Poss pcu

In situ endothelialization of cardiovascular implants has emerged in recent years as an attractive means of targeting the persistent problems of thrombosis and intimal hyperplasia. This study aimed to investigate the efficacy of immobilizing anti-CD34 antibodies onto a POSS-PCU nanocomposite polymer surface to sequester endothelial progenitor cells (EPCs) from human blood, and to characterize the surface properties and hemocompatibility of this surface. Amine-functionalized fumed silica was used to covalently conjugate anti-CD34 to the polymer surface...

With the continuous and expanding use of implantable biomaterials in a clinical setting, this study aims to elucidate the influence of sterilization techniques on the material surface and bulk properties of two polyurethane nanocomposite biomaterials. Both solid samples and porous membranes of nondegradable polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane (POSS-PCU) and a biodegradable poly(caprolactone-urea) urethane (POSS-PCL) were examined. Sterilization techniques included conventional steam sterilization (autoclaving), gamma irradiation, and disinfection via incubating with ethanol (EtOH) for 10 min or 24 h...

UNLABELLED: Scaffold cellularization for cartilage engineering can aid implant properties, their retention and minimize repeated intervention, particularly in paediatric reconstructive craniofacial surgery. We developed novel bionanoscaffolds using paediatric adipose tissue-derived stem cells (hADSCs), an accessible autologous cell source, and POSS-PCU. Little is known about cellular responses to this nanomaterial, though it was used in human. We assessed: 1) POSS-PCU cellularization and bioaffinity to hADSCs; 2) hADSC chondrogenic differentiation ability in POSS-PCU; 3) whether bionanoscaffolds became encased within a vascular network and/or vascularised...

UNLABELLED: Auricular reconstruction using sculpted autologous costal cartilage is effective, but complex and time consuming and may incur donor site sequelae and morbidity. Conventional synthetic alternatives are associated with infection and extrusion in up to about 15% of cases. We present a novel POSS-PCU nanocomposite auricular scaffold, which aims to reduce extrusion rates by mimicking the elastic modulus of human ears and by encouraging desirable cellular interactions. The fabrication, physicochemical properties (including nanoscale topography) and cellular interactions of these scaffolds were compared to Medpor®, the current synthetic standard...

With the continuous and expanding use of implantable biomaterials in a clinical setting, this study aims to elucidate the influence of sterilization techniques on the material surface and bulk properties of two polyurethane nanocomposite biomaterials. Both solid samples and porous membranes of nondegradable polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane (POSS-PCU) and a biodegradable poly(caprolactone-urea) urethane (POSS-PCL) were examined. Sterilization techniques included conventional steam sterilization (autoclaving), gamma irradiation, and disinfection via incubating with ethanol (EtOH) for 10 min or 24 h...

Despite extensive research into cartilage tissue engineering (CTE), there is still no scaffold ideal for clinical applications. Various synthetic and natural polymers have been investigated in vitro and in vivo, but none have reached widespread clinical use. The authors investigate the potential of POSS-PCU, a synthetic nanocomposite polymer, for use in CTE. POSS-PCU is modified with silsesquioxane nanostructures that improve its biological and physical properties. The ability of POSS-PCU to support the growth of ovine nasoseptal chondrocytes was evaluated against a polymer widely used in CTE, polycaprolactone (PCL)...

UNLABELLED: Quantum dots (QDs) are utilised in imaging diagnostics, tissue engineering and medical therapeutics, however, their influence on vascular function is not ascertained. Here, we examined small mesenteric arterial responses after acute intravascular exposure to QDs. Incubation in mercaptoundecanoic acid (MUA)-coated QDs (at 15 μg/mL) had no influence on endothelial-dependent dilator responses (Acetylcholine; Ach) but led to an attenuated relaxation to the nitric oxide donor, sodium nitroprusside (SNP)...

In 2011, the first in-man successful transplantation of a tissue engineered trachea-bronchial graft, using a synthetic POSS-PCU nanocomposite construct seeded with autologous stem cells, was performed. To further improve this technology, we investigated the feasibility of using polymers with a three dimensional structure more closely mimicking the morphology and size scale of native extracellular matrix (ECM) fibers. We therefore investigated the in vitro biocompatibility of electrospun polyethylene terephthalate (PET) and polyurethane (PU) scaffolds, and determined the effects on cell attachment by conditioning the fibers with adhesion proteins...

BACKGROUND: The application of nanotechnology in biology and medicine represents a significant paradigm shift in the approach to the treatment of cancer. Evidence suggests that when exposed to near-infrared radiation (NIR), carbon nanotubes (CNTs) dissipate a substantial amount of heat energy. We have developed a novel nanocomposite polymer, polyhedral oligomeric silsesquioxane poly (carbonate-urea) urethane (POSS-PCU). POSS-PCU displays excellent biocompatibility and has been used in making artificial organs as well as protective coatings for medical devices...

PURPOSE: To physiologically test the durability of a sutureless aortic stent-graft based on nitinol bonded to polyhedral oligomeric silsesquioxane (POSS) and poly(carbonate-urea) urethane (PCU) for 10 years according to Food and Drug Administration guidelines. METHODS: Aortic stent-grafts (n = 4) were tested in 37°C distilled water using simulated in vivo hydrodynamic pulse loading. After 400 million cycles, surface topography was assessed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy...

