PubMed · 15565161
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Myrna Watanabe. 2004-11-25. Material gains.. https://doi.org/10.1038/nj7016-532a
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We have designed a new synthesis route to create polyanhydrides based on monomers that contain hydrophilic entities within highly hydrophobic backbones. The method results in polyanhydrides that can be easily processed into drug-containing tablets. The synthesis, characterization, and erosion studies of polyanhydride copolymers based on 1,6-bis(p-carboxyphenoxy)hexane (CPH), which is highly hydrophobic, and 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane (CPTEG), which has hydrophilic oligomeric ethylene glycol segments in the monomer unit, was performed using a combination of molecular spectroscopy, thermal analysis, gravimetry, and scanning electron microscopy. The studies demonstrate that by increasing the CPH content in the CPTEG:CPH copolymers, the erosion of the system can be tailored from bulk-eroding to surface-eroding mechanism. These systems have promise as protein carriers.
The successful clinical application of materials should involve detailed investigations on interaction between them and tissue with which they will contact. We examined herein the behavior of endothelial cells (ECs) on a collagen material, using histological and immunohistochemical methods. We used isolated human umbilical cord vein cells (HUVECs) identified by means of endothelial-specific antibodies. Cells were seeded in a standard density on a collagen membrane (Lycoll, Resorba, Nuernberg, Germany) and on gelatin-coated, control plastic surfaces, after two passages. These were then maintained for periods of 1, 7, or 14 days. The cells adhered, spread, and proliferated, and within 24 h started forming a subconfluent monolayer. We observed that the cultured cells expressed integrins (alpha5beta1 and alpha(v)beta3) and synthesized fibronectin. After 14 days, we could observe a confluent layer of ECs. We could conclude that the collagen material supported growth and attachment of endothelial cells. In addition, the attachment seemed to be most related to the fibronectin synthesized by the cells and to its highly expressed receptor (the alpha5beta1 integrin); even though this is not the only protein related to this adhesion, we observed that our cultured HUVECs did not synthesize vitronectin.
The sol-gel method was employed to synthesize hydroxyapatite (HAp) coatings modified with Ag or Zn ions onto Ti-6Al-4V substrate. A bacterial strain Streptococcus mutans (S. mutans) and a human gingival fibroblast (HGF-1) cell line were used to investigate the antimicrobial effect and biocompatibility, respectively. HAp coatings containing 100 ppm Ag(+) ions suppressed the growth of S. mutans. An apparent inhibition zone around the HAp coating was further observed at Ag(+) concentration up to 10,000 ppm. However, for coatings containing Zn(2+) ions, a clear inhibition zone was observed at Zn(2+) concentration of 10,000 ppm. Nevertheless, the results of HGF-1 cultivation demonstrated that the Zn(2+)-modified HAp coatings exhibited better attachment and spread of HGF-1 than did the Ag(+)-modified coatings. Zn(2+) modified HAp coatings also increased the plating efficiency of HGF-1 cells. The cytotoxicity associated with the addition of Ag and the cell-conductive capacity associated with the addition of Zn are proportional to the added concentration, from 100 to 10,000 ppm. The dosages of both Ag(+) and Zn(2+) ions that should be added to HAp coatings were considered to prevent infection and improve biocompatibility. The results of this study ensure that HAp coatings modified with a moderate amount of Ag/Zn efficiently resist microorganisms and improve biocompatibility.