Chitosan-based promising scaffolds for the construction of tailored nanosystems against osteoporosis: Current status and future prospects
Despite advancements in therapeutic techniques, restoring bone tissue after damage remains a challenging task. Tissue engineering or targeted drug delivery solutions aim to meet the pressing clinical demand for treatment alternatives by creating substitute materials that imitate the structural and biological characteristics of healthy tissue. Polymers derived from natural sources typically exhibit enhanced biological compatibility and bioactivity when compared to manufactured polymers. Chitosan is a unique polysaccharide derived from chitin through deacetylation, offering biodegradability, biocompatibility, and antibacterial activity. Its cationic charge sets it apart from other polymers, making it a valuable resource for various applications. Modifications such as thiolation, alkylation, acetylation, or hydrophilic group incorporation can enhance chitosan's swelling behavior, cross-linking, adhesion, permeation, controllable drug release, enzyme inhibition, and antioxidative properties. Chitosan scaffolds possess considerable potential for utilization in several biological applications. An intriguing application is its use in the areas of drug distribution and bone tissue engineering. Due to their excellent biocompatibility and lack of toxicity, they are an optimal material for this particular usage. This article provides a comprehensive analysis of osteoporosis, including its pathophysiology, current treatment options, the utilization of natural polymers in disease management, and the potential use of chitosan scaffolds for drug delivery systems aimed at treating the condition.
Biomimetic HA-GO implant coating for enhanced osseointegration via macrophage M2 polarization-induced osteo-immunomodulation
The pro-inflammatory/anti-inflammatory polarized phenotypes of macrophages (M1/M2) can be used to predict the success of implant integration. Hence, activating and inducing the transformation of immunocytes that promote tissue repair appears to be a highly promising strategy for facilitating osteo-anagenesis. In a previous study, titanium implants were coated with a graphene oxide-hydroxyapatite (GO-HA) nanocomposite via electrophoretic deposition, and the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) was found to be significantly enhanced when the GO content was 2wt%. However, the effectiveness of the GO-HA nanocomposite coating in modifying the in vivo immune microenvironment still remains unclear. In this study, the effects of GO-HA coatings on osteogenesis were investigated based on the GO-HA-mediated immune regulation of macrophages. The HA-2wt%GO nanocomposite coatings exhibited good biocompatibility and favored M2 macrophage polarization. Meanwhile, they could also significantly upregulate IL-10 (anti-inflammatory factor) expression and downregulate TNF-α (pro-inflammatory factor) expression. Additionally, the microenvironment, which was established by M2 macrophages, favored the osteogenesis of BMSCs both in vivo and in vitro. These findings show that the GO-HA nanocomposite coating is a promising surface-modification material. Hence, this study provides a reference for the development of next-generation osteoimmunomodulatory biomaterials.
Retraction Influence of carbon and graphene oxide nanoparticle on the adhesive properties of dentin bonding polymer: A SEM, EDX, FTIR study
Retraction Comparison of adhesive bond strength among fiber reinforced post and core with different cementation techniques: In vitro study
extract-loaded electrospun gelatin wound dressing for treating diabetic wounds: An in vitro and in vivo study
In the current study, was loaded into electrospun gelatin scaffolds for diabetic wound healing applications. Scaffolds were characterized in vitro by mechanical testing, cell culture assays, electron microscopy, cell migration assay, and antibacterial assay. In vivo wound healing study was performed in a rat model of diabetic wound. In vitro studies revealed fibrous architecture of our developed dressings and their anti-inflammatory properties. In addition, loaded wound dressings prevented bacterial penetration. In vivo study showed that wound size reduction, collagen deposition, and epithelial thickness were significantly greater in extract-loaded scaffolds than other groups. Gene expression studies showed that the produced wound dressings significantly upregulated VEGF and IGF genes expression in diabetic wounds.
