Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The micro structured deposition of vital cells is an important challenge in tissue engineering, biosensor technology, and in all research dealing with cell-cell and cell-substrate contacts. Hence, an inkjet printing technology has been developed to manufacture Au-based micro electrodes by sputter coating inversely printed polyester-foils. These electrodes feature minimal structure sizes of 35 microm and consist of an anode and a cathode part. They were used with fibrinogenic epithelial cell suspensions to deposit human keratinocytes (HaCaT), mouse fibroblasts (L-929) and the protein fibrin by applying DC voltage. Subsequently cells were electrophoretically attracted to the anode, following exactly its shape, while the insoluble fibrin was simultaneously precipitated due to the electrically mediated polymerization of the soluble fibrinogen molecule. Furthermore, it was demonstrated that this technique is suitable to co-deposit both cell types in a layered fashion. The lower voltage boundary for successful deposition was set at approximately 0.8 V needed for the conversion of fibrinogen into fibrin, while the upper voltage boundary was set at approximately 1.85 V, when commencing electrolysis inhibited the deposition of vital cells. Subsequent to the anodic cell-fibrin deposition, cells were cultivated for up to 4 days and then characterized by FDA+EB staining, methyl violet staining, MNF staining and SEM. The conversion from fibrinogen into fibrin was studied using ATR/FTIR.
 ...
PMID:Inverse inkjet printed gold micro electrodes for the structured deposition of epithelial cells and fibrin. 1786 76

The generation of layer-by-layer silicate-chitosan composite biosorbent was studied. The films were evaluated on its stability regarding the polymer leakage and its capability in the removal of Cd(II), Cr(III) and Cr(VI) from an aqueous solution. SEM, EDAX and ATR-IR techniques were applied for material characterization. Silicate-chitosan films with a final layer of silicate demonstrated chitosan retention and had better sorption capacities than those without it. For metal species, such as Cd(II) and Cr(III), the greatest adsorption was obtained when the pH of the solution was 7. When Cr(VI) was evaluated, pH 4 was the optimal for its adsorption. Langmuir and Freundlich isotherms were modeled for the equilibrium data. An 80% of the adsorbed metal was recovered by HNO(3) incubation. This non-covalent immobilization method allowed chitosan surface retention and did not affect its adsorption properties. The use of a coated surface would facilitate sorbent removal from medium after adsorption.
 ...
PMID:Immobilized chitosan as biosorbent for the removal of Cd(II), Cr(III) and Cr(VI) from aqueous solutions. 1816 53

Due to its poor solubility in water and oil, silybin is hardly absorbed orally and cannot be dissolved directly for parenteral preparations. In this study, a silybin-phospholipid complex was prepared by single-factor design and orthogonal experimental design. Lipophilicity was improved to a large extent, which was determined by solubility experiments and oil/water partition studies. Various methods were used to confirm the formation and explore the properties of the silybin-phospholipid complex, such as UV, IR, ATR, CNMR, XRD,DSC, SEM and TEM. The structure of the phytosome when the complex was dispersed in aqueous solution is suggested.
 ...
PMID:Preparation and properties of a silybin-phospholipid complex. 1827 1

Surface modification by physical adsorption of Tween 20 was accomplished on polypropylene microporous membranes (PPMMs). Attenuated total reflection-Fourier transform infrared spectroscopy (ATR/FT-IR) and field emission scanning electron microscope (FE-SEM) were used to characterize the chemical and morphological changes on the membrane surfaces. Water contact angles and relative pure water fluxes were measured. The data showed that the hydrophilic performance for the modified membranes increased with the increase in the adsorption amount of Tween 20 onto the surface or into the pores of polypropylene microporous membranes. To test the antifouling property of the membranes by the adsorption of Tween 20 in a membrane bioreactor (MBR), filtration for active sludge was performed using synthetic wastewater. With the help of the data of water fluxes and the FE-SEM photos of the modified PPMMs before or after operating in a MBR for about 12 d, the PPMMs with monolayer adsorption of Tween 20 showed higher remained flux and stronger antifouling ability than unmodified membrane and other modification membranes studied.
 ...
PMID:Improvement of antifouling characteristics in a bioreactor of polypropylene microporous membrane by the adsorption of Tween 20. 1827 50

