Nitric oxide (NO) may be a simple compound but it plays a vital role as a signalling molecule in many different pathological and physiological pathways in our bodies. Among its many attributes, it is a potent antimicrobial agent with activity against biofilms. It also triggers vasodilation and prevents thrombus formation. Clinicians are keen to exploit NO, as exogenous delivery has the potential to offer many varied advanced therapies mimicking natural processes. Its gaseous nature however, makes it difficult to handle, and the biological response to NO is concentration and location dependant. In addition, NO has a very short half-life. To be effective, therefore, NO must be delivered directly to the target cells at the correct concentration for the desired effect. We have previously demonstrated that metal organic framework (MOF) materials offer the ability to adsorb, store and release NO from framework metal sites by a moisture exchange mechanism. Furthermore, on formulating these MOF powders into polymer matrices via solvent casting techniques, we have shown that we can load these MOF/polymer composites with NO and control the delivery of NO from the film surface. In our most recent work, we have advanced to using extrusion methods to produce MOF containing polymer tubing, using medical grade polymers that are currently utilised in catheter manufacture. The challenges associated with designing new materials for medical device applications is a balance between controlled, consistent delivery (dosage), toxicology and suitable form of the material. In this poster, we show how the physical characteristics of the tube, the NO release profile and biocompatibility vary with MOF loading levels. Using in vitro assays, we demonstrate that release of NO from the extruded composites can deliver anti-microbial activity, prevent blood platelet aggregation and induce vascular relaxation. Our results prove that we can prevent three pressing clinical challenges related to catheterisation – infection, thrombosis and vascular/arterial spasm.

The synthesis, characterization, and catalytic properties of the new medium-pore zeolite TNU-9 are described.

The structure solution of TNU-7 (Taejon National University number 7), a large-pore gallosilicate zeolite constructed of strictly alternating MOR and MAZ layers, is presented. This "boundary phase" zeolite was synthesized without recourse to organic additives in a crystallization field surrounded by those of the structurally related MAZ and MOR zeolites.

The Structure of a novel large pore gallosilicate zcolite, TNU-7, has been refined from X-ray powder diffraction data. The silicate framework is built Lip from two different types of layer which are shown by X-ray and electron diffraction to be arranged in a fully ordered way. This gives rise to 12-MR pores and asymmetric cation distributions. TNU-7 is prepared hydrothemally over a very narrow compositional range and only in the presence of Ga. Other zeolitic phases crystallise at lower and higher Ga contents confirming the unique structure-directing ability of this element. The location of ion exchanged Cs+ and Sr2+ cations in TNU-7 has been Studied by high resolution X-ray powder diffraction.