Vascular Scaffold Research Articles

Hofmeister effect driven dynamic-bond cross-linked dialdehyde xylan hydrogels with rapid response and robust mechanical properties for expanding stent

The biomedical field urgently needs for programmable stent materials with nontoxic, autonomous self-healing, injectability, and suitable mechanical strength, especially self-expanding characteristics. However, such materials are still lacking. Herein, based on gelatin and dialdehyde-functionalized xylan, we synthesized 3D-printable, autonomous, self-healing, and mechanically robust hydrogels with a reversible Schiff base crosslink network. The hydrogels exhibited excellent mechanical properties and automatic healing properties at room temperature. The solid mechanical properties originate from the Schiff base, hydrogen bonding interactions, and xylan nanoparticle reinforcement of the polymer networks. As a proof of concept, the Hofmeister effect enabled the hydrogel to contract in highly concentrated salt solutions. In contrast, the same hydrogel expanded and relaxed in dilute salt solutions (quick response within 10 s), showing ionic stimulus-response and excellent shape memory characteristics, which demonstrated that the prepared hydrogel could be used as self-expanding artificial vascular stents. In particular, good biocompatibility was confirmed by cytotoxicity and compatibility tests, and ex vivo arterial experiments further indicated the feasibility of these artificial vascular scaffolds (the expansion force reached 1.51 N). Combined with its ionic stimuli-responsive shape memory ability, the strong mechanical, self-healing, 3D-printable, and biocompatibility properties make this hydrogel a promising material for artificial stents in various biomedical applications.

Biomimetic bilayer scaffold from Bombyx mori silk materials for small diameter vascular applications in tissue engineering.

Enhancing the biocompatibility and mechanical stability of small diameter vascular scaffolds remain significant challenges. To address this challenge, small-diameter tubular structures were electrospun from silk fibroin (SF) from silk textile industry discarded materials to generate bilayer scaffolds that mimic native blood vessels, but derived from a sustainable natural material resource. The inner layer was obtained by directly dissolving SF in formic acid, while the middle layer (SF-M) was achieved through aqueous concentration of the protein. Structural and biological properties of each layer as well as the bilayer were evaluated. The inner layer exhibited nano-scale fiber diameters and 57.9% crystallinity, and degradation rates comparable with the SF-M layer. The middle layer displayed micrometer-scale fibers diameters with an ultimate extension of about 274%. Both layers presented contact angles suitable for cell growth and cytocompatibility, while the bilayer material displayed an intermediate mechanical response and a reduced enzymatic degradation rate when compared to each individual layer. The bilayer material emulates many of the characteristics of native small-diameter vessels, thereby suggesting further studies towards in vivo opportunities.

TCT-1011 Drug-Eluting Stent or Bioresorbable Vascular Scaffold for Preventive PCI: Post Hoc Analysis From the PREVENT Trial

TCT-1011 Drug-Eluting Stent or Bioresorbable Vascular Scaffold for Preventive PCI: Post Hoc Analysis From the PREVENT Trial

Analysis of the results of optical coherence tomography to assess the effectiveness and safety of implantable bioresorbable stenting frames in the long term

Objective: to evaluate the effectiveness and safety of implantation of everolimus-coated bioabsorbable vascular scaffolds (BSCs) based on the results of optical coherence tomography (OCT) in patients with coronary artery disease who have previously undergone percutaneous coronary intervention (PCI). Materials and methods: OCT data from 23 patients with coronary artery disease (CAD) were studied 10 years or more after intervention with BVS implantation. Standard criteria based on OCT analysis were used to evaluate the efficacy of BVS. The stented segment, proximal zone before the stent, and distal zone after the stent were the areas of interest. Results: in the long-term period, the structure of the artery in the area of the installed biodegradable scaffolds is a combination of fragments of an atherosclerotic plaque, a resorbed scaffold, and neointima. When visualized using coherence tomography, this structure appears as a monolayer with high signal intensity. In 42.3% of patients, structures similar to fragments of the stenting frame were visualized, but smaller in size, with a disconnected structure, without clear contours and the absence of a typical shape. In 15.4% of cases, pronounced positive remodeling of the coronary artery in the area of the installation of the bioresorbable frame was noted. Conclusions: analysis of coherence tomography data showed that the use of biodegradable frames is effective and safe, the process of degradation of the frames occurs with an increase in diameter in the stented zone and the formation of a protective monolayer, while maintaining the patency of all side branches in the implantation zone.

