An amine-functionalized succinyl chitosan and an oxidized dextran were synthesized and mixed in aqueous solution to form an in situ chitosan/dextran injectable, surgical hydrogel for adhesion prevention. Rheological characterization showed that the rate of gelation and moduli were tunable based on amine and aldehyde levels, as well as polymer concentrations. The CD hydrogels have been shown to be effective post-operative aids in prevention of adhesions in ear, nose, and throat surgeries and abdominal surgeries in vivo. In vitro biocompatibility testing was performed on CD hydrogels containing one of two oxidized dextrans, an 80 % oxidized (CD-100) or 25 % (CD-25) oxidized dextran. However, the CD-100 hydrogel showed moderate cytotoxicity in vitro to Vero cells. SC component of the CD hydrogel, however, showed no cytotoxic effect. In order to increase the biocompatibility of the hydrogel, a lower aldehyde level hydrogel was developed. CD-25 was found to be non-cytotoxic to L929 fibroblasts. The in vivo pro-inflammatory response of the CD-25 hydrogel, after intraperitoneal injection in BALB/c mice, was also determined by measuring serum TNF-α levels and by histological analysis of tissues. TNF-α levels were similar in mice injected with CD-25 hydrogel as compared to the negative saline injected control; and were significantly different (P < 0.05) as compared to the positive, lipopolysaccharide, injected control. Histological examination revealed no inflammation seen in CD hydrogel injected mice. The results of these in vitro and in vivo studies demonstrate the biocompatibility of the CD hydrogel as a post-operative aid for adhesion prevention.

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The synthesis and X-ray characterisation of four isomeric dipyridyl ketone oxime ligands, 4,49-dipyridyl ketone oxime, L 44 , 3,39-dipyridyl ketone oxime, L 33 , 2,4-dipyridyl ketone oxime, L 24 and 2,3-dipyridyl ketone oxime, L 23 is described. X-ray structural characterisation of the precursor ketones 3,39-dipyridyl ketone, L1, and 2,4-dipyridyl ketone, L2, is also reported for comparison. Four AgCF 3 SO 3 complexes of the dipyridyl ketone oxime ligands were prepared and structurally characterised, [Ag(L 44 ) 2 ](CF 3 SO 3 ), 1, ' , 3, and [Ag 2 L 23 (CF 3 SO 3 ) 2 ] ' , 4. The structural role of the CF 3 SO 3 2 anion in the formation of Ag(I) coordination polymer networks, together with the effect of the varying pyridyl substitution patterns of L 44 , L 33 , L 24 and L 23 was investigated. In 1 the CF 3 SO 3 2 anion was unbound and disordered. It was encapsulated in the channels of a honeycomb 3D H-bonded structure. In 2 the CF 3 SO 3 2 anion remained unbound, being encapsulated within the centre of a helical polymer chain. In 3 the CF 3 SO 3 2 anion was weakly bound to the Ag(I) ion and as such decorated the side of a bowed 1-D chain. The two different CF 3 SO 3 2 anions in 4 adopted a range of binding modes from monodentate, bismonodentate to tris-monodentate with the Ag(I) ions and gave rise to the formation of an unusual CF 3 SO 3 2 bridged 2-D network.

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