Biomedical materials (Bristol, England)最新文献

Because of its superior strength, esthetic properties, and excellent biocompatibility, zirconia is preferred for dental prosthetic such as crowns and bridges. However, zirconia crowns and bridges are susceptible to secondary caries owing to margin leakage. Silver is a well-known antibacterial agent, making it a desirable additive to zirconia crowns and bridges for secondary caries prevention. This study focuses on imparting zirconia composite with antibacterial properties to enhance its protective capacity in dental restorations. We used the sol-gel method to dope Ag into zirconia. Silver-doped zirconia powders were prepared at Zr:Ag molar ratios of 100:0,100:0.1, 100:0.5, 100:1, 100:3, and 100:5 (respective samples denoted as Ag-0, Ag-0.1, Ag-0.5, Ag-1, Ag-3, and Ag-5) and were subjected to firing at various temperatures (400 °C-1000 °C). We performed x-ray diffraction to investigate the crystal phase of these powders and x-ray fluorescence and field emission scanning electron microscopy to analyze their elemental composition and surface morphology, respectively. Moreover, we performed spectrophotometry to determine theL*a*b* color values, conducted dissolution tests, and quantified the Ag content through inductively coupled plasma optical emission spectroscopy. In addition, we studied the antibacterial activity of the samples. Analyses of the samples fired at ⩽600 °C revealed a predominantly white to grayish-white coloration and a tetragonal crystal phase. Firing at ⩾700 °C resulted in gray or dark gray coloration and a monoclinic crystal phase. The Ag content decreased after firing at 900 °C or 1000 °C. Ag-0.5 and above exhibited antibacterial activity against bothEscherichia coliandStaphylococcus aureus. Therefore, the minimum effective silver-doped zirconia sample was found to be Ag-0.5. This study allows the exploration of the antimicrobial potential of silver-doped zirconia materials in dental applications such as prosthdontical lining materials, promoting the development of innovative restorations with protective capacity against secondary caries.

Quantum dots (QDs) are with exceptional physicochemical and biological properties, making them highly versatile for a wide range of applications in cancer therapy. One of the key features of QDs is their unique electronic structure, which gives them functional attributes. Notably, their photoluminescence can be strong and adjustable, allowing them to be effectively used in fluorescence based diagnosis such as biosensing and bioimaging. In addition, QDs demonstrate an impressive capacity for loading cargo, making them ideal for drug delivery applications. Moreover, their ability to absorb incident radiation positions QDs as promising candidates for cancer-killing techniques like photodynamic therapy. The objective of this comprehensive review is to present a current and comprehensive overview of the recent advancements in utilizing QDs as multifunctional and innovative biomaterials. This review focuses on elucidating the biological, electronic, and physicochemical properties of QDs, along with discussing the technical advancements in QD synthesis. Furthermore, it thoroughly explores the progress made in utilizing QDs for diagnosis based on biosensing, bioimaging, and therapy applications including drug delivery and necrosis, highlighting their significant potential in the field of cancer treatment. Furthermore, the review addresses the current limitations associated with QDs in cancer therapy and provides valuable insights into future directions, thereby facilitating further advancements in this field. By presenting a comprehensive and well-structured overview, this review serves as an authoritative and informative resource that can guide future research endeavors and foster continued progress in the field of QDs for cancer therapy.

The design of three-dimensional (3D) scaffolds should focus on creating highly porous, 3D structures with an interconnected pore network that supports cell growth. The scaffold's pore interconnectivity is directly linked to vascularization, cell seeding, guided cell migration, and transportation of nutrients and metabolic waste. In this study, different types of food flavors including monosodium glutamate, sugar, and sodium chloride were used as the porogens along with PCL/PVP blend polymer for solvent casting/particulate leaching method. The morphology, porosity, interconnectivity, chemical composition, water absorption, and mechanical properties of the fabricated scaffolds are carefully characterized. The scaffolds are biocompatible in bothin vitroandin vivoexperiments and do not trigger any inflammatory response while enhancing new bone formation and vascularization in rabbit calvaria critical-sized defects. The new bone merges and becomes denser along with the experiment timeline. The results indicate that the 3D PCL/PVP scaffolds, using monosodium glutamate as porogen, exhibited suitable biological performance and held promise for bone tissue engineering in oral and maxillofacial surgery.

