Skeletal muscle regeneration with 3D bioprinted hyaluronate/gelatin hydrogels incorporating MXene nanoparticles.

There has been significant progress in the field of three-dimensional (3D) bioprinting technology, leading to active research on creating bioinks capable of producing structurally and functionally tissue-mimetic constructs. Ti3C2Tx MXene nanoparticles (NPs), promising two-dimensional nanomaterials, are being investigated for their potential in muscle regeneration due to their unique physicochemical properties. In this study, we integrated MXene NPs into composite hydrogels made of gelatin methacryloyl (GelMA) and hyaluronic acid methacryloyl (HAMA) to develop bioinks (namely, GHM bioink) that promote myogenesis. The prepared GHM bioinks were found to offer excellent printability with structural integrity, cytocompatibility, and microporosity. Additionally, MXene NPs within the 3D bioprinted constructs encouraged the differentiation of C2C12 cells into skeletal muscle cells without additional support of myogenic agents. Genetic analysis indicated that representative myogenic markers both for early and late myogenesis were significantly up-regulated. Moreover, animal studies demonstrated that GHM bioinks contributed to enhanced regeneration of skeletal muscle while reducing immune responses in mice models with volumetric muscle loss (VML). Our results suggest that the GHM hydrogel can be exploited to craft a range of strategies for the development of a novel bioink to facilitate skeletal muscle regeneration because these MXene-incorporated composite materials have the potential to promote myogenesis.

Recent Advances in Marine Biomaterials Tailored and Primed for the Treatment of Damaged Soft Tissues.

The inherent self-repair abilities of the body often fall short when it comes to addressing injuries in soft tissues like skin, nerves, and cartilage. Tissue engineering and regenerative medicine have concentrated their research efforts on creating natural biomaterials to overcome this intrinsic healing limitation. This comprehensive review delves into the advancement of such biomaterials using substances and components sourced from marine origins. These marine-derived materials offer a sustainable alternative to traditional mammal-derived sources, harnessing their advantageous biological traits including sustainability, scalability, reduced zoonotic disease risks, and fewer religious restrictions. The use of diverse engineering methodologies, ranging from nanoparticle engineering and decellularization to 3D bioprinting and electrospinning, has been employed to fabricate scaffolds based on marine biomaterials. Additionally, this review assesses the most promising aspects in this field while acknowledging existing constraints and outlining necessary future steps for advancement.

MXene and Xene: promising frontier beyond graphene in tissue engineering and regenerative medicine.

The emergence of 2D nanomaterials (2D NMs), which was initiated by the isolation of graphene (G) in 2004, revolutionized various biomedical applications, including bioimaging and -sensing, drug delivery, and tissue engineering, owing to their unique physicochemical and biological properties. Building on the success of G, a novel class of monoelemental 2D NMs, known as Xenes, has recently emerged, offering distinct advantages in the fields of tissue engineering and regenerative medicine. In this review, we focus on the comparison of G and Xene materials for use in fabricating tissue engineering scaffolds. After a brief introduction to the basic physicochemical properties of these materials, recent representative studies are classified in terms of the engineered tissue, i.e., bone, cartilage, neural, muscle, and skin tissues. We analyze several methods of improving the clinical potential of Xene-laden scaffolds using state-of-the-art fabrication technologies and innovative biomaterials. Despite the considerable advantages of Xene materials, critical concerns, such as biocompatibility, biodistribution and regulatory challenges, should be considered. This review and collaborative efforts should advance the field of Xene-based tissue engineering and enable innovative, effective solutions for use in future tissue regeneration.

3D printed membranes of polylactic acid and graphene oxide for guided bone regeneration.

We fabricated graphene oxide (GO)-incorporated polylactic acid (PLA) (GO-PLA) films by using three-dimensional (3D) printing to explore their potential benefits as barrier membranes for guided bone regeneration (GBR). Our results showed that the 3D printed GO-PLA films provided highly favorable matrices for preosteoblasts and accelerated new bone formation in rat calvarial bone defect models.

Spontaneous Osteogenic Differentiation of Human Mesenchymal Stem Cells by Tuna-Bone-Derived Hydroxyapatite Composites with Green Tea Polyphenol-Reduced Graphene Oxide.

