Hydroxyapatite (HAp) polymer composites have gained significant attention due to their applications in bone regeneration and tooth implants. This review examines the synthesis, properties, and applications of Hap, highlighting various manufacturing methods, including wet, dry, hydrothermal, and sol-gel processes. The properties of HAp are influenced by precursor materials and are commonly obtained from natural calcium-rich sources like eggshells, seashells, and fish scales. Composite materials, such as cellulose-hydroxyapatite and gelatin-hydroxyapatite, exhibit promising strength and biocompatibility for bone and tissue replacement. Metallic implants and scaffolds enhance stability, including well-known titanium-based and stainless steel-based implants and ceramic body implants. Biopolymers, like chitosan and alginate, combined with Hap, offer chemical stability and strength for tissue engineering. Collagen, fibrin, and gelatin play crucial roles in mimicking natural bone composition. Various synthesis methods like sol-gel, hydrothermal, and solution casting produce HAp crystals, with potential applications in bone repair and regeneration. Additionally, the use of biowaste materials, like eggshells and snails or seashells, not only supports sustainable HAp production but also reduces environmental impact. This review emphasizes the significance of understanding the properties of calcium-phosphate (Ca-P) compounds and processing methods for scaffold generation, highlighting novel characteristics and mechanisms of biomaterials in bone healing. Comparative studies of these methods in specific applications underscore the versatility and potential of HAp composites in biomedical engineering. Overall, HAp composites offer promising solutions for improving patient outcomes in bone replacement and tissue engineering and advancing medical practices.

Silk fibroin (SF) extracted from silk is non-toxic and has excellent biocompatibility and biodegradability, making it an excellent biomedical material. SF-based soft materials, including porous scaffolds and hydrogels, play an important role in accurately delivering drugs to wounds, creating microenvironments for the adhesion and proliferation of support cells, and in tissue remodeling, repair, and wound healing. This article focuses on the study of SF protein-based soft materials, summarizing their preparation methods and basic applications, as well as their regenerative effects, such as drug delivery carriers in various aspects of tissue engineering such as bone, blood vessels, nerves, and skin in recent years, as well as their promoting effects on wound healing and repair processes. The authors expect SF soft materials to play an important role in the field of tissue repair.

Mesh-augmented hernia repair is the gold standard in abdominal wall and hiatal/diaphragmatic hernia management and ranks among the most common procedures performed by general surgeons. However, it is associated with a series of drawbacks, including recurrence, mesh infection, and adhesion formation. To address these weaknesses, numerous biomaterials have been investigated for mesh coating. Platelet-rich plasma (PRP) is an autologous agent that promotes tissue healing through numerous cytokines and growth factors. In addition, many reports highlight its contribution to better integration of different types of coated meshes, compared to conventional uncoated meshes. The use of PRP-coated meshes for hernia repair has been reported in the literature, but a review of technical aspects and outcomes is missing. The aim of this comprehensive review is to report the experimental studies investigating the synergistic use of PRP and mesh implants in hernia animal models. A comprehensive literature search was conducted across PubMed/Medline, Web of Science, and Scopus without chronological constraints. In total, fourteen experimental and three clinical studies have been included. Among experimental trials, synthetic, biologic, and composite meshes were used in four, nine, and one study, respectively. In synthetic meshes, PRP-coating leads to increased antioxidant levels and collaged deposition, reduced oxidative stress, and improved inflammatory response, while studies on biological meshes revealed increased neovascularization and tissue integration, reduced inflammation, adhesion severity, and mechanical failure rates. Finally, PRP-coating of composite meshes results in reduced adhesions and improved mechanical strength. Despite the abundance of preclinical data, there is a scarcity of clinical studies, mainly due to the absence of an established protocol regarding PRP preparation and application. To this point in time, PRP has been used as a coating agent for the repair of abdominal and diaphragmatic hernias, as well as for mesh fixation. Clinical application of conclusions drawn from experimental studies may lead to improved results in hernia repair.

