Goldmanmathiesen3163

Materials modified with ammonium groups on the surface have shown antibacterial activity. In this paper, alkyl chains, carbosilane (CBS) dendrimers and dendrons and poly(amidoamine) (PAMAM) dendrimers containing amine and ammonium groups have been grafted to silica surface and the influence of molecule structure on the stability and on antibacterial activity have been evaluated. These materials have been characterized by thermogravimetric analysis (TGA), zeta (Z) potential, scanning electron microscopy (SEM), infrared spectroscopy (IR) and nuclear magnetic resonance (13C CP MAS NMR). The degree of silica functionalization depends on type of outer groups, amine or ammonium, type and core of dendrimer, and length of chains. The Z potential measurements of these materials in water suspensions were used to test their stability in this medium. These measurements showed, for some of the modified silicas, the diminishing of Z potential from positive values toward zero, probably due to interaction of the functional groups with the silica surface. This variation was also dependent on ligand structure and peripheral functions. Finally, studies of inhibition of bacteria growth stand out again the relevance of ligand structure and number of functional groups on silica surface. The most active systems were those with more surface covered, those with cationic groups further away from silica surface and higher dendritic generation. Breast cancer is a major cause of death among women worldwide. Resistance to conventional therapies has been observed in HER2-positive breast cancer patients, indicating the need for more effective treatments. Small interfering RNA (siRNA) therapy is an attractive strategy against HER2-positive tumors, but its success depends largely on the efficient delivery of agents to target tissues. check details In this study, we prepared a magnetic hybrid nanostructure composed of iron oxide nanoparticles coated with caffeic acid and stabilized by layers of calcium phosphate and PEG-polyanion block copolymer for incorporation of siRNA. Transmission electron microscopy images showed monodisperse, neutrally charged compact spheres sized less then 100 nm. Dynamic light scattering and nanoparticle tracking analysis revealed that the nanostructure had an average hydrodynamic diameter of 130 nm. Nanoparticle suspensions remained stable over 42 days of storage at 4 and 25 °C. Unloaded caffeic acid-magnetic calcium phosphate (Caf-MCaP) nanoparticles were not cytotoxic, and loaded nanoparticles were successfully taken up by the HER2-positive breast cancer cell line HCC1954, even more so under magnetic guidance. Nanoparticles escaped endosomal degradation and delivered siRNA into the cytoplasm, inducing HER2 gene silencing. The current gold standard for nasal reconstruction after rhinectomy or severe trauma includes transposition of autologous cartilage grafts in conjunction with coverage using an autologous skin flap. Harvesting autologous cartilage requires a major additional procedure that may create donor site morbidity. Major nasal reconstruction also requires sculpting autologous cartilages to form a cartilage framework, which is complex, highly skill-demanding and very time consuming. These limitations have prompted facial reconstructive surgeons to explore different techniques such as tissue engineered cartilage. This work explores the use of multi-material 3D bioprinting with chondrocyte-laden gelatin methacrylate (GelMA) and polycaprolactone (PCL) to fabricate constructs that can potentially be used for nasal reconstruction. In this study, we have investigated the effect of 3D manufacturing parameters including temperature, needle gauge, UV exposure time, and cell carrier formulation (GelMA) on the viability and functionality of chondrocytes in bioprinted constructs. Furthermore, we printed chondrocyte-laden GelMA and PCL into composite constructs to combine biological and mechanical properties. It was found that 20% w/v GelMA was the best concentration for the 3D bioprinting of the chondrocytes without comprising the scaffold's porous structure and cell functionality. In addition, the 3D bioprinted constructs showed neocartilage formation and similar mechanical properties to nasal alar cartilage after a 50-day culture period. Neocartilage formation was also observed in the composite constructs evidenced by the presence of glycosaminoglycans and collagen type II. This study shows the feasibility of manufacturing neocartilage using chondrocytes/GelMA/PCL 3D bioprinted porous constructs which could be applied as a method for fabricating implants for nose reconstruction. As one of the most effective treatments of end-stage liver disease, liver transplantation still suffers from a shortage of donor organs or a low degree of engraftment. Thus, alternatives to liver transplantation, such as liver support systems, have to be extensively explored. In this study, a novel liver microtissue with an inner gear-like structure, which achieved a larger body surface area, was designed and manufactured to improve hepatic functional restoration. The liver-specific bioinks were developed by combining photocurable methacrylated gelatin (GelMA) with liver decellularized extracellular matrix (dECM), and human-induced hepatocytes (hiHep cells) were encapsulated to form cell-laden bioinks. The mechanical properties, swelling, and cytocompatibility of GelMA/dECM bioinks were carefully characterized before 3D printing. Then, the digital light process (DLP)-based bioprinting was used to fabricate the liver microtissue, and liver dECM was found to improve both the printability and cell viability of GelMA bioinks. hiHep cells were also found to spread farther and have better hepatocyte-specific functions (albumin secretion and urea) in the liver microtissue when liver dECM was added to the GelMA bioinks. Our results provide a promising liver dECM-based cell-laden bioink for liver microtissue fabrication, which would be a potential liver tissue engineering product to help restore hepatic functions. Implantable medical devices infection and consequent failure is a severe health issue, which can result from bacterial adhesion, growth, and subsequent biofilm formation at the implantation site. Graphene-based materials, namely graphene oxide (GO), have been described as potential antibacterial agents when immobilized and exposed in polymeric matrices. This work focuses on the development of antibacterial and biocompatible 3D fibrous scaffolds incorporating GO. Poly(ε-caprolactone) scaffolds were produced, with and without GO, using wet-spinning combined with additive manufacturing. Scaffolds with different GO loadings were evaluated regarding physical-chemical characterization, namely GO surface exposure, antibacterial properties, and ability to promote human cells adhesion. Antimicrobial properties were evaluated through live/dead assays performed with Gram-positive and Gram-negative bacteria. 