scholarly journals Cytotoxicity of Catalysed Silicone Resin Coatings for Smart Biomedical Devices

2019 ◽  
Vol 5 (1) ◽  
pp. 165-170 ◽  
Author(s):  
Valerie M. K. Werner ◽  
Arian Kist ◽  
Markus Eblenkamp
Keyword(s):  
Cytotoxic Effect ◽  
Polymer Coatings ◽  
Silicone Resin ◽  
Electronic Systems ◽  
Biomedical Devices ◽  
Coating Materials ◽  
Organometallic Catalysts ◽  
Chemical Structures ◽  
Integration Strategies ◽  
Smart Technologies

AbstractEquipping medical devices with smart technologies holds great potential for the development of modern medical products. The development requires the identification of new integration strategies and the research of new material combinations due to the miniaturization of systems and increasing production figures. The realization of Smart Biomedical Devices requires a sufficient barrier effect (bioprotection) by appropriate encapsulation of the electronic components. Thinnest polymer coatings have proven to be suitable for conformal encapsulation. The aim of the study was to investigate the fundamental suitability of thin-film lacquers added with catalysts as coating materials for electronic systems with regard to their biological use. Due to long curing times of up to 14 days, eight different catalysts based on different chemical structures were added to the coating materials and their influence on a cytotoxic effect was investigated. A non-cytotoxic effect was observed for the organometallic catalysts based on tin, zirconium, titanium, bismuth, and tertiary amine. Most were resistant to steam sterilization. The curing time of the non-cytotoxic coatings could be significantly reduced by the addition of catalysts. The shortening of process times is an important economic aspect in the production of mass-produced Smart Biomedical Devices.

scholarly journals Silicone Resin Coating of Micro-Sized Ferrite Particles Using Supercritical Carbon Dioxide

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2012
Author(s):  
Idzumi Okajima ◽  
Tatsuya Kanie ◽  
Takeshi Sako
Keyword(s):  
Film Thickness ◽  
Organic Solvents ◽  
Supercritical Co2 ◽  
Fine Particles ◽  
Particle Diameter ◽  
Coating Material ◽  
Silicone Resin ◽  
Coating Film ◽  
Coating Materials ◽  
Coating Method

An environmentally friendly and efficient polymer coating method for micro-sized particles was developed using supercritical CO2. Because this method used supercritical CO2 as the solvent to dissolve the coating material, we avoided environmental pollution from organic solvents, saved the energy required to evaporate/remove organic solvents, realized a uniform coating film on the fine particles, and prevented agglomeration of the coating particles. The solubilities of the five silicone resins used as coating materials were measured using the flow method, and the data were well correlated by Chrastil’s equation with an average deviation of 5.7%. Resins comprising numerous methyl-group side chains exhibited high solubilities and were suitable coating materials. A new semi-flow-type coating method using supercritical CO2 was also developed, which deposited a film with a uniform thickness of 0.2–1.3 μm on whole fine particles. Notably, in this method, the film thickness was easily controlled. A simple and rapid technique was developed for measuring the coating thickness using X-ray fluorescence analysis. The model for calculating the coating film thickness was based on the material balance of the coating material. This model satisfactorily predicted the thickness with an average error of 0.085 μm by measuring the solubility of the coating material in supercritical CO2, integrated flow volume of supercritical CO2, particle diameter, density and charged weight of the fine particle, and coating material density.

scholarly journals Silicone Resin-Based Intumescent Paints

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4785
Author(s):  
Maria Zielecka ◽  
Anna Rabajczyk ◽  
Krzysztof Cygańczuk ◽  
Łukasz Pastuszka ◽  
Leszek Jurecki
Keyword(s):  
Heat Resistance ◽  
Expanded Graphite ◽  
Steel Structures ◽  
Silicone Resin ◽  
Hydroxyl Groups ◽  
The Novel ◽  
Coating Materials ◽  
Good Heat Resistance ◽  
Good Heat

