Journal of Materials Science: Materials in Medicine最新文献

Spinal cord injury (SCI) can cause paralysis, and although multiple therapeutic proposals have been developed in murine models, results have hardly been replicated in humans. As non-human primates (NHP) are more similar to humans than rodents, the current study investigated whether it was possible to reproduce in a NHP, the previously obtained beneficial results by using a plasma-synthesized polypyrrole/iodine (PPy/I) biopolymer, which reduce glial scar formation and inflammatory response and promotes nerve tissue preservation, regenerative processes and functional recovery in rats. In NHPs (Rhesus monkey) with SCI by complete transection (SCT) and with plasma-synthesized PPy/I application (experimental) or without (control), the expression of pro-inflammatory cytokines in blood, preservation of nervous tissue through magnetic resonance imaging and histological and morphometric techniques, regeneration through immunohistochemistry study and functional recovery through clinical examination, were evaluated. Control NHP showed a markedly increased of pro-inflammatory cytokines vs. experimental NHP, which preserved more nerve tissue. At the end of the follow-up, a thinner glial scar in the injured spinal cord was observed in the experimental NHP as well as regenerative nerve processes (NeuN and β-III tubulin expression), while control NHP had a marked glial scar, large cysts and less nerve tissue at the injured zone. Plasma-synthesized PPy/I also reduced the loss of pelvic limb muscle mass and allowed the experimental NHP recovered knee-jerk, withdrawal and plantar reflexes as well as movement in the hind limbs. Since most of the beneficial effects of plasma-synthesized PPy/I previously reported in rats were also observed in the NHP, these preliminary findings make their replication in humans with SCI more likely.

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In this study, 1393-B3 based borate bioactive glasses (BGs) undoped and doped with 1 wt% zinc (ZnBG), cerium (CeBG), or silver (AgBG) were prepared and were incorporated into gelatin/PCL (GEL/PCL) electrospun fibers for neural tissue engineering applications. Particle sizes of the prepared BGs were 3.1, 10.6, 14.6, and 3.7 µm for undoped BG, ZnBG, AgBG, and CeBG, respectively. Aligned electrospun fibers were prepared with 5 wt% of BG particles to produce 5BG/PCL/GEL, 5ZnBG/PCL/GEL, 5AgBG/PCL/GEL and 5CeBG/PCL/GEL fibers. Random 5CeBG/PCL/GEL fibers were also prepared for comparison. A rise in fiber diameter was measured for BG-incorporated fibers compared to PCL/GEL fibers. Mechanical tests on the fibers indicated ultimate tensile strength values of 1–3.5 MPa, the range of mechanical properties of neural tissue. Cell culture studies were carried out with the NG108-15 cell line. Cell alignment was observed on the electrospun fibers on day 2. On days 1 and 2, the optical density was higher for ZnBG/PCL/GEL, CeBG/PCL/GEL, and AgBG/PCL/GEL than for BG/PCL/GEL fibers. On day 4, undoped BG-containing nanofibers had higher optical density compared to those containing doped BGs. This result could be due to a slower release rate of boron from the pure BG/PCL/GEL fiber mat. Overall, within the studied range, all fiber mats were found to be suitable for neural tissue engineering in terms of neural cell compatibility and mechanical properties. In the future, a wider range of ion doping must be considered to fully comprehend the potential of such ion-releasing fibers for neural regeneration.