2 h and 24 h adhesion assays revealed a time-dependent bactericidal effect in the presence of GO, with death rates of adherent S. epidermidis and E. coli reaching ~80% after 24 h of contact with scaffolds with the highest GO concentration. Human fibroblasts cultured for up to 14 days were able to adhere and spread over the fibers, independently of the presence of GO. Overall, this work demonstrates the potential of GO-containing fibrous scaffolds to be used as biomaterials that hinder bacterial infection, while allowing human cells adhesion. V.Cardiovascular diseases (CVD) are a major cause of mortality worldwide. Accessibility to heart tissue is limited due to sampling issues and lack of appropriate culture conditions. In addition, animal models are not an ideal choice for physiological, pharmacological, and fundamental evaluations in the cardiovascular field due to interspecies differences. Hence, there is an inevitable need for functional in vitro cardiac models. In this study, we have synthesized a novel electroconductive scaffold comprised of cardiac extracellular matrix (ECM) derived pre-cardiogel (pCG) blended with polypyrrole (Ppy). Our data revealed that 2.5% (w/v) pyrrole (Py) had the highest possible Py ratio that provided pCG-Ppy gel formation. The prepared mixture was fabricated into a scaffold by using the freeze-dried method. The scaffolds had open interconnected pores that ranged from 55 ± 24 μm for the cardiogel (CG)-Ppy to 74 ± 26 μm for the CG scaffolds, with no alterations in vital ECM components of collagen, polysaccharides, and glycosaminoglycans (GAGs). Incorporation of Ppy increased the CG stiffness with a final complex modulus from 80 pa to 140 pa. The CG-Ppy group had significantly greater electrical conductivity than the CG group. Scaffolds supported neonatal mouse cardiomyocyte (NMCM) adhesion, viability, cardiac-specific gene expression, and spontaneous beating up to 14 days after seeding. Among the fabricated hydrogels, the CG-Ppy group resulted in the synchronous beating of cardiomyocyte clusters and upregulation of cardiac genes involved in cardiac muscle contraction (cardiac troponin T [cTNT]) and cardiomyocyte electrical coupling (connexin 43 [Cx43]). Thus, this ECM-based electro-conductive scaffold might provide a promising substrate for constructing in vitro cardiac models for drug testing, disease modeling, developmental studies, and cardiac regenerative approaches. Metallic nanoparticles (NPs) possess unique properties which makes them attractive candidates for various applications especially in field of experimental medicine and drug delivery. Many approaches were developed to synthesize divers and customized metallic NPs that can be useful in many areas such as, experimental medicine, drug design, drug delivery, electrical and electronic engineering, electrochemical sensors, and biochemical sensors. Among different metallic nanoparticles, manganese (Mn) NPs are the most prominent materials, in the present study, we have synthetized unique Mn0.5Zn0.5DyxEuxFe1.8-2xO4 NPs by using ultrasonication method (x ≤ 0.1). The structure, and surface morphology of Mn0.5Zn0.5DyxEuxFe1.8-2xO4 NPs was characterized by XRD, SEM, TEM and EDX methods. We have examined the biological effects of Mn0.5Zn0.5DyxEuxFe1.8-2xO4 NPs on both normal (HEK-293) and cancerous (HCT-116) cells. We have found that the treatment of Mn0.5Zn0.5DyxEuxFe1.8-2xO4 NPs post 48 h, showed significant decline in cancer cells population as revealed by MTT assay. The IC50 value of Mn0.5Zn0.5DyxEuxFe1.8-2xO4 NPs was ranged between (2.35 μg/mL to 2.33 μg/mL). To check the specificity of the actions, we found that the treatment of Mn0.5Zn0.5DyxEuxFe1.8-2xO4 NPs did not produce any effects on the normal cells, which suggest that Mn0.5Zn0.5DyxEuxFe1.8-2xO4 NPs selectively targeted the cancerous cells. The anti-bacterial properties of Mn0.5Zn0.5DyxEuxFe1.8-2xO4 NPs were also evaluated by MIC and MBC assays. We suggest that Mn0.5Zn0.5DyxEuxFe1.8-2xO4 NPs produced by sonochemical method possess potential anti-cancer and anti-bacterial capabilities. Periodontal disease is a common complication and conventional periodontal surgery can lead to severe bleeding. Guided tissue regeneration (GTR) membranes favor periodontal regrowth, but they still have limitations, such as improper biodegradation, poor mechanical property, and no effective hemostatic property. To overcome these shortcomings, we generated unique multifunctional scaffolds. A chitosan/polycaprolactone/gelatin sandwich-like construction was fabricated by electrospinning and lyophilization. These composite scaffolds showed favorable physicochemical properties, including appropriate porosity ( less then 50%), pore size (about 10 μm) and mechanical stability (increasing with more PCL), good swelling and hydrophilicity. Appropriate degradation rates were approved by degradability analysis in vitro and in vivo, which resembled tissue regeneration process more closely. As shown in cell viability assay, cell attachment assay and Sirius red staining, we knew that the scaffolds had good biocompatibility, did not adversely affect cell ability for attachment, and induced high levels of collagen secretion.