Tissue Engineering. Part B, Reviews最新文献

Bone defects are a prevalent clinical issue that presents a serious medical challenge. Bone tissue engineering (BTE) has emerged as an effective approach for treating large bone defects. Hydrogels, as hydrophilic three-dimensional polymers, are recognized as suitable material for BTE due to their excellent biocompatibility and degradability. However, the submicron and nanoporous structure of hydrogels limits the survival of osteoblasts, hindering bone tissue regeneration. In recent years, 3D printing technology has attracted appreciable attention. The use of hydrogels as 3D-printed ink facilitates the printing of hydrogels in any desired shape, enabling personalized or more complex requirements. This article provides a systematic review of the latest applications of 3D-printed hydrogels in BTE. These hydrogels serve as a multifunctional platform for the next generation technology in treating bone defects. The advantages and limitations of 3D-printed hydrogels in BTE are discussed, and future research directions are explored. This review can form the basis for future hydrogel design.

After tendon or ligament reconstruction, the interface between the hard bone and soft connective tissue is considerably weakened and is difficult to restore through healing. The tendon/ligament-bone interface is mechanically the weakest point under tensile loading and is often the source of various postoperative complications, such as bone resorption and graft laxity. A comprehensive understanding of the macro- and microfeatures of the native tendon/ligament-bone interface would be beneficial for developing strategies for regenerating the tissue. This article discusses the structural, biological, and mechanical features of the tendon/ligament-bone interfaces and how these can be affected by aging and loading conditions.

Cardiovascular disease stemmed from atherosclerosis (AS) is well recognized to be the predominant cause of global death. To comprehensively clarify the pathogenesis of AS, exploit effective drugs, as well as develop therapeutic solutions, various atherosclerotic models were constructed in vitro and widely utilized by the scientific community. Compared with animal models, the in vitro atherosclerotic models play a prominent role not only in the targeted research of single pathological factor related to AS in the human derived system, but also in the combined study on multipathological factors leading to AS, thereby contributing tremendously to the in-depth elucidation of atherosclerotic pathological process. In the current review, a variety of pathological factors incorporated into the existing atherosclerotic models in vitro are broadly elaborated, including the pathological mechanism, in vitro simulation approaches, and the desired improvement perspectives for reproducing each pathological factor. In addition, this review also summarizes the advantages and disadvantages of current atherosclerotic models as well as their potential functionality. Finally, the promising aspects for future atherosclerotic models in vitro with potential advances are also discussed.

Human vocal folds (VFs), a pair of small, soft tissues in the larynx, have a layered mucosal structure with unique mechanical strength to support high-level tissue deformation by phonation. Severe pathological changes to VF have causes including surgery, trauma, age-related atrophy, and radiation, and lead to partial or complete communication loss and difficulty in breathing and swallowing. VF glottal insufficiency requires injectable VF biomaterials such as hyaluronan, calcium hydroxyapatite, and autologous fat to augment VF functions. Although these biomaterials provide an effective short-term solution, significant variations in patient response and requirements of repeat reinjection remain notable challenges in clinical practice. Tissue engineering strategies have been actively explored in the search of an injectable biomaterial that possesses the capacity to match native tissue's material properties while promoting permanent tissue regeneration. This review aims to assess the current status of biomaterial development in VF tissue engineering. The focus will be on examining state-of-the-art techniques including modification with bioactive molecules, cell encapsulation, composite materials, and in situ crosslinking with click chemistry. We will discuss potential opportunities that can further leverage these engineering techniques in the advancement of VF injectable biomaterials. Impact Statement Injectable vocal fold (VF) biomaterials augment tissue function through minimally invasive procedures, yet there remains a need for long-term VF reparation. This article reviews cutting-edge research in VF biomaterial development to propose safe and effective tissue engineering strategies for improving regenerative outcomes. Special focus is paid to methods to enhance bioactivity and achieve tissue-mimicking mechanical properties, longer in situ stability, and inherent biomaterial bioactivity.

Articular cartilage is crucial in human physiology, and its degeneration poses a significant public health challenge. While recent advancements in 3D bioprinting and tissue engineering show promise for cartilage regeneration, there remains a gap between research findings and clinical application. This review critically examines the mechanical and biological properties of hyaline cartilage, along with current 3D manufacturing methods and analysis techniques. Moreover, we provide a quantitative synthesis of bioink properties used in cartilage tissue engineering. After screening 181 initial works, 33 studies using extrusion bioprinting were analyzed and synthesized, presenting results that indicate the main materials, cells, and methods utilized for mechanical and biological evaluation. Altogether, this review motivates the standardization of mechanical analyses and biomaterial assessments of 3D bioprinted constructs to clarify their chondrogenic potential.