Covalent immobilization of collagen onto poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) film was achieved to improve its cell compatibility. Amide groups photografted on PHBV films were initially converted into amine groups through Hofmann degradation and collagen was then chemically bonded to amine groups, consequently forming the amide, amine, and collagen-modified PHBV. The structures of these modified PHBV films were confirmed by ATR-FTIR, XPS, and SEM analyses. Compared with that of PHBV film, surface wettability of the modified PHBV films enhanced remarkably. In particular, water contact angle of the collagen-modified PHBV film decreased from 65.0 degrees to 2.1 degrees within 130 s. Sheep chondrocytes cultured on PHBV and modified PHBV films were evaluated by cell adhesion test, MTT assay, and morphological observation under SEM. Results showed that the collagen-modified PHBV film had better cell adhesion and proliferation than other modified PHBV films and PHBV film. Chondrocytes on the collagen-modified PHBV film adhered through filopodia, spread by cytoplasmic webbing, and formed cells layer earlier than other modified ones, indicating that the collagen-modified PHBV is a promising biomaterial for cartilage tissue engineering.
 ...
PMID:Surface engineering of PHBV by covalent collagen immobilization to improve cell compatibility. 1831 94

Poly(2,2-Dimethyl-3,4-propylenedioxythiophene) (PProDOT-Me2) thin films have been cyclovoltametrically coated onto carbon fiber microelectrode (CFME) as an active functionalized microelectrode. An electrochemical impedance spectroscopic study on the prepared electrodes is reported in this paper which electropolymerization performed under different initial monomer concentrations. The electrochemical impedance data fitted to equivalent circuit model, used to find out numerical values of the proposed components. Effect of the parameters on the capacitive behavior of the (PProDOT-Me2) coated carbon fiber microelectrode and morphology of films obtained by AFM and SEM was discussed. Highly porous coating was obtained at 100 mV/s scan rate and 10 cycles. EDX and ATR-FTIR results indicated the doping of anion of electrolyte due to formation of polaronic and bipolaronic sites. The presence of surface functional groups were determined by ATR-FTIR. Nanoscale conjugated polymer modified carbon fiber microelectrodes exhibited high capacitance of approximately 90 degrees phase angle, and vertical line in Nyquist plot. The capacitive behavior of CFME was increased by this very thin film coating of PProDOT-Me2. The electroactivity of Poly 2,2-Dimethyl-3,4-propylenedioxythiophene on the carbon fiber microelectrode open the possibility of using these coated electrodes for electrochemical microsupercapacitors and biosensor electrodes.
 ...
PMID:Nanoscale surface morphology and monomer concentration dependence on impedance of electrocoated 2,2-dimethyl-3,4-propylene-dioxythiophene on carbon fiber microelectrode. 1833 Jan 72

Double-surface-silvered polyimide films have been successfully fabricated using silver ammonia complex cation ([Ag(NH3)2]+) as the silver precursor and 3,3',4,4'-benzophenonetetracarboxylic dianhydride/4,4'-oxidianile- (BTDA/ODA-) based poly(amic acid) (PAA) as the polyimide precursor via a direct ion-exchange self-metallization technique. The process has been clarified to involve the loading of silver(I) into PAA via ion exchange, the thermally induced reduction of silver(I) to silver(0) and the concomitant imidization of PAA to polyimide upon thermal treatment, the subsequent silver-catalyzed and oxygen-assisted decomposition of the polyimide overlayer, and the self-accelerated aggregation of silver clusters on the film surface to produce well-defined surface silver layers. By employing [Ag(NH3)2]+ solution with a concentration of only 0.01 M and an ion-exchange time of no more than 10 min, the controlled formation of highly reflective and conductive silver surfaces upon thermal treatment at 300 degrees C for less than 4.5 h indicates that the present work provides an efficient route and an effacious silver species for polyimide surface metallization. Although the alkaline characteristics of [Ag(NH3)2]+ have a strong hydrolysis effect on the polyimide precursor chains, the final metallized films retain the key mechanical and thermal properties of the pure polyimide. Films were characterized by ATR-FTIR, XPS, ICP-AES, SEM, TEM, DSC, TGA, reflectivity, conductivity, and mechanical measurements.
 ...
PMID:Controlled formation of optically reflective and electrically conductive silvered surfaces on polyimide film via a direct ion-exchange self-metallization technique using silver ammonia complex cation as the precursor. 1840 10