The therapy of large defects in peripheral nerve injury (PNI) suffers from several drawbacks, especially the lack of autologous nerve donors. Nerve conduits are considered as a solution for nerve injury treatment, but biocompatibility improvements is still required for conduits prepared with synthetic materials. Cell-derived extracellular matrix (ECM) has drawn attention due to its lower risk of immunogenic response and independence from donor availability. The goal of this study is to coat bone mesenchymal stem cell-derived ECMs on poly(lactic-co-glycolic) acid (PLGA) conduits to enhance their ability to support neural growth and neurite extensions. The ECM-coated conduits have better hydrophilic properties than the pure PLGA conduits. A marked increase on PC12 and RSC96 cells' viability, proliferation and dorsal root ganglion neurite extension was observed. Quantitative PCR analysis exhibited a significant increase in markers for cell proliferation (GAP43), neurite extension (NF-H, MAP2, andβIII-tubulin) and neural function (TREK-1). These results show the potential of ECM-coated PLGA conduits in PNI therapy.

Nisin is a bacteriocin produced by Gram-positive lactic acid bacterium,Lactococcus lactisand currently recognized in the Generally Recognızed as Safe (GRAS) category due to its non-toxicity. Herein, nisin has been grafted to chitosan structure to obtain natural bio-active films with enhanced antibacterial activity. Grafting was performed using ethyl ester lysine diisocyanate and dimer fatty acid-based diisocyanate (DDI); two different close to fully bio-based diisocyanates and Disuccinimidyl suberate; a homo-bifunctional molecule acting as a crosslinker between amino groups. The grafting process allowed the chemical immobilization of nisin to chitosan structure. Physicochemical characterization studies showed the successful grafting of nisin. The antibacterial activity againstStaphylococcus aureuswas evident for all nisin modified chitosan films and best pronounced when DDI was used as a crosslinker with a maximum zone of inhibition of ∼13 mm. All nisin grafted chitosan films were cytocompatible and the cell viability of L929 fibroblasts were >80% pointing out the non-toxic structure. Considering the results of the presented study, bio-based diisocyanates and homo-bifunctional crosslinkers are effective molecules in synthesis of nisin grafted chitosan structures and the new chitosan based antibacterial biopolymers obtained after nisin modification come forward as promising non-toxic and bioactive candidates to be applied in medical devices, implants, and various food coating products.

(+)4-cholesten-3-one has been proved to have potential wound healing effect in the process of wound regeneration. This study aimed to evaluate the effect of (+)4-cholesten-3-one/sodium alginate/gelatin on skin injury and reveal its potential molecular mechanism. First, we prepared sodium alginate/gelatin hydrogel (SA/Gel hydrogel) with different ratios and tested their characteristics. Based on these results, different concentrations of (+)4-cholesten-3-one were added into SA/Gel hydrogel. A full-thickness skin injury model was successfully established to evaluate wound healing activityin vivo. HE staining and Masson staining were used to evaluate the thickness of granulation tissue and collagen deposition level. Immunohistochemical staining and immunofluorescence staining were applied to detect the level of revascularization and proliferation in each group of wounds. Western blot, quantitative-PCR and immunofluorescence staining were used to detect the expression of proteins related to Wnt/β-catenin signaling pathway in each group of wounds.In vitroresults showed that the hydrogel not only created a 3D structure for cell adhesion and growth, but also exhibited good swelling ability, excellent degradability and favorable bio-compatibility. Most importantly,in vivoexperiments further indicated that (+)4-cholesten-3-one/SA/Gel hydrogel effectively enhanced wound healing. The effectiveness is due to its superior abilities in accelerating healing process, granulation tissue regeneration, collagen deposition, promoting angiogenesis, tissue proliferation, as well as fibroblast activation and differentiation. The underlying mechanism was related to the Wnt/β-catenin signaling pathway. This study highlighted that (+)4-cholesten-3-one/SA/Gel hydrogel holds promise as a wound healing dressing in future clinical applications.

To explore the feasibility and safety of biomaterials for posterior scleral reinforcement (PSR) in rabbits. Decellularization and genipin crosslink were applied to the fresh bovine pericardium and porcine endocranium, and then mechanical properties, suture retention strength, and stability were tested. PSR operation was performed on 24 rabbit eyes using treated biological materials. Ophthalmic examination was performed regularly before and after PSR operation (1 week, 1 month, 3 months, 6 months). To evaluate the effectiveness, A ultrasound, diopter, and optical coherence tomography were conducted. General condition, fundus photograph, and pathological examination were recorded to evaluate the safety. Compared with genipin crosslinked bovine pericardium (Gen-BP) (21.29 ± 13.29 Mpa), genipin crosslinked porcine endocranium (Gen-PE) (34.85 ± 3.67 Mpa,P< 0.01) showed a closer elastic modulus to that of genipin crosslinked human sclera. There were no complications or toxic reactions directly related to the materials. Capillary hyperplasia, inflammatory cell infiltration, and collagen fiber deposition were observed, and the content of type I collagen fibers increased after PSR. Overall, the choroidal thickness of treated eyes was significantly thickened at different time points after PSR, which were 96.84 ± 21.08 μm, 96.72 ± 22.00 μm, 90.90 ± 16.57 μm, 97.28 ± 14.74 μm, respectively. The Gen-PE group showed changes that were almost consistent with the overall data. Gen-BP and Gen-PE are safe biological materials for PSR. The Gen-PE group demonstrated more significant advantages over the Gen-BP group in terms of material properties.