Cardiovascular implants must resist infection and thrombosis. A nanocomposite polymeric material [polyhedral-oligomeric-silsesquioxane-poly(carbonate-urea)urethane; POSS-PCU] demonstrates ideal properties for cardiovascular applications. Silver nanoparticles or nanosilver (NS) are recognized for efficient antibacterial properties. This study aims to determine the influence of NS integrated POSS-PCU on thrombogenicity. Silver nitrate was reduced with dimethylformamide and stabilized by the inclusion of fumed silica nanoparticles to prevent aggregation of NS and were incorporated into POSS-PCU to form a range of POSS-PCU-NS concentrations (by weight); 0...

Synthetic leaflet heart valves have been widely studied as possible alternatives to the current mechanical and bioprosthetic valves. Assessing the in vitro hydrodynamic function of these prostheses is of great importance to predict their hemodynamic behaviour prior to implantation. This study introduces an innovative concept of a low-profile semi-stented surgical aortic valve (SSAV) made of a novel nanocomposite polyurethane with a polycarbonate soft segment (PCU) and polyhedral oligomeric silsesquioxane (POSS) nanoparticles covalently bonded as a pendant cage to the hard segment...

Composite materials based on the coupling of conductive organic polymers and carbon nanotubes have shown that they possess properties of the individual components with a synergistic effect. Multi-wall carbon nanotube (MWCNT)/ polymer composites are hybrid materials that combine numerous mechanical, electrical and chemical properties and thus, constitute ideal biomaterials for a wide range of regenerative medicine applications. Although, complete dispersion of CNT in a polymer matrix has rarely been achieved, in this study we have succeeded high dispersibility of CNT in POSS-PCU and POSS-PCL, novel polymers based on polyprolactone and polycarbonate polyurethane (PCU) and poly(caprolactoneurea)urethane both having incorporated polyhedral oligomeric silsesquioxane (POSS)...

Lacrimal surgery in cases of severely obstructed or missing canalicular ducts is highly challenging. In these cases, the placement of a bypass tube is currently the only option to restore the drainage of tears into the nose and reduce the symptomatic watery eye. Different approaches to achieve functional drainage have been tried using blood vessels or artificial implants. The implantation of the rigid Lester Jones tube is, since its introduction in the late 1960s, the gold standard. The functional success is satisfactory...

There is a significant worldwide demand for a small calibre vascular graft for use as a bypass or replacement conduit. An important feature in determining the success of a graft is the wall structure, which includes porosity, pore size and pore interconnectivity, as these play a crucial role in determining the long-term patency of a bypass graft. In this study we fabricate a small diameter (<5mm) vascular graft from polyhedral oligomeric silsesquioxane-poly(carbonate urea)urethane (POSS-PCU) via an extrusion, phase inversion method using an automated, custom built machine...

In this study, central composite design (CCD) was used to develop predictive models to optimize operating conditions of plasma surface modification. It was concluded that out of the two process variables, power and duration of plasma exposure, the latter was significantly affecting the surface energy (γ(s) ), chemistry, and topography of polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU) films. On the basis of experimental data, CCD was used to model the γ(s) using a quadratic modeling of the process variables to achieve optimum surface energy to improve the interaction between endothelial cells (ECs)...

Stent angioplasty is a successful treatment for arterial occlusion, particularly in coronary artery disease. The clinical communities were enthusiastic about the use of drug-eluting stents; however, these stents have a tendency to be a contributory factor towards late stage thrombosis, leading to mortality in a significant number of patients per year. This work presents an innovative approach in self-expanding coronary stents preparation. We developed a new nanocomposite polymer based on polyhedral oligomeric silsesquioxanes (POSS) and poly(carbonate-urea)urethane (PCU), which is an antithrombogenic and a non-biodegradable polymer with in situ endothelialization properties...

Small calibre (〈6mm) polytetrafluoroethylene (PTFE) bypass grafts have poor medium and long term patency due to the development of neointimal hyperplasia at the distal anastomosis. The inelasticity of PTFE is implicated in this mechanism of failure. We have developed a novel polyhedral oligomeric silsesquioxane (POSS) nanocage incorporated into a poly(carbonate)urethane (PCU) biomaterial with enhanced biostability and improved antithrombogenicity making it ideal for cardiovascular applications. In this study the compliance and viscous component of a POSS-PCU small calibre graft was measured using a biomimetic pulsatile flow circuit and wall tracking ultrasound...

Multi-wall carbon nanotube (MWCNT)/polymer composites are hybrid materials that combine numerous mechanical, electrical and chemical properties and thus, constitute ideal biomaterials for a wide range of regenerative medicine applications. Although, complete dispersion of MWCNT in a polymer matrix has rarely been achieved, in this study we have studied the dispersibility of MWCNT in POSS-PCU, a novel polymer based on polyprolactone and polycarbonate polyurethane (PCU) with an incorporated polyhedral oligomeric silsesquioxane (POSS)...

Calcification currently represents a major cause of failure of biological tissue heart valves. It is a complex phenomenon influenced by a number of biochemical and mechanical factors. Recent advances in material science offer new polymers with improved properties, potentially suitable for synthetic leaflets heart valves manufacturing. In this study, the calcification-resistance efficacy and mechanical and surface properties of a new nanocomposite polymeric material (polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane; POSS-PCU) which has been developed by our group are assessed by means of in vitro testing...