Scars may represent more than a cosmetic concern for patients; they may impose functional limitations and are frequently associated with the sensation of itching or pain, thus impacting both psychological and physical well-being. From an aesthetic perspective, scars display variances in color, thickness, texture, contour, and their homogeneity, while the functional aspect encompasses considerations of functionality, pliability, and sensory perception. Scars located in critical anatomic areas have the potential to induce profound impairments, including contracture-related mobility restrictions, thereby significantly impacting daily functioning and the quality of life. Conventional approaches to scar management may suffice to a certain extent, yet there are cases where tailored interventions are warranted. Autologous fat grafting emerges as a promising therapeutic avenue in such instances. Fundamental mechanisms underlying scar formation include chronic inflammation, fibrogenesis and dysregulated wound healing, among other contributing factors. These mechanisms can potentially be alleviated through the application of adipose-derived stem cells, which represent the principal cellular component utilized in the process of lipofilling. Adipose-derived stem cells possess the capacity to secrete proangiogenic factors such as fibroblast growth factor, vascular endothelial growth factor and hepatocyte growth factor, as well as neurotrophic factors, such as brain-derived neurotrophic factors. Moreover, they exhibit multipotency, remodel the extracellular matrix, act in a paracrine manner, and exert immunomodulatory effects through cytokine secretion. These molecular processes contribute to neoangiogenesis, the alleviation of chronic inflammation, and the promotion of a conducive milieu for wound healing. Beyond the obvious benefit in restoring volume, the adipose-derived stem cells and their regenerative capacities facilitate a reduction in pain, pruritus, and fibrosis. This review elucidates the regenerative potential of autologous fat grafting and its beneficial and promising effects on both functional and aesthetic outcomes when applied to scar tissue.

Within native ECM, Hyaluronan (HA) undergoes remarkable structural remodeling through its binding receptors and proteins called hyaladherins. Hyaladherins contain a group of tandem repeat sequences, such as LINK domains, BxB7 homologous sequences, or 20-50 amino acid long short peptide sequences that have high affinity towards side chains of HA. The HA binding sequences are critical players in HA distribution and regulation within tissues and potentially attractive therapeutic targets to regulate HA synthesis and organization. While HA is a versatile and successful biopolymer, most HA-based therapeutics have major differences from a native HA molecule, such as molecular weight discrepancies, crosslinking state, and remodeling with other HA binding proteins. Recent studies showed the promise of HA binding domains being used as therapeutic biomaterials for osteoarthritic, ocular, or cardiovascular therapeutic products. However, we propose that there is a significant potential for HA binding materials to reveal the physiological functions of HA in a more realistic setting. This review is focused on giving a comprehensive overview of the connections between HA\'s role in the body and the potential of HA binding material applications in therapeutics and regenerative medicine. We begin with an introduction to HA then discuss HA binding molecules and the process of HA binding. Finally, we discuss HA binding materials anf the future prospects of potential HA binding biomaterials systems in the field of biomaterials and tissue engineering.

Induced pluripotent stem cells (iPSCs) that are generated from adult somatic cells are induced to express genes that make them pluripotent through reprogramming techniques. With their unlimited proliferative capacity and multifaceted differentiation potential and circumventing the ethical problems encountered in the application of embryonic stem cells (ESC), iPSCs have a broad application in the fields of cell therapy, drug screening, and disease models and may open up new possibilities for regenerative medicine to treat diseases in the future. In this review, we begin with different reprogramming cell technologies to obtain iPSCs, including biotechnological, chemical, and physical modulation techniques, and present their respective strengths, and limitations, as well as the recent progress of research. Secondly, we review recent research advances in iPSC reprogramming-based regenerative therapies. iPSCs are now widely used to study various clinical diseases of hair follicle defects, myocardial infarction, neurological disorders, liver diseases, and spinal cord injuries. This review focuses on the translational clinical research around iPSCs as well as their potential for growth in the medical field. Finally, we summarize the overall review and look at the potential future of iPSCs in the field of cell therapy as well as tissue regeneration engineering and possible problems. We believe that the advancing iPSC research will help drive long-awaited breakthroughs in cellular therapy.

Biological organisms play important roles in human health, either in a commensal or pathogenic manner. Harnessing inactivated organisms or living organisms is a promising way to treat diseases. As two types of freezing, cryoablation makes it simple to inactivate organisms that must be in a non-pathogenic state when needed, while cryopreservation is a facile way to address the problem of long-term storage challenged by living organism-based therapy. In this review, we present the latest studies of freezing biological organisms for biomedical applications. To begin with, the freezing strategies of cryoablation and cryopreservation, as well as their corresponding technical essentials, are illustrated. Besides, biomedical applications of freezing biological organisms are presented, including transplantation, tissue regeneration, anti-infection therapy, and anti-tumor therapy. The challenges and prospects of freezing living organisms for biomedical applications are well discussed. We believe that the freezing method will provide a potential direction for the standardization and commercialization of inactivated or living organism-based therapeutic systems, and promote the clinical application of organism-based therapy.