Silicone resins are widely applied as coating materials due to their unique properties, especially those related to very good heat resistance. The most important effect on the long-term heat resistance of the coating is connected with the type of resin. Moreover, this structure is stabilized by a chemical reaction between the hydroxyl groups from the organoclay and the silicone resin. The novel trends in application of silicone resins in intumescent paints used mostly for protection of steel structures against fire will be presented based on literature review. Some examples of innovative applications for fire protection of other materials will be also presented. The effect of silicone resin structure and the type of filler used in these paints on the properties of the char formed during the thermal decomposition of the intumescent paint will be discussed in detail. The most frequently used additives are expanded graphite and organoclay. It has been demonstrated that silicate platelets are intercalated in the silicone matrix, significantly increasing its mechanical strength and resulting in high protection against fire.

scholarly journals Nanostructured Conducting Polymer Coatings for Biomedical Devices

2006 ◽  
Vol 12 (S02) ◽  
pp. 550-551 ◽  
Author(s):  
D Martin ◽  
M Abidian ◽  
J Hendricks ◽  
S Richardson-Burns ◽  
M Meier ◽  
...  
Keyword(s):  
Conducting Polymer ◽  
Polymer Coatings ◽  
Biomedical Devices

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

Controlled Release of Aspirin from SiO2-PEG Hybrid Coating on 316Lss Substrate for the Preparation of Drug Eluting Stents

2011 ◽  
Vol 287-290 ◽  
pp. 1956-1959 ◽  
Author(s):  
Min Kun Jian ◽  
Wen Ping Chen ◽  
Miao Feng ◽  
Hong Bing Zhan
Keyword(s):  
Steel Substrate ◽  
Sol Gel ◽  
Interventional Cardiology ◽  
Polymer Coatings ◽  
Silica Matrix ◽  
Drug Eluting Stents ◽  
Burst Release ◽  
Coating Materials ◽  
Inorganic Coatings ◽  
Drug Eluting

Despite drug eluting stents (DESs) have revolutionized the interventional cardiology over the past decade since the first DES became commercially available nearly a decade ago, burst release of loaded drugs and late thrombosis caused by polymer coatings of the stents are high concerned. In this situation, inorganic coatings, such as silica-based hybrid materials, have aroused researcher’s interest. In this study, aspirin (ASA) was incorporated into the sol-gel derived silica matrix with polyethylene glycol (PEG) as an organic modifier to improve the flexibility and extensibility of the inorganic matrices. We also used L-3,4-dihydroxyphenylalanine (L-DOPA) as a bio-adhesive reagent to enhance interface adhesion between the coating materials and the 316L stainless steel substrate. The results show that the introduction of D-LOPA can greatly improve the coating quality by enhancement of uniformity and adhesion. The loading ASA was slowly released from the coatings and burst release was effectively inhibited owing to the encapsulation of ASA molecules in the silica-PEG matrices.

scholarly journals STRUCTURAL DESIGN OF POLYMER PROTECTIVE COATINGS FOR REINFORCED CONCRETE STRUCTURES. PART I: THEORETICAL CONSIDERATIONS

2007 ◽  
Vol 13 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Zenonas Kamaitis
Keyword(s):  
Reinforced Concrete ◽  
Protective Coatings ◽  
Concrete Structures ◽  
Concrete Surface ◽  
Polymer Coatings ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Coating Materials ◽  
Barrier Materials ◽  
Mechanism Of Degradation

In a number of situations reinforced concrete structures must be protected by barrier materials to prevent contact with aggressive agents. One of the ways to protect concrete structures from corrosion is to use protective polymer coatings. Polymers as coating materials are not totally resistant and impermeable to all aggressive agents. Gases, vapors and liquids penetrate into a polymer so that the polymer mass swells and eventually disintegrates. However, the penetration/disintegration progresses at a much lower rate than that in the concrete. Surface coatings are able to reduce considerably the penetration, to slow down the rate of deterioration of concrete cover and to overcome most durability problems associated with external attack. In this article the mechanism of degradation of polymer coatings are analyzed. Methodology and predictive models for the degradation over time caused by aggressive actions of polymer coatings are presented. Proposed models can be applied to design of polymer coatings. Such a design of coatings is presented in a simple form for engineering design purposes.