Evolution of Atomic-Level Interfacial Fracture Mechanics in Magnesium-Zinc Compounds Used for Bioresorbable Vascular Stents.

Bioresorbable magnesium-metal vascular stents are gaining popularity due to their biodegradable nature and good biological and mechanical properties. They are also suitable candidate materials for biodegradable stents. Due to the rapid degradation rate of Mg metal vascular scaffolds, a Mg/Zn bilayer composite was formed by a number of means, such as magnetron sputtering and physical vapor deposition, thus delaying the degradation time of the Mg metal vascular scaffolds while providing good radial support for the stenotic vessels. However, the interlaminar compounds at the metal interface have an essential impact on the mechanical properties of the bi-material interface, especially the cracking and delamination of the Mg matrix Zn coating vascular stent in the radially expanded process layer. Intermetallic compounds (IMCs) are commonly found in dual-layer composites, such as Mg/Zn composites and multi-layer structures. They are frequently overlooked in simulations aiming to predict mechanical properties. This paper analyses the interfacial failure processes and evolutionary mechanisms of interfacial fracture mechanics of a Mg/Zn interface with an intermetallic compound layer between coated Zn and Mg matrix metallic vascular stents. The simulation results show that the fracture mode in the Mg/Zn interface with an intermetallic compound involves typical ductile fracture under static tensile conditions. The dislocation line defects mainly occur on the side of the Mg, which induces the Mg/Zn interfacial crack to expand along the interface into the pure Mg. The stress intensity factor and the critical strain energy release rate decrease as the intermetallic compound layer's thickness gradually increases, indicating that the intensity of stress and the force of the crack extending and expanding along the crack tip are weakened. The presence of intermetallic compounds at the interface can significantly strengthen the mechanical properties of the material interface and alleviate the crack propagation between the interfaces.

Molecular Dynamics Analysis of Multi-Factor Influences on Structural Defects in Deposited Mg-Matrix Zn Atom Films.

Mg metal vascular stents not only have good mechanical support properties but also can be entirely absorbed by the human body as a trace element beneficial to the human body, but because Mg metal is quickly dissolved and absorbed in the human body, magnesium metal alone cannot be ideally used as a vascular stent. Since the dense oxide Zn film formed by Zn contact with oxygen in the air has good anti-corrosion performance, the Zn nanolayer film deposited on the Mg matrix vascular scaffold by magnetron sputtering can effectively inhibit the rapid dissolution of Mg metal. However, there are few studies on the molecular dynamic structural defects of Mg-matrix Zn atomic magnetron sputtering, and the atomic level simulation of Mg-matrix Zn thin-film depositions can comprehensively understand the atomic level structural defects in the deposition process of Zn thin films from a theoretical perspective to further guide experimental research. Based on this, this research first studied and analyzed the atomic layer structure defects, surface morphology, surface roughness, atomic density of different deposited layers, radial distribution function, and residual stress of the thin-film deposition layer of 1500 deposited Zn atoms at the initial deposition stage, during and after deposition under Mg-matrix thermal layer 500K and a deposited velocity 5 Å/ps by molecular dynamics. At the same time, the effects of temperature and deposited velocity of the Mg-matrix thermal layer on the surface morphology, roughness, and biaxial stress of the deposited films were studied.

