scholarly journals Degradable Poly(ether-ester-urethane)s Based on Well-Defined Aliphatic Diurethane Diisocyanate with Excellent Shape Recovery Properties at Body Temperature for Biomedical Application

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1002 ◽  
Author(s):  
Minghui Xiao ◽  
Na Zhang ◽  
Jie Zhuang ◽  
Yuchen Sun ◽  
Fang Ren ◽  
...  
Keyword(s):  
Body Temperature ◽  
Shape Memory ◽  
Tensile Properties ◽  
Shape Recovery ◽  
Biomedical Application ◽  
Degradation Products ◽  
Chain Extension ◽  
Chemical Structures ◽  
Ether Ester

The aim of this study is to offer a new class of degradable shape-memory poly(ether-ester-urethane)s (SMPEEUs) based on poly(ether-ester) (PECL) and well-defined aliphatic diurethane diisocyanate (HBH) for further biomedical application. The prepolymers of PECLs were synthesized through bulk ring-opening polymerization using ε-caprolactone as the monomer and poly(ethylene glycol) as the initiator. By chain extension of PECL with HBH, SMPEEUs with varying PEG content were prepared. The chemical structures of the prepolymers and products were characterized by GPC, 1H NMR, and FT-IR, and the effect of PEG content on the physicochemical properties (especially the shape recovery properties) of SMPEEUs was studied. The microsphase-separated structures of the SMPEEUs were demonstrated by DSC and XRD. The SMPEEU films exhibited good tensile properties with the strain at a break of 483%–956% and an ultimate stress of 23.1–9.0 MPa. Hydrolytic degradation in vitro studies indicated that the time of the SMPEEU films becoming fragments was 4–12 weeks and the introduction of PEG facilitates the degradation rate of the films. The shape memory properties studies found that SMPEEU films with a PEG content of 23.4 wt % displayed excellent recovery properties with a recovery ratio of 99.8% and a recovery time of 3.9 s at body temperature. In addition, the relative growth rates of the SMPEEU films were greater than 75% after incubation for 72 h, indicating good cytocompatibility in vitro. The SMPEEUs, which possess not only satisfactory tensile properties, degradability, nontoxic degradation products, and cytocompatibility, but also excellent shape recovery properties at body temperature, promised to be an excellent candidate for medical device applications.

scholarly journals Preparation, Physicochemical Properties, and Hemocompatibility of the Composites Based on Biodegradable Poly(Ether-Ester-Urethane) and Phosphorylcholine-Containing Copolymer

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 860 ◽  
Author(s):  
Jun Zhang ◽  
Bing Yang ◽  
Qi Jia ◽  
Minghui Xiao ◽  
Zhaosheng Hou
Keyword(s):  
Physicochemical Properties ◽  
Tensile Properties ◽  
Platelet Rich Plasma ◽  
Composite Films ◽  
Homogeneous Solution ◽  
Uniform Size ◽  
Good Surface ◽  
Biodegradable Poly ◽  
Ether Ester

To improve the hemocompatibility of the biodegradable medical poly(ether-ester-urethane) (PEEU), containing uniform-size aliphatic hard segments that was prepared in our lab, a copolymer containing phosphorylcholine (PC) groups was blended with the PEEU. The PC-copolymer of poly(MPC-co-EHMA) (PMEH) was first obtained by copolymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-ethylhexyl methacrylate (EHMA), and then dissolved in mixed solvent of ethanol/chloroform to obtain a homogeneous solution. The composite films (PMPU) with varying PMEH content were prepared by solvent evaporation method. The physicochemical properties of the composite films with varying PMEH content were researched. The PMPU films exhibited higher thermal stability than that of the pure PEEU film. With the PMEH content increasing from 5 to 20 wt%, the PMPU films also possessed satisfied tensile properties with ultimate stress of 22.9–15.8 MPa and strain at break of 925–820%. The surface and bulk hydrophilicity of the films were improved after incorporation of PMEH. In vitro degradation studies indicated that the degradation rate increased with PMEH content, and it took 12–24 days for composite films to become fragments. The protein adsorption and platelet-rich plasma contact tests were adapted to evaluate the surface hemocompatibility of the composite films. It was found that the amount of adsorbed protein and adherent platelet on the surface decreased significantly, and almost no activated platelets were observed when PMEH content was above 5 wt%, which manifested good surface hemocompatibility. Due to the biodegradability, acceptable tensile properties and good surface hemocompatibility, the composites can be expected to be applied in blood-contacting implant materials.

scholarly journals Structural Characterization, Antioxidant Activity, and Biomedical Application of Astragalus Polysaccharide Degradation Products

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Jian-Min Wang ◽  
Xin-Yuan Sun ◽  
Jian-Ming Ouyang
Keyword(s):  
Molecular Weight ◽  
Antioxidant Activity ◽  
Biomedical Application ◽  
Degradation Products ◽  
Human Kidney ◽  
Degradation Process ◽  
Chain Structure ◽  
Molecular Weights ◽  
Reducing Ability

