Hydrogen Bonding Interaction of Poly(<scp>d</scp>,<scp>l</scp>-Lactide)/hydroxyapatite Nanocomposites

Zhou, Shaobing; Zheng, Xiaotong; Yu, Xiaolan; Wang, Jianxin; Weng, Jie; Li, Xiaohong; Feng, Bo; Yin, Ming

doi:10.1021/cm0619398

Cited by 245 publications

(159 citation statements)

References 49 publications

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“…This observation, as well as observed optical transparency, supports an amorphous network structure where POSS cores are well-dispersed rather than crystallizing as in the case of the SMPs containing mono-or difunctional POSS (4,5,19). Unlike linear high molecular weight poly(D,L-lactide) (T g ∼ 54°C) (20), the T g s exhibited by POSS-SMPs, 42.8-48.4°C, are more suitable for biomedical applications. Conventional cross-linked elastomers and the Org-SMPs (Fig.…”

Section: Cross-linkingsupporting

confidence: 60%

High performance shape memory polymer networks based on rigid nanoparticle cores

Song

2010

Proc. Natl. Acad. Sci. U.S.A.

122

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Smart materials that can respond to external stimuli are of widespread interest in biomedical science. Thermal-responsive shape memory polymers, a class of intelligent materials that can be fixed at a temporary shape below their transition temperature (T trans ) and thermally triggered to resume their original shapes on demand, hold great potential as minimally invasive self-fitting tissue scaffolds or implants. The intrinsic mechanism for shape memory behavior of polymers is the freezing and activation of the long-range motion of polymer chain segments below and above T trans , respectively. Both T trans and the extent of polymer chain participation in effective elastic deformation and recovery are determined by the network composition and structure, which are also defining factors for their mechanical properties, degradability, and bioactivities. Such complexity has made it extremely challenging to achieve the ideal combination of a T trans slightly above physiological temperature, rapid and complete recovery, and suitable mechanical and biological properties for clinical applications. Here we report a shape memory polymer network constructed from a polyhedral oligomeric silsesquioxane nanoparticle core functionalized with eight polyester arms. The cross-linked networks comprising this macromer possessed a gigapascal-storage modulus at body temperature and a T trans between 42 and 48°C. The materials could stably hold their temporary shapes for >1 year at room temperature and achieve full shape recovery ≤51°C in a matter of seconds. Their versatile structures allowed for tunable biodegradability and biofunctionalizability. These materials have tremendous promise for tissue engineering applications.nanocompsite | shape memory materials | thermal responsive materials A thermal-responsive shape memory polymer (SMP) can be imparted with a "permanent" shape above a critical transition temperature (T trans ) when it is cast in a mold. For polymers, the T trans is either glass transition temperature T g or melting temperature T m . Such a permanent shape, formed at the elastic state of the material without external stress, is retained (memorized) as the SMP cools to a temperature below its T trans . The SMP can be deformed into a desired "temporary" shape by force at T > T trans , and this strained configuration can be fixed as the temperature cools below the T trans . When a thermal stimulus above the T trans is reapplied, however, the SMP recovers to its less strained permanent shape. This unique shape memory behavior has captured the imagination of the biomedical community as scientists strive to design smart implants and tissue scaffolds that can be delivered in a minimally invasive configuration and be subsequently reverted to a preprogrammed permanent shape in vivo.Since the first demonstration of degradable SMPs for potential tissue engineering applications (1, 2), many semicrystalline and amorphous polyester and polyurethane SMP networks have been reported. Adjustment of thermomechanical properties and degrad...

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Section: Cross-linkingsupporting

confidence: 60%

High performance shape memory polymer networks based on rigid nanoparticle cores

Song

2010

Proc. Natl. Acad. Sci. U.S.A.

122

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“…80 to 98% upon filling. This was attributed to H-bonding between the matrix and nanoparticles creating net points in an additional physical network-like structure [10,11]. Accordingly, a more efficient network should be configured.…”

Section: Molecular Structure 211 T G -Based Systemsmentioning

confidence: 99%

Biodegradable polyester-based shape memory polymers: Concepts of (supra)molecular architecturing

Karger‐Kocsis

Kéki

2014

Express Polym. Lett.

