scholarly journals Enhanced X-ray Visibility of Shape Memory Polymer Foam Using Iodine Motifs and Tantalum Microparticles

2021 ◽  
Vol 5 (1) ◽  
pp. 14
Author(s):  
Lindy K. Jang ◽  
Landon D. Nash ◽  
Grace K. Fletcher ◽  
Thomas Cheung ◽  
Andrew Soewito ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
High Surface ◽  
High Surface Area ◽  
Polymer Foam ◽  
Brain Aneurysm ◽  
X Ray ◽  
Safe Delivery ◽  
Aneurysm Embolization

Shape memory polymer (SMP) foams are porous materials with high surface area and large volumetric expansion capabilities that are well suited for endovascular occlusion applications, including brain aneurysm embolization. However, many polyurethane SMP foams are inherently radiolucent when X-ray visibility is required to ensure the safe delivery of the foam to the targeted aneurysm site using fluoroscopy. Here, highly radio-dense tantalum microparticles were added to a previously reported triiodobenzene-containing SMP foam (ATIPA foam) premix to fabricate ATIPA foam-tantalum composites (AT_T). The AT_T foams showed comparable glass transition temperatures, faster expansion profiles, increased X-ray visibility, good cytocompatibility, and faster oxidative degradation compared to the control ATIPA foam without tantalum. The mechanical properties were improved up to 4 vol% tantalum and the X-ray visibility was most appropriate for the 2 vol% (AT_2%T) and 4 vol% (AT_4%T) tantalum foams. E-beam sterilization did not impair the critical properties of the ATIPA foams. Overall, AT_2%T was the optimal foam composition for neurovascular prototypes due to its high oxidative stability in vitro compared to previous low-density SMP foams. The AT_T foams are very promising materials with high toughness and sufficient X-ray visibility for use as neurovascular embolization devices.

Synthesis and Characterization of Radiopaque Shape Memory Polymers

2017 ◽  
Author(s):  
Kendal Ezell ◽  
Landon Nash ◽  
Sonya Gordon ◽  
Duncan Maitland
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
The United States ◽  
Endovascular Embolization ◽  
Polymer Foam ◽  
X Ray ◽  
Unruptured Cerebral Aneurysm ◽  
Composite Foams ◽  
Function Impairment

An estimated 6 million people in the United States have an unruptured cerebral aneurysm [1]. If left untreated, these aneurysms can rupture and to lead to severe brain function impairment or even death. Shape memory polymer (SMP) foams have been proposed for use to optimize endovascular embolization in place of current embolization devices [2,3]. SMPs are capable of actuating from a programmed secondary geometry to their expanded primary geometry in response to a stimulus, such as body temperature [4]. The expanded foam geometry provides an interface for embolization of the aneurysm to occur, however, treatment with these devices has limited visibility under fluoroscopy. Previous work by Hasan et al. increased radiopacity through the incorporation of tungsten (W) nanoparticles. These composite foams showed successful x-ray visibility, but aggregate disruption of the SMP matrix led to decreased mechanical properties [5]. This work addresses limitations of composite SMP foams, namely toughness, by chemically incorporating x-ray visible monomers, such as the triodobenzene containing monomer, 5-Amino-2,4,6-triiodoisophthalic acid (AT), into the material composition. These materials enable contrast agent loading without disrupting the polymer matrix. This polymer foam system was characterized to determine the clinical relevance of the improved radiopaque SMP foam for occlusion devices.

scholarly journals In vitro performance of a shape memory polymer foam-coated coil embolization device

2017 ◽  
Vol 49 ◽  
pp. 56-62 ◽  
Author(s):  
Anthony J. Boyle ◽  
Mark A. Wierzbicki ◽  
Scott Herting ◽  
Andrew C. Weems ◽  
Adam Nathan ◽  
...  
Keyword(s):  
Shape Memory ◽  
Coil Embolization ◽  
Shape Memory Polymer ◽  
Polymer Foam ◽  
Shape Memory Polymer Foam ◽  
In Vitro Performance

scholarly journals Shape Memory Polymer Foams Synthesized Using Glycerol and Hexanetriol for Enhanced Degradation Resistance

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2290
Author(s):  
Sayyeda Marziya Hasan ◽  
Grace K. Fletcher ◽  
Mary Beth Browning Monroe ◽  
Mark A. Wierzbicki ◽  
Landon D. Nash ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer System ◽  
Vascular Occlusion ◽  
Superior Performance ◽  
Polymer Foams ◽  
Polymer Foam ◽  
Shape Memory Behavior ◽  
Wide Range

