenesis imperfecta. A series of collagen peptide sequences, including GPO₁₃S, GPO₁₃pS, GPO₁₂S, GPO₁₂pS, GPO₁₁S, and GPO₁₁pS, were synthesized to explore the role of phosphorylation in peptide stability and its templating effect on biomineralization. The CD results indicated that the phosphorylation of Gly-pSer mutants reduces the stability of collagen peptides. SEM images revealed that phosphorylated peptides acted as templates, guiding the morphology of calcium carbonate into either olive-like or spherical structures, depending on their conformational state of the peptides. Non-phosphorylated peptides maintained a calcite crystal structure. The XRD patterns predominantly exhibited peaks associated with calcite and vaterite for GPO₁₃pS-CaCO₃, GPO₁₂pS-CaCO₃, and GPO₁₁pS-CaCO₃, and peaks associated with calcite for GPO₁₃S-CaCO₃, GPO₁₂S-CaCO₃, and GPO₁₁S-CaCO₃, indicating a transformation of mesocrystals influenced by peptide phosphorylation. Our findings elucidate the crucial role of phosphorylated collagen peptides in mediating biomineralization morphology and polymorph selection, offering insights into the complex pathophysiology of OI.

Polymer-drug conjugates are widely used for drug delivery. Herein, we report an injectable hydrogel for local delivery of nonsteroidal anti-inflammatory drugs (NSAIDs) using chitosan (CS) as a carrier polymer. Loxoprofen (LOX) was conjugated to the backbone of CS via carbodiimide chemistry to obtain the LOX-CS conjugate. This conjugation transformed the water-insoluble unmodified CS into the water-soluble LOX-CS conjugate. In particular, the LOX-CS conjugate did not precipitate at pH 7, allowing smooth subsequent chemical modification with methacrylic anhydride (MA) to synthesize LOX-CS methacrylate (LOX-CS-MA) with significantly higher methacrylation substitution. The LOX-CS-MA was capable of in situ gel formation under visible light irradiation in the presence of a benzoin-2,4,6-trimethylbenzoylphosphinate lithium (LAP) photoinitiator. Our results show that the LOX-CS-MA hydrogel exhibited good cytocompatibility and blood compatibility. It promoted M2 polarization, inhibited pro-inflammatory gene expression, and upregulated anti-inflammatory gene expression of macrophages. Furthermore, the LOX-CS-MA hydrogel significantly reduced reactive oxygen species (ROS) and nitric oxide (NO) produced by lipopolysaccharide (LPS)-stimulated macrophages. A subcutaneous implanted LOX-CS-MA hydrogel in a rat model revealed significantly reduced inflammatory cell density, decreased cell infiltration, and a much thinner fibrous capsule compared to the CS methacrylate (CS-MA) hydrogel, thus markedly alleviating the inflammatory response. This study highlights the feasibility of CS-drug conjugates in preparing CS-based methacrylate hydrogels for sustained drug release.

Photodynamic therapy (PDT) employing two-photon (TP) excitation is increasingly recognized to induce cell damage selectively in targeted areas, underscoring the importance of developing TP photosensitizers (TP-PSs). In this study, we developed BSe-B, a novel PS that combines a selenium containing dye with biotin, a cancer-selective ligand, and is optimized for TP excitation. BSe-B demonstrated enhanced cancer selectivity, efficient generation of type-I based reactive oxygen species (ROS), low dark toxicity, and excellent cell-staining capability. Evaluation across diverse cell lines (HeLa, A549, OVCAR-3, WI-38, and L-929) demonstrated that BSe-B differentiated and targeted cancer cells while sparing normal cells. BSe-B displayed excellent in vivo biocompatibility. In cancer models such as three-dimensional spheroids and actual colon cancer tissues, BSe-B selectively induced ROS production and cell death under TP irradiation, demonstrating precise spatial control. These findings highlight the potential of BSe-B for imaging-guided PDT and its capability for micro treatment within tissues. Thus, BSe-B demonstrates robust TP-PDT capabilities, making it a promising dual-purpose tool for cancer diagnosis and treatment.

The development of bioactive materials with controllable preparation is of great significance for biomedical engineering. Citric acid-based biomaterials are one of the few bioactive materials with many advantages such as simple synthesis, controllable structure, biocompatibility, biomimetic viscoelastic mechanical behavior, controllable biodegradability, and further functionalization. In this paper, we review the development of multifunctional citrate-based biomaterials for biomedical applications, and summarize their multifunctional properties in terms of physical, chemical, and biological aspects, and finally the applications of citrate-based biomaterials in biomedical engineering, including bone tissue engineering, skin tissue engineering, drug/cell delivery, vascular and neural tissue engineering, and bioimaging.