To study the antioxidant capacity of Astragalus polysaccharides (APS) with different molecular weights, we used hydrogen peroxide to degrade original Astragalus polysaccharide (APS0) with an initial molecular weight of 11.03 kDa and obtained three degraded polysaccharides with molecular weights of 8.38 (APS1), 4.72 (APS2), and 2.60 kDa (APS3). The structures of these polysaccharides were characterized by 1H NMR, 13C NMR, FT-IR, and GC/MS. The degradation process did not cause significant changes in the main chain structure of APS. The monosaccharide component of APS before and after degradation was slightly changed. The antioxidant ability in vitro (removing hydroxyl and ABTS radicals and reducing ability) and in cells (superoxide dismutase and malondialdehyde generation) of these polysaccharides is closely related to their molecular weight. If the molecular weight of APS is very high or low, it is not conducive to their activity. Only APS2 with moderate molecular weight showed the greatest antioxidant activity and ability to repair human kidney epithelial (HK-2) cells. Therefore, APS2 can be used as a potential antistone polysaccharide drug.

scholarly journals Primary Evaluation of Shape Recovery of Orthodontic Aligners Fabricated from Shape Memory Polymer (A Typodont Study)

2021 ◽  
Vol 9 (3) ◽  
pp. 31
Author(s):  
Tarek M. Elshazly ◽  
Ludger Keilig ◽  
Yasmine Alkabani ◽  
Ahmed Ghoneima ◽  
Moosa Abuzayda ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
In Vitro Study ◽  
Central Incisor ◽  
Custom Made ◽  
Corrective Movement ◽  
Primary Evaluation ◽  
Rate Limiting

As an innovative approach to overcome the rate-limiting staging of conventional aligners, using shape memory polymers (SMPs) as aligners’ materials was investigated in this in vitro study. The ability of SMPs to shape recover and consequently move tooth, upon appropriate stimuli, was evaluated on a typodont model before clinical application. The study design was to achieve 1.9 mm correction movement of an upper central incisor by one aligner after multiple steps/activation. A custom-made aligned typodont model with a movable upper central incisor was scanned. Using an orthodontic software and a 3D printer, resin-models were generated. Seven aligners of ClearX sheets (SMPs) were fabricated by thermoforming on the resin aligned model. Each aligner was tested for repositioning of the central incisor in the typodont model. The model was scanned after each step and the corrective movement was measured through the superimposition of scans. Results showed that the total correction efficiency of the SMPs’ aligner was ≈93% (1.76 mm). The corrective movement was 0.94 ± 0.04 mm after the reforming step, 0.66 ± 0.07 mm after the first activation step, and 0.15 ± 0.10 mm after the second activation step. It was concluded that aligners made of SMPs could have a promising future-use in orthodontic aesthetic treatment.

Remote, fast actuation of programmable multiple shape memory composites by magnetic fields

2015 ◽  
Vol 3 (43) ◽  
pp. 11290-11293 ◽  
Author(s):  
F. H. Zhang ◽  
Z. C. Zhang ◽  
C. J. Luo ◽  
I-Ting Lin ◽  
Yanju Liu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Body Temperature ◽  
Magnetic Fields ◽  
Surface Temperature ◽  
Shape Memory ◽  
Composite Membrane ◽  
Shape Recovery ◽  
Recovery Behavior ◽  
Shape Memory Composites

Magnetic field actuated shape recovery behavior of a 3D box folded by a Nafion/Fe3O4composite membrane with its surface temperature near body temperature.

SPECIAL METALS BODY-TEMPERATURE Ni-Ti

Alloy Digest ◽  
2007 ◽  
Vol 56 (10) ◽  
Keyword(s):  
Body Temperature ◽  
Shape Memory Alloy ◽  
Physical Properties ◽  
Shape Memory ◽  
Titanium Alloys ◽  
Tensile Properties ◽  
Nickel Titanium ◽  
Ti Alloys ◽  
Nickel Titanium Alloys ◽  
Start Temperature

Abstract Body-Temperature Ni-Ti alloys are binary nickel-titanium alloys better known as shape memory or nitinol alloys. This is the second of several data sheets that cover these materials by austenite start temperature. This data sheet covers materials with an austenite start temperature of approximately 15 ± 5 deg C (59 ± 9 deg F). This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on forming and machining. Filing Code: Ni-654. Producer or source: Special Metals, Shape Memory Alloy Division.

Degradation products of poly(ester-ether-ester) block copolymers do not alter endothelial metabolism in vitro

1995 ◽  
Vol 6 (12) ◽  
pp. 824-828 ◽  
Author(s):  
R. Sbarbati Del Guerra ◽  
P. Gazzetti ◽  
G. Lazzerini ◽  
P. Cerrai ◽  
G. D. Guerra ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Degradation Products ◽  
Ether Ester

In vitro mutagenicity of Acid Violet 7 and its degradation products by Pseudomonas putida mt-2: Correlation with chemical structures

2009 ◽  
Vol 27 (2) ◽  
pp. 231-236 ◽  
Author(s):  
Hedi Ben Mansour ◽  
Ridha Mosrati ◽  
David Corroler ◽  
Kamel Ghedira ◽  
Daniel Barillier ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Degradation Products ◽  
Chemical Structures ◽  
Acid Violet ◽  
Acid Violet 7
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