Surface modification
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The potential of solar cells have not been fully tapped due to the lack of energy conversion efficiency. There are three important mechanisms in producing high efficiency cells to harvest solar energy; reduction of light reflectance, enhancement of light trapping in the cell and increment of light absorption. The current work represent studies conducted in surface modification of single-crystalline silicon solar cells using wet chemical etching techniques. Two etching types are applied; alkaline etching (KOH:IPA:DI) and acidic etching (HF:HNO3:DI). The alkaline solution resulted in anisotropic profile that leads to the formation of inverted pyramids. While acidic solution formed circular craters along the front surface of silicon wafer. This surface modification will leads to the reduction of light reflectance via texturizing the surface and thereby increases the short circuit current and conversion rate of the solar cells.
- MeSH
- analýza selhání vybavení MeSH
- design vybavení MeSH
- hydroxidy chemie MeSH
- křemík chemie MeSH
- kyseliny chemie MeSH
- nanočástice chemie ultrastruktura MeSH
- povrchové vlastnosti MeSH
- sloučeniny draslíku chemie MeSH
- sluneční energie * MeSH
- smáčivost MeSH
- zdroje elektrické energie * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Active pharmaceutical ingredients (APIs) are predominantly organic solid powders. Due to their bulk properties many APIs require processing to improve pharmaceutical formulation and manufacturing in the preparation for various drug dosage forms. Improved powder flow and protection of the APIs are often anticipated characteristics in pharmaceutical manufacturing. In this work, we have modified acetaminophen particles with atomic layer deposition (ALD) by conformal nanometer scale coatings in a one-step coating process. According to the results, ALD, utilizing common chemistries for Al2O3, TiO2and ZnO, is shown to be a promising coating method for solid pharmaceutical powders. Acetaminophen does not undergo degradation during the ALD coating process and maintains its stable polymorphic structure. Acetaminophen with nanometer scale ALD coatings shows slowed drug release. ALD TiO2coated acetaminophen particles show cytocompatibility whereas those coated with thicker ZnO coatings exhibit the most cytotoxicity among the ALD materials under study when assessed in vitro by their effect on intestinal Caco-2 cells.
- MeSH
- Caco-2 buňky MeSH
- lidé MeSH
- nanotechnologie * MeSH
- paracetamol chemie MeSH
- pomocné látky chemie MeSH
- povrchové vlastnosti MeSH
- prášky, zásypy, pudry MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Infrared attenuated total reflection spectroscopy was used for in situ observation of the deposition of collagen I on poly(2-hydroxyethyl methacrylate-co-methacrylic acid, 2.9%) hydrogels and subsequent attachment of laminin or fibronectin on the collagen surface. While there was no adsorption of collagen dissolved in an acid solution on the hydrogel surface, it deposited on the surface at pH 6.5. The collagen layers with attached laminin or fibronectin were stable on hydrogel surface in physiological solution. The modification with collagen and particularly with collagen and laminin or fibronectin allowed the adhesion and growth of mesenchymal stromal cells and astrocytes on the hydrogel surface.
- MeSH
- extracelulární matrix - proteiny * chemie MeSH
- hydrogely * chemie MeSH
- koncentrace vodíkových iontů MeSH
- mikroskopie atomárních sil MeSH
- polyhydroxyethylmethakrylát * analogy a deriváty chemie MeSH
- povrchové vlastnosti MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- Publikační typ
- práce podpořená grantem MeSH
Plasma discharge was used to modify the ETFE surface properties. The changes induced by various plasma power and exposure time were determined by goniometry, gravimetric analysis and atomic force microscopy. It was found that a significant decrease of contact angle after plasma exposure is connected with the surface oxygen increase. Plasma treatment also induced a significant ablation of ETFE and fragmentation of its lamellar structure. The disruption of the lamellar structure was more pronounced for higher plasma power. It was found that by varying plasma power and exposure time it is possible to induce selective surface changes which can subsequently be used for various tissue engineering applications.