Enhancing flexibility of smart bioresorbable vascular scaffolds through 3D printing using polycaprolactone and polylactic acid

With the growing use of stent implantations, the risk of in-stent restenosis represents a major concern for cardiovascular patients. Herein, we propose a hybrid bioresorbable vascular scaffold (H-BVS) integrated with a wireless sensor that could enable significant advances in cardiovascular therapeutics. The H-BVS was carefully manufactured using a state-of-the-art customized 3D printer equipped with dual nozzles to achieve a synergistic combination of polycaprolactone (PCL) and polylactic acid (PLA), both of which are known for their bioresorbable properties. This characteristic is particularly valuable in medical applications where the scaffold is gradually absorbed by the body, eliminating the need for a second procedure to remove it. Furthermore, the H-BVS was integrated with a wireless, battery-less LC-type pressure sensor for real-time monitoring of in-stent restenosis. This wireless sensor was meticulously connected with the H-BVS framework through engineered microstructures, which not only ensured a robust bond but also significantly enhanced the overall integrity and functionality of the device. Additionally, the combination of the H-BVS and sensor was optimized to exhibit superior bending flexibility and radial strength, which are key factors in ensuring effectiveness and patient safety. The feasibility of the smart H-BVS (SH-BVS) was verified through comprehensive testing within a phantom system designed to simulate real blood flow conditions. We believe that the SH-BVS system holds strong potential to significantly improve patient monitoring and treatment strategies within the cardiovascular healthcare domain.

Ten-year clinical outcomes of everolimus- and biolimus-eluting coronary stents vs. everolimus-eluting bioresorbable vascular scaffolds—insights from the EVERBIO-2 trial

BackgroundBioresorbable vascular scaffolds (BVSs) have been developed as a potential solution to mitigate late complications associated with drug-eluting metallic stents (DESs) in percutaneous coronary intervention for coronary artery disease. While numerous studies have compared BVSs to DESs, none have assessed clinical outcomes beyond 5 years.ObjectivesThis study aimed to compare the 10-year clinical outcomes of patients treated with BVSs vs. DESs.MethodsThe EverBio-2 trial (Comparison of Everolimus- and Biolimus-Eluting Coronary Stents with Everolimus-Eluting Bioresorbable Vascular Scaffold) is a single-center, assessor-blinded, randomized controlled trial that enrolled 240 patients allocated in a 1:1:1 ratio to receive BVSs, everolimus-eluting stents, or biolimus-eluting stents (BESs). Clinical follow-up was scheduled for 10 years.ResultsClinical follow-up was completed in 222 patients (93%) at the 10-year mark. The rate of device-oriented composite events (DOCE) was 28% in the DES group and 29% in the BVS group (p = 0.72) at 10 years. Similarly, the rate of patient-oriented composite events (POCE) was 55% in the DES group and 49% in the BVS group (p = 0.43) at 10 years. Notably, the rate of myocardial infarction (MI) within the target vessel was 5% in the BVS group and 0% in the BES group (p = 0.04), while the rate of any MI was 10% in the BVS group and 2% in the BES group (p = 0.04). In addition, the rate of Academic Research Consortium (ARC) possible stent thrombosis was 3% in the BVS group and 0% in the DES group (p = 0.04).ConclusionsOver 10 years, the rates of clinical DOCE and POCE were similar between the BVS and DES groups but individual outcomes of stent thrombosis were higher (3%) in the BVS group compared to the DES group. Clinical Trial RegistrationClinicalTrials.gov, identifier (NCT01711931).

A vascular endothelial growth factor-loaded chitosanhyaluronic acid hydrogel scaffold enhances the therapeutic effect of adipose-derived stem cells in the context of stroke.

