Materials For Regeneration Research Articles

Application and Perspectives: Magnesium Materials in Bone Regeneration.

The field of bone regeneration has always been a hot and difficult research area, and there is no perfect strategy at present. As a new type of biodegradable material, magnesium alloys have excellent mechanical properties and bone promoting ability. Compared with other inert metals, magnesium alloys have significant advantages and broad application prospects in the field of bone regeneration. By searching the official Web sites and databases of various funds, this paper summarizes the research status of magnesium composites in the field of bone regeneration and introduces the latest scientific research achievements and clinical transformations of scholars in various countries and regions, such as improving the corrosion resistance of magnesium alloys by adding coatings. Finally, this paper points out the current problems and challenges, aiming to provide ideas and help for the development of new strategies for the treatment of bone defects and fractures.

Biomimetic Materials for Skin Tissue Regeneration and Electronic Skin.

Biomimetic materials have become a promising alternative in the field of tissue engineering and regenerative medicine to address critical challenges in wound healing and skin regeneration. Skin-mimetic materials have enormous potential to improve wound healing outcomes and enable innovative diagnostic and sensor applications. Human skin, with its complex structure and diverse functions, serves as an excellent model for designing biomaterials. Creating effective wound coverings requires mimicking the unique extracellular matrix composition, mechanical properties, and biochemical cues. Additionally, integrating electronic functionality into these materials presents exciting possibilities for real-time monitoring, diagnostics, and personalized healthcare. This review examines biomimetic skin materials and their role in regenerative wound healing, as well as their integration with electronic skin technologies. It discusses recent advances, challenges, and future directions in this rapidly evolving field.

Effects of different fire slash artificial promotion regeneration and natural material regeneration on ecological function

IntroductionIn the aftermath of a fire, prompt reforestation of the affected areas is crucial to mitigate economic losses and ecological impacts.MethodsThis paper introduces an ecological function assessment model leveraging the Back Propagation Neural Network (BPNN). The model's efficacy is validated through simulation comparison experiments. Subsequently, an analysis of the ecosystem's material circulation and energy flow capabilities is undertaken.ResultsSimulation outcomes reveal that our proposed model attains convergence by the 10th training iteration, with a loss function value of just 0.28, highlighting minimal training loss. This underscores the model's rapid convergence and impressive training performance. Our method proves superior to the comparison method in both initial and later operational phases. Notably, it offers a significantly faster response speed and boasts an accuracy rate exceeding 95%.DiscussionConsequently, employing this model to analyze ecological function changes is deemed feasible. The analysis of ecosystem material circulation and energy flow capabilities reveals that while initial assessments show minimal change, scores exhibit a clear acceleration as the cycle progresses.

Enhancing calvarial defects repair with PDGF-BB mimetic peptide hydrogels

Addressing bone defects represents a significant challenge to public health. Localized delivery of growth factor has emerged as promising approach for bone regeneration. However, the clinical application of Platelet-Derived Growth Factor (PDGF) is hindered by its high cost and short half-life. In this work, we introduce the application of PDGF-mimicking peptide (PMP1) hydrogels for calvarial defect restoration, showcasing their remarkable effectiveness. Through osteogenic differentiation assays and q-PCR analyses, we demonstrate PMP1's substantial capacity to enhance osteogenic differentiation of bone marrow mesenchymal stem cell (BMSC), leading to increased expression of crucial osteogenic genes. Further molecular mechanistic investigations reveal PMP1's activation of the PI3K-AKT-mTOR signaling pathway, a key element of its osteogenic effect. In vivo experiments utilizing a rat calvaria critical-sized defect model underscore the hydrogels' exceptional ability to accelerate new bone formation, thereby significantly advancing the restoration of calvaria defects. This research provides a promising bioactive material for bone tissue regeneration.