Shape memory polymer foams have been used in a wide range of medical applications, including, but not limited to, vessel occlusion and aneurysm treatment. This unique polymer system has been proven to shape-fill a void, which makes it useful for occlusion applications. While the shape memory polymer foam has superior performance and healing outcomes compared to its leading competitors, some device applications may benefit from longer material degradation times, or degradation-resistant formulations with increased fibrous encapsulation. In this study, biostable shape memory polymer foams were synthesized, and their physical and chemical properties were characterized as an initial evaluation of feasibility for vascular occlusion applications. After characterizing their shape memory behavior in an aqueous environment, degradation of this polymer system was studied in vitro using accelerated oxidative and hydrolytic solutions. Results indicated that the foams did not lose mass under oxidative or hydrolytic conditions, and they maintained high shape recovery in aqueous in vitro models. These degradation-resistant systems have potential for use in vascular occlusion and other wound healing applications that benefit from permanent, space-filling shape memory behavior.

Characterization of shape memory polymer foam hemostats in in vitro hemorrhagic wound models

2020 ◽  
Author(s):  
Nakira Christmas ◽  
Anand Utpal Vakil ◽  
Christopher J. Hatch ◽  
Shi Dong ◽  
David Fikhman ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Foam ◽  
Shape Memory Polymer Foam

scholarly journals Particulate Release From Nanoparticle-Loaded Shape Memory Polymer Foams

2017 ◽  
Vol 11 (1) ◽  
Author(s):  
Adam L. Nathan ◽  
Grace K. Fletcher ◽  
Mary Beth B. Monroe ◽  
Wonjun Hwang ◽  
Scott M. Herting ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
High Surface ◽  
High Surface Area ◽  
Vascular Occlusion ◽  
Peripheral Vascular ◽  
Abdominal Aortic ◽  
Guidance Documents ◽  
High Surface Area Materials ◽  
Highly Porous

Highly porous, open-celled shape memory polymer (SMP) foams are being developed for a number of vascular occlusion devices. Applications include abdominal aortic and neurovascular aneurysm or peripheral vascular occlusion. A major concern with implanting these high surface area materials in the vasculature is the potential to generate unacceptable particulate burden, in terms of number, size, and composition. This study demonstrates that particulate numbers and sizes in SMP foams are in compliance with limits stated by the most relevant standard and guidance documents. Particulates were quantified in SMP foams as made, postreticulation, and after incorporating nanoparticles intended to increase material toughness and improve radiopacity. When concentrated particulate treatments were administered to fibroblasts, they exhibited high cell viability (100%). These results demonstrate that the SMP foams do not induce an unacceptable level of risk to potential vascular occlusion devices due to particulate generation.

Shape Memory Polymer Foam With Tunable Properties for Treatment of Intracranial Aneurysm

2020 ◽  
Author(s):  
Sergio A. Pineda-Castillo ◽  
Jishan Luo ◽  
Bradley N. Bohnstedt ◽  
Chung-Hao Lee ◽  
Yingtao Liu
Keyword(s):  
Shape Memory ◽  
Intracranial Aneurysms ◽  
Shape Memory Polymer ◽  
Specific Treatment ◽  
Mass Effect ◽  
Patient Specific ◽  
Polymer Foam ◽  
Composite Foams ◽  
Incomplete Occlusion

Abstract Intracranial aneurysms have the potential to be fatal; when detected, they must be treated promptly by surgical clipping or by endovascular methods. The latter, while having better long-term overall survival than the former, fail to provide complete occlusion of the aneurysm lumen, creating risks for therapy-related adverse events, such as embolic device migration or recanalization. Polyurethane shape memory polymers (SMPs) have the potential to provide patient-specific treatment to reduce rates of incomplete occlusion and mass effect. In this study, SMP matrices are infiltrated with carbon nanotubes (CNTs) to induce electrical conductivity and provide a precise triggering method for deployment of the embolic device. Through thermomechanical characterization of the composite, it was determined that CNTs play a significant role in resistivity of the SMP foam and its ultimate shape recovery properties. Cyclic mechanical testing allowed to determine that CNTs might induce polymeric matrix damage, creating the need for new approaches to CNT infiltration. The studied composite foams were able to occlude an in vitro idealized aneurysm phantom model, which allowed to conclude that the proposed CNT-infiltrated SMP foams exhibit potential as biomedical devices for endovascular therapy of intracranial aneurysms.

