ORCID Profile
0000-0003-1498-9393
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Publisher: Wiley
Date: 17-10-2022
Abstract: Native arteries contain a distinctive intima‐media composed of organized elastin and an adventitia containing mature collagen fibrils. In contrast, implanted biodegradable small‐diameter vascular grafts do not present spatially regenerated, organized elastin. The elastin‐containing structures within the intima‐media region encompass the elastic lamellae (EL) and internal elastic lamina (IEL) and are crucial for normal arterial function. Here, the development of a novel electrospun small‐diameter vascular graft that facilitates de novo formation of a structurally appropriate elastin‐containing intima‐media region following implantation is described. The graft comprises a non‐porous microstructure characterized by tropoelastin fibers that are embedded in a PGS matrix. After implantation in mouse abdominal aorta, the graft develops distinct cell and extracellular matrix profiles that approximate the native adventitia and intima‐media by 8 weeks. Within the newly formed intima‐media region there are circumferentially aligned smooth muscle cell layers that alternate with multiple EL similar to that found in the arterial wall. By 8 months, the developed adventitia region contains mature collagen fibrils and the neoartery presents a distinct IEL with thickness comparable to that in mouse abdominal aorta. It is proposed that this new class of material can generate the critically required, organized elastin needed for arterial regeneration.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0BM01284J
Abstract: This review highlights the importance of flow in medical device thrombosis and explores current and emerging technologies to evaluate dynamic biomaterial Thrombosis in vitro .
Publisher: Elsevier BV
Date: 09-2021
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2023
DOI: 10.1161/ATVBAHA.122.318238
Abstract: Medical devices form a critical component of health care systems for treating and maintaining patient health. However, devices exposed to blood are prone to blood clotting (thrombosis) and bleeding complications leading to device occlusion, device failure, embolism and stroke, and increased morbidity and mortality. Over the years, developments in innovative material design strategies have been made to help reduce the occurrence of thrombotic events on medical devices, but complications persist. Here, we review material and surface coating technologies that have taken bioinspiration from the endothelium to reduce medical device thrombosis, either by mimicking aspects of the glycocalyx to prevent adhesion of proteins and cells to the material surface or mimicking the bioactive function of the endothelium through immobilized or released bioactive molecules to actively inhibit thrombosis. We highlight newer strategies that take inspiration from multiple aspects of the endothelium or are stimuli responsive, only releasing antithrombotic biomolecules when thrombosis is triggered. Emerging areas of innovation target inflammation to decrease thrombosis without increasing bleeding, and interesting results are coming from underexplored aspects of material properties, such as material interfacial mobility and stiffness, which show that increased mobility and decreased stiffness are less thrombogenic. These exciting new strategies require further research and development before clinical translation, including consideration of longevity, cost, and sterilization, but show capacity for the development of more sophisticated antithrombotic medical device materials.
Publisher: Elsevier BV
Date: 11-2010
DOI: 10.1016/J.BIOMATERIALS.2010.07.062
Abstract: Current endovascular stents have sub-optimal biocompatibility reducing their clinical efficacy. We previously demonstrated a plasma-activated coating (PAC) that covalently bound recombinant human tropoelastin (TE), a major regulator of vascular cells in vivo, to enhance endothelial cell interactions. We sought to develop this coating to enhance its mechanical properties and hemocompatibility for application onto coronary stents. The plasma vapor composition was altered by incorporating argon, nitrogen, hydrogen or oxygen to modulate coating properties. Coatings were characterized for 1) surface properties, 2) mechanical durability, 3) covalent protein binding, 4) endothelial cell interactions and 5) thrombogenicity. The N(2)/Ar PAC had optimal mechanical properties and did not delaminate after stent expansion. The N(2)/Ar PAC was mildly hydrophilic and covalently bound the highest proportion of TE, which enhanced endothelial cell proliferation. Acute thrombogenicity was assessed in a modified Chandler loop using human blood. Strikingly, the N(2)/Ar PAC alone reduced thrombus weight by ten-fold compared to 316L SS, a finding unaltered with immobilized TE. Serum soluble P-selectin was reduced on N(2)/Ar PAC and N(2)/Ar PAC + TE (p < 0.05), consistent with reduced platelet activation. We have demonstrated a coating for metal alloys with multifaceted biocompatibility that resists delamination and is non-thrombogenic, with implications for improving coronary stent efficacy.
