ABSTRACT
This study describes the synthesis, surface analysis, and biological evaluation of bioactive titanium surfaces. The aim was to achieve an improved effect on osteoinduction in dental and orthopedic implants. For this purpose, a chemistry was developed, which allows to bind the bioactive cyclopeptide cRGDfK covalently to biomedically used titanium via polyethylene glycol linkers of different lengths. The chemical process is practicable, robust, and metal-free. The resulting chemically modified titanium plates show improved osteoinductive properties. The modification with cRGDfK targets the integrin αvß3, which is highly expressed in osteoblasts and is essential for many basic functions in the development of bone tissue. The successful immobilization of cRGDfK on titanium surfaces has been demonstrated by contact angle measurements and X-ray photoelectron spectroscopy. We show in in vitro studies that the presence of the cRGDfK peptide on titanium surfaces has a positive effect on bone formation.
Subject(s)
Biocompatible Materials , Titanium , Biocompatible Materials/metabolism , Biocompatible Materials/pharmacology , Coated Materials, Biocompatible/chemistry , Oligopeptides/chemistry , Osteoblasts , Surface Properties , Titanium/chemistry , Titanium/pharmacologyABSTRACT
Starting from small cyclic ketones, continuous flow synthesis is used to produce medium-sized rings and macrocycles that are relevant for the fragrance industry. Triperoxides are important intermediates in this process and are pyrolyzed at temperatures above 250 °C. The synthesis is carried out in two continuously operated flow reactors connected by a membrane-operated separator. The practicality of flow chemistry is impressively demonstrated in this work by the use of hazardous reagent mixtures (30% H2O2, 65% HNO3) and the pyrolysis of no less problematic peroxides. All new macrocycles were tested for their olfactory properties in relation to musk.
Subject(s)
Hydrogen Peroxide , Ketones , Indicators and Reagents , Physical PhenomenaABSTRACT
A novel type of hypervalent iodine(III) reagents, vinylbenziodoxolones (VBX), has been synthesized in a one-pot reaction from 2-iodobenzoic acid. VBX is bench stable, has been thoroughly characterized and the cyclic structure is supported by X-ray analysis. The reactivity of VBX was investigated in vinylation of nitrocyclohexane, and delivered vinylated products with opposite regioselectivity compared to acyclic vinyl(aryl)iodonium salts. The reagents could become a powerful tool in vinylation reactions under both metal-free and metal-catalyzed conditions.