The microstructure, composition, physical properties, and bioactivity of calcium silicate cement prototypes for vital pulp therapies
Hydraulic calcium silicate cements (HCSCs) are valuable for various dental procedures. However, several reports document inherent limitations and complaints about their high costs, hindering accessibility in low-and middle-income countries. This study aimed to characterize four low-cost HCSC prototypes to show their microstructure, composition, and fundamental physical properties. Four HCSC prototypes were formulated: 1- calcium silicate powder with 17.5 wt. % replacement of calcium tungstate, 2- calcium silicate powder with 17.5 wt. % replacement of zirconium oxide, 3- calcium silicate powder with 17.5 wt. % replacement of calcium tungstate and 2.5 wt. % of zirconium oxide and 4- calcium silicate powder with 10 wt. % replacement of calcium tungstate and 10 wt. % replacement of zirconium oxide. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction were used to assess their microstructure and composition. Additionally, radiopacity, setting time, solubility, pH, and in vitro bioactivity were evaluated at different time points and contrasted with controls (Mineral trioxide aggregate -MTA Angelus- and Intermediate restorative material -IRM-). Their production cost was significantly lower than commercially available HCSCs. All prototypes exhibited a microstructure and composition comparable to MTA Angelus. All the prototypes exhibited radiopacity exceeding 3 mm of aluminum and shorter initial and final setting times than MTA Angelus. The solubility of some prototypes closely adhered to the ISO standard recommendation of 3% after 1 day, and all promoted an alkaline pH and the formation of calcium/phosphate precipitates. These promising findings suggest the potential clinical application of these prototypes. However, further research is necessary to evaluate their mechanical and biological properties for definitive clinical use.
Development of 5-fluorouracil/etoposide co-loaded electrospun nanofibrous scaffold for localized anti-melanoma therapy
Nanofibrous scaffolds have emerged as promising candidates for localized drug delivery systems in the treatment of cutaneous cancers. In this study, we prepared an electrospun nanofibrous scaffold incorporating 5-fluorouracil (5-FU) and etoposide (ETP) for chemotherapy targeting melanoma cutaneous cancer. The scaffold was composed of polyvinyl alcohol (PVA) and chitosan (CS), prepared via the electrospinning process and loaded with the chemotherapeutic agents. We conducted relevant physicochemical characterizations, assessed cytotoxicity, and evaluated apoptosis against melanoma A375 cells. The prepared 5-FU/ETP co-loaded PVA/CS scaffold exhibited nanofibers (NFs) with an average diameter of 321 ± 61 nm, defect-free and homogenous morphology. FTIR spectroscopy confirmed successful incorporation of chemotherapeutics into the scaffold. Additionally, the scaffold demonstrated a hydrophilic surface, proper mechanical strength, high porosity, and efficient liquid absorption capacity. Notably, sustained and controlled drug release was observed from the nanofibrous scaffold. Furthermore, the scaffold significantly increased cytotoxicity (95%) and apoptosis (74%) in A375 melanoma cells. Consequently, the prepared 5-FU/ETP co-loaded PVA/CS nanofibrous scaffold holds promise as a valuable system for localized eradication of cutaneous melanoma tumors and mitigation of adverse drug reactions associated with chemotherapy.
Effects of composition and pH on the degradation of hyaluronate and carboxymethyl cellulose gels and release of nanocrystalline silver
Adhesions are fibrous tissue connections which are a common complication of surgical procedures and may be prevented by protecting tissue surfaces and reducing inflammation. The combination of biodegradable polymers and nanocrystalline silver can be used to create an anti-inflammatory gel to be applied during surgery. In this study, sodium hyaluronate and sodium carboxymethyl cellulose were added in concentrations from 0.25% to 1% w/v to aqueous nanocrystalline silver solutions to create viscous gels. Gels were loaded into dialysis cassettes and placed in PBS for 3 days. pH was adjusted using potassium phosphate monobasic and sodium hydroxide. Release of silver into the PBS was measured at several time points. Polymer degradation was compared by measuring the viscosity of the gels before and after the experiment. Gels lost up to 84% of initial viscosity over 3 days and released between 24% and 41% of the added silver. Gels with higher initial viscosity did not have a greater degree of degradation, as measured by percent viscosity reduction, but still resulted in a higher final viscosity. Silver release was not significantly impacted by pH or composition, but still varied between experimental groups.
