ABSTRACT
Titanium alloys exhibit excellent biocompatibility and corrosion resistance in the body fluid and possess mechanical properties similar of the bones' properties. When the loss of osseous is important in osseous surgery, large biomaterials are implanted and should be accepted by the organism. For increasing the biomaterials biocompatibility, biological compounds can be linked or deposited on the material surface making them biologically active. In order to study the tissue-implant interaction and to favor osteoblast-adhesion onto titanium, our work deals with the grafting of cell-binding peptides containing the Arginine-Glycine-Aspartic acid (RGD) sequence. In the present study, we focus on the elaboration of patterned biomaterial surfaces with highly functionalized nanodomains. The strategy of RGD peptide immobilization involves first the grafting if an amino-functional organosilane (APTES). Then, each of the free amino moieties were used as an initiator core for a dendrimer-like synthesis to multiply the number of free groups available for RGD immobilization on the material surface.
Subject(s)
Coated Materials, Biocompatible/chemistry , Nanostructures/chemistry , Nanostructures/ultrastructure , Oligopeptides/chemistry , Titanium/chemistry , Adsorption , Bone Substitutes/chemistry , Crystallization/methods , Materials Testing , Particle Size , Protein Binding , Surface PropertiesABSTRACT
The aim of this work was to test a recycling method for imidazole used in immobilized metal affinity chromatography (IMAC) as eluent for recombinant histidine-tag (His-tag) protein. After evaluating two supports, the method was optimized with a mixture of bovine serum albumin, sodium chloride and imidazole. Recycling was performed with an eluate fraction from IMAC of His-tag enhanced green fluorescent protein produced in our laboratory and pure imidazole was recovered in water and was analyzed after being freeze-dried. The imidazole was then reused as eluent in IMAC without any modification in its structure or behavior. This procedure can be used for large-scale chromatography.
Subject(s)
Chromatography, Affinity/methods , Histidine/chemistry , Imidazoles/analysis , Recombinant Proteins/isolation & purification , Reproducibility of ResultsABSTRACT
Enzymatic hydrolysis of a mixture of (chloromethyldimethylsilyl)-2-propenyl acetate isomers was investigated by using immobilized Candida antarctica lipase as biocatalyst. TLC analysis and 1H NMR spectroscopy were used to monitor the extent of the reaction. At 60 degrees C, the enzyme exhibited a high selectivity towards 3-(chloromethyldimethylsilyl)-2-propenyl acetate which was almost quantitatively hydrolyzed, whereas, only 11% of 2-(chloromethyldimethylsilyl)-2-propenyl acetate reacted with the lipase. Consequently, the unreacted acetate was readily purified from the reaction medium by flash column chromatography and deacetoxylated in acidic methanol to give the corresponding hydroxy compound in a 71% global yield. On the other hand, without lipase, chemical treatment of the acetate mixture resulted in much lower yields in hydroxy compounds followed by a tedious purification process.