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Shape memory (SM) biodegradable polymers (SMPs) and related composites are emerging smart materials in different applications. SMPs may adopt one (dual-shape), two (triple-shape) or several (multishape) stable temporary shapes and recover their permanent shape (or other temporary shapes in case of multi-shape versions) upon the action of an external stimulus. The external stimulus may be temperature, pH, water, light irradiation, redox condition etc. In most cases, however, the SMPs are thermally activated. The 'switching' or transformation temperature (T trans ), enabling the material to return to its permanent shape, is either linked with the glass transition (T g ) or with the melting temperature (T m ).Thus, SMPs are often subdivided based on their switch types into T g -or T m -based SMPs. As reversible 'switches' other mechanisms such as liquid crystallization and related transitions, supermolecular assembly/disassembly, irradiation-induced reversible network formation, formation and disruption of a percolation network, may also serve [1]. The permanent shape is guaranteed by physical or chemical network structures. The latter may be both on molecular and supramolecular levels. Linkages of these networks are termed net points. The temporary shape is created by mechanical deformation above T trans . In some cases the deformation temperature may be below Abstract. Shape memory polymers (SMPs) are capable of memorizing one or more temporary shapes and recovering to the permanent shape upon an external stimulus that is usually heat. Biodegradable polymers are an emerging family within the SMPs. This minireview delivers an overlook on actual concepts of molecular and supramolecular architectures which are followed to tailor the shape memory (SM) properties of biodegradable polyesters. Because the underlying switching mechanisms of SM actions is either related to the glass transition (T g ) or melting temperatures (T m ), the related SMPs are classified as T g -or T m -activated ones. For fixing of the permanent shape various physical and chemical networks serve, which were also introduced and discussed. Beside of the structure developments in one-way, also those in two-way SM polyesters were considered. Adjustment of the switching temperature to that of the human body, acceleration of the shape recovery, enhancement of the recovery stress, controlled degradation, and recycling aspects were concluded as main targets for the future development of SM systems with biodegradable polyesters.

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“…Apart from the selection of the most suitable filler, there are other critical factors, such as the effective dispersion and distribution of filler into the matrix by the prevention of agglomeration [20], introducing H-bonds [21], or the functionalization of the filler. These are the pre-requisite vital factors to enhancing the affinity between the filler and polymer, to create surface roughness, to tailor the aspect ratio of filler (2D) and to increase interfacial adhesion in polymer nanocomposites [22,23].…”

Section: Introductionmentioning

confidence: 99%

Microwave-Assisted Dip Coating of Aloe Vera on Metallocene Polyethylene Incorporated with Nano-Rods of Hydroxyapaptite for Bone Tissue Engineering

et al. 2017

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Bone tissue engineering widely explores the use of ceramic reinforced polymer-matrix composites. Among the various widely-used ceramic reinforcements, hydroxyapatite is an undisputed choice due to its inherent osteoconductive nature. In this study, a novel nanocomposite comprising metallocene polyethylene (mPE) incorporated with nano-hydroxyapaptite nanorods (mPE-nHA) was synthesized and dip coated with Aloe vera after subjecting it to microwave treatment. The samples were characterized using contact angle, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), atomic force microscopy (AFM) and 3D Hirox microscopy scanning. Contact angle results show that the hydrophilicity of mPE-nHA improved notably with the coating of Aloe vera. The surface topology and increase in surface roughness were observed using the SEM, AFM and 3D Hirox microscopy. Blood compatibility assays of pure mPE and the Aloe vera coated nanocomposite were performed. The prothrombin time (PT) was delayed by 1.06% for 24 h Aloe-vera-treated mPE-nHA compared to the pristine mPE-nHA. Similarly, the 24 h Aloe-vera-coated mPE-nHA nanocomposite prolonged the activated partial thromboplastin time (APTT) by 41 s against the control of pristine mPE-nHA. The hemolysis percentage was also found to be the least for the 24 h Aloe-vera-treated mPE-nHA which was only 0.2449% compared to the pristine mPE-nHA, which was 2.188%. To conclude, this novel hydroxyapatite-reinforced, Aloe-vera-coated mPE with a better mechanical and anti-thrombogenic nature may hold a great potential to be exploited for bone tissue engineering applications.

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Hydrogen Bonding Interaction of Poly(d,l-Lactide)/hydroxyapatite Nanocomposites

Cited by 245 publications

References 49 publications

High performance shape memory polymer networks based on rigid nanoparticle cores

High performance shape memory polymer networks based on rigid nanoparticle cores

Biodegradable polyester-based shape memory polymers: Concepts of (supra)molecular architecturing

Microwave-Assisted Dip Coating of Aloe Vera on Metallocene Polyethylene Incorporated with Nano-Rods of Hydroxyapaptite for Bone Tissue Engineering

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