Two different phosphonic acid monolayer films for immobilization of bioactive molecules like the protein BMP-2 on titanium surfaces have been prepared. Monolayers of (11-hydroxyundecyl) phosphonic acid and (12-carboxydodecyl)phosphonic acid molecules were produced by a simple dipping process (the T-BAG method). The terminal functional groups on these monolayers were activated (carbonyl diimidazole for hydroxyl groups and N-hydroxysuccinimide for carboxyl groups) to bind amine containing molecules. The reactivity of the surfaces was investigated using trifluoroethylamine hydrochloride and BMP-2. Each step of the surface modification procedure was characterized by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (ToF-SIMS).
By selecting suitable paclitaxel-elution kinetics, it was feasible to develop a bioresorbable magnesium scaffold whose efficacy and healing characteristics in a porcine coronary model are comparable with those of established paclitaxel-eluting permanent metallic stents.
A bifunctional copolymer series of (4-vinylbenzyl)phosphonic acid diethylester and N-acryloxysuccinimide was developed as an interlayer with the aim of immobilizing proteins on titanium surfaces. Copolymers with varying compositions were synthesized, and an alternating copolymerization of the two monomers was found. The copolymers form ultrathin films of about 2-8 nm on titanium surfaces in a simple dipping process, as estimated from the attenuation of the titanium X-ray photoelectron spectroscopy (Ti-XPS) signal. The films were characterized by infrared spectroscopy, XPS, and time-of-flight secondary ion mass spectrometry. The results indicate that the immobilization is due to phosphonate groups, and thus the phosphonate content of the copolymers is decisive for the final film thickness. These polymer films were examined for their potential protein binding capacity by using trifluoroethylamine derivatization and subsequent XPS analysis as a reactivity assay.
Background: The goal of this pilot study was to design an external quality assessment (EQA) scheme for German cystic fibrosis (CF) clinical microbiology laboratories. Therefore, a multicentre-study of 18 German CF laboratories was performed to evaluate their proficiency in analysing CF respiratory secretions.
Methods:Simulated clinical specimens containing a set of four frequent CF pathogens, namely two Pseudomonas aeruginosa strains differing in morphotype (mucoid versus non-mucoid) and resistotype, one Staphyloccocus aureus strain and one Burkholderia multivorans strain, were distributed to each laboratory. Isolation, identification and antimicrobial susceptibility testing (AST) of any bacterial pathogen present and completion of a questionnaire about applied microbiological protocols were requested.Results: Three of four strains were isolated and identified correctly by almost all laboratories. B. multivorans was once misidentified as B. cenocepacia. Fourteen laboratories failed to detect the second multidrug resistant P. aeruginosa isolate. AST errors occured most often for P. aeruginosa 2 followed by B. cepacia complex, P. aeruginosa 1 and S. aureus.Evaluation of the questionnaires revealed major differences in cultivation and identification techniques applied by the participating laboratories.
Conclusions:A periodical EQA programme for German CF laboratories and standardized microbiological procedures seem to be necessary to advance diagnostic microbiology employed on CF respiratory tract specimens and may help to improve antiinfective treatment and infection control practices for CF patients.3
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