Carbon Nanotubes Induce Mineralization of Human Cementoblasts

IntroductionCarbon nanotubes (CNT) are 1 of the allotropes of carbon with unique properties. CNT shows good bone-tissue compatibility and has been reported to induce osteogenesis; therefore, it is regarded as an ideal material in a wide range of applications. However, the therapeutic effect of CNT-containing materials in the healing of apical periodontal tissue is unknown. The purpose of this study was to clarify the effect of CNT on the proliferation and mineralization of the human cementoblast cell line (HCEM). MethodsThe proliferation of HCEM cells with CNT stimulation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay performed from 24–72 hours. Calcium deposition levels were evaluated by alizarin red S staining on days 7 and 10, and mineralization-related gene expression was examined by quantitative real-time polymerase chain reaction on days 3, 7, and 10. Scanning electron microscopy was used to observe the culture with CNT on day 14. ResultsCNT showed no cytotoxicity to HCEM cell proliferation. Treatment was performed with mineralization medium, CNT-induced HCEM mineralization on day 7, and increased calcium deposition on days 7 and 14. Messenger RNA expression of alkaline phosphatase was significantly increased throughout the experimental period, and bone sialoprotein was significantly increased on day 3 by CNT, whereas no effect was found on mRNA expression of type I collagen. CNT was observed in attachment to the cell surface on day 14. ConclusionsCNT promotes the mineralization of HCEM cells, indicating the potential as a new bioactive component for apical periodontal tissue regeneration materials through the regulation of cementoblast mineralization.

Perceptions and Surgical Approaches of Periodontists and Residency Students for Bone Augmentation Procedures

Aim: Bone deficiency due to various systemic and periodontal diseases, trauma, and tumors remains a major challenge for osseointegration in implant therapies. To provide implant survival, sufficient bone volume is mandatory. The purpose of the present study is to assess the techniques used by periodontists in implant applications, treatment plans, and solutions to the complications they experience. Material and Methods: 126 periodontists and/or residency students participated in this study. A questionnaire consisting of 20 questions was used. The knowledge and treatment methods about the technique, materials, and planning they use in bone regeneration and the management of complications were questioned. Descriptive statistics and the Pearson Chi-square test were used to analyze the data. Results: All participants needed bone regeneration in implant cases. The most used material for regeneration by the participants was xenograft, with 43.5%. The most preferred application in bone regeneration is guided bone regeneration (GBR) using the collagen membrane, with a rate of 78.3%. The most common complication was membrane exposure. In order to prevent complications, 77.3% of the participants performed adequate soft tissue release, while 63.6% controlled periodontitis. The most commonly used treatment option for complications was the use of postoperative antibiotics/antiseptics. 82.6% of the participants received support in the management of complications. Conclusion: In our study, it was observed that periodontists frequently chose different planning methods and treatment options when performing bone reconstruction/regeneration. It will be beneficial for periodontists to include the latest treatment models applied in the current literature in periodontology residency education.

Fabrication of magnesium-doped biphasic calcium phosphate granules with sea urchin spine-derived porous structure

In bone regeneration, synthetic materials are required to replace autogenous bone grafts. The shape, composition, surface, and porous structure of the material are key factors in bone formation and material resorption. In this study, we describe the fabrication of Mg-doped biphasic calcium phosphate (Mg-BCP) granules comprising hydroxyapatite (HAp) and beta-tricalcium phosphate (β-TCP) by exploiting the structural and chemical characteristics of sea urchin spines. The Mg-BCP granules were cylinders with a 1.2–1.8 mm diameter and height of 1.4–1.7 mm. The β-TCP/HAp ratio and Mg content in the Mg-BCP granules were controlled within the ranges of 0.36–0.45 and 2.40–6.21 mol%, respectively. Controlling the β-TCP/HAp ratio and Mg content may contribute to controlling the material resorption rate and promoting osteogenesis and angiogenesis. The Mg-BCP granules maintained the structural characteristics of the sea urchin spines. The granules comprised radial wedges termed septa, and a meshwork termed stereom. The interseptal gaps, or micropores, decreased from the granular exterior (24–29 μm) to the interior (14–28 μm). The septa in the outermost layer provide concavities on the sides of the cylindrical granules. The stereom meshworks in the core and outer layers involved micropores in the ranges of 3–15 and 3–10 μm, respectively. These multiscale pores and surface undulations may improve cell penetration and attachment, bodily fluid permeability, and protein adsorption. The compressive strengths of the Mg-BCP granules were in the range of 45.2–46.1 MPa, which are useful as bone grafts. Due to their rounded shapes, the Mg-BCP granules filled a mold more densely than the clinically used and irregularly shaped granules. These findings demonstrated that Mg-BCP granules are promising materials for bone regeneration.