Electrogenerated PPy doped with pSA was used as a substrate for immobilization of GOD. This was achieved via covalent bonding of carboxyl groups of the main chain of alginate with amino groups of the enzyme. The pH-induced aggregation behavior of SA in aqueous solution was employed to provide optimum conditions for electrochemical preparation of PPy by galvanostatic methods. GOD was attached to the electrode surface by reaction between the carboxyl groups in the main chain of pSA with amino groups of GOD after treatment with EDC and NHS. The linkage of GOD enzyme to the conductive surface was characterized by ATR spectroscopy and SEM CV was used to demonstrate the bioactivity of the enzyme electrode toward glucose.
 ...
PMID:Electrogeneration of polypyrrole/alginate films for immobilization of glucose oxidase. 1842 24

Polymers have been used to deliver therapeutic agents in a range of medical devices with drug eluting stents being the most widespread current application. Although polymers enable controlled release of a therapeutic agent, the polymeric surface has been reported to provide suboptimal biocompatibility and haemocompatibility and it has been suggested that currently used polymers may be at least partly responsible for the late adverse events observed in intravascular stent systems. In this study, the biostability and biological performance of a siloxane-based polyurethane elastomer (E2A) demonstrating excellent long-term biostability in the unloaded state was investigated following incorporation of a therapeutic agent. After implantation in an ovine model for 6 months, samples were assessed using SEM and ATR-FTIR to determine changes in the surface chemical structure and morphology of the materials and tensile testing was used to examine changes in bulk characteristics. Biological response was assessed using in vitro cytotoxicity testing and histological analysis. Results indicated that incorporation of 25mg/g dexamethasone acetate (DexA) into the siloxane-based polyurethane resulted in no significant difference in the biostability and biocompatibility of the material. Some level of cytotoxic potential was exhibited which was believed to result from residual DexA leaching from samples during the extraction process. These findings suggest that E2A is a potential candidate for a delivery vehicle of therapeutic agents in implantable drug delivery applications.
 ...
PMID:Biostability and biological performance of a PDMS-based polyurethane for controlled drug release. 1843

New smart surface-modified polypropylene (PP) was prepared for improving the loading and the sustained delivery of vancomycin and, thus, reducing the risk of biofilm formation when used as component of biomedical devices. Isothermal titration calorimetry (ITC) served for screening the most suitable monomers for grafting; the drug preferentially bonding to ionized acrylic acid (AAc). A net-PP-g-PNIPAAm-inter-net-PAAc was synthesized by first grafting and cross-linking of N-isopropylacrylamide onto PP films and then interpenetrating a second network by redox polymerization and cross-linking of AAc. PP-g-PAAc slabs were prepared by grafting AAc and, optionally, cross-linking. The amount and composition of grafted polymer (FTIR-ATR), morphology (SEM), temperature- and pH-responsiveness (swelling measurements), thermal behavior (DSC), friction coefficient (rheometry), drug loading and release rate, and effect against methicillin-resistant Staphylococcus aureus (MRSA) biofilms (modified robbins device) were evaluated. Grafting of AAc notably decreased the friction coefficient from 0.28+/-0.03 to 0.05+/-0.02 and enhanced the vancomycin loading (up to 2.5mg/cm(2)). Drug-loaded films showed a pH-dependent release rate, sustaining the release in pH 7.4 aqueous media at 37 degrees C for several hours. All drug-loaded films reduced biofilm formation by MRSA; the anti-biofilm effect being statistically significant (91.7% reduction, alpha<0.05) for PP-g-PAAc with the thinnest grafting layer.
 ...
PMID:Polypropylene grafted with smart polymers (PNIPAAm/PAAc) for loading and controlled release of vancomycin. 1857 53


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>