Publisher: Springer Science and Business Media LLC
Date: 14-09-2014
DOI: 10.1038/NM.3640
Abstract: Here we describe a blood-cleansing device for sepsis therapy inspired by the spleen, which can continuously remove pathogens and toxins from blood without first identifying the infectious agent. Blood flowing from an infected in idual is mixed with magnetic nanobeads coated with an engineered human opsonin--mannose-binding lectin (MBL)--that captures a broad range of pathogens and toxins without activating complement factors or coagulation. Magnets pull the opsonin-bound pathogens and toxins from the blood the cleansed blood is then returned back to the in idual. The biospleen efficiently removes multiple Gram-negative and Gram-positive bacteria, fungi and endotoxins from whole human blood flowing through a single biospleen unit at up to 1.25 liters per h in vitro. In rats infected with Staphylococcus aureus or Escherichia coli, the biospleen cleared >90% of bacteria from blood, reduced pathogen and immune cell infiltration in multiple organs and decreased inflammatory cytokine levels. In a model of endotoxemic shock, the biospleen increased survival rates after a 5-h treatment.
Publisher: American Chemical Society (ACS)
Date: 23-01-2018
Publisher: Informa UK Limited
Date: 1979
Publisher: Proceedings of the National Academy of Sciences
Date: 15-08-2011
Abstract: Immobilizing a protein, that is fully compatible with the patient, on the surface of a biomedical device should make it possible to avoid adverse responses such as inflammation, rejection, or excessive fibrosis. A surface that strongly binds and does not denature the compatible protein is required. Hydrophilic surfaces do not induce denaturation of immobilized protein but exhibit a low binding affinity for protein. Here, we describe an energetic ion-assisted plasma process that can make any surface hydrophilic and at the same time enable it to covalently immobilize functional biological molecules. We show that the modification creates free radicals that migrate to the surface from a reservoir beneath. When they reach the surface, the radicals form covalent bonds with biomolecules. The kinetics and number densities of protein molecules in solution and free radicals in the reservoir control the time required to form a full protein monolayer that is covalently bound. The shelf life of the covalent binding capability is governed by the initial density of free radicals and the depth of the reservoir. We show that the high reactivity of the radicals renders the binding universal across all biological macromolecules. Because the free radical reservoir can be created on any solid material, this approach can be used in medical applications ranging from cardiovascular stents to heart-lung machines.
Publisher: American Chemical Society (ACS)
Date: 22-12-2023
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.BIOMATERIALS.2014.04.082
Abstract: Polymers currently utilized for dermal and vascular applications possess sub-optimal biocompatibility which reduces their efficacy. Improving the cell-binding and blood-contacting properties of these polymers would substantially improve their clinical utility. Tropoelastin is a highly extensible extracellular matrix protein with beneficial cell interactive and low thrombogenic properties. We transferred these benefits to the polyurethane block copolymer Elast-Eon E2A through a specific combination of surface plasma modifications and coating with human tropoelastin. The cell-binding activity of bound tropoelastin was modulated by ion implantation of the underlying polymer, and correlated with surface hydrophobicity, carbon and oxygen content. This combined treatment enhanced human dermal fibroblast (HDF) and human umbilical vein endothelial cell (HUVEC) attachment, cytoskeletal assembly and viability, combined with elevated PECAM-1 staining of HUVEC cell junctions. The thrombogenicity of the polymer was ameliorated by tropoelastin coating. We propose that a combination of metered plasma treatment and tropoelastin coating of Elast-Eon can serve to improve the biological performance of implantable devices such as vascular conduits.
Publisher: Elsevier BV
Date: 03-2011
Publisher: Elsevier BV
Date: 10-2017
Publisher: Springer Science and Business Media LLC
Date: 12-10-2014
DOI: 10.1038/NBT.3020
Abstract: Thrombosis and biofouling of extracorporeal circuits and indwelling medical devices cause significant morbidity and mortality worldwide. We apply a bioinspired, omniphobic coating to tubing and catheters and show that it completely repels blood and suppresses biofilm formation. The coating is a covalently tethered, flexible molecular layer of perfluorocarbon, which holds a thin liquid film of medical-grade perfluorocarbon on the surface. This coating prevents fibrin attachment, reduces platelet adhesion and activation, suppresses biofilm formation and is stable under blood flow in vitro. Surface-coated medical-grade tubing and catheters, assembled into arteriovenous shunts and implanted in pigs, remain patent for at least 8 h without anticoagulation. This surface-coating technology could reduce the use of anticoagulants in patients and help to prevent thrombotic occlusion and biofouling of medical devices.