Lithium-Doped Titanium Dioxide-Based Multilayer Hierarchical Structure for Accelerating Nerve-Induced Bone Regeneration.

Despite considerable advances in artificial bone tissues, the absence of neural network reconstruction in their design often leads to delayed or ineffective bone healing. Hence, we propose a multilayer hierarchical lithium (Li)-doped titanium dioxide structure, constructed through microarc oxidation combined with alkaline heat treatment. This structure can induce the sustained release of Li ions, mimicking the environment of neurogenic osteogenesis characterized by high brain-derived neurotrophic factor (BDNF) expression. During in vitro experiments, the structure enhanced the differentiation of Schwann cells (SCs) and the growth of human umbilical vein endothelial cells (HUVECs) and mouse embryo osteoblast progenitor cells (MC3T3-E1). Additionally, in a coculture system, the SC-conditioned media markedly increased alkaline phosphatase expression and the formation of calcium nodules, demonstrating the excellent potential of the material for nerve-induced bone regeneration. In an in vivo experiment based on a rat distal femoral lesion model, the structure substantially enhanced bone healing by increasing the density of the neural network in the tissue around the implant. In conclusion, this study elucidates the neuromodulatory pathways involved in bone regeneration, providing a promising method for addressing bone deformities.

Genetically engineered bacteriophages as novel nanomaterials: applications beyond antimicrobial agents.

Bacteriophages, also known as phages, are viruses that replicate in bacteria and archaea. Phages were initially discovered as antimicrobial agents, and they have been used as therapeutic agents for bacterial infection in a process known as "phage therapy." Recently, phages have been investigated as functional nanomaterials in a variety of areas, as they can function not only as therapeutic agents but also as biosensors and tissue regenerative materials. Phages are nontoxic to humans, and they possess self-assembled nanostructures and functional properties. Additionally, phages can be easily genetically modified to display specific peptides or to screen for functional peptides via phage display. Here, we demonstrated the application of phage nanomaterials in the context of tissue engineering, sensing, and probing.

Glycosylation in autoimmune diseases: A bibliometric and visualization study

An increasing amount of research has shown that glycosylation plays a crucial role in autoimmune diseases (ADs), prompting our interest in conducting research on the knowledge framework and hot topics in this field based on bibliometric analysis. Studies on glycosylation in the field of ADs from 2003 to 2023 were collected by searching the Web of Science Core Collection database. Bibliometric analysis was conducted using VOSviewer, CiteSpace, and Bibliometrix software. This study included a total of 530 studies. According to the H, G, and M indices, the United States has made the most contributions worldwide, with China making significant contributions in recent years. Leiden University from the Netherlands ranks among the top institutions in terms of publication and citation rankings, with the institution's author Manfred Wuhrer contributing the most to this field. Frontiers in Immunology is the journal with the highest H-index. Research in this field has focused on antibody glycosylation, particularly the specific glycosylation of IgG and IgA, and its role in various ADs. The application of glycoengineering glycosylated proteins in the synthesis of targeted monoclonal antibodies, drug delivery, and regenerative medical materials may be a new trend in the treatment of ADs. Artificial intelligence is an emerging tool in glycobiology. This study summarizes the objective data on glycosylation in the field of AD publications in recent years, providing a reference for researchers in this field.

Transforming Natural Eggshell and Diatomite into Bioactive Calcium Silicate Material for Bone Regeneration.

Calcium silicate (CS), a new and important bioceramic bone graft material, is prepared by using eggshells, which have a porous structure and are rich in calcium ions. Furthermore, the preparation of new CS materials using eggshells and diatomaceous earth minimizes their negative impact on the environment. In this study, we prepared CS materials using a high-temperature calcination method. The composition of the material was demonstrated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. Scanning electron microscopy (SEM) analysis confirmed the porous structure of the CS material. We also introduced ZnO to prepare ZnO-CS with antibacterial properties and showed that ZnO-CS exhibits excellent antibacterial effects through in vitro antibacterial experiments. Subsequent in vitro mineralization experiments demonstrated that ZnO-CS promoted the formation of a hydroxyapatite layer. Furthermore, in vitro cytotoxicity experiments demonstrated that ZnO-CS had very good biosafety and promoted cell proliferation. These findings were confirmed through subsequent cell proliferation experiments. Our results indicate that the novel ZnO-CS is a promising candidate for bone tissue engineering.

