Maglev-fabricated long and biodegradable stent for interventional treatment of peripheral vessels.

While chronic limb-threatening ischemia is a serious peripheral artery disease, the lack of an appropriate stent significantly limits the potential of interventional treatment. In spite of much progress in coronary stents, little is towards peripheral stents, which are expected to be both long and biodegradable and thus require a breakthrough in core techniques. Herein, we develop a long and biodegradable stent with a length of up to 118 mm based on a metal-polymer composite material. To achieve a well-prepared homogeneous coating on a long stent during ultrasonic spraying, a magnetic levitation is employed. In vivo degradation of the stent is investigated in rabbit abdominal aorta/iliac arteries, and its preclinical safety is evaluated in canine infrapopliteal arteries. First-in-man implantation of the stent is carried out in the below-the-knee artery. The 13 months' follow-ups demonstrate the feasibility of the long and biodegradable stent in clinical applications.

A Biodegradable Metal-Polymer Composite Stent Safe and Effective on Physiological and Serum-Containing Biomimetic Conditions.

The new-generation coronary stents are expected to be biodegradable, and then the biocompatibility along with biodegradation becomes more challenging. It is a critical issue to choose appropriate biomimetic conditions to evaluate biocompatibility. Compared with other candidates for biodegradable stents, iron-based materials are of high mechanical strength, yet have raised more concerns about biodegradability and biocompatibility. Herein, a metal-polymer composite strategy is applied to accelerate the degradation of iron-based stents in vitro and in a porcine model. Furthermore, it is found that serum, the main environment of vascular stents, ensured the safety of iron corrosion through its antioxidants. This work highlights the importance of serum, particularly albumin, for an in vitro condition mimicking blood-related physiological condition, when reactive oxygen species, inflammatory response, and neointimal hyperplasia are concerned. The resultant metal-polymer composite stent is implanted into a patient in clinical research via interventional treatment, and the follow-up confirms its safety, efficacy, and appropriate biodegradability.

Cochlear Transfection Gene Guinea Pigs Mediates Atoh1-EGFP Based Hyaluronic Acid Modified Polyethyleneimine Nanoparticles.

To modify polyethyleneimine (PEI) nanoparticles using hyaluronic acid (HA) to prepare a novel nonviral vector and use it to coat Atoh1-EGFP plasmid to detect its translocation in living guinea pig cochlea dyeing efficiency. Atoh1-EGFP plasmid was extracted and characterized using a Zetasizer particle size analyzer. HA/PEI/DNA complexion was characterized and introduced into the round window membrane. EGFP green fluorescence carried in the Atoh1 plasmid was observed by confocal microscopy. The transfection results were verified by Western blot and reverse transcription polymerase chain reaction (RT-PCR) from the perspective of protein and nucleic acid to verify its expression results. In this study, HA-modified PEI nanoparticles are negatively-charged nanoscale gene carrier complexes. After the Atoh1-EGFP plasmid was introduced into the cochlea, the results of confocal microscopy showed that the inner and outer hair cells of the basement membrane could be detected in green fluorescent protein. The transfection efficiency of basement membrane is as high as 81.7±4.71%, while the transversion is 33.8±9.02%. Western Blot and RT-PCR also confirmed that the Atoh1 gene can be successfully transfected on the basement membrane. The gene transfection of cochlea may be achieved by HA-modified PEI nanoparticle gene vector with no obvious toxicity to basement membrane cells. It is also an ideal inner-end gene transfection vector owing to its simple synthesis method and low cost.

Investigation of Localized States in GaAsSb Epilayers Grown by Molecular Beam Epitaxy.

We report the carrier dynamics in GaAsSb ternary alloy grown by molecular beam epitaxy through comprehensive spectroscopic characterization over a wide temperature range. A detailed analysis of the experimental data reveals a complex carrier relaxation process involving both localized and delocalized states. At low temperature, the localized degree shows linear relationship with the increase of Sb component. The existence of localized states is also confirmed by the temperature dependence of peak position and band width of the emission. At temperature higher than 60 K, emissions related to localized states are quenched while the band to band transition dominates the whole spectrum. This study indicates that the localized states are related to the Sb component in the GaAsSb alloy, while it leads to the poor crystal quality of the material, and the application of GaAsSb alloy would be limited by this deterioration.