Electroless silver plating on fabrics for antimicrobial coating: comparison between cotton and polyester
In the past few years, due to the Covid-19 pandemic, the interest towards textiles with antimicrobial functionalities faced a significant boost. This study proposes a rapid and convenient method, in terms of reactants and equipment, for fabricating antimicrobial coatings on textiles. Through the electroless silver plating reaction, silver coatings were successfully applied on cotton and polyester, rapidly and at room temperature. Functionalized samples were characterized by morphological (optical and scanning electron microscopies) and chemical tests (X-ray photoelectron spectroscopy, XPS) to investigate the nature of the silver coating. Although distinct nanoparticles did not form, XPS analysis detected the presence of silver, which resulted in an increased surface roughness and hydrophobicity of both cotton and polyester textiles. Ag-coated samples exhibited approximately 80% biocompatibility with murine L929 fibroblasts or human HaCaT cells, and strong antibacterial properties against in direct contact tests. In antiviral experiments with SARS-CoV-2 virus, treated cotton showed a 100% viral reduction in 30 min, while polyester achieved 100% reduction in 1 h. With a human norovirus surrogate, the Feline Calicivirus, both treated textiles have a faster antiviral response, with more than 60% viral reduction after 5 min, while achieving a 100% reduction in 1 h. In conclusion, this study presents a fast, efficient, and low-cost solution for producing antimicrobial textiles with broad applications in medical and healthcare scenarios.
Physicochemical and biocompatibility characterisation of a 3D lyophilised platelet-rich fibrin scaffold for cleft lip and palate repair
Craniofacial bone defects result from various disorders such as trauma, congenital malformations and infections. Cleft lip and palate are the most prevalent congenital craniofacial birth defect in humans. Growth factors (GFs) are soluble proteins secreted by cells that regulate various cellular processes and tissue regeneration. At present, developing three-dimensional scaffolds for delivering GFs to the site of injury has become an important aspect in craniofacial bone regeneration. This study aims to develop a novel 3D bone substitute using lyophilized-platelet-rich fibrin (LyPRF) biocomposite scaffolds for potential application for CLP repair. Collagen (C), bioglass (BG), and LyPRF were used to fabricate a biocomposite (C-BG-LyPRF) scaffold. The physical, chemical, and biocompatibility properties of the scaffold were evaluated. The C-BG-LyPRF scaffold demonstrated a mean pore diameter of 146 µm within a porosity of 87.26%. The FTIR spectra verified the presence of am-ide I, II, and III functional groups. The inorganic phase of the C-BG-LyPRF scaffold was composed of sodium, calcium, silicon, and phosphorus, as determined by EDX analysis. Furthermore, C-BG-LyPRF scaffold was biocompatible with MC3T3-E1 cells in both the Live/Dead and prolif-eration assays. Data demonstrate the developed C-BG-LyPRF scaffold exhibits biomimetic and biocompatibility properties, establishing it as a promising biomaterial for craniofacial regeneration.
The injectable hydrogel loading cannabidiol to regulate macrophage polarization in vitro for the treatment of chronic enteritis
Chronic bowel disease has the characteristics of high recurrence rate, prolonged and non-healing, and the incidence has increased year by year in recent years. Cannabidiol (CBD) has significant anti-inflammatory and antioxidant activities, but it is limited by its characteristics of fat solubility and low bioavailability. This study aims to treat chronic inflammatory bowel disease by preparing a CBD-loaded hydrogel system (GelMA + CBD) that can deliver CBD in situ and improve its bioavailability through slow release.
Physical and mechanical properties assessment of glass ionomer cements modified with TiO and Mg-doped hydroxyapatite nanoparticles
High viscosity glass ionomer cements (GICs) are widely used in various clinical applications, being particularly effective in atraumatic restorative treatment (ART) due to the synergistic interaction between the material and the technique. However, the inadequate mechanical properties of GICs raise concerns regarding the predictability and longevity of these restorations in areas exposed to occlusal stress. Various modifications of the powder components have been proposed to improve the mechanical strength of GICs to withstand occlusal loading during mastication. In this in vitro study, we investigated whether the nanoparticles (NPs) added to commercially available GICs could fulfill this requirement, which would likely broaden the spectrum of their potential clinical applications. Two commercially available GIC powders (Fuji IX and Ketac Molar), modified by the addition of 5 wt.% TiO, MgHAp100 or MgHAp1000 NPs, were incorporated into the corresponding liquid in an appropriate ratio, and the mixed cements were evaluated in terms of fracture toughness, flexural strength, Vickers microhardness and rheological tests and compared with the original material. Fuji IX containing 5 wt.% MgHAp100 NPs had lower flexural strength, while Ketac Molar with 5 wt.% TiO NPs showed increased fracture toughness. Vickers microhardness increased in Fuji IX following the addition of 5 wt.% TiO and MgHAp100 but decreased in Ketac Molar comprising 5 wt.% MgHAp100 ( < 0.05). Achieving a predictable bond between NPs and cement matrix, as well as ensuring a uniform distribution of the NPs within the cement, are critical prerequisites for enhancing the mechanical performance of the original cement.
