Core-shell nano-latex blending method to prepare multi-shape memory polymers

The Value of CTA Based on Gold Nanorod Contrast Agent in Coronary Artery Diagnosis and Plaque Property Analysis

Coronary CT angiography (CTA) with the characteristics of noninvasive and simple operation is widely used in the diagnosis of coronary artery stenosis. The choice of contrast agent exerts an important impact on the imaging quality of CTA. Conventional iodine contrast agents are easily excreted by the kidneys, from which the imaging window is short, and the imaging quality is poor. Metal nanomaterials have unique optical properties and have broad application prospects in imaging. Our aim is to explore the value of gold nanorod contrast agent in the diagnosis of coronary heart disease. A gold nanorod suspension was first prepared, and the prepared gold nanorod was uniform and had good dispersibility. It can be seen from the light absorption curve that there are two obvious peaks on the UV absorption peak of the gold nanorods. The gold nanorods were cultured in different solutions, and it was found that the particle size of the gold nanorods did not change significantly within 72 hours, indicating that the prepared gold nanorods had good stability. When observing the damage degree of mouse kidney tissue, it was shown that the damage degree of gold nanorod contrast agent to mouse kidney tissue was less than that of iodine contrast agent. The above results indicate that the gold nanorod contrast agent has good stability and safety. Therefore, our study demonstrated that the gold nanorod contrast agent has high value in the diagnosis of coronary arteries and the analysis of plaque properties.

Triple-Shape Memory Behavior of Modified Lactide/Glycolide Copolymers

The paper presents the formation and properties of biodegradable thermoplastic blends with triple-shape memory behavior, which were obtained by the blending and extrusion of poly(l-lactide-co-glycolide) and bioresorbable aliphatic oligoesters with side hydroxyl groups: oligo (butylene succinate-co-butylene citrate) and oligo(butylene citrate). Addition of the oligoesters to poly (l-lactide-co-glycolide) reduces the glass transition temperature (Tg) and also increases the flexibility and shape memory behavior of the final blends. Among the tested blends, materials containing less than 20 wt % of oligo (butylene succinate-co-butylene citrate) seem especially promising for biomedical applications as materials for manufacturing bioresorbable implants with high flexibility and relatively good mechanical properties. These blends show compatibility, exhibiting one glass transition temperature and macroscopically uniform physical properties.

Emulsion Lyophilization as a Facile Pathway to Fabricate Stretchable Polymer Foams Enabling Multishape Memory Effect and Clip Application

Solvent freezing is an important method to produce polymer foams with highly tunable pore structure. However, foams prepared from aqueous solution precursors commonly suffer from poor water resistance, whereas those organo-phase systems are not environmental friendly. Here, we present that using an emulsion lyophilization method can overcome such a contradiction and synthesize multifunctional polymer foams. Commercially available polyacrylate-based emulsions with various targeted glass transition temperatures (T_gs) were applied. Adipodihydrazide molecules contained in the water phase of the emulsions reacted with the acetyl groups on the polymers during the freeze-drying, forming elastic networks to maintain the pore structure. The foams can tolerate a 650% elongation without failure and are notch insensitive. The porosity of the foams can be tuned from approximately 45 to 90% via lyophilization of diluted emulsions. The facile blending of emulsions with different targeted T_gs enabled foams with multishape memory capability. Moreover, the foams showed an excellent mechanical damping property, and the slow recovery nature enabled a clip application of clamping extremely weak objects.