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.COLSURFB.2014.01.042
Abstract: Current vascular biomaterials exhibit poor biocompatibility characterised by failure to promote endothelialisation, predisposition to neoinitmal hyperplasia and excessive thrombogenicity. Fibrillin-1, a major constituent of microfibrils is associated with elastic fibres in the arterial wall. Fibrillin-1 binds to endothelial cells through an RGD cell adhesion motif in the fourth TB module. The RGD motif is present in PF8, a recombinant fibrillin-1 fragment. We investigated the potential of PF8 to improve the biocompatibility of PTFE. PF8 enhanced endothelial cell attachment and cell proliferation to a greater extent than fibronectin (p<0.01). PF8 immobilised on PTFE using plasma immersion ion implantation (PIII), retained these favourable cell interactive properties, again promoting endothelial cell attachment and proliferation. The thrombogenicity of covalently bound PF8 on PTFE was assessed in both static and dynamic conditions. In static conditions, uncoated PIII treated PTFE was more thrombogenic than untreated PTFE, while PF8 coating reduced thrombogenicity. Under flow, there was no difference in the thrombogenicity of PF8 coated PTFE and untreated PTFE. Immobilised PF8 shows a striking ability to promote attachment and growth of endothelial cells on PTFE, while providing a non-thrombogenic surface. These features make PF8 a promising candidate to improve the biocompatibility of current synthetic vascular grafts.
Publisher: Informa UK Limited
Date: 1979
Publisher: Springer Science and Business Media LLC
Date: 06-01-2016
DOI: 10.1038/NCOMMS10176
Abstract: Accurate assessment of blood haemostasis is essential for the management of patients who use extracorporeal devices, receive anticoagulation therapy or experience coagulopathies. However, current monitoring devices do not measure effects of haemodynamic forces that contribute significantly to platelet function and thrombus formation. Here we describe a microfluidic device that mimics a network of stenosed arteriolar vessels, permitting evaluation of blood clotting within small s le volumes under pathophysiological flow. By applying a clotting time analysis based on a phenomenological mathematical model of thrombus formation, coagulation and platelet function can be accurately measured in vitro in patient blood s les. When the device is integrated into an extracorporeal circuit in pig endotoxemia or heparin therapy models, it produces real-time readouts of alterations in coagulation ex vivo that are more reliable than standard clotting assays. Thus, this disposable device may be useful for personalized diagnostics and for real-time surveillance of antithrombotic therapy in clinic.
Publisher: Elsevier BV
Date: 11-2012
DOI: 10.1016/J.BIOMATERIALS.2012.07.059
Abstract: Bare metal and drug-eluting coronary stents suffer an inherent lack of vascular cell and blood compatibility resulting in adverse patient responses. We have developed a plasma-activated coating (PAC) for metallic coronary stents that is durable, withstands crimping and expansion, has low thrombogenicity and can covalently bind proteins, linker-free. This has been shown to enhance endothelial cell interactions in vitro and has the potential to promote biointegration of stents. Using the rabbit denuded iliac artery model, we show for the first time that PAC is a feasible coating for coronary stents in vivo. The coating integrity of PAC was maintained following implantation and expansion. The rate of endothelialization, strut coverage, neointimal response and the initial immune response were equivalent to bare metal stents. Furthermore, the initial thrombogenicity caused by the PAC stents showed a reduced trend compared to bare metal stents. This work demonstrates a robust, durable, non-cytotoxic plasma-based coating technology that has the ability to covalently immobilize bioactive molecules for surface modification of coronary stents. Improvements in the clinical performance of implantable cardiovascular devices could be achieved by the immobilization of proteins or peptides that trigger desirable cellular responses.
