Antibody-Conjugated Electrospun Vascular Scaffolds to Enhance In Situ Endothelialization

Biofunctionalized Electrospun Vascular Scaffolds for Enhanced Antithrombotic Properties and In Situ Endothelialization

The development of innovative vascular substitutes has become increasingly significant due to the prevalence of vascular diseases. In this study, we designed a biofunctionalized electrospun vascular scaffold by chemically conjugating heparin molecules as an antithrombotic agent with an endothelial cell (EC)-specific antibody to promote in situ endothelialization. To optimize this biofunctionalized electrospun vascular scaffolding system, we examined various parameters, including material compositions, cross-linker concentrations, and cross-linking and conjugation processes. The findings revealed that a higher degree of heparin conjugation onto the vascular scaffold resulted in improved antithrombotic properties, as confirmed by the platelet adhesion test. Additionally, the flow chamber study demonstrated that the EC-specific antibody immobilization enhanced the scaffold's EC-capturing capability compared to a nonconjugated vascular scaffold. The optimized biofunctionalized vascular scaffolds also displayed exceptional mechanical properties, such as suture retention strength and tensile properties. Our research demonstrated that the biofunctionalized vascular scaffolds and the directed immobilization of bioactive molecules could provide the necessary elements for successful acellular vascular tissue engineering applications.

Translational tissue-engineered vascular grafts: From bench to bedside

Cardiovascular disease is a primary cause of mortality worldwide, and patients often require bypass surgery that utilizes autologous vessels as conduits. However, the limited availability of suitable vessels and the risk of failure and complications have driven the need for alternative solutions. Tissue-engineered vascular grafts (TEVGs) offer a promising solution to these challenges. TEVGs are artificial vascular grafts made of biomaterials and/or vascular cells that can mimic the structure and function of natural blood vessels. The ideal TEVG should possess biocompatibility, biomechanical mechanical properties, and durability for long-term success in vivo. Achieving these characteristics requires a multi-disciplinary approach involving material science, engineering, biology, and clinical translation. Recent advancements in scaffold fabrication have led to the development of TEVGs with improved functional and biomechanical properties. Innovative techniques such as electrospinning, 3D bioprinting, and multi-part microfluidic channel systems have allowed the creation of intricate and customized tubular scaffolds. Nevertheless, multiple obstacles must be overcome to apply these innovations effectively in clinical practice, including the need for standardized preclinical models and cost-effective and scalable manufacturing methods. This review highlights the fundamental approaches required to successfully fabricate functional vascular grafts and the necessary translational methodologies to advance their use in clinical practice.

Angiogenesis and Re-endothelialization in decellularized scaffolds: Recent advances and current challenges in tissue engineering

Decellularization of tissues and organs has recently become a promising approach in tissue engineering and regenerative medicine to circumvent the challenges of organ donation and complications of transplantations. However, one main obstacle to reaching this goal is acellular vasculature angiogenesis and endothelialization. Achieving an intact and functional vascular structure as a vital pathway for supplying oxygen and nutrients remains the decisive challenge in the decellularization/re-endothelialization procedure. In order to better understand and overcome this issue, complete and appropriate knowledge of endothelialization and its determining variables is required. Decellularization methods and their effectiveness, biological and mechanical characteristics of acellular scaffolds, artificial and biological bioreactors, and their possible applications, extracellular matrix surface modification, and different types of utilized cells are factors affecting endothelialization consequences. This review focuses on the characteristics of endothelialization and how to optimize them, as well as discussing recent developments in the process of re-endothelialization.

Quercetin improves rapid endothelialization and inflammatory microenvironment in electrospun vascular grafts

There is a great need for small diameter vascular grafts among patients with cardiovascular diseases annually. However, continuous foreign body reactions and fibrosis capsules brought by biomaterials are both prone to poor vascular tissue regeneration. To address this problem, we fabricated a polycaprolactone (PCL) vascular graft incorporated with quercetin (PCL/QCT graft) in this study. In vitro cell assay showed that quercetin reduced the expressions of pro-inflammatory genes of macrophages while increased the expressions of anti-inflammatory genes. Furthermore, in vivo implantation was performed in a rat abdominal aorta replacement model. Upon implantation, the grafts exhibited sustained quercetin release and effectively enhanced the regeneration of vascular tissue. The results revealed that quercetin improved endothelial layer formation along the lumen of the vascular grafts at 4 weeks. Furthermore, the thickness of vascular smooth muscle layers significantly increased in PCL/QCT group compared with PCL group. More importantly, the presence of quercetin stimulated the infiltration of a large amount of M2 phenotype macrophages into the grafts. Collectively, the above data reinforced our hypothesis that the incorporation of quercetin may be in favor of modulating the inflammatory microenvironment and improving vascular tissue regeneration and remodeling in vascular grafts.

Endothelialization strategy of implant materials surface: The newest research in recent 5 years

In recent years, more and more metal or non-metal materials have been used in the treatment of cardiovascular diseases, but the vascular complications after transplantation are still the main factors restricting the clinical application of most grafts, such as acute thrombosis and graft restenosis. Implant materials have been extensively designed and surface optimized by researchers, but it is still too difficult to avoid complications. Natural vascular endodermis has excellent function, anti-coagulant and anti-intimal hyperplasia, and it is also the key to maintaining the homeostasis of normal vascular microenvironment. Therefore, how to promote the adhesion of endothelial cells (ECs) on the surface of cardiovascular materials to achieve endothelialization of the surface is the key to overcoming the complications after implant materialization. At present, the surface endothelialization design of materials based on materials surface science, bioactive molecules, and biological function intervention and feedback has attracted much attention. In this review, we summarize the related research on the surface modification of materials by endothelialization in recent years, and analyze the advantages and challenges of current endothelialization design ideas, explain the relationship between materials, cells, and vascular remodeling in order to find a more ideal endothelialization surface modification strategy for future researchers to meet the requirements of clinical biocompatibility of cardiovascular materials.

Enzyme-responsive strategy as a prospective cue to construct intelligent biomaterials for disease diagnosis and therapy

Stimuli-responsive materials have been widely studied and applied in biomedical field. Under the stimulation of enzymes, the enzyme-responsive materials (ERMs) can be triggered to change their structures, properties and functions....