Adipose-derived stem cell, one type of mesenchymal stem cells, is a promising approach in treating ischemia-reperfusion injury caused by occlusion of the middle cerebral artery. However, its application has been limited by the complexities of the ischemic microenvironment. Hydrogel scaffolds, which are composed of hyaluronic acid and chitosan, exhibit excellent biocompatibility and biodegradability, making them promising candidates as cell carriers. Vascular endothelial growth factor is a crucial regulatory factor for stem cells. Both hyaluronic acid and chitosan have the potential to make the microenvironment more hospitable to transplanted stem cells, thereby enhancing the therapeutic effect of mesenchymal stem cell transplantation in the context of stroke. Here, we found that vascular endothelial growth factor significantly improved the activity and paracrine function of adipose-derived stem cells. Subsequently, we developed a chitosan-hyaluronic acid hydrogel scaffold that incorporated vascular endothelial growth factor and first injected the scaffold into an animal model of cerebral ischemia-reperfusion injury. When loaded with adipose-derived stem cells, this vascular endothelial growth factor-loaded scaffold markedly reduced neuronal apoptosis caused by oxygen-glucose deprivation/reoxygenation and substantially restored mitochondrial membrane potential and axon morphology. Further in vivo experiments revealed that this vascular endothelial growth factor-loaded hydrogel scaffold facilitated the transplantation of adipose-derived stem cells, leading to a reduction in infarct volume and neuronal apoptosis in a rat model of stroke induced by transient middle cerebral artery occlusion. It also helped maintain mitochondrial integrity and axonal morphology, greatly improving rat motor function and angiogenesis. Therefore, utilizing a hydrogel scaffold loaded with vascular endothelial growth factor as a stem cell delivery system can mitigate the adverse effects of ischemic microenvironment on transplanted stem cells and enhance the therapeutic effect of stem cells in the context of stroke.

Vascular network-inspired diffusible scaffolds for engineering functional neural organoids.

Organoids, three-dimensional in vitro organ-like tissue cultures derived from stem cells, show promising potential for developmental biology, drug discovery, and regenerative medicine. However, the function and phenotype of current organoids, especially neural organoids, are still limited by insufficient diffusion of oxygen, nutrients, metabolites, signaling molecules, and drugs. Herein, we present Vascular network-Inspired Diffusible (VID) scaffolds to fully recapture the benefits of physiological diffusion physics for generating functional organoids and phenotyping their drug response. In a proof-of-concept application, the VID scaffolds, 3D-printed meshed tubular channel networks, support the successful generation of engineered human midbrain organoids almost without necrosis and hypoxia in commonly used well-plates. Compared to conventional organoids, these engineered organoids develop with more physiologically relevant features and functions including midbrain-specific identity, oxygen metabolism, neuronal maturation, and network activity. Moreover, these engineered organoids also better recapitulate pharmacological responses, such as neural activity changes to fentanyl exposure, compared to conventional organoids with significant diffusion limits. Combining these unique scaffolds and engineered organoids may provide insights for organoid development and therapeutic innovation.

Influence of different pressure regimes on the properties of an engineered small-diameter vascular scaffold tested in a custom-made bioreactor.

Vascular tissue engineering endeavors to design, fabricate, and validate biodegradable and bioabsorbable small-diameter vascular scaffolds engineered with bioactive molecules, capable of meeting the challenges imposed by commercial vascular prostheses. A comprehensive investigation of these engineered scaffolds in bioreactor is deemed essential as a prerequisite before any in vivo experimentation in order to get information regarding their behavior under physiological conditions and predict the biological activities they will possess. This study focuses on an innovative electrospun scaffold made of poly(caprolactone) and poly(glycerol sebacate), integrating quercetin, able to modulate inflammation, and gelatin, necessary to reduce permeability. A custom-made bioreactor was used to assess the performances of the scaffolds maintained under different pressure regimes, covering the human physiological pressure range. As results, the 3D microfibrous architecture was notably influenced by the release of bioactives, maintaining the adequate properties needed for the in vivo regeneration and scaffolds showed mechanical properties similar to human native artery. Release of gelatin was adequate to avoid blood leakage and useful to make the material porous during the testing period, whereas the amount of released quercetin was useful to counteract the post-surgery inflammation. This study showcases the successful validation of an engineered scaffold in a bioreactor, enabling to consider it as a promising candidate for vascular substitutes in in vivo applications. Our approach represents a significant leap forward in the field of vascular tissue engineering, offering a multifaceted solution to the complex challenges associated with small-diameter vascular prostheses.&#xD.

