Fabrication Processes for Creating Micro Features in Thin Film NiTi Endovascular Grafts

2009 ◽  
Author(s):  
Youngjae Chun ◽  
Daniel S. Levi ◽  
K. P. Mohanchandra ◽  
Gregory P. Carman
Keyword(s):  
Thin Film ◽  
Tissue Growth ◽  
Sem Images ◽  
Process Use ◽  
Biomedical Device ◽  
Endovascular Grafts ◽  
Micro Features ◽  
Lift Off ◽  
Micro Patterns

Micro features were created in thin film NiTi using a novel lift-off process to create an endovascular biomedical device. This manuscript describes fabrication problems with wet etching and introduces an effective way, named “Lift-off” process to solve undercut and nonuniform pattern issues. Two lift-off processes (i.e., lift-off I and II) are discussed. Lift-off I process has fracture issues and the film peels off the substrate due to high aspect ratio post structures. Lift-off II process use the film on the top of the Si substrate to fabricate various shape patterns (i.e., ellipse, diamond, circle, square, etc.) in the range of 5∼60μm. The lift-off II process shows smooth and well aligned micro patterns in thin film NiTi. In-vivo tests in swine were performed to evaluate the endothelial tissue growth through fabricated micro patterns. Angiography and SEM images show patency of the artery and a uniform endothelial layer covering the device without thromobosis.

Synthesis and characterization of Chitosan-Catechol conjugates: Development and in vitro, in silico and in vivo evaluation of mucoadhesive pellets of lafutidine

2021 ◽  
pp. 088391152199784
Author(s):  
Loveleen Kaur ◽  
Ajay Kumar Thakur ◽  
Pradeep Kumar ◽  
Inderbir Singh
Keyword(s):  
Drug Release ◽  
In Silico ◽  
Ex Vivo ◽  
Strong Interactions ◽  
Dissolution Time ◽  
Sem Images ◽  
In Vivo Evaluation ◽  
Release Studies

Present study was aimed to synthesize and characterize Chitosan-Catechol conjugates and to design and develop mucoadhesive pellets loaded with lafutidine. SEM images indicated the presence of fibrous structures responsible for enhanced mucoadhesive potential of Chitosan-Catechol conjugates. Thermodynamic stability and amorphous nature of conjugates was confirmed by DSC and XRD studies respectively. Rheological studies were used to evaluate polymer mucin interactions wherein strong interactions between Chitosan-Catechol conjugate and mucin was observed in comparison to pristine chitosan and mucin. The mucoadhesion potential of Chitosan-Catechol (Cht-C) versus Chitosan (Cht) was assessed in silico using molecular mechanics simulations and the results obtained were compared with the in vitro and ex vivo results. Cht-C/mucin demonstrated much higher energy stabilization (∆E ≈ −65 kcal/mol) as compared to Cht/mucin molecular complex. Lafutidine-loaded pellets were prepared from Chitosan (LPC) and Chitosan-Catechol conjugates (LPCC) and were evaluated for various physical properties viz. flow, circularity, roundness, friability, drug content, particle size and percent mucoadhesion. In vitro drug release studies on LPC and LPCC pellets were performed for computing t50%, t90% and mean dissolution time. The values of release exponent from Korsmeyer-Peppas model was reported to be 0.443 and 0.759 for LPC and LPCC pellets suggesting Fickian and non-Fickian mechanism representing drug release, respectively. In vivo results depicted significant controlled release and enhanced residence of the drug after being released from the chitosan-catechol coated pellets. Chitosan-Catechol conjugates were found to be a promising biooadhesive polymer for the development of various mucoadhesive formulations.

Epitaxial lift-off CdTe/MgCdTe double heterostructures for thin-film and flexible solar cells applications

2021 ◽  
Vol 118 (18) ◽  
pp. 181101
Author(s):  
Jia Ding ◽  
Cheng-Ying Tsai ◽  
Zheng Ju ◽  
Yong-Hang Zhang
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Double Heterostructures ◽  
Lift Off

scholarly journals High-yield fabrication of perpendicularly magnetised synthetic antiferromagnetic nanodiscs

Nano Research ◽  
2021 ◽  
Author(s):  
Emma N. Welbourne ◽  
Tarun Vemulkar ◽  
Russell P. Cowburn
Keyword(s):  
Thin Film ◽  
Magnetic Properties ◽  
Sacrificial Layer ◽  
Nanosphere Lithography ◽  
High Yield ◽  
Perpendicular Anisotropy ◽  
Ion Milling ◽  
Lift Off

AbstractSynthetic antiferromagnetic (SAF) particles with perpendicular anisotropy display a number of desirable characteristics for applications in biological and other fluid environments. We present an efficient and effective method for the patterning of ultrathin Ruderman-Kittel-Kasuya-Yoshida coupled, perpendicularly magnetised SAFs using a combination of nanosphere lithography and ion milling. A Ge sacrificial layer is utilised, which provides a clean and simple lift-off process, as well as maintaining the key magnetic properties that are beneficial to target applications. We demonstrate that the method is capable of producing a particularly high yield of well-defined, thin film based nanoparticles.

