Titanium, chitosan-coated

Muzzarelli et al. (2000) described a method for coating prosthetic articles with chitosan-oxychitin. Plates of titanium (Ti) and its alloys were plasma sprayed with hydroxyapatite and glass layers, and subsequently a chitosan coat was deposited on the plasma-sprayed layers using chitosan acetate. These layers were treated with 6-oxychitin to form a polyelectrolytic complex. This complex was optionally contacted with l-ethyl-3-(3-dimethylami-nopropyl) carbodiimide at 4°C for 2 hours to form amide links between the two polysaccharides, or acetylation with acetic anhydride in methanol to obtain a chitin film. In all cases, the modified coats were insoluble, uniformly flat, and smooth. Prosthetic materials coated with chitosan-oxychitin were capable of provoking colonization by cells, osteogenesis, and osteointegration. 

Initial efforts to bond chitosan coatings to metal implant surfaces used ethanol/ water solutions, ranging from 95% ethanol and 5% water to 70% ethanol and 30% water, to deposit APTES onto the surface of titanium substrates [39, 46, 75, 78]. Ethanol and water have been used to deposit the silane because they are safe and easy to use. The use of ethanol/water to deposit APTES significantly increased the bond strength of chitosan on titanium from a mean 0.5 MPa for chitosan simply absorbed to the titanium to 1.5 MPa (Table 1) [46]. Using an isocyantopropyl-triethoxysilane (ICPTES), mechanical bond strengths were increased to between... 

Table 1 Adhesion strength of chitosan coatings bound to titanium via alkyloxysilane deposition...

In vitro studies by Bumgardner et al. showed that, after only 15 min, the number of cells from a human osteoprogenitor cell line on chitosan-coated titanium was eightfold higher than on the control titanium surface [39]. This increase in cell attachment was attributed in part to the increased attachment or adsorption of... 

Use of Chitosan as a Bioactive Implant Coating for Bone-Implant Applications Cell attachment on chitosan-coated titanium... 

Fig. 10 Photomicrographs of paragon-stained sections of (a) CaP-coated, (b) chitosan-coated, and (c) uncoated titanium pins after 12 weeks in rabbit tibia. A mixture of mature lamellar and new bone was observed around all implanted pins, (d) Good bone formation was also observed around a chitosan-coated titanium pin that had migrated toward the rabbit tibial marrow space (original magnification 2x). Reprinted with kind permission from Bumgardner et al. [62], Wolters Kluwer Health/Lippincott Williams Wilkins, 2007...

Using toluene to deposit APTES onto titanium samples, Martin et al. was able to increase the bond strength of the chitosan coating to titanium more than tenfold as compared to the ethanol/water-deposited APTES (Table 1) [85]. This increase in bond strength was attributed to increased silane deposition with toluene solvent as... 

Martin et al. in a preliminary in vitro investigation evaluated the 2-h attachment and 6-day growth of human osteosarcoma bone cells on 86% DDA chitosan coatings bound via toluene-deposited APTES or TESBA solvents to titanium as compared to uncoated titanium control [87]. They observed that cell attachment increased with time, but that there were no differences between the test chitosan coatings or uncoated controls. For cell growth, increases in cell numbers were observed over the 6-day evaluation period on the test chitosan coatings and uncoated controls. There were no differences in the growth of the cells on the test... 

Fig. 15 Radiographic images for (a) electrophoretic deposited apatite-wollastonite/chitosan coatings on titanium and (b) uncoated titanium implant in a rabbit tibia after 42 days. Reprinted with kind permission from Sharma et al. [141], Springer Science+Business Media,...

Bumgardner JD et al (2003) Contact angle, protein adsorption and osteoblast precursor cell attachment to chitosan coatings bonded to titanium. J Biomater Sci Polym Ed 14(12) 1401-1409... 

Bumgardner JD et al (2007) The integration of chitosan-coated titanium in bone an in vivo study in rabbits. Implant Dent 16(l) 66-79... 

Yuan Y et al (2008) Mechanical property, degradation rate, and bone cell growth of chitosan coated titanium influenced by degree of deacetylation of chitosan. J Biomed Mater Res B Appl Biomater 86(l) 245-252... 

Norowski PA, Courtney HS, Babu J, Haggard WO, Bumgardner JD (2011) Chitosan coatings deliver antimicrobials from titanium implants a preliminary study. Implant Dent 20 56-67... 

Wang J, van Apeldoom A, de Groot K (2006) Electrolytic deposition of calcium phosphate/ chitosan coating on titanium alloy growth kinetics and influence of current density, acetic acid, and chitosan. J Biomed Mater Res A 76(3) 503-511... 

Sharma S et al (2009) Bone healing performance of electrophoretic deposited apatite-wollastonite/chitosan coating on titanium implants in rabbit tibiae. J Tissue Eng Regen Med 3(7) 501-511... 

Redepenning et al. developed a novel electrodeposition method of composite coatings of brushite (CaHP04-2H20) and chitosan on titanium to achieve an electrodeposited coating with material properties similar to bone [115]. They... 

Fig. 14 Scanning electron photomicrographs of electrodeposited coatings onto titanium (a) brushite (b) bmshite after conversion to hydroxyapatite (c) brushite-chitosan composite (d) brushite-chitosan composite coating after conversion to HA-chitosan. Reprinted with kind permission from Redepenning et al. [115], John Wiley Sons, Inc., 2003...

Norowski P (2008) Chitosan as an antimicrobial coating for titanium implants. MS Thesis, Biomedical engineering. University of Memphis... 

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