- MeSH
- barvicí látky chemie terapeutické užití MeSH
- citlivost dentinu etiologie terapie MeSH
- dentin chemie účinky záření ultrastruktura MeSH
- erythrosin MeSH
- extrakce zubů MeSH
- finanční podpora výzkumu jako téma MeSH
- laserová koagulace metody využití MeSH
- laserová terapie MeSH
- lasery MeSH
- lidé MeSH
- molár třetí účinky záření MeSH
- Check Tag
- lidé MeSH
Nowadays, titanium and its alloys are the most commonly used implantable materials. The surface topography and chemistry of titanium-based implants are responsible for osseointegration. One of the methods to improve biocompatibility of Ti implants is a modification with sodium hydroxide (NaOH) or 3-aminopropyltriethoxysilane (APTES). In the present study, anodic titanium dioxide (ATO) layers were electrochemically fabricated, and then immersed in a NaOH solution or in NaOH and APTES solutions. The functionalized samples were characterized by using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). All samples were examined as drug delivery systems and scaffolds for cell culturing. Based on the parameters of the fitted desorption-desorption-diffusion (DDD) model parameters, it was concluded that the modification with NaOH increased the amount of released ibuprofen and inhibited the release process. Osteoblast-like cell line (SAOS-2) was used to investigate the cell response on the non-modified and modified ATO samples. The MTS test and immunofluorescent staining were carried out to examine cell adhesion and proliferation. The data showed that the modification of nanoporous TiO2 layers with small molecules such as APTES enhanced metabolic activity of adhered cells compared with the non-modified and NaOH-modified TiO2 layers. In addition, the cells had a polygonal-like morphology with distinct projecting actin filaments and were well dispersed over the whole analyzed surface.
- MeSH
- buněčná adheze účinky léků MeSH
- buněčné linie MeSH
- elektrochemické techniky MeSH
- elektrody MeSH
- hydroxid sodný chemie MeSH
- lékové transportní systémy * MeSH
- lidé MeSH
- osteoblasty cytologie účinky léků MeSH
- poréznost MeSH
- povrchové vlastnosti MeSH
- proliferace buněk účinky léků MeSH
- propylaminy chemie MeSH
- silany chemie MeSH
- titan chemie MeSH
- velikost částic MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
INTRODUCTION: The aim of this work was the evaluation of surface modification in surgery of normally used hernia implants and thus improving their antimicrobial properties. The modification consisted of applying hybrid nanolayers with immobilized antiseptic substances (metal cations of Ag, Cu, and Zn) by sol-gel method which ensures prolonged effect of these substances and thus enables a greater resistance of the implant towards infection. In this work, attention is drawn to the issue of applying hybrid nanolayers, activation of mesh surfaces by physical plasma modification or ultraviolet C (UV C) radiation, and influence of these modifications on the mechanical properties of the final meshes. Next work will continue concentrating on the issue of antimicrobial efficacy and eventual toxicity of the prepared layers. MATERIALS AND METHODS: Present-day materials of the most commonly used types of implants for reconstruction of the abdominal wall in surgery (polypropylene, polyester, polyvinylidenefluoride) were tested. Optimum conditions of application of nanolayers by sol-gel method and their thermal stabilization were examined first. Surface modification was verified by scanning electron microscope. The surface of implants was first activated for better adhesion by plasma treatment or UV radiation after preliminary tests. Maximum strength and ductility after activation and hybrid nanolayer modification were objectively measured on a universal Testometric tensile testing machine. RESULTS: The results of surface activation of the meshes (by both plasma treatment or UV C radiation) provided similar and satisfactory results, and particular conditions differed based on the type of material of the mesh. Usage of antimicrobial sol AD30 diluted by isopropyl alcohol in 1:1 proportion appear to be optimal. All tested cases of meshes activated by plasma treatment or UV C radiation and with applied nanolayer concluded in a slight reduction of mechanical properties in modified meshes in comparison with the original ones. However, a slight reduction of test values was not of clinical importance. CONCLUSION: It was verified that surface modification of implants by sol-gel method is effective and technically possible, providing hopeful results.