A facile and combined methodology to fabricate sputtered thin film micro-patterns for heater/sensor applications utilizing CO2 laser-cut masks

2021 ◽  
pp. 1-10
Author(s):  
Mohammed Adnan Hasan ◽  
K. Prajwal ◽  
Dwarika Nath Sahu ◽  
Arpana Prasad ◽  
Arjun Dey ◽  
...  
Keyword(s):  
Thin Film ◽  
Co2 Laser ◽  
Sensor Applications ◽  
Micro Patterns

scholarly journals Nanoscale Strontium-Substituted Hydroxyapatite Pastes and Gels for Bone Tissue Regeneration

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1611
Author(s):  
Caroline J. Harrison ◽  
Paul V. Hatton ◽  
Piergiorgio Gentile ◽  
Cheryl A. Miller
Keyword(s):  
Bone Tissue ◽  
Tissue Regeneration ◽  
Culture Media ◽  
Full Range ◽  
Sol Gel ◽  
Tissue Growth ◽  
Bone Tissue Regeneration ◽  
Tissue Culture Media ◽  
Bone Deposition

Injectable nanoscale hydroxyapatite (nHA) systems are highly promising biomaterials to address clinical needs in bone tissue regeneration, due to their excellent biocompatibility, bioinspired nature, and ability to be delivered in a minimally invasive manner. Bulk strontium-substituted hydroxyapatite (SrHA) is reported to encourage bone tissue growth by stimulating bone deposition and reducing bone resorption, but there are no detailed reports describing the preparation of a systematic substitution up to 100% at the nanoscale. The aim of this work was therefore to fabricate systematic series (0–100 atomic% Sr) of SrHA pastes and gels using two different rapid-mixing methodological approaches, wet precipitation and sol-gel. The full range of nanoscale SrHA materials were successfully prepared using both methods, with a measured substitution very close to the calculated amounts. As anticipated, the SrHA samples showed increased radiopacity, a beneficial property to aid in vivo or clinical monitoring of the material in situ over time. For indirect methods, the greatest cell viabilities were observed for the 100% substituted SrHA paste and gel, while direct viability results were most likely influenced by material disaggregation in the tissue culture media. It was concluded that nanoscale SrHAs were superior biomaterials for applications in bone surgery, due to increased radiopacity and improved biocompatibility.

scholarly journals Nanoimprinted multifunctional nanoprobes for a homogeneous immunoassay in a top-down fabrication approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hubert Brueckl ◽  
Astrit Shoshi ◽  
Stefan Schrittwieser ◽  
Barbara Schmid ◽  
Pia Schneeweiss ◽  
...  
Keyword(s):  
Thin Film ◽  
Nanoimprint Lithography ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
In Vitro Diagnostics ◽  
Top Down ◽  
Highly Sensitive ◽  
Optical And Magnetic Properties ◽  
Lift Off

AbstractMultifunctional nanoparticles are discussed as versatile probes for homogeneous immunoassays for in-vitro diagnostics. Top-down fabrication allows to combine and tailor magnetic and plasmonic anisotropic properties. The combination of nanoimprint lithography, thin film deposition, and lift-off processing provides a top-down fabrication platform, which is both flexible and reliable. Here, we discuss the material compositions and geometrical designs of monodisperse multicomponent nanoparticles and their consequences on optical and magnetic properties. The rotational hydrodynamics of nanoparticles is measured and considered under the influence of magnetic shape anisotropy in the framework of the Stoner-Wohlfarth theory. The plasmon-optical properties are explained by discrete-dipole finite-element simulations. Rotational dynamical measurements of imprinted nanoprobes for two test proteins demonstrate the applicability as highly sensitive biomolecular nanoprobes.

In vivo and in vitro application of thin film interferometry to assess contact lens wettability

2018 ◽  
Vol 41 ◽  
pp. S9
Author(s):  
Raied Fagehi ◽  
Ian Pearce ◽  
Katherine Oliver ◽  
Alan Tomlinson
Keyword(s):  
Thin Film ◽  
Contact Lens

scholarly journals Influence of icariin on inflammation, apoptosis, invasion, and tumor immunity in cervical cancer by reducing the TLR4/MyD88/NF-κB and Wnt/β-catenin pathways

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chunyang Li ◽  
Shuangqing Yang ◽  
Huaqing Ma ◽  
Mengjia Ruan ◽  
Luyan Fang ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Underlying Mechanism ◽  
Tissue Growth ◽  
Migration And Invasion ◽  
Dependent Manner ◽  
Antitumor Effects ◽  
Siha Cells ◽  
Cervical Cancer Cells