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This study examines the influence of pH on the energy band gap and crystallite size during the synthesis of a novel Ag-Ag₂O nanocomposites through the mixed cultivation of Lactobacillus sp. and Bacillus sp. A range of analytical techniques, including X-ray Diffraction (XRD), UV-visible Spectroscopy (UV-vis), Fourier Transform Infrared Spectroscopy (FTIR), and Transmission Electron Microscopy (TEM), were employed to investigate the structural and optical characteristics of the nanocomposites. XRD analysis confirmed the presence of cubic phases of Ag and Ag₂O, with crystallite sizes varying from 8 to 44 nm; notably, smaller crystallites were observed at a pH of 6.5. UV-vis spectroscopy indicated an energy band gap ranging from 1.83 to 1.897 eV, suggesting promising applications for the material. The optimal pH for synthesis, which yielded the smallest particle size as verified by TEM, was identified as 6.5. FTIR analysis revealed the presence of biologically derived coating agents that may enhance the immutability and bioactivity of the nanocomposite. Antibacterial assays demonstrated significant efficacy against Enterococcus faecalis(E. faecalis) and Escherichia coli, particularly highlighting its effectiveness against E. faecalis. Hemolytic assays confirmed the biocompatibility of the nanocomposite at lower concentrations. These findings indicate the potential applications of the biogenic Ag-Ag₂O nanocomposites in medical and environmental fields, offering a sustainable solution to challenges associated with bacterial contamination. Future research may focus on integrating these biologically synthesized nanoparticles into advanced materials and coatings to improve their performance.

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Hemorrhages are still considered a common cause of death and despite the availability of different hemostatic agents it is still necessary to develop more effective hemostats for bleeding managements in emergency situations. Herein, large-pores mesoporous silica microspheres (MSM) were synthesized, and their surface was modified to enrich the hydroxyls population with the aim of achieving a material with enhanced water adsorption capacity and high hemostatic ability. The success of surface modification was investigated by Fourier Transform Infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA), which confirmed the increase in the amount of surface hydroxyl groups. A hemolysis assay as well as a clotting test were carried out to evaluate the hemocompatibility and hemostatic ability, respectively. It was found that the modified material presented the lowest hemolytic ratio and the lowest clotting time. The novelty of the paper is mainly due to the coupling of the hemostatic ability test with the adsorption microcalorimetry of water. In fact, being the water adsorption on the material surface a crucial factor in the hemostatic activity, microcalorimetry was used for the first time to study the adsorption of water and estimate its heat of adsorption. The data obtained showed that the modified MSM presents a surface able to adsorb a higher amount of water, compared to the pristine MSM, with a low molar heat of adsorption (about 35 kJ/mol), which renders the modified MSM presented in the present study an excellent candidate for producing novel hemostats.

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This study aimed to synthesize MgFe_1.9Ln_0.1O₄ (where, Ln = Yb, Pr, Gd, and Nd) ferrite nanoparticles via the sol-gel process and investigate their structural, morphological, and magnetic properties for potential hyperthermia applications. X-ray diffraction analysis (XRD) confirmed the cubic spinel structure for all samples. Transmission electron microscopy (TEM) images revealed nanometer-scale dimensions and nearly spherical morphology. Vibrating sample magnetometer measurements (VSM) indicated superparamagnetic behavior, with decreasing saturation magnetization (Ms) observed as Ln³⁺ content decreased. Specific absorption rate (SAR) analysis at 198 kHz demonstrated the influence of Ln³⁺ substitution on magnetic properties. Compared to existing studies, Ln³⁺ substituted (Yb, Pr, Gd, and Nd) nanoparticles demonstrate tunable magnetic properties and enhanced SAR performance, offering a more efficient design for hyperthermia treatment of solid tumors.

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The objective of this study is to fabricate and develop hydroxypropyl methylcellulose (HPMC) hydrogel (HG)-based composite bone cements with incorporation of hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP), and with/without polymethylmethacrylate (PMMA) for vertebroplasty. For animal study, twenty female Wister rats (250–300 g, 12 weeks of age) were divided into four groups including a two non-ovariectomy (NOVX) groups and two ovariectomy (OVX)-induced osteoporosis groups. Two prepared biocomposites including HG/β-TCP/HA and HG/β-TCP/HA/PMMA were injected into the tibial defects of both OVX and NOVX rats for evaluating in vivo osteogenesis after 12 weeks. Micro-computed tomography and histological analysis using hematoxylin and eosin (H&E) and Masson's trichrome stains of the two composite cements implanted into the tibial defects of OVX and NOVX rats revealed enhanced bone regeneration potential. However, no statistically significant differences were noted among the groups based on new bone formation, demonstrating that the injected composite cements showed similar osteogenesis effects in both OVX and NOVX rats. These findings suggest that the newly developed composite bone cement composed of HG, β-TCP, HA and/or PMMA may be a promising and professional tool for treating osteoporotic and non-osteoporotic vertebral fractures.

