Oxygen-plasma treatment-induced surface engineering of biomimetic polyurethane nanofibrous scaffolds for gelatin-heparin immobilization

AbstractPolyurethane (PU) has been extensively used in vascular tissue engineering due to its outstanding mechanical performance and blood compatibility behavior. Here, biomimetic PU-based scaffolds were prepared using an electrospinning technique and gelatin-heparin was introduced as a surface modifier after oxygen plasma treatment to improve cell attachment and release an anticoagulation agent. Morphology, Fourier transform infrared (FTIR) spectroscopy, compression strength, swelling and biodegradation ratio, drug release level and cellular interactions were evaluated. According to the scanning electron microscopy (SEM) micrographs, gelatin-heparin immobilized PU nanofibers exhibited a smooth surface and a bead free structure that nanofibers distributed in the range of 300–1000 nm. The mechanical strength of constructs, swelling and biodegradation ratio, and drug release level illustrated higher values for oxygen plasma-treated samples compared with bilayered scaffolds. Cellular adhesion and biocompatibility ameliorated after plasma treatment. All the mentioned findings indicated the initial physicomechanical and biological potential of biomimetic PU-based fibers in the improvements of vascular scaffolds.

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High Breakdown Voltage GaN HEMT Device Fabricated on Self-Standing GaN Substrate

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.347-350.1535 ◽

2013 ◽

Vol 347-350 ◽

pp. 1535-1539

Author(s):

Jian Jun Zhou ◽

Liang Li ◽

Hai Yan Lu ◽

Ceng Kong ◽

Yue Chan Kong ◽

...

Keyword(s):

Plasma Treatment ◽

Breakdown Voltage ◽

Oxygen Plasma ◽

Cutoff Frequency ◽

Chemical Vapor ◽

Current Gain ◽

Organic Chemical ◽

Oxygen Plasma Treatment ◽

Gan Hemt ◽

High Breakdown Voltage

In this letter, a high breakdown voltage GaN HEMT device fabricated on semi-insulating self-standing GaN substrate is presented. High quality AlGaN/GaN epilayer was grown on self-standing GaN substrate by metal organic chemical vapor deposition. A 0.8μm gate length GaN HEMT device was fabricated with oxygen plasma treatment. By using oxygen plasma treatment, gate forward working voltage is increased, and a breakdown voltage of more than 170V is demonstrated. The measured maximum drain current of the device is larger than 700 mA/mm at 4V gate bias voltage. The maximum transconductance of the device is 162 mS/mm. In addition, high frequency performance of the GaN HEMT device is also obtained. The current gain cutoff frequency and power gain cutoff frequency are 19.7 GHz and 32.8 GHz, respectively. A high fT-LG product of 15.76 GHzμm indicating that homoepitaxy technology is helpful to improve the frequency performance of the device.

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Polydopamine-Inspired Surface Modification of Polypropylene Hernia Mesh Devices via Cold Oxygen Plasma: Antibacterial and Drug Release Properties

Coatings ◽

10.3390/coatings9030164 ◽

2019 ◽

Vol 9 (3) ◽

pp. 164 ◽

Cited By ~ 3

Author(s):

Xiakeer Saitaer ◽

Noor Sanbhal ◽

Yansha Qiao ◽

Yan Li ◽

Jing Gao ◽

...

Keyword(s):

Drug Release ◽

Plasma Treatment ◽

Oxygen Plasma ◽

Antimicrobial Property ◽

Antimicrobial Properties ◽

Major Complication ◽

Inhibition Zone ◽

Repair Process ◽

Hernia Surgery ◽

Maximum Inhibition

Mesh infection is a major complication of hernia surgery after polypropylene (PP) mesh implantation. Modifying the PP mesh with antibacterial drugs is an effective way to reduce the chance of infection, but the hydrophobic characteristic of PP fibers has obstructed the drug adhesion. Therefore, to prepare antimicrobial PP mesh with a stable drug coating layer and to slow the drug release property during the hernia repair process has a great practical meaning. In this work, PP meshes were coated by bio-inspired polydopamine (PDA), which can load and release levofloxacin. PP meshes were activated with cold oxygen plasma and then plasma activated PP fibers were coated with PDA. The PDA coated meshes were further soaked in levofloxacin. The levofloxacin loaded PP meshes demonstrate excellent antimicrobial properties for 6 days and the drug release has lasted for at least 24 h. Moreover, a control PP mesh sample without plasma treatment was also prepared, after coating with PDA and loading levofloxacin. The antimicrobial property was sustained only for two days. The maximum inhibition zone of PDA coated meshes with and without plasma treatment was 12.5 and 9 mm, respectively. On all accounts, the modification strategy can facilely lead to long-term property of infection prevention.

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