Abstract Background Cervical cancer is a type of the most common gynecology tumor in women of the whole world. Accumulating data have shown that icariin (ICA), a natural compound, has anti-cancer activity in different cancers, including cervical cancer. The study aimed to reveal the antitumor effects and the possible underlying mechanism of ICA in U14 tumor-bearing mice and SiHa cells. Methods The antitumor effects of ICA were investigated in vivo and in vitro. The expression of TLR4/MyD88/NF-κB and Wnt/β-catenin signaling pathways were evaluated. Results We found that ICA significantly suppressed tumor tissue growth and SiHa cells viability in a dose-dependent manner. Also, ICA enhanced the anti-tumor humoral immunity in vivo. Moreover, ICA significantly improved the composition of the microbiota in mice models. Additionally, the results clarified that ICA significantly inhibited the migration, invasion capacity, and expression levels of TGF-β1, TNF-α, IL-6, IL-17A, IL-10 in SiHa cells. Meanwhile, ICA was revealed to promote the apoptosis of cervical cancer cells by down-regulating Ki67, survivin, Bcl-2, c-Myc, and up-regulating P16, P53, Bax levels in vivo and in vitro. For the part of mechanism exploration, we showed that ICA inhibits the inflammation, proliferation, migration, and invasion, as well as promotes apoptosis and immunity in cervical cancer through impairment of TLR4/MyD88/NF-κB and Wnt/β-catenin pathways. Conclusions Taken together, ICA could be a potential supplementary agent for cervical cancer treatment.

scholarly journals The Bone Regeneration Capacity of BMP-2 + MMP-10 Loaded Scaffolds Depends on the Tissue Status

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 979
Author(s):  
Patricia Garcia-Garcia ◽  
Ricardo Reyes ◽  
José Antonio Rodriguez ◽  
Tomas Martín ◽  
Carmen Evora ◽  
...  
Keyword(s):  
Bone Formation ◽  
Bone Regeneration ◽  
Growth Promotion ◽  
Tissue Growth ◽  
Bone Morphogenetic Protein 2 ◽  
Morphogenetic Protein ◽  
Therapeutic Molecules ◽  
Positive Effect

Biomaterials-mediated bone formation in osteoporosis (OP) is challenging as it requires tissue growth promotion and adequate mineralization. Based on our previous findings, the development of scaffolds combining bone morphogenetic protein 2 (BMP-2) and matrix metalloproteinase 10 (MMP-10) shows promise for OP management. To test our hypothesis, scaffolds containing BMP-2 + MMP-10 at variable ratios or BMP-2 + Alendronate (ALD) were prepared. Systems were characterized and tested in vitro on healthy and OP mesenchymal stem cells and in vivo bone formation was studied on healthy and OP animals. Therapeutic molecules were efficiently encapsulated into PLGA microspheres and embedded into chitosan foams. The use of PLGA (poly(lactic-co-glycolic acid)) microspheres as therapeutic molecule reservoirs allowed them to achieve an in vitro and in vivo controlled release. A beneficial effect on the alkaline phosphatase activity of non-OP cells was observed for both combinations when compared with BMP-2 alone. This effect was not detected on OP cells where all treatments promoted a similar increase in ALP activity compared with control. The in vivo results indicated a positive effect of the BMP-2 + MMP-10 combination at both of the doses tested on tissue repair for OP mice while it had the opposite effect on non-OP animals. This fact can be explained by the scaffold’s slow-release rate and degradation that could be beneficial for delayed bone regeneration conditions but had the reverse effect on healthy animals. Therefore, the development of adequate scaffolds for bone regeneration requires consideration of the tissue catabolic/anabolic balance to obtain biomaterials with degradation/release behaviors suited for the existing tissue status.

scholarly journals Nanocrystal-Loaded Micelles for the Enhanced In Vivo Circulation of Docetaxel

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4481
Author(s):  
Meng Cheng ◽  
Qiaoming Liu ◽  
Tiantian Gan ◽  
Yuanying Fang ◽  
Pengfei Yue ◽  
...  
Keyword(s):  
Thin Film ◽  
Retention Time ◽  
Blood Circulation ◽  
Crystalline State ◽  
Circulation System ◽  
Particle Sizes ◽  
High Pressure Homogenization ◽  
Rapid Dissolution ◽  
Efficient Route

Prolonging in vivo circulation has proved to be an efficient route for enhancing the therapeutic effect of rapidly metabolized drugs. In this study, we aimed to construct a nanocrystal-loaded micelles delivery system to enhance the blood circulation of docetaxel (DOC). We employed high-pressure homogenization to prepare docetaxel nanocrystals (DOC(Nc)), and then produced docetaxel nanocrystal-loaded micelles (DOC(Nc)@mPEG-PLA) by a thin-film hydration method. The particle sizes of optimized DOC(Nc), docetaxel micelles (DOC@mPEG-PLA), and DOC(Nc)@mPEG-PLA were 168.4, 36.3, and 72.5 nm, respectively. The crystallinity of docetaxel was decreased after transforming it into nanocrystals, and the crystalline state of docetaxel in micelles was amorphous. The constructed DOC(Nc)@mPEG-PLA showed good stability as its particle size showed no significant change in 7 days. Despite their rapid dissolution, docetaxel nanocrystals exhibited higher bioavailability. The micelles prolonged the retention time of docetaxel in the circulation system of rats, and DOC(Nc)@mPEG-PLA exhibited the highest retention time and bioavailability. These results reveal that constructing nanocrystal-loaded micelles may be a promising way to enhance the in vivo circulation and bioavailability of rapidly metabolized drugs such as docetaxel.

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