Human hair keratin, a natural protein derived from human hair, has emerged prominently in the field of wound repair, showcasing its unique regenerative capabilities and extensive application potential. However, it is a challenge for the keratin to efficiently therapy the impaired wound healing, such as combined radiation-wound injury. Here, we report a keratin/chitosan (KRT/CS) film for skin repair of chronic wounds in in rats with combined radiation-wound injury. In brief, the KRT/CS film was characterized by scanning electron microscopy (SEM), mechanical property analysis, water absorption, and swelling analysis. A rat model of combined radiation-wound injury was employed to evaluate the therapeutic efficacy of the KRT/CS film. Finally, the systemic biotoxicity of KRT/CS film was assessed through histological analysis. The surface of KRT/CS film was uniform and smooth compared with the KRT film, and the mechanical property, swelling rate and water absorption rate of KRT/CS film were significantly improved, which can meet the application requirements of wound excipient dressing. Furthermore, the combined radiation-wound injury in rats was established that the wound closure rate was achieved 74.46% after 14 days of treatment with KRT/CS film, comparing to the single KRT membrane and commercially available Band-Aids. Histological analysis demonstrated that the amount of angiogenesis and collagen deposition in wounds treated with KRT/CS were significantly improved. These findings demonstrate the KRT/CS film as a promising therapeutic agent for combined radiation-wound injury.

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Macrophage metabolism is closely linked to their phenotype and function, which is why there is growing interest in studying the metabolic reprogramming of macrophages. Bioactive glass (BG) S53P4 is a bioactive material used especially in bone applications. Additionally, BG S53P4 has been shown to affect macrophages, but the mechanisms through which the possible immunomodulatory effects are conveyed remain unclear. According to the results presented here, the lipopolysaccharide (LPS) induced suppression in oxidative phosphorylation is rescued in macrophages cultured with BG S53P4 before the inflammatory stimulus. Additionally, BG S53P4-exposed macrophages expressed lower mRNA levels of inflammatory cytokines Il6 and Il1b, as well as demonstrated decreased activation of inflammatory interferon regulatory factor (IRF) and NF-κB pathways and nitrogen oxide secretion in response to LPS. These results did not rely on cells being in direct contact with the material as similar effects were observed in the presence of BG S53P4-conditioned medium. Our findings link the immunomodulatory properties of BG S53P4 and macrophage metabolism, which improves our understanding of the mechanisms underlying the clinical efficacy of bioactive glasses.

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Implants aim to restore skeletal dysfunction associated with ageing and trauma, yet infection and ineffective immune responses can lead to failure. This project characterized the microbiological and host cell responses to titanium alloy with or without electroplated metallic copper. Bacterial viability counting and scanning electron microscopy quantified and visualized the direct and indirect bactericidal effects of the Cu-electroplated titanium (Cu-Ep-Ti) against two different Staphylococcus aureus strains. Human THP-1 macrophage adhesion and viability was analyzed, along with phagocytosis. Results showed potent antimicrobial activity alongside promising host-immunomodulatory properties. Direct and indirect exposure to Cu-Ep-Ti produced potent bactericidal effects resulting in 94–100% reductions in bacterial viability at 24 h, with complete eradication in some cases. As expected, cytotoxicity was observed in THP-1 macrophages without media exchange, though when media was exchanged at 8, 24 and 48 h cell viability was equivalent to Control-Ti. Interestingly macrophages adhered to the copper material or grown in the presence of copper ions showed 7-fold increase in phagocytosis of S. aureus bioparticles compared to Control-Ti, suggesting a dual bactericidal and host immunomodulatory mechanism. In conclusion, this Cu-electroplated Ti biomaterial can limit bacterial contamination on the implant surface, whilst simultaneously promoting a beneficial antimicrobial immune response.

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