Functionalized Nano-graphene Oxide as Multi-modal Clinic for Effective Drug Delivery

2017 ◽  
Vol 10 (4) ◽  
pp. 3768-3771
Author(s):  
Soumitra Satapathi ◽  
Rutusmita Mishra ◽  
Manisha Chatterjee ◽  
Partha Roy ◽  
Somesh Mohapatra
Keyword(s):  
Drug Delivery ◽  
Graphene Oxide ◽  
Cancer Cell ◽  
High Surface ◽  
High Surface Area ◽  
Cancer Cell Line ◽  
Xrd Analysis ◽  
Graphene Derivatives ◽  
Nano Graphene

Nano-materials based drug delivery modalities to specific organs and tissues has become one of the critical endeavors in pharmaceutical research. Recently, two-dimensional graphene has elicited considerable research interest because of its potential application in drug delivery systems. Here we report, the drug delivery applications of PEGylated nano-graphene oxide (nGO-PEG), complexed with a multiphoton active and anti-cancerous diarylheptanoid drug curcumin. Specifically, graphene-derivatives were used as nanovectors for the delivery of the hydrophobic anticancer drug curcumin due to its high surface area and easy surface functionalization. nGO was synthesized by modified Hummer’s method and confirmed by XRD analysis. The formation of nGO, nGO-PEG and nGO-PEG-Curcumin complex were monitored through UV-vis, IR spectroscopy. MTT assay and AO/EB staining found that nGO-PEG-Curcumin complex afforded highly potent cancer cell killing in vitro with a human breast cancer cell line MCF7.

Smart Gn-Keto Nanohybrid Embedded Topical System for Effective Management of Dermatophytosis

2019 ◽  
Vol 9 (1) ◽  
pp. 21-28
Author(s):  
Nisha Sharma ◽  
Shashikiran Misra
Keyword(s):  
Antifungal Activity ◽  
Fungal Infections ◽  
High Surface ◽  
High Surface Area ◽  
Vital Role ◽  
Common Disease ◽  
Microdilution Method ◽  
Enhanced Solubility ◽  
Bioactive Agents

Background and Objectives: Dermatophytosis (topical fungal infection) is the 4th common disease in the last decade, affecting 20-25% world’s population. Patients of AIDS, cancer, old age senescence, diabetes, cystic fibrosis become more vulnerable to dermatophytosis. The conventional topical dosage proves effective as prophylactic in preliminary stage. In the advanced stage, the therapeutics interacts with healthy tissues before reaching the pathogen site, showing undesirable effects, thus resulting in pitiable patient compliance. The youngest carbon nano-trope “Graphene” is recently used to manipulate bioactive agents for therapeutic purposes. Here, we explore graphene via smart engineering by virtue of high surface area and high payload for therapeutics and developed graphene–ketoconazole nanohybrid (Gn-keto) for potent efficacy towards dermatophytes in a controlled manner. </P><P> Methods: Polymethacrylate derivative Eudragit (ERL100 and ERS 100) microspheres embedded with keto and Gn-keto nanohybrid were formulated and characterized through FTIR, TGA, and SEM. In vitro drug release and antifungal activity of formulated Gn-keto microspheres were assessed for controlled release and better efficacy against selected dermatophytes. </P><P> Results: Presence of numerous pores within the surface of ERL100 microspheres advocated enhanced solubility and diffusion at the site of action. Controlled diffusion across the dialysis membrane was observed with ERS100 microspheres owing to the nonporous surface and poor permeability. Antifungal activity against T. rubrum and M. canis using microdilution method focused on a preeminent activity (99.785 % growth inhibition) of developed nanohybrid loaded microspheres as compared to 80.876% of keto loaded microspheres for T. rubrum. The culture of M. canis was found to be less susceptible to formulated microspheres. Conclusion: Synergistic antifungal activity was achieved by nanohybrid Gn-Keto loaded microspheres against selected topical fungal infections suggesting a vital role of graphene towards fungi.

scholarly journals Non-Thermal Plasma-Modified Ru-Sn-Ti Catalyst for Chlorinated Volatile Organic Compound Degradation

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1456
Author(s):  
Yujie Fu ◽  
You Zhang ◽  
Qi Xin ◽  
Zhong Zheng ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Photoelectron Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Surface Oxidation ◽  
Treatment Method ◽  
X Ray ◽  
Chlorinated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Doped Titania

Chlorinated volatile organic compounds (CVOCs) are vital environmental concerns due to their low biodegradability and long-term persistence. Catalytic combustion technology is one of the more commonly used technologies for the treatment of CVOCs. Catalysts with high low-temperature activity, superior selectivity of non-toxic products, and resistance to chlorine poisoning are desirable. Here we adopted a plasma treatment method to synthesize a tin-doped titania loaded with ruthenium dioxide (RuO2) catalyst, possessing enhanced activity (T90%, the temperature at which 90% of dichloromethane (DCM) is decomposed, is 262 °C) compared to the catalyst prepared by the conventional calcination method. As revealed by transmission electron microscopy, X-ray diffraction, N2 adsorption, X-ray photoelectron spectroscopy, and hydrogen temperature-programmed reduction, the high surface area of the tin-doped titania catalyst and the enhanced dispersion and surface oxidation of RuO2 induced by plasma treatment were found to be the main factors determining excellent catalytic activities.

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