Improvement of corrosion resistance and adhesion of hydroxyapatite coating on AZ31 alloy by an anodizing intermediate layer
The primary objective of this study is using an anodizing intermediate layer to improve corrosion resistance and adhesion of hydroxyapatite coated AZ31 alloy for applications in biodegradable implants.
Effect of coating time on the formation of coating layer and degradation behavior of hydroxyapatite coated ZK60 alloy
This study aims to investigate the effect of coating time on the formation of hydroxyapatite (HA) coating layer on ZK60 substrate and understand the biodegradation behavior of the coated alloy for biodegradable implant applications.
Antimicrobial hard denture reliners using quaternary ammonium methacryloxy silicate (K18 QAMS) and K18-functionalized filler
To determine the effects of adding a quaternary ammonium methacryloxy silicate (K18) and K18-functionalized filler (K18-Filler) on the material and antimicrobial properties of a hard denture reline material.
Effect of atomization on the composition and structure of recombinant humanized collagen type III
Atomization is a treatment method to make inhaled liquids into aerosols and transport them to target organs in the form of fog or smoke. It has the advantages of improving the bioavailability of drugs, being painless, and non-invasive, and is now widely used in the treatment of lung and oral lesions. Aerosol inhalation as the route of administration of therapeutic proteins holds significant promise due to its ability to achieve high bioavailability in non-invasive pathways. Currently, a great number of therapeutic proteins such as alpha-1 antitrypsin and Dornase alfa are effective. Recombinant humanized collagen type III (rhCol III) as a therapeutic protein is widely used in the biomedical field, but atomization is not a common route of administration for rhCol III, presenting great potential for development. However, the structural stability of recombinant humanized collagen after atomization needs further investigation. This study demonstrated that the rhCol III subjected to atomization through compressed air had retained its original molecular weights, triple helical structures, and the ability to promote cell adhesion. In other words, the rhCol III can maintain its stability after undergoing atomization. Although more research is required to determine the efficacy and safety of the rhCol III after atomization, this study can lay the groundwork for future research.
Vanillin loaded-physically crosslinked PVA/chitosan/itaconic membranes for topical wound healing applications
Vanillin loaded-physically crosslinked hydrogel membranes made of PVA/chitosan/itaconic acid (PVA-CS-IA) were prepared using freezing-thawing (F-T) cycle method. To ensure the entanglement of PVA-CS-IA chains, three F-T cycles were repeated. The polymeric chains entanglements were confirmed and characterized by different instrumental characterizations. Physicochemical properties for example, swelling ratio, mechanical characteristics, gel fraction percentage (GF%), hydrolytic degradation, and thermal stability of PVA-CS-IA membrane were discussed in detail. The findings showed that the swelling ratio, mechanical characteristics, and hydrolytic degradation of the crosslinked membranes enhanced with increasing CS-IA contents in membranes composition; however, GF% gradually declined with CS-IA content. Additionally, cell viability test using HFB-4 cell line and antimicrobial activity against and were evaluated using MTT assay and the bacterium growth inhibition percentage method; respectively. Notably, with varying incubation durations and membrane concentrations, all examined constructed hydrogels showed significant cell survival percentages. The findings supported the notion that produced hydrogel membranes might be used in a professional setting as antibacterial dressings or biomaterials for quick wound healing rate.
Exploring the purity of chitin from crustacean sources using deep eutectic solvents: A machine learning approach
Chitin a natural polymer is abundant in several sources such as shells of crustaceans, mollusks, insects, and fungi. Several possible attempts have been made to recover chitin because of its importance in biomedical applications in various forms such as hydrogel, nanoparticles, nanosheets, nanowires, etc. Among them, deep eutectic solvents have gained much consideration because of their eco-friendly and recyclable nature. However, several factors need to be addressed to obtain a pure form of chitin with a high yield. The development of an innovative system for the production of quality chitin is of prime importance and is still challenging.