Cytotoxic and Pro-apoptotic Activities of Diterpenoids from Zhumeria Majdae

2020 ◽  
Vol 17 ◽  
Author(s):  
Abolfazl Shakeri ◽  
Samira Navabi Nejad ◽  
Javad Asili ◽  
Milena Masullo ◽  
Mansoor Saeidi ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cytotoxic Effect ◽  
Therapeutic Agent ◽  
2D Nmr ◽  
Etoac Extract ◽  
Chemical Structures ◽  
Ic50 Value ◽  
Cytotoxic Compounds ◽  
First Time ◽  
Mcf 7

Abstract:: Since the ethylacetate (EtOAc) extract of the roots of Zhumeria majdae had the potent cytotoxic effect (IC50 < 50 μg/ml) on three cancer cell lines; MCF-7, PC3 and MDA-MB-231, therefore the purpous of this study is to isolation of the responcible cytotoxic compounds from the plant. Isolation of the extract led to the identification of four diterpenoids named as lanugon Q (1), 12,16-dideoxy aegyptinone B (2), 12-deoxy-salvipisone (3) and manool (4). The chemical structures have been determined on the basis of 1D and 2D NMR experiments. Compound 1 is reported for the first time in the plants of Zhumeria genus. The results of cytotoxic and apoptotic evaluation revealed that compound 2 had the strong cytotoxic effect with the IC50 value of 15.90 μg/ml against MCF-7 cell lines. Sub-G1 peak in flow cytometry histogram of cells treated with EtOAc axtract and compound 2 showed the induction of apoptosis. Changes in the Bax/Bcl-2 ratio and cleavage of PARP were observed. It is to be noted that owing to strong cytotoxic effect, Z. majdae extract could be represented as therapeutic agent against cancer.

scholarly journals Micro/Nano Technologies for High-Density Retinal Implant

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 419 ◽  
Author(s):  
Qi Zeng ◽  
Saisai Zhao ◽  
Hangao Yang ◽  
Yi Zhang ◽  
Tianzhun Wu
Keyword(s):  
High Performance ◽  
Electrode Materials ◽  
High Density ◽  
Future Research ◽  
Electronic Systems ◽  
Retinal Neuron ◽  
Retinal Implant ◽  
Coating Materials ◽  
Retinal Stimulation ◽  
High Performance Coating

During the past decades, there have been leaps in the development of micro/nano retinal implant technologies, which is one of the emerging applications in neural interfaces to restore vision. However, higher feedthroughs within a limited space are needed for more complex electronic systems and precise neural modulations. Active implantable medical electronics are required to have good electrical and mechanical properties, such as being small, light, and biocompatible, and with low power consumption and minimal immunological reactions during long-term implantation. For this purpose, high-density implantable packaging and flexible microelectrode arrays (fMEAs) as well as high-performance coating materials for retinal stimulation are crucial to achieve high resolution. In this review, we mainly focus on the considerations of the high-feedthrough encapsulation of implantable biomedical components to prolong working life, and fMEAs for different implant sites to deliver electrical stimulation to targeted retinal neuron cells. In addition, the functional electrode materials to achieve superior stimulation efficiency are also reviewed. The existing challenge and future research directions of micro/nano technologies for retinal implant are briefly discussed at the end of the review.

scholarly journals Effect of the B:Zn:H2O Molar Ratio on the Properties of Poly(Vinyl Acetate) and Zinc Borate-Based Intumescent Coating Materials Exposed to a Quasi-Real Cellulosic Fire

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2542
Author(s):  
Jakub Łopiński ◽  
Beata Schmidt ◽  
Yongping Bai ◽  
Krzysztof Kowalczyk
Keyword(s):  
Mechanical Strength ◽  
Vinyl Acetate ◽  
Thermal Insulation ◽  
Fire Protection ◽  
Zinc Borate ◽  
Molar Ratio ◽  
Vertical Position ◽  
Coating Materials ◽  
Intumescent Coating ◽  
Chemical Structures