Polydiolcitrate-MoS2 Composite for 3D Printing Radio-Opaque, Bioresorbable Vascular Scaffolds.

Implantable polymeric biodegradable devices, such as biodegradable vascular scaffolds, cannot be fully visualized using standard X-ray-based techniques, compromising their performance due to malposition after deployment. To address this challenge, we describe a new radiopaque and photocurable liquid polymer-ceramic composite (mPDC-MoS2) consisting of methacrylated poly(1,12 dodecamethylene citrate) (mPDC) and molybdenum disulfide (MoS2) nanosheets. The composite was used as an ink with microcontinuous liquid interface production (μCLIP) to fabricate bioresorbable vascular scaffolds (BVS). Prints exhibited excellent crimping and expansion mechanics without strut failures and, importantly, with X-ray visibility in air and muscle tissue. Notably, MoS2 nanosheets displayed physical degradation over time in phosphate-buffered saline solution, suggesting the potential for producing radiopaque, fully bioresorbable devices. mPDC-MoS2 is a promising bioresorbable X-ray-visible composite material suitable for 3D printing medical devices, such as vascular scaffolds, that require noninvasive X-ray-based monitoring techniques for implantation and evaluation. This innovative biomaterial composite system holds significant promise for the development of biocompatible, fluoroscopically visible medical implants, potentially enhancing patient outcomes and reducing medical complications.

Digital light processing printed hydrogel scaffolds with adjustable modulus

Hydrogels are extensively explored as biomaterials for tissue scaffolds, and their controlled fabrication has been the subject of wide investigation. However, the tedious mechanical property adjusting process through formula control hindered their application for diverse tissue scaffolds. To overcome this limitation, we proposed a two-step process to realize simple adjustment of mechanical modulus over a broad range, by combining digital light processing (DLP) and post-processing steps. UV-curable hydrogels (polyacrylamide-alginate) are 3D printed via DLP, with the ability to create complex 3D patterns. Subsequent post-processing with Fe3+ ions bath induces secondary crosslinking of hydrogel scaffolds, tuning the modulus as required through soaking in solutions with different Fe3+ concentrations. This innovative two-step process offers high-precision (10 μm) and broad modulus adjusting capability (15.8–345 kPa), covering a broad range of tissues in the human body. As a practical demonstration, hydrogel scaffolds with tissue-mimicking patterns were printed for cultivating cardiac tissue and vascular scaffolds, which can effectively support tissue growth and induce tissue morphologies.

Five-Year Outcomes of Bioresorbable Stent Therapy for Coronary Heart Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The efficacy of bioresorbable vascular scaffolds (BVS) compared to metallic stents for the treatment of coronary heart disease remains controversial. The analysis of clinical outcomes at five years following the initial treatment has yet to be reviewed. This study sought to assess the five-year outcomes in randomized controlled trials of BVS in the treatment of coronary heart disease using a systematic review and meta-analysis. A systematic database search was conducted from their inception to June 30th, 2023 using various Medical Subject Headings (MeSH) terms including: "Coronary Disease", "Bioresorbable stent", "Randomized controlled trials". After a rigorous selection process, a total of five high-quality articles were finally included in this study. Each trial demonstrated a low risk of bias. After 5 years, bioresorbable stents showed outcomes similar to conventional metal stents in terms of cardiac mortality. However, they were inferior in terms of lesion revascularization rates, in-stent thrombosis rates, target lesion failure, target vessel failure, and myocardial infarction. While bioresorbable stents are comparable to metallic stents in terms of cardiac mortality rates, they exhibit significant drawbacks that warrant clinical consideration.

