Construction and characterization of an electrospun tubular scaffold for small-diameter tissue-engineered vascular grafts: A scaffold membrane approach

Small-diameter synthetic vascular grafts are required for surgical bypass grafting when there is a lack of suitable autologous vessels due to different reasons, such as previous operations. Thrombosis is the main cause of failure of small-diameter synthetic vascular grafts when used for this revascularization technique. Therefore, the development of biodegradable vascular grafts capable of providing a localized and sustained antithrombotic drug release mark a major step forward in the fight against cardiovascular diseases, which are the leading cause of death globally. The present paper describes the use of an extrusion-based 3D printing technology for the production of biodegradable antiplatelet tubular grafts for cardiovascular applications. For this purpose, acetylsalicylic acid (ASA) was chosen as a model molecule due to its antiplatelet activity. Poly(caprolactone) and ASA were combined for the fabrication and characterization of ASA-loaded tubular grafts. Moreover, rifampicin (RIF) was added to the formulation containing the higher ASA loading, as a model molecule that can be used to prevent vascular prosthesis infections. The produced tubular grafts were fully characterized through multiple techniques and the last step was to evaluate their drug release, antiplatelet and antimicrobial activity and cytocompatibility. The results suggested that these materials were capable of providing a sustained ASA release for periods of up to 2 weeks. Tubular grafts containing 10% (w/w) of ASA showed lower platelet adhesion onto the surface than the blank and grafts containing 5% (w/w) of ASA. Moreover, tubular grafts scaffolds containing 1% (w/w) of RIF were capable of inhibiting the growth of Staphylococcus aureus. Finally, the evaluation of the cytocompatibility of the scaffold samples revealed that the incorporation of ASA or RIF into the composition did not compromise cell viability and proliferation at short incubation periods (24 h).

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Applications of SIMS to electronic materials and devices

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133047 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1682-1683

Author(s):

S.F. Corcoran

Keyword(s):

Depth Distribution ◽

Secondary Ion Mass Spectrometry ◽

Semiconductor Device ◽

Electronic Materials ◽

Profile Analysis ◽

Semiconductor Industry ◽

Small Diameter ◽

Depth Resolution ◽

Detection Sensitivity

Over the past decade secondary ion mass spectrometry (SIMS) has played an increasingly important role in the characterization of electronic materials and devices. The ability of SIMS to provide part per million detection sensitivity for most elements while maintaining excellent depth resolution has made this technique indispensable in the semiconductor industry. Today SIMS is used extensively in the characterization of dopant profiles, thin film analysis, and trace analysis in bulk materials. The SIMS technique also lends itself to 2-D and 3-D imaging via either the use of stigmatic ion optics or small diameter primary beams.By far the most common application of SIMS is the determination of the depth distribution of dopants (B, As, P) intentionally introduced into semiconductor materials via ion implantation or epitaxial growth. Such measurements are critical since the dopant concentration and depth distribution can seriously affect the performance of a semiconductor device. In a typical depth profile analysis, keV ion sputtering is used to remove successive layers the sample.

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Highly Fluorescent Au25-xAgx Nanoclusters Protected with Poly(ethylene glycol) - and Zwitterion-Modified Thiolate Ligands

10.26434/chemrxiv.6987479 ◽

2018 ◽

Author(s):

Dinesh Mishra ◽

Sisi Wang ◽

Zhicheng Jin ◽

Eric Lochner ◽

Hedi Mattoussi

Keyword(s):

Quantum Yield ◽

Near Infrared ◽

Small Diameter ◽

Binding Energies ◽

Thiolate Ligands ◽

Nir Emission ◽

Thiolate Complexes ◽

Long Lifetime ◽

Poly Ethylene

We describe the growth and characterization of highly fluorescing, near-infrared-emitting nanoclusters made of bimetallic Au25-xAgx cores, prepared using various monothiol-appended hydrophobic and hydrophilic ligands. The reaction uses well-defined triphenylphosphine-protected Au11 clusters (as precursors), which are reacted with Ag(I)-thiolate complexes. The prepared nanoclusters are small (diameter < 2nm, as characterized by TEM) with emission peak at 760 nm and long lifetime (~12 µs). The quantum yield measured for these materials was 0.3 - 0.4 depending on the ligand. XPS measurements show the presence of both metal atoms in the core, with measured binding energies that agree with reported values for nanocluster materials. The NIR emission combined with high quantum yield, small size and ease of surface functionalization afforded by the coating, make these materials suitable to implement investigations that address fundamental questions and potentially useful for biological sensing and imaging applications.

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Bio-composites reinforced with unique coral collagen fibers: Towards biomimetic-based small diameter vascular grafts

Journal of the Mechanical Behavior of Biomedical Materials ◽

10.1016/j.jmbbm.2021.104526 ◽

2021 ◽

pp. 104526

Author(s):

Shir Wertheimer ◽

Mirit Sharabi ◽

Ortal Shelah ◽

Ayelet Lesman ◽

Rami Haj-Ali

Keyword(s):

Vascular Grafts ◽

Small Diameter ◽

Collagen Fibers ◽

Small Diameter Vascular Grafts

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Comparative Evaluation on Impacts of Fibronectin, Heparin–Chitosan, and Albumin Coating of Bacterial Nanocellulose Small-Diameter Vascular Grafts on Endothelialization In Vitro

Nanomaterials ◽

10.3390/nano11081952 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1952

Author(s):

Max Wacker ◽

Jan Riedel ◽

Heike Walles ◽

Maximilian Scherner ◽

George Awad ◽

...

Keyword(s):

Low Density Lipoprotein ◽

Vascular Grafts ◽

Small Diameter ◽

Density Lipoprotein ◽

Human Albumin ◽

Water Soluble ◽

Bacterial Nanocellulose ◽

Functionally Impaired ◽

Small Diameter Vascular Grafts

In this study, we contrast the impacts of surface coating bacterial nanocellulose small-diameter vascular grafts (BNC-SDVGs) with human albumin, fibronectin, or heparin–chitosan upon endothelialization with human saphenous vein endothelial cells (VEC) or endothelial progenitor cells (EPC) in vitro. In one scenario, coated grafts were cut into 2D circular patches for static colonization of a defined inner surface area; in another scenario, they were mounted on a customized bioreactor and subsequently perfused for cell seeding. We evaluated the colonization by emerging metabolic activity and the preservation of endothelial functionality by water soluble tetrazolium salts (WST-1), acetylated low-density lipoprotein (AcLDL) uptake assays, and immune fluorescence staining. Uncoated BNC scaffolds served as controls. The fibronectin coating significantly promoted adhesion and growth of VECs and EPCs, while albumin only promoted adhesion of VECs, but here, the cells were functionally impaired as indicated by missing AcLDL uptake. The heparin–chitosan coating led to significantly improved adhesion of EPCs, but not VECs. In summary, both fibronectin and heparin–chitosan coatings could beneficially impact the endothelialization of BNC-SDVGs and might therefore represent promising approaches to help improve the longevity and reduce the thrombogenicity of BNC-SDVGs in the future.

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