Publisher: Elsevier BV
Date: 02-2013
Publisher: Ocean Drilling Program
Date: 14-11-2003
Publisher: American Geophysical Union
Date: 1987
DOI: 10.1029/GD019P0039
Publisher: Elsevier BV
Date: 03-1985
Publisher: Elsevier BV
Date: 03-2009
DOI: 10.1016/J.BIOMATERIALS.2008.11.009
Abstract: Currently available endovascular metallic implants such as stents exhibit suboptimal biocompatibility in that they re-endothelialise poorly leaving them susceptible to thrombosis. To improve the interaction of these implants with endothelial cells we developed a surface coating technology, enabling the covalent attachment of biomolecules to previously inert metal surfaces. Using horseradish peroxidase as a probe, we demonstrate that the polymerised surface can retain the presentation and activity of an immobilised protein. We further demonstrated the attachment of tropoelastin, an extracellular matrix protein critical to the correct arrangement and function of vasculature. Not only it is structurally important, but it plays a major role in supporting endothelial cell growth, while modulating smooth muscle cell infiltration. Tropoelastin was shown to bind to the surface in a covalent monolayer, supplemented with additional physisorbed multilayers on extended incubation. The physisorbed tropoelastin layers can be washed away in buffer or SDS while the first layer of tropoelastin remains tightly bound. The plasma coated stainless steel surface with immobilised tropoelastin was subsequently found to have improved biocompatibility by promoting endothelial cell attachment and proliferation relative to uncoated stainless steel controls. Tropoelastin coatings applied to otherwise inert substrates using this technology could thus have broad applications to a range of non-polymeric vascular devices.
Publisher: Oxford University Press (OUP)
Date: 08-2013
DOI: 10.1002/STEM.1426
Abstract: Robust development of the early embryo may benefit from mechanisms that ensure that not all pluripotent cells differentiate at exactly the same time: such mechanisms would build flexibility into the process of lineage allocation. This idea is supported by the observation that pluripotent stem cells differentiate at different rates in vitro. We use a clonal commitment assay to confirm that pluripotent cells commit to differentiate asynchronously even under uniform differentiation conditions. Stochastic variability in expression of the Notch target gene Hes1 has previously been reported to influence neural versus mesodermal differentiation through modulation of Notch activity. Here we report that Hes1 also has an earlier role to delay exit from the pluripotent state into all lineages. The early function of Hes1 to delay differentiation can be explained by an ability of Hes1 to lify STAT3 responsiveness in a cell-autonomous manner. Variability in Hes1 expression therefore helps to explain why STAT3 responsiveness varies between in idual ES cells, and this in turn helps to explain why pluripotent cells commit to differentiate asynchronously.
Publisher: Informa UK Limited
Date: 04-1982
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.COLSURFB.2015.10.035
Abstract: Components of many vascular prostheses including endovascular stents, heart valves and ventricular assist devices are made using metal alloys. In these blood contacting applications, metallic devices promote blood clotting, which is managed clinically by profound platelet suppression and/or anticoagulation. Here it is proposed that the localized immobilization of bioactive plasmin, a critical mediator of blood clot stability, may attenuate metallic prosthesis-induced thrombus formation. Previously described approaches to covalently immobilize biomolecules on implantable materials have relied on complex chemical linker chemistry, increasing the possibility of toxic side effects and reducing bioactivity. We utilize a plasma deposited thin film platform to covalently immobilize biologically active plasmin on stainless steel substrates, including stents. A range of in vitro whole blood assays demonstrate striking reductions in thrombus formation. This approach has profound potential to improve the efficacy of a wide range of metallic vascular implants.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.BIOMATERIALS.2015.07.046
Abstract: Here we describe development of an extracorporeal hemoadsorption device for sepsis therapy that employs commercially available polysulfone or polyethersulfone hollow fiber filters similar to those used clinically for hemodialysis, covalently coated with a genetically engineered form of the human opsonin Mannose Binding Lectin linked to an Fc domain (FcMBL) that can cleanse a broad range of pathogens and endotoxin from flowing blood without having to first determine their identity. When tested with human whole blood in vitro, the FcMBL hemoadsorption filter (FcMBL-HF) produced efficient (90-99%) removal of Gram negative (Escherichia coli) and positive (Staphylococcus aureus) bacteria, fungi (Candida albicans) and lipopolysaccharide (LPS)-endotoxin. When tested in rats, extracorporeal therapy with the FcMBL-HF device reduced circulating pathogen and endotoxin levels by more than 99%, and prevented pathogen engraftment and inflammatory cell recruitment in the spleen, lung, liver and kidney when compared to controls. Studies in rats revealed that treatment with bacteriocidal antibiotics resulted in a major increase in the release of microbial fragments or 'pathogen-associated molecular patterns' (PAMPs) in vivo, and that these PAMPs were efficiently removed from blood within 2 h using the FcMBL-HF in contrast, they remained at high levels in animals treated with antibiotics alone. Importantly, cleansing of PAMPs from the blood of antibiotic-treated animals with the FcMBL-hemoadsorbent device resulted in reduced organ pathogen and endotoxin loads, suppressed inflammatory responses, and resulted in more stable vital signs compared to treatment with antibiotics alone. As PAMPs trigger the cytokine cascades that lead to development of systemic inflammatory response syndrome and contribute to septic shock and death, co-administration of FcMBL-hemoadsorption with antibiotics could offer a more effective approach to sepsis therapy.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B919452P
Abstract: Elastin is a versatile elastic protein that dominates flexible tissues capable of recoil, and facilitates commensurate cell interactions in these tissues in all higher vertebrates. Elastin's persistence and insolubility h ered early efforts to construct versatile biomaterials. Subsequently the field has progressed substantially through the adapted use of solubilized elastin, elastin-based peptides and the increasing availability of recombinant forms of the natural soluble elastin precursor, tropoelastin. These interactions allow for the formation of a sophisticated range of biomaterial constructs and composites that benefit from elastin's physical properties of innate assembly and elasticity, and cell interactive properties as discussed in this tutorial review.