The promotion of vascular reconstruction by hierarchical structures in biodegradable small-diameter vascular scaffolds

Tissue engineering of small-diameter vessels remains challenging due to the inadequate ability to promote endothelialization and infiltration of smooth muscle cells (SMCs). Ideal vascular graft is expected to provide the ability to support endothelial monolayer formation and SMCs infiltration. To achieve this, vascular scaffolds with both orientation and dimension hierarchies were prepared, including hierarchically random vascular scaffold (RVS) and aligned vascular scaffold (AVS), by utilizing degradable poly(ε-caprolactone)-co-poly(ethylene glycol) (PCE) and the blend of PCE/gelatin (PCEG) as raw materials. In addition to the orientation hierarchy, dimension hierarchy with small pores in the inner layer and large pores in the outer layer was also constructed in both RVS and AVS to further investigate the promotion of vascular reconstruction by hierarchical structures in vascular scaffolds. The results show that the AVS with an orientation hierarchy that consists with the natural vascular structure had better mechanical properties and promotion effect on the proliferation of vascular cells than RVS, and also exhibited excellent contact guidance effects on cells. While the dimension hierarchy in both RVS and AVS was favorable to the rapid infiltration of SMCs in a short culture time in vitro. Besides, the results of subcutaneous implantation further demonstrate that AVS achieved a fully infiltrated outer layer with wavy elastic fibers-mimic strips formation by day 14, ascribing to hierarchies of aligned orientation and porous dimension. The results further indicate that the scaffolds with both orientation and dimension hierarchical structures have great potential in the application of promoting the vascular reconstruction.

A 25-year-long journey into interventional cardiology: looking back, and rushing forward.

Cardiovascular disease remains decade after decade a leading cause of mortality, morbidity and resource use globally as well as locally. We have had the opportunity of being involved in several iterative breakthroughs in invasive cardiovascular procedures, ranging from the advent of coronary stents to transcatheter mitral valve repair. Building up such extensive clinical and research experience, we hereby present 25 years of cardiovascular interventions at Pineta Grande Hospital and Casa di Salute S. Lucia, respectively in Castel Volturno, and S. Giuseppe Vesuviano, both in the Italian Campania region, where the same team of interventional cardiologists has managed to adopt and master several cardiovascular innovations for the benefit of thousands of patients. Our experience showcases the evolution of invasive cardiology, especially in diagnostic and therapeutic practices. Key highlights include advancements in coronary procedures, with the introduction of bare-metal stents, drug-eluting stents and drug-coated balloons, despite the setback of bioresorbable vascular scaffolds, as well as transcatheter aortic valve implantation and innovative approaches to mitral regurgitation. Furthermore, this overview scrutinizes procedural challenges, patient outcomes, and quality of life improvements, providing a rich tapestry of clinical experiences and research insights. It serves as a testament to the dynamic nature of interventional cardiology, offering a forward-looking perspective on future trends and technologies. We hope that this overview will prove an informative and insightful read for those seeking to understand the intricate journey of invasive cardiovascular care over the past decades and its trajectory into the future.

The Absorb GT1 Bioresorbable Vascular Scaffold System - 5-Year Post-Market Surveillance Study in Japan.

The 1-year clinical outcomes of the Absorb GT1 Japan post-market surveillance (PMS) suggested that an appropriate intracoronary imaging-guided bioresorbable vascular scaffold (BVS) implantation technique may reduce the risk of target lesion failure (TLF) and scaffold thrombosis (ST) associated with the Absorb GT1 BVS. The long-term outcomes through 5 years are now available.Methods and Results: This study enrolled 135 consecutive patients (n=139 lesions) with ischemic heart disease in whom percutaneous coronary intervention (PCI) with the Absorb GT1 BVS was attempted. Adequate lesion preparation, imaging-guided appropriate sizing, and high-pressure post-dilatation using a non-compliant balloon were strongly encouraged. All patients had at least 1 Absorb GT1 successfully implanted at the index procedure. Intracoronary imaging was performed in all patients (optical coherence tomography: 127/139 [91.4%] lesions) and adherence to the implantation technique recommendations was excellent: predilatation, 100% (139/139) lesions; post-dilatation, 98.6% (137/139) lesions; mean (±SD) post-dilatation pressure, 18.8±3.5 atm. At 5 years, the follow-up rate was 87.4% (118/135). No definite/probable ST was reported through 5 years. The cumulative TLF rate was 5.1% (6/118), including 2 cardiac deaths, 1 target vessel-attributable myocardial infarction, and 3 ischemia-driven target lesion revascularizations. Appropriate intracoronary imaging-guided BVS implantation, including the proactive use of pre- and post-balloon dilatation during implantation may be beneficial, reducing the risk of TLF and ST through 5 years.