Multiscale characterization of additively manufactured PMMA: the influence of sterilization

PurposePolymethyl methacrylate (PMMA) is a remarkable biocompatible material for bone cement and regeneration. It is also considered 3D printable but requires in-depth process–structure–properties studies. This study aims to elucidate the mechanistic effects of processing parameters and sterilization on PMMA-based implants.Design/methodology/approachThe approach comprised manufacturing samples with different raster angle orientations to capitalize on the influence of the filament alignment with the loading direction. One sample set was sterilized using an autoclave, while another was kept as a reference. The samples underwent a comprehensive characterization regimen of mechanical tension, compression and flexural testing. Thermal and microscale mechanical properties were also analyzed to explore the extent of the appreciated modifications as a function of processing conditions.FindingsThermal and microscale mechanical properties remained almost unaltered, whereas the mesoscale mechanical behavior varied from the as-printed to the after-autoclaving specimens. Although the mechanical behavior reported a pronounced dependence on the printing orientation, sterilization had minimal effects on the properties of 3D printed PMMA structures. Nonetheless, notable changes in appearance were attributed, and heat reversed as a response to thermally driven conformational rearrangements of the molecules.Originality/valueThis research further deepens the viability of 3D printed PMMA for biomedical applications, contributing to the overall comprehension of the polymer and the thermal processes associated with its implementation in biomedical applications, including personalized implants.

Plant-Assisted Green Synthesis of MgO Nanoparticles as a Sustainable Material for Bone Regeneration: Spectroscopic Properties.

This work is devoted to magnesium oxide (MgO) nanoparticles (NPs) for their use as additives for bone implants. Extracts from four different widely used plants, including Aloe vera, Echeveria elegans, Sansevieria trifasciata, and Sedum morganianum, were evaluated for their ability to facilitate the "green synthesis" of MgO nanoparticles. The thermal stability and decomposition behavior of the MgONPs were analyzed by thermogravimetric analysis (TGA). Structure characterization was performed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), ultraviolet-visible spectroscopy (UV-Vis), dynamic light scattering (DLS), and Raman scattering spectroscopy (RS). Morphology was studied by scanning electron microscopy (SEM). The photocatalytic activity of MgO nanoparticles was investigated based on the degradation of methyl orange (MeO) using UV-Vis spectroscopy. Surface-enhanced Raman scattering spectroscopy (SERS) was used to monitor the adsorption of L-phenylalanine (L-Phe) on the surface of MgONPs. The calculated enhancement factor (EF) is up to 102 orders of magnitude for MgO. This is the first work showing the SERS spectra of a chemical compound immobilized on the surface of MgO nanoparticles.

Development of an Injectable Biphasic Hyaluronic Acid-Based Hydrogel With Stress Relaxation Properties for Cartilage Regeneration.

Biomimetic stress-relaxing hydrogels with reversible crosslinks attract significant attention for stem cell tissue regeneration compared with elastic hydrogels. However, stress-relaxing hyaluronic acid (HA)-based hydrogels fabricated using conventional technologies lack stability, biocompatibility, and mechanical tunability. Here, it is aimed to address these challenges by incorporating calcium or phosphate components into the HA backbone, which allows reversible crosslinking of HA with alginate to form interpenetrating networks, offering stability and mechanical tunability for mimicking cartilage. Diverse stress-relaxing hydrogels (τ1/2; SR50, 60-2000 s) are successfully prepared at ≈3 kPa stiffness with self-healing and shear-thinning abilities, favoring hydrogel injection. In vitro cell experiments with RNA sequencing analysis demonstrate that hydrogels tune chondrogenesis in a biphasic manner (hyaline or calcified) depending on the stress-relaxation properties and phosphate components. In vivo studies confirm the potential for biphasic chondrogenesis. These results indicate that the proposed stress-relaxing HA-based hydrogel with biphasic chondrogenesis (hyaline or calcified) is a promising material for cartilage regeneration.

Formulation of a Novel Polymeric Hydrogel Membrane for Periodontal Tissue Regeneration Using Tricalcium Phosphate-Alginate Reinforcement.