In order to investigate an influence of the B:Zn:H2O molar ratio on the fire protection efficiency of poly(vinyl acetate)-based thermoplastic intumescent coating materials (ICs), systems containing ammonium polyphosphate, melamine, pentaerythritol and different types of zinc borates (ZBs) were tested in a vertical position in quasi-real fire conditions. 3ZnO·2B2O3·6H2O (ZB6), 2ZnO·3B2O3·3.5H2O (ZB3.5) or 3ZnO·2B2O3 (ZB0) were added in amounts of 1–10 wt. parts/100 wt. parts of the other coating components mixture. Char formation processes and thermal insulation features were investigated using an open-flame furnace heated according to the cellulosic fire curve. Thermogravimetric features (DTG), chemical structures (FTIR) and mechanical strength of the ICs and the chars were analyzed as well. It was revealed that the type and dose of the ZBs significantly affect thermal insulation time (TIT) (up to 450 °C of a steel substrate) and sagging (SI) of the fire-heated coatings as well as the compressive strength of the created chars. The highest TIT value (+89%) was noted for the sample with 2.5 wt. parts of ZB3.5 while the lowest SI (−65%) was observed for the coatings containing 10 wt. parts of the hydrated borates (i.e., ZB3.5 or ZB6). The best mechanical strength was registered for the sample filled with the anhydrous modifier (3 wt. parts of ZB0). The presented results show that the ICs with the proper ZBs can be used for effective fire protection of vertically positioned steel elements.

scholarly journals Oil-Based Polymer Coatings on CAN Fertilizer in Oilseed Rape (Brassica napus L.) Nutrition

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1605
Author(s):  
Petr Škarpa ◽  
Dominika Mikušová ◽  
Jiří Antošovský ◽  
Milan Kučera ◽  
Pavel Ryant
Keyword(s):  
Brassica Napus ◽  
Negative Impact ◽  
Nitrogen Loss ◽  
Polymer Coatings ◽  
Single Application ◽  
Brassica Napus L ◽  
Coating Materials ◽  
Calcium Ammonium Nitrate ◽  
Yield And Quality

Fertilizer coating can increase the efficiency of N fertilizers and reduce their negative impact on the environment. This may be achieved by the utilization of biodegradable natural coating materials instead of polyurethane-based polymers. The aim of this study was to detect the effect of calcium ammonium nitrate (CAN) fertilizer coated with modified conventional polyurethane enhanced with vegetable oils on the yield and quality of Brassica napus L. compared to CAN fertilizer with a vegetable oil-based polymer and to assess the risks of nitrogen loss. Three types of treatments were tested for both coated fertilizers: divided application (CAN, coated CAN), a single application of coated CAN, and a single application of CAN with coated CAN (1:2). A single application of coated CAN with both types of coating in the growth stage of the 9th true leaf significantly increased the yield, the thousand seed weight, and oil production compared to the uncoated CAN. The potential of using coated CAN may be seen in a slow nitrogen release ensuring the nitrogen demand for rapeseed plants throughout vegetation and eliminating the risk of its loss. The increased potential of NH4+ volatilization and NO3− leaching were determined using the uncoated CAN fertilizer compared to the coated variants. Oil-based polymer coatings on CAN fertilizer can be considered as an adequate replacement for partially modified conventional polyurethane.

scholarly journals Steroids from The Stem Bark of Dysoxylum nutans (Meliaceae) and Their Cytotoxic Effect Against MCF-7 Breast Cancer Cell Lines

2020 ◽  
Vol 6 (2) ◽  
pp. 133-139
Author(s):  
Tri Mayanti ◽  
Nur Insani Amir ◽  
Dewa Gede Katja ◽  
Sofa Fajriah ◽  
Ahmad Darmawan ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Lines ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Cytotoxic Effect ◽  
Stem Bark ◽  
Cancer Cell Lines ◽  
Breast Cancer Cell Lines ◽  
Chemical Structures ◽  
Mcf 7

Three steroids, 3α-hydroxystigmast-5(6), 22-diene-7-one (1), stigmasterol (2) and 3-hydroxy-7β-methoxystigmast-5(6)-ene (3), were isolated from the stem bark of Dysoxylum nutans. The chemical structures were identified by spectroscopic data, which includes IR, 1D-NMR, 2D-NMR, and HR-TOFMS as well as by comparing previously reported spectral data. Compounds 1-3 were tested for cytotoxic effect against MCF-7 breast cancer cell lines and compound 1 showed the strongest cytotoxic activity with an IC50 value of 20.13 ± 0.06 μM.

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