Impact of combining dental composite brushes with modeling resins on the color stability and topographic features of composites
This study explores the effect of using dental brushes with or without metacrylate-based modeling resins on long-term color stability and surface topographies of resin-based composites. This study examined the effects of two variables: (1) the type of brush used (Art brush, Micro-brush, or Mylar strip) and (2) the application of a modeling resin (applied or not applied). The specimens were artificially aged through 10,000 cycles of thermocycling and subsequently immersed in coffee for 30 days. Measurements of color and surface roughness were taken at baseline and after the aging, using a non-contact profilometer for surface roughness and a spectrophotometer for color. Data were analyzed using paired t-tests and one-way ANOVA. Resin-based composites smoothed with dental brushes or micro brushes without modeling resins exhibited lower color change (ΔE) than other groups. Paired t-tests revealed significant differences in average surface roughness (Ra) and valley depth (Rv) for each surfacing technique before and after aging ( ⩽ 0.01). The root means square average of the profile heights (Rq) significantly increased in the control and micro-brush groups ( ⩽ 0.01). In conclusion, the use of brushes in resin-based composites placement does not increase the susceptibility to staining. Instead, the inclusion of resin modeling contributes to discoloration over time.
Full-ceramic resin-bonded fixed dental prostheses: A systematic review
Despite the development of implant-supported prostheses, there are still patients for whom conservative treatments such as resin-bonded fixed dental prostheses (RBFDPs) are more appropriate. This study's objective was to analyze the available research on full-ceramic RBFDPs. In this study, Web of Science, MEDLINE/PubMed, Scopus, Embase, Cochrane Library, and Google Scholar databases were searched for articles published in English between 2010 and 2020. A total of 14 studies were reviewed based on the eligibility criteria. The results showed that using a cantilever design with one abutment had an advantage over two abutments. Additionally, it was proposed that preparations designed with retentive aids, such as a proximal box, groove, and pinhole, could improve RBFDP survival rates. IPS e.max ZirCAD, In-Ceram alumina, and zirconia CAD/CAM were the most commonly used framework materials. Most studies used air abrasion, salinization, or hydrofluoric acid for surface treatment. Adhesive resin cements were the most frequently used type of cement. The survival rate of In-Ceram ceramics (85.3%-94.8%) was lower than that of In-Ceram zirconia and IPS e.max ZirCAD. Debonding, followed by framework fracture, was the leading cause of failure. Following 3-10 years follow-up, the survival percentage of all-ceramic RBFDPs ranged from 76% to 100%. Although RBFDPs have demonstrated satisfactory success as a conservative treatment, long-term follow-ups and higher sample sizes in clinical research are required to gain more reliable outcomes on the clinical success rate of various RBFDP designs.
Engineering VEGF-like peptide QKCMP promotes rapid endothelialization of blood vessels
Angiogenesis, which involves many essential processes, such as human reproduction, organ development, and wound healing, is regulated by multiple signaling pathways. QKCMP is a polypeptide with similar effects to vascular endothelial growth factor (VEGF), which promotes angiogenesis. In this study, zebrafish were treated with different concentrations of QKCMP, and it was found that QKCMP significantly promoted the growth of blood vessels. Human umbilical vein endothelial cells (HUVECs) was then treated with different concentrations of QKCMP, which proved that QKCMP could promote cell proliferation and inhibit cell apoptosis, and thus obtain a complete gene expression matrix. Genes and biological functions or pathways significantly associated with QKCMP were obtained using differential gene expression analysis, weighted gene co-expression network analysis (WGCNA), and enrichment analyses. Among them, genes significantly related to QKCMP are enriched in biological processes (BP) such as vascular formation and development, as well as the main signaling pathway: PI3K/AKT signaling pathway. The proproliferative and antiapoptotic effects of QKCMP on the HUVECs and the induction of cell cycle were then verified using cell counting kit 8 (CCK-8) and flow cytometry. Finally, it was confirmed that QKCMP promotes angiogenesis and rapid endothelialization by stimulating the PI3K-AKT and Hippo signaling pathways using quantitative real-time PCR (qRT-PCR) and western blot (WB).