In recent years, bone tissue engineering (BTE) has made significant progress in promoting the direct and functional connection between bone and graft, including osseointegration and osteoconduction, to facilitate the healing of damaged bone tissues. Herein, we introduce a new, environmentally friendly, and cost-effective method for synthesizing reduced graphene oxide (rGO) and hydroxyapatite (HAp). The method uses epigallocatechin-3-O-gallate (EGCG) as a reducing agent to synthesize rGO (E-rGO), and HAp powder is obtained from Atlantic bluefin tuna (Thunnus thynnus). The physicochemical analysis indicated that the E-rGO/HAp composites had exceptional properties for use as BTE scaffolds, as well as high purity. Moreover, we discovered that E-rGO/HAp composites facilitated not only the proliferation, but also early and late osteogenic differentiation of human mesenchymal stem cells (hMSCs). Our work suggests that E-rGO/HAp composites may play a significant role in promoting the spontaneous osteogenic differentiation of hMSCs, and we envision that E-rGO/HAp composites could serve as promising candidates for BTE scaffolds, stem-cell differentiation stimulators, and implantable device components because of their biocompatible and bioactive properties. Overall, we suggest a new approach for developing cost-effective and environmentally friendly E-rGO/HAp composite materials for BTE application.

Recent Trends in Macromolecule-Based Approaches for Hair Loss Treatment.

Macromolecules are large, complex molecules composed of smaller subunits known as monomers. The four primary categories of macromolecules found in living organisms are carbohydrates, lipids, proteins, and nucleic acids; they also encompass a broad range of natural and synthetic polymers. Recent studies have shown that biologically active macromolecules can help regenerate hair, providing a potential solution for current hair regeneration therapies. This review examines the latest developments in the use of macromolecules for the treatment of hair loss. The fundamental principles of hair follicle (HF) morphogenesis, hair shaft (HS) development, hair cycle regulation, and alopecia have been introduced. Microneedle (MN) and nanoparticle (NP) delivery systems are innovative treatments for hair loss. Additionally, the application of macromolecule-based tissue-engineered scaffolds for the in vitro and in vivo neogenesis of HFs is discussed. Furthermore, a new research direction is explored wherein artificial skin platforms are adopted as a promising screening method for hair loss treatment drugs. Through these multifaceted approaches, promising aspects of macromolecules for future hair loss treatments are identified.

A systematic study on the use of multifunctional nanodiamonds for neuritogenesis and super-resolution imaging.

BACKGROUND: Regeneration of defective neurons in central nervous system is a highlighted issue for neurodegenerative disease treatment. Various tissue engineering approaches have focused on neuritogenesis to achieve the regeneration of damaged neuronal cells because damaged neurons often fail to achieve spontaneous restoration of neonatal neurites. Meanwhile, owing to the demand for a better diagnosis, studies of super-resolution imaging techniques in fluorescence microscopy have triggered the technological development to surpass the classical resolution dictated by the optical diffraction limit for precise observations of neuronal behaviors. Herein, the multifunctional nanodiamonds (NDs) as neuritogenesis promoters and super-resolution imaging probes were studied. METHODS: To investigate the neuritogenesis-inducing capability of NDs, ND-containing growing medium and differentiation medium were added to the HT-22 hippocampal neuronal cells and incubated for 10 d. In vitro and ex vivo images were visualized through custom-built two-photon microscopy using NDs as imaging probes and the direct stochastic optical reconstruction microscopy (dSTORM) process was performed for the super-resolution reconstruction owing to the photoblinking properties of NDs. Moreover, ex vivo imaging of the mouse brain was performed 24 h after the intravenous injection of NDs. RESULTS: NDs were endocytosed by the cells and promoted spontaneous neuritogenesis without any differentiation factors, where NDs exhibited no significant toxicity with their outstanding biocompatibility. The images of ND-endocytosed cells were reconstructed into super-resolution images through dSTORM, thereby addressing the problem of image distortion due to nano-sized particles, including size expansion and the challenge in distinguishing the nearby located particles. Furthermore, the ex vivo images of NDs in mouse brain confirmed that NDs could penetrate the blood-brain barrier (BBB) and retain their photoblinking property for dSTORM application. CONCLUSIONS: It was demonstrated that the NDs are capable of dSTORM super-resolution imaging, neuritogenic facilitation, and BBB penetration, suggesting their remarkable potential in biological applications.

3D bioprinting of human mesenchymal stem cells-laden hydrogels incorporating MXene for spontaneous osteodifferentiation.