Drug-Eluting Balloon for Coronary In-Stent Restenosis: Could it be an Emerging Strategy?

Despite significant improvement in PCI, including drug-eluting stent (DES) applications, in-stent restenosis (ISR) remains a problem. ISR is challenging to manage. Repeat stenting with bare metal stent (BMS), repeat stenting with DES and bioresorbable vascular scaffolds is primarily used to prevent and treat ISR. Current European guidelines recommend DES or a drug-eluting balloon (DEB) to treat ISR with a Class I indication. However, its use in coronary artery interventions has not yet been approved in the United States. DEB allows the application of the antiproliferative drug to the ISR site without leaving an additional layer of stent strut. Studies show that DEB is superior to plain balloon alone and comparable to DES in ISR treatment. They are increasingly preferred due to their good therapeutic effect in preventing intimal proliferation and restenosis. This review aims to provide an overview on the feasibility of using DEB in ISR management based on current knowledge

Fabrication of a Triple-Layer Bionic Vascular Scaffold via Hybrid Electrospinning.

Tissue engineering aims to develop bionic scaffolds as alternatives to autologous vascular grafts due to their limited availability. This study introduces a novel wet-electrospinning fabrication technique to create small-diameter, uniformly aligned tubular scaffolds. By combining this innovative method with conventional electrospinning, a bionic tri-layer scaffold that mimics the zonal structure of vascular tissues is produced. The inner and outer layers consist of PCL/Gelatin and PCL/PLGA fibers, respectively, while the middle layer is crafted using PCL through Wet Vertical Magnetic Rod Electrospinning (WVMRE). The scaffold's morphology is analyzed using Scanning Electron Microscopy (SEM) to confirm its bionic structure. The mechanical properties, degradation profile, wettability, and biocompatibility of the scaffold are also characterized. To enhance hemocompatibility, the scaffold is crosslinked with heparin. The results demonstrate sufficient mechanical properties, good wettability of the inner layer, proper degradability of the inner and middle layers, and overall good biocompatibility. In conclusion, this study successfully develops a small-diameter tri-layer tubular scaffold that meets the required specifications.

Design and fabrication of dual-layer PCL nanofibrous scaffolds with inductive influence on vascular cell responses

Confronted with the profound threat of cardiovascular diseases to health, vascular tissue engineering presents potential beyond the limitations of autologous and allogeneic grafts, offering a promising solution. This study undertakes an initial exploration into the impact of a natural active protein, elastin, on vascular cell behavior, by incorporating with polycaprolactone to prepare fibrous tissue engineering scaffold. The results reveal that elastin serves to foster endothelial cell adhesion and proliferation, suppress smooth muscle cell proliferation, and induce macrophage polarization. Furthermore, the incorporation of elastin contributes to heightened scaffold strength, compliance, and elongation, concomitantly lowering the elastic modulus. Subsequently, a bilayer oriented polycaprolactone (PCL) scaffold infused with elastin is proposed. This design draws inspiration from the cellular arrangement of native blood vessels, leveraging oriented fibers to guide cell orientation. The resulting fiber scaffold exhibits commendable mechanical properties and cell infiltration capacity, imparting valuable insights for the rapid endothelialization of vascular scaffolds.