Abstract No. 387 Fabrication of a Radiopaque, Drug-Eluting Resorbable Polymer for Medical Device Development

Poly-p-dioxanone (PPDO) polymers have been used to manufacture a myriad of resorbable medical devices (e.g., sutures, plates, vascular clips, stents, and IVC filters). PPDO is inherently radiolucent and may induce a pathologic inflammatory reaction that can result in neointimal hyperplasia (NH). The objective of our study was to increase the radiopacity of PPDO by incorporation of gadolinium nanoparticles (GdNPs) and to mitigate the potential for pathologic NH by incorporation of an anti-platelet agent (i.e., dipyridamole, DPA). GdNPs were synthesized through thermal decomposition. GdNP size and morphology were characterized using transmission electron microscopy (TEM). PPDO suture were loaded with GdNPs, DPA, or GdNP+DPA via the wet dipping method. Characterization of surface texture, radiopacity, and strength of PPDO (control), PPDO+GdNP, PPDO+DPA, and PPDO+GdNP+DPA was performed using scanning electron microscopy (SEM), micro-computed tomography (mCT), and tensile strength testing, respectively. Hemolysis assay and in vitro cell toxicity was done against RF24 and MOVAS cells lines. Synthesis of GdNP yielded plate-like structures with average diameters of 35.76 ± 3.71 nm. SEM showed increased surface irregularities following incorporation of GdNP and/or DPA, as compared to control. Physicochemical characterizations showed no significant difference among the groups (i.e., PPDO, PPDO+GdNP, PPDO+DAP, PPDO+GdNP+DPA) in terms of melting temperature (103.32-105.90°C, P >0.05) and load-at-break (4.39-5.38 kg, P >0.05). mCT imaging showed that polymer blends containing GdNPs had a mean ± SD radiopacity of 2,713 ± 105 HU for GdNP alone and 1,516 ± 281 HU for GdNP+DPA; mean ± SD radiopacity measured -130 ± 38 HU for PPDO alone and -135 ± 172 HU for PPDO+DPA. PPDO coated with GdNP alone and GdNP+DPA showed gradual decreases in radiopacity over the 6-week study period. There was no evidence of hemolysis or in vitro cellular toxicity between groups. PPDO can be infused with GdNPs and DPA allowing for improved radiopacity and potential for sustained drug-elution. Our project may address limitations encountered with resorbable medical devices fabricated from PPDO allowing for more wide-spread clinical adoption.