Ischemic events can culminate in acute myocardial infarction, which is generated by irreversible cardiac lesions that cannot be restored due to the limited regenerative capacity of the heart. Cardiac cell therapy aims to replace injured or necrotic cells with healthy and functional cells. Tissue engineering and cardiovascular regenerative medicine propose therapeutic alternatives using biomaterials that mimic the native extracellular environment and improve cellular and tissue functionality. This investigation evaluates the effect of thermosensitive hydrogels, and murine fetal ventricular cardiomyocytes encapsulated in thermosensitive hydrogels, on the contractile function of cardiomyocyte regeneration during an ischemic event. Chitosan and hydrolyzed collagen thermosensitive hydrogels were developed, and they were physically and chemically characterized. Likewise, their biocompatibility was evaluated through cytotoxicity assays by MTT, LDH, and their hemolytic capacity. The hydrogels, and cells inside the hydrogels, were used as an intervention for primary cardiomyocytes under hypoxic conditions to determine the restoration of the contractile capacity by measuring intracellular calcium levels and the expressions of binding proteins, such as a-actinin and connexin 43. These results evidence the potential of natural thermosensitive hydrogels to restore the bioelectrical functionality of ischemic cardiomyocytes.

Periodontitis, delineated by the destruction of structures that support teeth, is predominantly propelled by intricate immune responses. Immunomodulatory treatments offer considerable promise for the management of this ailment; however, the modulation of the periodontal immune microenvironment to facilitate tissue regeneration presents a substantial biomedical challenge. Herein, our study investigates the role of Wilms\' tumor 1-associating protein (WTAP), a critical m6A methyltransferase, in the immunomodulation of periodontitis and assesses its viability as a therapeutic target. We observed heightened expression of WTAP in macrophages extracted from gingival tissues impacted by periodontitis, with a strong association with M1 polarization. Via loss-of-function experiments, we demonstrated that diminishing WTAP expression precipitates a transition from M1 to M2 macrophage phenotypes amidst inflammatory conditions, thus improving the periodontal immune landscape. Further, RNA sequencing and indirect co-culture assays indicated that suppressing of WTAP expression modulates osteoimmune responses and enhances the osteogenic differentiation of bone marrow stromal cells. The local deployment of adeno-associated virus-shWTAP in murine models of periodontitis robustly validated the therapeutic promise of targeting WTAP in this disease. Collectively, our findings highlight the crucial role of WTAP in orchestrating macrophage-mediated osteoimmune responses and tissue regeneration in periodontitis, proposing novel avenues for immunotherapeutic interventions in its treatment.

Periodontitis is a highly prevalent disease that damages the supporting tissues of a tooth, including the alveolar bone. Alveolar bone loss owing to periodontitis is broadly categorized as supra-alveolar and intra-alveolar bone loss. In intra-alveolar bone loss, the defect has an angular or oblique orientation to the long axis of the tooth in an apical direction. In contrast, the defect is perpendicular to the long axis of the tooth in supra-alveolar bone loss. Unlike intra-alveolar bone defects, supra-alveolar bone defects lack supporting adjacent space, which makes supra-alveolar bone regeneration more challenging. In addition, the limited availability of resources in terms of vascularity and underlying tissues is another obstacle to supra-alveolar bone regeneration. Currently, supra-alveolar bone loss is the least predictable periodontal defect type in regenerative periodontal therapy. In addition, supra-alveolar bone loss is much more common than other alveolar bone loss. Despite its prevalence, research on supra-alveolar bone regeneration remains sparse, indicating an unmet need for significant research efforts in this area. This review summarize recent advances, obstacles, and future directions in the field of supra-alveolar bone regeneration. We discuss the biomaterials, bioactive molecules, and cells that have been tested for supra-alveolar bone regeneration, followed by pre-clinical and clinical approaches employed in this field. Additionally, we highlight obstacles and present future directions that will propel supra-alveolar bone research forward.