title: Shape memory polymers with enhanced visibility for magnetic resonance- and X-ray imaging modalities.
abstract: Currently, monitoring of minimally invasive medical devices is performed using fluoroscopy. The risks associated with fluoroscopy, including increased risk of cancer, make this method especially unsuitable for pediatric device delivery and follow-up procedures. A more suitable method is magnetic resonance (MR) imaging, which makes use of harmless magnetic fields rather than ionizing radiation when imaging the patient; this method is safer for both the patient and the performing technicians. Unfortunately, there is a lack of research available on bulk polymeric materials to enhance MR-visibility for use in medical devices. Here we show the incorporation of both physical and chemical modifying agents for the enhancement of both MR and X-ray visibility. Through the incorporation of these additives, we are able to control shape recovery of the polymer without sacrificing the thermal transition temperatures or the mechanical properties. For long-term implantation, these MR-visible materials do not have altered degradation profiles, and the release of additives is well below significant thresholds for daily dosages of MR-visible compounds. We anticipate our materials to be a starting point for safer, MR-visible medical devices incorporating polymeric components.
  
  
  
  Shape memory polymers (SMPs) are polymeric materials with unique shape recovery abilities that are being considered for use in biomedical and medical device applications. This paper presents a methodology for the development of MR and X-ray visible SMPs using either a chemically loaded or physical loaded method during polymer synthesis. Such knowledge is imperative for the development and clinical application of SMPs for biomedical devices, specifically for minimally-invasive vascular occlusion treatments, and while there are studies pertaining to the visibility of polymeric particles, little work has been performed on the utility of biomaterials intended for medical devices and the impact of how adding multiple functionalities, such as imaging, may impact material safety and degradation.
authors.affiliation: Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU Texas A&M University, College Station, TX 77843-3120, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Weems
authors.affiliation: Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU Texas A&M University, College Station, TX 77843-3120, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Szafron
authors.affiliation: Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU Texas A&M University, College Station, TX 77843-3120, USA.
authors.forename: A D
authors.initials: AD
authors.lastname: Easley
authors.affiliation: Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU Texas A&M University, College Station, TX 77843-3120, USA.
authors.forename: S
authors.initials: S
authors.lastname: Herting
authors.affiliation: Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU Texas A&M University, College Station, TX 77843-3120, USA.
authors.forename: J
authors.initials: J
authors.lastname: Smolen
authors.affiliation: Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU Texas A&M University, College Station, TX 77843-3120, USA. Electronic address: djmaitland@tamu.edu.
authors.forename: D J
authors.initials: DJ
authors.lastname: Maitland
mesh_terms: D016475:3T3 Cells; D000818:Animals; D063566:Biodegradable Plastics / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D003287:Contrast Media / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D008279:Magnetic Resonance Imaging; D008422:Materials Testing; D051379:Mice; D014056:Tomography, X-Ray
chemical_list: D063566:Biodegradable Plastics; D003287:Contrast Media
keywords: Cytocompatibility; Magnetic resonance imaging; Shape memory polymer; X-ray imaging