Many kinds of human tumors, including breast carcinomas, frequently metastasize to the bone, making it prone to pathologic fractures. Surgical management of bone metastases ranges from the resection of metastases to bone repair. Current surgical methods for the repair of bone defects include the use of polymethyl methacrylate (PMMA)-based bone cements. A promising alternative material are bioactive glass (BG) particles that in addition to providing physical stability can also induce bone regeneration. Moreover, BGs doped with Fe₂O₃may also have a negative impact on tumor cells. Here, we tested the hypothesis that BGs can affect metastatic human breast cancer cells. To this end, we assessed the effects of different BG compositions with and without Fe₂O₃on metastatic human MDA-MB-231 breast cancer cellsin vitro. We found that all BGs tested impaired the viability and proliferation of breast cancer cells in a concentration-dependent manner. The anti-proliferative effects inversely correlated with BG particle size, and were in general less pronounced in mesenchymal stromal cells (MSCs) that served as a control. Moreover, Fe₂O₃-doped BGs were more potent inhibitors of tumor cell proliferation and metabolic activity than Fe₂O₃-free BG. Our data therefore indicate that BGs can affect human breast cancer cells more strongly than MSCs, and suggest that the presence of Fe₂O₃can potentiate anti-proliferative and anti-metabolic effects of BGs. Fe₂O₃-doped BGs thus have the potential to be used for the surgical management of metastatic bone lesions, and may in addition to their regenerative properties also allow the local control of bone metastases.

Bioresorbable chitosan scaffolds have shown potential for osteochondral repair applications. Thein vivodegradation of chitosan, mediated by lysozyme and releasing glucosamine, enables progressive replacement by ingrowing tissue. Here the degradation process of a chitosan-nHA based bioresorbable scaffold was investigated for mass loss, mechanical properties and degradation products released from the scaffold when subjected to clinically relevant enzyme concentrations. The scaffold showed accelerated mass loss during the early stages of degradation but without substantial reduction in mechanical strength or structure deterioration. Although not cytotoxic, the medium in which the scaffold was degraded for over 2 weeks showed a transient decrease in mesenchymal stem cell viability, and the main degradation product (glucosamine) demonstrated a possible adverse effect on viability when added at its peak concentration. This study has implications for the design and biomedical application of chitosan scaffolds, underlining the importance of modelling degradation products to determine suitability for clinical translation.

Endoscopic submucosal dissection (ESD) is the gold-standard surgical procedure for superficial esophageal cancer. A significant and challenging complication of this technique is post-ESD esophageal stricture. In this study, the feasibility of endoscopic catheter delivery of bioadhesive to esophageal lesions in a porcine model was tested. Injectable bioadhesive was composed of oxidized dextran (ODA) and chitosan hydrochloride (CS), its physicochemical properties, injectability, antibacterial activity, and cytocompatibility were investigated beforein vivotest. ODA-CS bioadhesive was delivered to the wound bed of the esophageal tissue using a custom-made catheter device after ESD in a porcine model. Our results show that the ODA-CS bioadhesive is of good injectability, tissue adhesive strength, antibacterial capacity, and blood compatibility.In vivodelivery was achieved by endoscopic spraying of ODA and CS in separate catheters fixed on the endoscopic probe. ODA and CS can be mixed well to allow in situ bioadhesive formation and firmly adhere to the esophageal wound surface. After two weeks, the bioadhesive maintained structural integrity and adhered to the surface of esophageal wounds. However, histological analysis reveals that the ODA-CS bioadhesive did not show improvement in attenuating inflammatory response after ESD. This pilot study demonstrates the feasibility of ODA-CS bioadhesive for shielding esophageal wounds after ESD, whereas efforts need to improve its anti-inflammatory activity to reduce fibrosis for stricture prevention.