Publisher: American Chemical Society (ACS)
Date: 20-02-2015
DOI: 10.1021/CM504652G
Publisher: American Chemical Society (ACS)
Date: 27-12-2018
Publisher: Springer Science and Business Media LLC
Date: 27-12-2004
Abstract: Metastases in breast cancer are a vital concern in treatment, with epidermal growth factor receptor and ErbB2 strongly implicated in mediating tumor invasion and spreading. In this study, we investigated the role of decorin in suppressing both primary breast carcinomas and pulmonary metastases. We show that decorin causes marked growth suppression both in vitro and in vivo using a metastatic breast cancer cell line and an orthotopic mammary carcinoma model. Treatment with decorin protein core reduced primary tumor growth by 70% and eliminated observed metastases. An adenoviral vector containing the decorin transgene caused primary tumor retardation of 70%, in addition to greatly reducing observed metastases. Moreover, we demonstrate that ErbB2 phosphorylation and total receptor protein levels are reduced in this model system upon de novo expression of decorin under the control of a doxycycline-inducible promoter. Primary tumor growth in vivo was reduced by up to 67% upon decorin induction, and pulmonary metastases were markedly h ered as well. These effects are likely occurring through decorin's long-term downregulation of the ErbB2 tyrosine kinase cascade. These results demonstrate a novel role for decorin in reduction or prevention of tumor metastases in this breast cancer model and could eventually lead to improved therapeutics for metastatic breast cancer.
Publisher: Informa UK Limited
Date: 10-1982
Publisher: Elsevier BV
Date: 10-2013
Publisher: American Association for the Advancement of Science (AAAS)
Date: 13-02-2019
DOI: 10.1126/SCITRANSLMED.AAU5898
Abstract: Human platelet decoys prevented thrombosis in rabbits and inhibited cancer cell aggregation and extravasation in vitro and in a mouse model.
Publisher: Wiley
Date: 23-08-2021
Abstract: Thrombosis on blood‐contacting medical devices can cause patient fatalities through device failure and unstable thrombi causing embolism. The effect of material wettability on fibrin network formation, structure, and stability is poorly understood. Under static conditions, fibrin fiber network volume and density increase in clots formed on hydrophilic compared to hydrophobic polystyrene surfaces. This correlates with reduced plasma clotting time and increased factor XIIa (FXIIa) activity. These structural differences are consistent up to 50 µm away from the material surface and are FXIIa dependent. Fibrin forms fibers immediately at the material interface on hydrophilic surfaces but are incompletely formed in the first 5 µm above hydrophobic surfaces. Additionally, fibrin clots on hydrophobic surfaces have increased susceptibility to fibrinolysis compared to clots formed on hydrophilic surfaces. Under low‐flow conditions, clots are still denser on hydrophilic surfaces, but only 5 µm above the surface, showing the combined effect of the surface wettability and coagulation factor dilution with low flow. Overall, wettability affects fibrin fiber formation at material interfaces, which leads to differences in bulk fibrin clot density and susceptibility to fibrinolysis. These findings have implications for thrombus formed in stagnant or low‐flow regions of medical devices and the design of nonthrombogenic materials.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.TIBTECH.2018.08.003
Abstract: Immobilized liquid (IL) surface coatings are an emerging technology that provide to materials the ability to repel complex biological fluids and hold promise in medical applications to prevent biological fouling, especially in the context of preventing medical device-induced thrombosis, fibrosis, and biofilm formation. However, little is known about the biological interactions of the IL with proteins and cells, and an increased understanding is critical for optimal device application, function, and successful clinical translation. Here, we review existing clinical and biological knowledge of the liquids used in these surface coatings, recent developments in understanding the biological interactions of IL coatings, and future directions and challenges for the clinical translation of this new class of IL surface coatings.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CS00036A
Abstract: We review the rational choice, the analysis, the depletion and the properties imparted by the liquid layer in liquid-infused surfaces – a new class of low-adhesion surface.
