Porous Shape-Memory Polymers

Hearon, Keith; Singhal, Pooja; Horn, John; Small, Ward; Olsovsky, Cory; Maitland, Kristen C.; Wilson, Thomas S.; Maitland, Duncan J.

doi:10.1080/15583724.2012.751399

Cited by 89 publications

(71 citation statements)

References 96 publications

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“…[5, 6] Several materials including polyurethane and epoxy based SMP foams have been investigated for a wide range of applications that utilize their unique ability of “smart” stimuli sensitive shape recovery [7-12]; their details may be found in a recently published literature review on porous SMPs. [13] However, for high efficiency in embolic medical applications, such as aneurysm treatment, these materials are required to have some essential properties. Most importantly, they must have ultra low densities that can enable transcatheter delivery and high volume expansion on actuation.…”

Section: Introductionmentioning

confidence: 99%

Low density biodegradable shape memory polyurethane foams for embolic biomedical applications

et al. 2014

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Low density shape memory polymer foams hold significant interest in the biomaterials community for their potential use in minimally invasive embolic biomedical applications. The unique shape memory behavior of these foams allows them to be compressed to a miniaturized form, which can be delivered to an anatomical site via a transcatheter process, and thereafter actuated to embolize the desired area. Previous work in this field has described the use of a highly covalently crosslinked polymer structure for maintaining excellent mechanical and shape memory properties at the application-specific ultra low densities. This work is aimed at further expanding the utility of these biomaterials, as implantable low density shape memory polymer foams, by introducing controlled biodegradability. A highly covalently crosslinked network structure was maintained by use of low molecular weight, symmetrical and polyfunctional hydroxyl monomers such as Polycaprolactone triol (PCL-t, Mn 900 g), N,N,N0,N0-Tetrakis (hydroxypropyl) ethylenediamine (HPED), and Tris (2-hydroxyethyl) amine (TEA). Control over the degradation rate of the materials was achieved by changing the concentration of the degradable PCL-t monomer, and by varying the material hydrophobicity. These porous SMP materials exhibit a uniform cell morphology and excellent shape recovery, along with controllable actuation temperature and degradation rate. We believe that they form a new class of low density biodegradable SMP scaffolds that can potentially be used as “smart” non-permanent implants in multiple minimally invasive biomedical applications.

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Section: Introductionmentioning

confidence: 99%

Low density biodegradable shape memory polyurethane foams for embolic biomedical applications

et al. 2014

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“…This indicates gelation at short time, gelation at proper temperature, achieving of specific mechanical strength, gel persistence during proper time, development of a convenient and practical fabrication or administration, and avoidance of significant pH decreases in tissues. 5 In addition, biodegradability, bio-eliminability, and minimal immune response are important factors for the in vivo biomedical applications of in situ-forming hydrogels. These aspects must be taken into consideration in the selection or design of materials for in situ-forming hydrogels.…”

Section: Introductionmentioning

confidence: 99%

“…The in situ-forming hydrogels must be formed spontaneously or in response to physiological stimuli. 4,5 Gelation stimuli can be characterized as physical-temperature, light, electricity, pressure, and sound, or chemical-covalent bonds. However, the in situ-forming hydrogels prepared via chemical stimuli are permanent hydrogels formed through irreversible chemical reactions with irreversible covalent bonds.…”

Section: Introductionmentioning

confidence: 99%

“…Of the several physical and biological stimuli, the most important stimulus is temperature change which prompts the hydrogel formation after injection into the human body. [4][5][6] For in situ-forming hydrogels to respond to temperature, they must be designed using materials with large hydrophilic surface areas. This feature shortens the water-diffusion distances in the inner parts of the hydrogels, thereby inducing rapid water absorption, swelling, and reversible volume changes.…”

Section: Introductionmentioning

confidence: 99%

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Stimuli-Responsive InjectableIn situ-Forming Hydrogels for Regenerative Medicines

Kim

Kwon

et al. 2015

Polymer Reviews

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Research on injectable in situ-forming hydrogels has been conducted in diverse biomedical applications for a long period. These hydrogels exhibit sol-to-gel phase transition in accordance with the external stimuli such as temperature change. Also, unlike the traditional surgical procedures the hydrogels have the distinct properties of easy management and minimal invasiveness via simple aqueous state injections at target sites. Currently, numerous polymer materials have been reported as potential stimulusinduced in situ-forming hydrogels. In this review, a comprehensive overview of the state-of-the-art of these rapidly developing materials has been outlined. In situ-forming hydrogels formed by electrostatic and hydrophobic interactions as well as their mechanistic characteristics and biomedical applications in regenerative medicine have also been discussed. The review concludes with perspectives on the future of stimulus-induced in situ-forming hydrogels.

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“…Shape memory polymers (SMPs) are “smart” materials that have the capability of shape change from a programmed secondary shape to a primary shape upon the input of an external stimulus, such as heat, light, or electricity [1–3]. For thermal actuation, the polymer can be synthesized in a primary shape, heated above its transition temperature (T trans ), and mechanically programmed into a secondary shape [4].…”

Section: Introductionmentioning

confidence: 99%

Development of siloxane-based amphiphiles as cell stabilizers for porous shape memory polymer systems

Hasan

Easley

Monroe

et al. 2016

Journal of Colloid and Interface Science

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Hypothesis Polyurethane foaming surfactants are cell stabilized at the polymer-gas interface during foam blowing to prevent bubble coalescence. Siloxane-based surfactants are typically used to generate a surface tension gradient at the interface. The chemical structure of the hydrophobic and hydrophilic units affects surfactant properties, which can further influence foam morphology. Experiments Siloxane-polyethylene glycol (PEG) ether amphiphiles were synthesized in high yield via hydrosilylation to serve as surfactants for shape memory polymer (SMP) foams. Hydrophobic units consisted of trisiloxane and polydimethyl siloxane, and PEG allyl methyl ether (n = 8 or 25) was the hydrophilic component. Upon confirming successful synthesis of the surfactants, their surface tension was measured to study their suitability for use in foaming. SMP foams were synthesized using the four surfactants, and the effects of surfactant structure and concentration on foam morphology were evaluated. Findings Spectroscopic data confirmed successful siloxane-PEG coupling. All surfactants had a low surface tension of 20–21 mN/m, indicating their ability to reduce interfacial tension. SMP foams were successfully fabricated with tunable cell size and morphology as a function of surfactant type and concentration.

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Porous Shape-Memory Polymers

Cited by 89 publications

References 96 publications

Low density biodegradable shape memory polyurethane foams for embolic biomedical applications

Low density biodegradable shape memory polyurethane foams for embolic biomedical applications

Stimuli-Responsive InjectableIn situ-Forming Hydrogels for Regenerative Medicines

Development of siloxane-based amphiphiles as cell stabilizers for porous shape memory polymer systems

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