Characterization of Partially Covered Self-Expandable Metallic Stents for Esophageal Cancer Treatment: In Vivo Degradation

A functional stent with near-infrared light triggered localized photothermal-chemo synergistic therapy for malignant stenosis of esophageal cancer

Stent implantation is a widely used palliative treatment for relieving strictures in malignant esophageal cancer. However, conventional fully covered stents play a role in preventing the tumor from ingrowth but increasing the risk of migration. Therefore, there is an urgent need for a multifunctional stent that not only reduces migration but also provides synergistic therapeutic benefits to inhibit tumor growth. This study proposed a braided esophageal stent with synergistic photothermal and chemotherapy functions to achieve precise controllable drug release. The stent was braided of Nitinol fiber and polyethylene terephthalate fiber in one-step, in which Nitinol loaded with high-efficiency photothermal conversion agent gold nanoparticles and polyethylene terephthalate loaded anti-tumor drugs release mediated by a temperature-responsive coating. The stent showed anti-migration ability and orchestrated the localized hyperthermia plus thermal-stimuli drug release during the tumor lesion. Cell experiments confirmed that the stent showed a significantly synergistic tumor cell killing effect (28.29 %). In 3D tumor sphere model, the apoptosis rate of tumor cells reached 31.34 %. In summary, the composite stent design strategy integrates anti-migration features and photoheating-controlled drug release for synergistic cancer therapy, providing a new design idea for the application of nickel-titanium alloy stents in the treatment of malignant esophageal stenosis.

Novel Silk Fibroin Based Bilayer Scaffolds for Bioabsorbable Internal Biliary Stenting

Biliary duct reconstruction is one of the most challenging parts of liver transplantation and accounts for 40%-60% of complications. While current stent-based devices on the market show promising results in reducing complications, they are manufactured from permanent synthetic materials and require a second reintervention for their removal. This exposes the patients to other potential complications and increases healthcare costs. This study develops a fabrication technique to produce a bioabsorbable biliary stent based on silk fibroin. The process used a dip-coating procedure for silk fibroin that produced highly smooth monolayer tubular specimens without the use of any additional surfactants during removal. This process was combined with an electrospinning step to produce bilayer structures through the deposition of electrospun silk fibroin on the outer surface. The structures proved to have promising mechanical, morphological, and cytocompatibility properties for use in the field of biliary stenting. Furthermore, the technique investigated proved to be reproducible, achieving an important requirement for large-scale use even in the presence of a biomaterial derived from a natural source. These results show the possibility of obtaining a completely bioabsorbable internal biliary stent that does not require any second reintervention. This study can be the starting point for further investigations both in vitro and in vivo to assess the suitability of silk fibroin biliary stents for clinical applications.

Manufacturing, Processing, and Characterization of Self-Expanding Metallic Stents: A Comprehensive Review

This paper aims to review the State of the Art in metal self-expanding stents made from nitinol (NiTi), showing shape memory and superelastic behaviors, to identify the challenges and the opportunities for improving patient outcomes. A significant contribution of this paper is its extensive coverage of multidisciplinary aspects, including design, simulation, materials development, manufacturing, bio/hemocompatibility, biomechanics, biomimicry, patency, and testing methodologies. Additionally, the paper offers in-depth insights into the latest practices and emerging trends, with a special emphasis on the transformative potential of additive manufacturing techniques in the development of metal stents. By consolidating existing knowledge and highlighting areas for future innovation, this review provides a valuable roadmap for advancing nitinol stents.

Advances in the development of biodegradable coronary stents: A translational perspective

Implantation of cardiovascular stents is an important therapeutic method to treat coronary artery diseases. Bare-metal and drug-eluting stents show promising clinical outcomes, however, their permanent presence may create complications. In recent years, numerous preclinical and clinical trials have evaluated the properties of bioresorbable stents, including polymer and magnesium-based stents. Three-dimensional (3D) printed-shape-memory polymeric materials enable the self-deployment of stents and provide a novel approach for individualized treatment. Novel bioresorbable metallic stents such as iron- and zinc-based stents have also been investigated and refined. However, the development of novel bioresorbable stents accompanied by clinical translation remains time-consuming and challenging. This review comprehensively summarizes the development of bioresorbable stents based on their preclinical/clinical trials and highlights translational research as well as novel technologies for stents (e.g., bioresorbable electronic stents integrated with biosensors). These findings are expected to inspire the design of novel stents and optimization approaches to improve the efficacy of treatments for cardiovascular diseases.

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Bioresorbable stents can overcome the limitations of non-degradable stents.

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3D printing of shape-memory polymeric stents can lead to better clinical outcomes.

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Advances in Mg-, Fe- and Zn-based stents from a translational perspective.

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Electronic stents integrated with biosensors can covey stent status in real time.

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Development in the assessment of stent performance in vivo.

Recent advances in 3D-printed polylactide and polycaprolactone-based biomaterials for tissue engineering applications

The three-dimensional printing (3DP) also known as the additive manufacturing (AM), a novel and futuristic technology that facilitates the printing of multiscale, biomimetic, intricate cytoarchitecture, function-structure hierarchy, multi-cellular tissues in the complicated micro-environment, patient-specific scaffolds, and medical devices. There is an increasing demand for developing 3D-printed products that can be utilized for organ transplantations due to the organ shortage. Nowadays, the 3DP has gained considerable interest in the tissue engineering (TE) field. Polylactide (PLA) and polycaprolactone (PCL) are exemplary biomaterials with excellent physicochemical properties and biocompatibility, which have drawn notable attraction in tissue regeneration. Herein, the recent advancements in the PLA and PCL biodegradable polymer-based composites as well as their reinforcement with hydrogels and bio-ceramics scaffolds manufactured through 3DP are systematically summarized and the applications of bone, cardiac, neural, vascularized and skin tissue regeneration are thoroughly elucidated. The interaction between implanted biodegradable polymers, in-vivo and in-vitro testing models for possible evaluation of degradation and biological properties are also illustrated. The final section of this review incorporates the current challenges and future opportunities in the 3DP of PCL- and PLA-based composites that will prove helpful for biomedical engineers to fulfill the demands of the clinical field.