Publisher: Springer Science and Business Media LLC
Date: 20-11-2010
DOI: 10.1007/S11095-010-0327-Z
Abstract: To modify blood-contacting stainless surfaces by covalently coating them with a serum-protease resistant form of tropoelastin (TE). To demonstrate that the modified TE retains an exposed, cell-adhesive C-terminus that persists in the presence of blood plasma proteases. Recombinant human TE and a point mutant variant (R515A) of TE were labeled with (125)Iodine and immobilized on plasma-activated stainless steel (PAC) surfaces. Covalent attachment was confirmed using rigorous detergent washing. As kallikrein and thrombin dominate the serum degradation of tropoelastin, supraphysiological levels of these proteases were incubated with covalently bound TE and R515A, then assayed for protein levels by radioactivity detection. Persistence of the C-terminus was assessed by ELISA. TE was significantly retained covalently on PAC surfaces at 88 ± 5% and 71 ± 5% after treatment with kallikrein and thrombin, respectively. Retention of R515A was 100 ± 1.3% and 87 ± 2.3% after treatment with kallikrein and thrombin, respectively, representing significant improvements over TE. The functionally important C-terminus was cleaved in wild-type TE but retained by R515A. Protein persists in the presence of human kallikrein and thrombin when covalently immobilized on metal substrata. R515A displays enhanced protease resistance and retains the C-terminus presenting a protein interface that is viable for blood-contacting applications.
Publisher: Elsevier BV
Date: 1984
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.ACTBIO.2010.07.022
Abstract: Small-diameter synthetic vascular graft materials fail to match the patency of human tissue conduits used in vascular bypass surgery. The foreign surface retards endothelialization and is highly thrombogenic, while the mismatch in mechanical properties induces intimal hyperplasia. Using recombinant human tropoelastin, we have developed a synthetic vascular conduit for small-diameter applications. We show that tropoelastin enhances endothelial cell attachment (threefold vs. control) and proliferation by 54.7 ± 1.1% (3 days vs. control). Tropoelastin, when presented as a monomer and when cross-linked into synthetic elastin for biomaterials applications, had low thrombogenicity. Activation of the intrinsic pathway of coagulation, measured by plasma clotting time, was reduced for tropoelastin (60.4 ± 8.2% vs. control). Platelet attachment was also reduced compared to collagen. Reductions in platelet interactions were mirrored on cross-linked synthetic elastin scaffolds. Tropoelastin was subsequently incorporated into a synthetic elastin olycaprolactone conduit with mechanical properties optimized to mimic the human internal mammary artery, including permeability, compliance, elastic modulus and burst pressure. Further, this multilayered conduit presented a synthetic elastin internal lamina to circulating blood and demonstrated suturability and mechanical durability in a small scale rabbit carotid interposition model.
Publisher: Informa UK Limited
Date: 11-1981
Publisher: Geological Society of America
Date: 1986
Publisher: Wiley
Date: 04-2022
Publisher: SAGE Publications
Date: 27-03-2016
Abstract: Surface fouling and undesired adhesion are nearly ubiquitous problems in the medical field, complicating everything from surgeries to routine daily care of patients. Recently, the concept of immobilized liquid (IL) interfaces has been gaining attention as a highly versatile new approach to antifouling, with a wide variety of promising applications in medicine. Here, we review the general concepts behind IL layers and discuss the fabrication strategies on medically relevant materials developed so far. We also summarize the most important findings to date on applications of potential interest to the medical community, including the use of these surfaces as anti-thrombogenic and anti-bacterial materials, anti-adhesive textiles, high-performance coatings for optics, and as unique platforms for diagnostics. Although the full potential and pitfalls of IL layers in medicine are just beginning to be explored, we believe that this approach to anti-adhesive surfaces will prove broadly useful for medical applications in the future.
