Biocompatibility and Fatigue Properties of Polystyrene−Polyisobutylene−Polystyrene, an Emerging Thermoplastic Elastomeric Biomaterial

Fray, Mirosława El; Prowans, Piotr; Puskás, Judit E.; Altstädt, Volker

doi:10.1021/bm050971c

Cited by 104 publications

(68 citation statements)

References 20 publications

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“…While showing no evidence of in vivo degradation [18], the original thermoplastic SIBS polymer, which was adapted for the PHV application by reinforcing the valve leaflets with Dacron fiber mesh, did exhibit a significant dynamic creep in sheep experiments [25]. The optimized valve was designed around the improved thermoset version of this polymer-xSIBS [19], with the specific goal of reducing its dynamic creep and increasing its tensile strength [27]. This facilitated manufacturing the valve prototypes entirely from xSIBS, using heated compression molding without the reinforcing fiber mesh of the previous design.…”

Section: Discussionmentioning

confidence: 99%

“…We continue to collaborate with Innovia, who have since developed an improved version of this polymer, xSIBS [19], which is designed to eliminate the significant dynamic creep of thermoplastic SIBS that has limited its utility in PHVs [27]. We have designed a new trileaflet polymeric valve using our device thrombogenicity emulation (DTE) methodology [28,29], which employs state-of-the-art numerical and experimental methods to virtually test and hemodynamically optimize, via an iterative process, blood recirculation medical devices with the goal of eliminating the need for anticoagulants and making the research and design process more efficient.…”

Section: Introductionmentioning

confidence: 99%

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In Vitro Evaluation of a Novel Hemodynamically Optimized Trileaflet Polymeric Prosthetic Heart Valve

Claiborne

Sheriff

Kuetting³

et al. 2013

Journal of Biomechanical Engineering

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Calcific aortic valve disease is the most common and life threatening form of valvular heart disease, characterized by stenosis and regurgitation, which is currently treated at the symptomatic end-stages via open-heart surgical replacement of the diseased valve with, typically, either a xenograft tissue valve or a pyrolytic carbon mechanical heart valve. These options offer the clinician a choice between structural valve deterioration and chronic anticoagulant therapy, respectively, effectively replacing one disease with another. Polymeric prosthetic heart valves (PHV) offer the promise of reducing or eliminating these complications, and they may be better suited for the new transcatheter aortic valve replacement (TAVR) procedure, which currently utilizes tissue valves. New evidence indicates that the latter may incur damage during implantation. Polymer PHVs may also be incorporated into pulsatile circulatory support devices such as total artificial heart and ventricular assist devices that currently employ mechanical PHVs. Development of polymer PHVs, however, has been slow due to the lack of sufficiently durable and biocompatible polymers. We have designed a new trileaflet polymer PHV for surgical implantation employing a novel polymer-xSIBS-that offers superior bio-stability and durability. The design of this polymer PHV was optimized for reduced stresses, improved hemodynamic performance, and reduced thrombogenicity using our device thrombogenicity emulation (DTE) methodology, the results of which have been published separately. Here we present our new design, prototype fabrication methods, hydrodynamics performance testing, and platelet activation measurements performed in the optimized valve prototype and compare it to the performance of a gold standard tissue valve. The hydrodynamic performance of the two valves was comparable in all measures, with a certain advantage to our valve during regurgitation. There was no significant difference between the platelet activation rates of our polymer valve and the tissue valve, indicating that similar to the latter, its recipients may not require anticoagulation. This work proves the feasibility of our optimized polymer PHV design and brings polymeric valves closer to clinical viability.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In Vitro Evaluation of a Novel Hemodynamically Optimized Trileaflet Polymeric Prosthetic Heart Valve

Claiborne

Sheriff

Kuetting³

et al. 2013

Journal of Biomechanical Engineering

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“…Poly(styrene-block-isobutylene-block-styrene) (SIBS) copolymer is a thermoplastic elastomer (TPE) that possesses outstanding biocompatibility and generates close to no foreign body reaction when implanted in the human body [1][2][3][4][5][6]. SIBS has a triblock linear structure formed by a block of polyisobutylene between blocks of polystyrene (PS).…”

Section: Introductionmentioning

confidence: 99%

Improving tensile strength of an injection-molded biocompatible thermoplastic elastomer

et al. 2015

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“…Furthermore, accelerated cyclic fatigue (by tension) has shown that SIBS coated stents maintained physical integrity at low loading levels. SIBS also showed superior fatigue properties compared to silicone and it has been successfully reinforced with polypropylene fibers, further improving fatigue performance [3,11]. However, accelerated cyclic fatigue fails to capture the effects of absorbed fluids on the physical deterioration of the material.…”

Section: Introductionmentioning

confidence: 99%

The effect of water absorption on the viscoelastic properties of poly(styrene-block-isobutylene-block-styrene) for use in biomedical applications

Fittipaldi¹,

Rodríguez²,

Grace³

2015

AIP Conference Proceedings

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Abstract. The decrease in glass transition temperature and change in creep compliance due to water diffusion in a biocompatible thermoplastic elastomer was studied and quantified. Knowledge of the mechanical and viscoelastic performance of the styrene-isobutylene-styrene block (SIBS) copolymer is important to determine the feasibility of certain in-vivo applications. Furthermore, the deterioration in these types of properties due to the plasticizing effect of water must be well understood for long term usage. Samples were formed with an injection molding press and fully dried prior to immersion in distilled water at 37 C. Water diffusion kinetics were studied for four different SIBS copolymers of varying molecular weight and styrene content by measuring weight changes as a function of time. These gravimetric diffusion studies showed an inverse relationship between diffusivity and styrene content and molecular weight for the first thousand hours of immersion. Measurements of storage modulus, loss modulus, tangent delta, strain recovery and creep compliance were performed using a dynamic mechanical analyzer for the high molecular weight, high styrene content SIBS version at different absorbed water contents. A measurable and nearly linear decrease of the glass transition temperature and creep recovery with respect to water content was observed for the samples tested even at relatively low water content: an increase in water content of 0.27% correlated to a decrease of 4 C in glass transition temperature while a 0.16% weight increase corresponded to a 12.5% decrease in creep recovery. These quantified material properties restrict the use of SIBS in certain implantable operations that undergo cyclic strains, and in sterilization techniques that require high temperatures. As such, they are important to understand in order to determine the viability of in vivo usage of this biocompatible polymer.

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Biocompatibility and Fatigue Properties of Polystyrene−Polyisobutylene−Polystyrene, an Emerging Thermoplastic Elastomeric Biomaterial

Cited by 104 publications

References 20 publications

In Vitro Evaluation of a Novel Hemodynamically Optimized Trileaflet Polymeric Prosthetic Heart Valve

In Vitro Evaluation of a Novel Hemodynamically Optimized Trileaflet Polymeric Prosthetic Heart Valve

Improving tensile strength of an injection-molded biocompatible thermoplastic elastomer

The effect of water absorption on the viscoelastic properties of poly(styrene-block-isobutylene-block-styrene) for use in biomedical applications

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