Arterial stenosis caused by atherosclerosis often requires stent implantation to increase the patency of target artery. However, such external devices often lead to in-stent restenosis due to inadequate re-endothelialization and subsequent inflammatory responses. Therefore, re-endothelialization strategies after stent implantation have been developed to enhance endothelial cell recruitment or to capture circulating endothelial progenitor cells. Notably, recent research indicates that coating stent surfaces with biogenic materials enhances the long-term safety of implantation, markedly diminishing the risk of in-stent restenosis. In this review, we begin by describing the pathophysiology of coronary artery disease and in-stent restenosis. Then, we review the characteristics and materials of existing stents used in clinical practice. Lastly, we explore biogenic materials aimed at accelerating re-endothelialization, including extracellular matrix, cells, and extracellular vesicles. This review helps overcome the limitations of current stents for cardiovascular disease and outlines the next phase of research and development.

Meniscal damage is one of the prevalent causes of knee pain, swelling, instability, and functional compromise, frequently culminating in osteoarthritis (OA). Timely and appropriate interventions are crucial to relieve symptoms and prevent or delay the onset of OA. Contemporary surgical treatments include total or partial meniscectomy, meniscal repair, allograft meniscal transplantation, and synthetic meniscal implants, but each presents its specific limitations. Recently, regenerative medicine and tissue engineering have emerged as promising fields, offering innovative prospects for meniscal regeneration and repair. This review delineates current surgical methods, elucidating their specific indications, advantages, and disadvantages. Concurrently, it delves into state-of-the-art tissue engineering techniques aimed at the functional regenerative repair of meniscus. Recommendations for future research and clinical practice are also provided.

Bone defects because of age, trauma, and surgery, which are exacerbated by medication side effects and common diseases such as osteoporosis, diabetes, and rheumatoid arthritis, are a problem of epidemic scale. The present clinical standard for treating these defects includes autografts and allografts. Although both treatments can promote robust regenerative outcomes, they fail to strike a desirable balance of availability, side effect profile, consistent regenerative efficacy, and affordability. This difficulty has contributed to the rise of bone tissue engineering (BTE) as a potential avenue through which enhanced bone regeneration could be delivered. BTE is founded upon a paradigm of using biomaterials, bioactive factors, osteoblast lineage cells (ObLCs), and vascularization to cue deficient bone tissue into a state of regeneration. Despite promising preclinical results, BTE has had modest success in being translated into the clinical setting. One barrier has been the simplicity of its paradigm relative to the complexity of biological bone. Therefore, this paradigm must be critically examined and expanded to better account for this complexity. One potential avenue for this is a more detailed consideration of osteoclast lineage cells (OcLCs). Although these cells ostensibly oppose ObLCs and bone regeneration through their resorptive functions, a myriad of investigations have shed light on their potential to influence bone equilibrium in more complex ways through their interactions with both ObLCs and bone matrix. Most BTE research has not systematically evaluated their influence. Yet contrary to expectations associated with the paradigm, a selection of BTE investigations has demonstrated that this influence can enhance bone regeneration in certain contexts. In addition, much work has elucidated the role of many controllable scaffold parameters in both inhibiting and stimulating the activity of OcLCs in parallel to bone regeneration. Therefore, this review aims to detail and explore the implications of OcLCs in BTE and how they can be leveraged to improve upon the existing BTE paradigm.

There is a critical need for novel approaches to translate cell therapy and regenerative medicine to clinical practice. Magnetic cell targeting with site specificity has started to open avenues in these fields as a potential therapeutic platform. Magnetic targeting is gaining popularity in the field of biomedicine due to its ability to concentrate and retain at a target site while minimizing deleterious effects at off-target sites. It is regarded as a relatively straightforward and safe approach for a wide range of therapeutic applications. This review discusses the latest advancements and approaches in magnetic cell targeting using endocytosed and surface-bound magnetic nanoparticles as well as in vivo tracking using magnetic resonance imaging (MRI). The most common form of magnetic nanoparticles is superparamagnetic iron oxide nanoparticles (SPION). The biodegradable and biocompatible properties of these magnetically responsive particles and capacity for rapid endocytosis into cells make them a breakthrough in targeted therapy. This review further discusses specific applications of magnetic targeting approaches in cardiovascular tissue engineering including myocardial regeneration, therapeutic angiogenesis, and endothelialization of implantable cardiovascular devices.