Contemporary advances in three-dimensional (3D) bioprinting technologies have enabled the fabrication of tailored live 3D tissue mimetics. Furthermore, the development of advanced bioink materials has been highlighted to accurately reproduce the composition of a native extracellular matrix and mimic the intrinsic properties of laden cells. Recent research has shown that MXene is one of promising nanobiomaterials with osteogenic activity for bone grafts and scaffolds due to its unique atomic structure of three titanium layers between two carbon layers. In this study, the MXene-incorporated gelatin methacryloyl (GelMA) and hyaluronic acid methacryloyl (HAMA) (i.e., GelMA/HAMA-MXene) bioinks were prepared to explore if they have the potential to enable the spontaneous osteodifferentiation of human mesenchymal stem cells (hMSCs) when the hMSCs-laden GelMA/HAMA-MXene bioinks were 3D printed. The physicochemical and rheological characteristics of the GelMA/HAMA-MXene hydrogels were proven to be unprecedentedly favorable supportive matrices suited for the growth and survival of hMSCs. Furthermore, hMSCs were shown to spontaneously differentiate into osteoblasts within GelMA-HAMA/MXene composites to provide favorable microenvironments for osteogenesis. Therefore, our results suggest that the remarkable biofunctional advantages of the MXene-incorporated GelMA/HAMA bioink can be utilized in a wide range of strategies for the development of effective scaffolds in bone tissue regeneration.

3D Printing of Skin Equivalents with Hair Follicle Structures and Epidermal-Papillary-Dermal Layers Using Gelatin/Hyaluronic Acid Hydrogels.

Recent advances in three-dimensional (3D) bioprinting technologies have enabled the fabrication of sophisticated live 3D tissue analogs. Despite the existing hydrogel-based bioinks, the development of advanced bioink materials that can accurately reproduce the composition of a native extracellular matrix and mimic the intrinsic properties of laden cells remains challenging. In this study, 3D printed skin equivalents incorporating hair follicle structures and epidermal/papillary dermal layers were fabricated using gelatin methacryloyl/hyaluronic acid methacryloyl (GelMA/HAMA) bioink. The composition of collagen and glycosaminoglycan in native skin was recapitulated by adjusting the combination of GelMA and HAMA. The GelMA/HAMA bioink exhibited excellent viscoelastic and physicochemical properties, 3D printability, cytocompatibility, and functionality to maintain hair-inductive potency while facilitating spontaneous hair pore development. The results indicate that GelMA/HAMA hydrogels are promising candidates as bioinks for the 3D printing of skin equivalents. Furthermore, they may serve as useful models for skin tissue engineering and regeneration.

Advances and Innovations of 3D Bioprinting Skin.

Three-dimensional (3D) bioprinted skin equivalents are highlighted as the new gold standard for alternative models to animal testing, as well as full-thickness wound healing. In this review, we focus on the advances and innovations of 3D bioprinting skin for skin regeneration, within the last five years. After a brief introduction to skin anatomy, 3D bioprinting methods and the remarkable features of recent studies are classified as advances in materials, structures, and functions. We will discuss several ways to improve the clinical potential of 3D bioprinted skin, with state-of-the-art printing technology and novel biomaterials. After the breakthrough in the bottleneck of the current studies, highly developed skin can be fabricated, comprising stratified epidermis, dermis, and hypodermis with blood vessels, nerves, muscles, and skin appendages. We hope that this review will be priming water for future research and clinical applications, that will guide us to break new ground for the next generation of skin regeneration.

Potential of Carbon-Based Nanocomposites for Dental Tissue Engineering and Regeneration.

While conventional dental implants focus on mechanical properties, recent advances in functional carbon nanomaterials (CNMs) accelerated the facilitation of functionalities including osteoinduction, osteoconduction, and osseointegration. The surface functionalization with CNMs in dental implants has emerged as a novel strategy for reinforcement and as a bioactive cue due to their potential for mechanical reinforcing, osseointegration, and antimicrobial properties. Numerous developments in the fabrication and biological studies of CNMs have provided various opportunities to expand their application to dental regeneration and restoration. In this review, we discuss the advances in novel dental implants with CNMs in terms of tissue engineering, including material combination, coating strategies, and biofunctionalities. We present a brief overview of recent findings and progression in the research to show the promising aspect of CNMs for dental implant application. In conclusion, it is shown that further development of surface functionalization with CNMs may provide innovative results with clinical potential for improved osseointegration after implantation.