Enzymatically triggered shape memory polymers

Buffington, Shelby L.; Paul, Justine E.; Ali, Matthew M.; Macios, Mark M.; Mather, Patrick T.; Henderson, James H.

doi:10.1016/j.actbio.2018.11.031

Cited by 47 publications

(50 citation statements)

References 50 publications

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“…Shape memory polymers (SMPs) are materials that can be transformed into a temporary shape by simultaneously applying a mechanical force and an external stimulus, such as heat, light, an electrical or magnetic field, or a specific chemical, and removing the stimulus while the object is kept in a deformed state. [1][2][3][4][5][6][7][8][9][10] The original shape can subsequently be recovered by exposure to the same or another suitable stimulus. Polymers in which one temporary shape is programmed and released upon heating represent the most-widely investigated sub-family of SMPs.…”

Section: Introductionmentioning

confidence: 99%

Blends of poly(ester urethane)s and polyesters as a general design approach for triple‐shape memory polymers

Karasu

Weder

2020

J of Applied Polymer Sci

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Poly(ester urethane)s represent a widely investigated class of thermoplastic polymers that exhibit a thermally triggered dual shape memory effect. This behavior is the result of urethane-rich hard segments that define the permanent shape, while domains formed by the crystallizable polyester segments act as the memory switch. We show here that blending poly(ester urethane)s with a second polyester having a different melting temperature is a straightforward and possibly general approach to create triple-shape memory polymers, in which two different temporary shapes can be programmed. To demonstrate this, we blended a poly(ester urethane) containing crystallizable poly(1,-4-butylene adipate) segments with poly(butylene succinate) or poly(hexamethylene dodecanoate). The blends microphase separate and the different polyester segments form separate semicrystalline domains, which serve as switching elements that can be activated at different temperatures. The blends retain attractive mechanical properties and the shape memory characteristics are characterized by high fixities (70%-96%) and recovery rates (82%-94%).

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Section: Introductionmentioning

confidence: 99%

Blends of poly(ester urethane)s and polyesters as a general design approach for triple‐shape memory polymers

Karasu

Weder

2020

J of Applied Polymer Sci

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“…20 When the polymer is cooled to its temporary shape, PCL is compressed by pellethane and pellethane is restricted into an entropically unfavorable state by the PCL crystalline structure. 20 This temporary state is stable at body temperature. With the addition of lipase, PCL was degraded allowing pellethane to recover its permanent shape.…”

Section: Programing Shape Memory Polymersmentioning

confidence: 99%

“…20 Cell viability assays were conducted with cultured fibroblasts demonstrating low toxicity of the polymer both prior to and during enzymatic cleavage. 20 The experiments were all conducted in vitro, however, low concentrations of lipase were evaluated in order to simulate in vivo conditions. 20 Future studies will need to be conducted to further evaluate this material for in vivo use, however, enzymatically activated SMPs show promise for biomedical devices.…”

Section: Programing Shape Memory Polymersmentioning

confidence: 99%

Smart materials in cardiovascular implants: Shape memory alloys and shape memory polymers

2020

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Smart materials have intrinsic properties that change in a controlled fashion in response to external stimuli. Currently, the only smart materials with a significant clinical impact in cardiovascular implant design are shape memory alloys, particularly Nitinol. Recent prodigious progress in material science has resulted in the development of sophisticated shape memory polymers. In this article, we have reviewed the literature and outline the characteristics, advantages, and disadvantages of shape memory alloys and shape memory polymers which are relevant to clinical cardiovascular applications, and describe the potential of these smart materials for applications in coronary stents and transcatheter valves.

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“…Shape memory polymers (SMPs) are considered to be a smart material that can change their shapes from the temporary (named "soft phase") to the permanent (named "hard phase") when exposed to external stimuli, such as heat [1], light [2][3][4], pH [5,6], electricity [7], magnetism [8], and biological enzymes [9], and this ability to change shape is called the shape memory effect (SME). SME can be traced back to the "elastic memory" in a US patent on dental materials made of methacrylic ester resin by Vernon in 1941 [10].…”

Section: Introductionmentioning

confidence: 99%

Effect of PEW and CS on the Thermal, Mechanical, and Shape Memory Properties of UHMWPE

et al. 2020

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Modified ultra-high-molecular-weight polyethylene (UHMWPE) with calcium stearate (CS) and polyethylene wax (PEW) is a feasible method to improve the fluidity of materials because of the tense entanglement network formed by the extremely long molecular chains of UHMWPE, and a modified UHMWPE sheet was fabricated by compression molding technology. A Fourier-transform infrared spectroscopy test found that a new chemical bond was generated at 1097 cm−1 in the materials. Besides, further tests on the thermal, thermomechanical, mechanical, and shape memory properties of the samples were also conducted, which indicates that all properties are affected by the dimension and distribution of crystal regions. Moreover, the experimental results indicate that the addition of PEW and CS can effectively improve the mechanical properties. Additionally, the best comprehensive performance of the samples was obtained at the PEW content of 5 wt % and the CS content of 1 wt %. In addition, the effect of temperature on the shape memory properties of the samples was investigated, and the results indicate that the shape fixity ratio (Rf) and the shape recovery ratio (Rr) can reach 100% at 115 °C and 79% at 100 °C, respectively, which can contribute to the development of UHMWPE-based shape memory polymers.

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Enzymatically triggered shape memory polymers

Cited by 47 publications

References 50 publications

Blends of poly(ester urethane)s and polyesters as a general design approach for triple‐shape memory polymers

Blends of poly(ester urethane)s and polyesters as a general design approach for triple‐shape memory polymers

Smart materials in cardiovascular implants: Shape memory alloys and shape memory polymers

Effect of PEW and CS on the Thermal, Mechanical, and Shape Memory Properties of UHMWPE

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