Biodegradable intravascular stent has attracted more and more focus in recent years as an effective solution for angiostenosis. Ideal stents were expected to exhibit sufficient radial force to support the vascular wall, while suitable flexibility for the angioplasty. After vascular remodeling, stents should be degraded into small molecular and be eliminated from human body, causing no potential risk. In this paper, poly-p-dioxanone (PDO) monofilament was braided into net structure with four different braiding density, two of which exhibited sufficient radial force larger than 30 kPa, and three of which showed the bending rigidity within 11.7–88.1 N•mm2. The degradation behaviors of monofilaments and stents have been observed for 16 weeks. The findings obtained indicate that degradation first occurred in morphology region, which induced temporary increase of crystallinity, monofilament bending rigidity and stent mechanical properties. During this period, monofilament tends to be hard and brittle and lost its tensile properties. Then the crystalline region was degraded and stent mechanical properties decreased. All the results reveal that the PDO intravascular stents with braided structure were able to afford at least 10 weeks of sufficient support to the vascular wall.

Porous scaffold is widely used in the field of tissue engineering. However, the anisotropic structure of actual extracellular matrix (ECM) of human tissue pose a challenge to the scaffold structure that pore size should be changed in gradient. Here we report a stage cooling method to fabricate alginate scaffold with gradient pores. Eight cooling models were set according to different temperature steps, different initial temperature, and different time duration. The thermal characterization of solution during cooling process were recorded and scaffold morphology were observed. The results revealed that the temperature steps mainly affected pore shape, while the initial temperature and time duration mainly affected pore size. By altering the initial temperature and time duration, scaffold exhibited cellular and gradually enlarged pores on the vertical axial direction (10–65 μm at base, 50–141 μm at top). With this stage cooling method, pore shape and pore size could be easily tailored and scaffold with gradient structure could be fabricated.

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Two novel biodegradable intravascular stents (BIS) with different structures are introduced. Braiding-structural BIS and Z-structural BIS were fabricated from polydioxanone (PDO) monofilament by a hand-braiding method with a perforated mold, imitating commercial stents that have been used clinically. The fabrication process of these two BIS is described and stent parameters, mechanical properties, and degradation properties are reported. The findings reveal that Z-structural BIS have higher porosity, smaller longitudinal shortening rate, and higher radial force and recovery rate compared with the braiding-structural stent. During the degradation process, braiding-structural BIS maintained their mechanical properties higher than international standards for 12 weeks, while Z-structural stents maintained them for 16 weeks.