Publisher: Future Medicine Ltd
Date: 12-2012
DOI: 10.2217/NNM.12.161
Abstract: Polymeric and metallic materials are used extensively in permanently implanted cardiovascular devices and devices that make temporary but often prolonged contact with body fluids and tissues. Foreign body responses are typically triggered by host interactions at the implant surface, making surface modifications to increase biointegration desirable. Plasma-based treatments are extensively used to modify erse substrates modulating surface chemistry, wettability and surface roughness, as well as facilitating covalent biomolecule binding. Each aspect impacts on facets of vascular compatibility including endothelialization and blood contact. These modifications can be readily applied to polymers such as Dacron ® and expanded polytetrafluoroethylene, which are widely used in bypass grafting and the metallic substrates of stents, valves and pacemaker components. Plasma modification of metals is more challenging given the need for coating deposition in addition to surface activation, adding the necessity for robust interface adhesion. This review examines the evolving plasma treatment technology facilitating the biofunctionalization of polymeric and metallic implantable cardiovascular materials.
Publisher: Mary Ann Liebert Inc
Date: 04-2011
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4802352
Publisher: Wiley
Date: 09-09-2022
Abstract: Biomedical devices are prone to blood clot formation (thrombosis), and liquid‐infused surfaces (LIS) are effective in reducing the thrombotic response. However, the mechanisms that underpin this performance, and in particular the role of the lubricant, are not well understood. In this work, it is investigated whether the mechanism of LIS action is related to i) inhibition of factor XII (FXII) activation and the contact pathway ii) reduced fibrin density of clots formed on surfaces iii) increased mobility of proteins or cells on the surface due to the interfacial flow of the lubricant. The chosen LIS is covalently tethered, nanostructured layers of perfluorocarbons, infused with thin films of medical‐grade perfluorodecalin (tethered‐liquid perfluorocarbon), prepared with chemical vapor deposition previously optimized to retain lubricant under flow. Results show that in the absence of external flow, interfacial mobility is inherently higher at the liquid–blood interface, making it a key contributor to the low thrombogenicity of LIS, as FXII activity and fibrin density are equivalent at the interface. The findings of this study advance the understanding of the anti‐thrombotic behavior of LIS‐coated biomedical devices for future coating design. More broadly, enhanced interfacial mobility may be an important, underexplored mechanism for the anti‐fouling behavior of surface coatings.
Publisher: Elsevier BV
Date: 07-2016
Publisher: American Association for Laboratory Animal Science
Date: 2022
DOI: 10.30802/AALAS-JAALAS-21-000014
Abstract: Swine are widely used in biomedical research, translational research, xenotransplantation, and agriculture. For these uses, physiologic reference intervals are extremely important for assessing the health status of the swine and diagnosing disease. However, few biochemical and hematologic reference intervals that comply with guidelines from the Clinical and Laboratory Standards Institute and the American Society for Veterinary Clinical Pathology are available for swine. These guidelines state that reference intervals should be determined by using 120 subjects or more. The aim of this study was to generate hematologic and biochemical reference intervals for female, juvenile Yorkshire swine ( Sus scrofa domesticus ) and to compare these values with those for humans and baboons ( Papio hamadryas ). Blood s les were collected from the femoral artery or vein of female, juvenile Yorkshire swine, and standard hematologic and biochemical parameters were analyzed in multiple studies. Hematologic and biochemical reference intervals were calculated for arterial blood s les from Yorkshire swine ( n = 121 to 124) human and baboon reference intervals were obtained from the literature. Arterial reference intervals for Yorkshire swine differed significantly from those for humans and baboons in all commonly measured parameters except platelet count, which did not differ significantly from the human value, and glucose, which was not significantly different from the baboon value. These data provide valuable information for investigators using female, juvenile Yorkshire swine for biomedical re- search, as disease models, and in xenotransplantation studies as well as useful physiologic information for veterinarians and livestock producers. Our findings highlight the need for caution when comparing data and study outcomes between species.
No related grants have been discovered for Anna Waterhouse.