The primary goal of periodontal therapy is to facilitate the regeneration of tissues damaged by periodontal disease. In recent years, there has been a growing utilization of guided tissue regeneration (GTR) membranes with bioabsorbable properties as these membranes are increasingly employed to guide the growth of gingival tissue away from the root surface. Both resorbable and non-resorbable membranes currently employed act as physical barriers, preventing the ingrowth of connective and epithelial tissues into the defect and thereby facilitating periodontal tissue regeneration. This study aimed to develop a polymeric hydrogel membrane reinforced with tricalcium phosphate (TCP)-alginate and assess its potential for periodontal regeneration. TCPnanoparticles were incorporated into the alginate mixture to form TCP alginate. Subsequently, the mixture was cross-linked with calcium chloride to produce a TCP-alginate polymeric hydrogel membrane. The membrane underwent hemocompatibility analysis, and also scanning electron microscopyand Fourier-transform infrared (FTIR) spectroscopy analyses were done. The SEM analysis revealed granulations and a bonded thread-like structure in the membrane, indicative of favorable conditions for cell attachment necessary for periodontal regeneration. FTIR analysis showed characteristic peaks in the spectrum, including those attributed to phosphate ion (PO4-3) at 1000.85 cm-1 and 600 cm-1, indicating the presence of β-TCP phases. Hemocompatibility assessment demonstrated a hemolysis rate of less than 5% for the TCP-alginate membrane, which is found to be within the limits. The developed TCP-reinforced alginate membrane exhibited hemocompatibility and safety, suggesting its suitability for utilization in periodontal therapy as an effective regenerative material.

Enhancing osteoblast proliferation and bone regeneration by poly (amino acid)/selenium-doped hydroxyapatite

Among various biomaterials employed for bone repair, composites with good biocompatibility and osteogenic ability had received increasing attention from biomedical applications. In this study, we doped selenium (Se) into hydroxyapatite (Se-HA) by the precipitation method, and prepared different amounts of Se-HA-loaded poly (amino acid)/Se-HA (PAA/Se-HA) composites (0, 10 wt%, 20 wt%, 30 wt%) by in-situ melting polycondensation. The physical and chemical properties of PAA/Se-HA composites were characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and their mechanical properties. XRD and FT-IR results showed that PAA/Se-HA composites contained characteristic peaks of PAA and Se-HA with amide linkage and HA structures. DSC and TGA results specified the PAA/Se-HA30 composite crystallization, melting, and maximum weight loss temperatures at 203.33 °C, 162.54 °C, and 468.92 °C, respectively, which implied good thermal stability. SEM results showed that Se-HA was uniformly dispersed in PAA. The mechanical properties of PAA/Se-HA30 composites included bending, compressive, and yield strengths at 83.07 ± 0.57, 106.56 ± 0.46, and 99.17 ± 1.11 MPa, respectively. The cellular responses of PAA/Se-HA composites in vitro were studied using bone marrow mesenchymal stem cells (BMSCs) by cell counting kit-8 assay, and results showed that PAA/Se-HA30 composites significantly promoted the proliferation of BMSCs at the concentration of 2 mg ml−1. The alkaline phosphatase activity (ALP) and alizarin red staining results showed that the introduction of Se-HA into PAA enhanced ALP activity and formation of calcium nodule. Western blotting and Real-time polymerase chain reaction results showed that the introduction of Se-HA into PAA could promoted the expression of osteogenic-related proteins and mRNA (integrin-binding sialoprotein, osteopontin, runt-related transcription factor 2 and Osterix) in BMSCs. A muscle defect at the back and a bone defect at the femoral condyle of New Zealand white rabbits were introduced for evaluating the enhancement of bone regeneration of PAA and PAA/Se-HA30 composites. The implantation of muscle tissue revealed good biocompatibility of PAA and PAA/Se-HA30 composites. The implantation of bone defect showed that PAA/Se-HA30 composites enhanced bone formation at the defect site (8 weeks), exhibiting good bone conductivity. Therefore, the PAA-based composite was a promising candidate material for bone tissue regeneration.

TPG-functionalized PLGA/PCL nanofiber membrane facilitates periodontal tissue regeneration by modulating macrophages polarization via suppressing PI3K/AKT and NF-κB signaling pathways

Traditional fibrous membranes employed in guided tissue regeneration (GTR) in the treatment of periodontitis have limitations of bioactive and immunomodulatory properties. We fabricated a novel nTPG/PLGA/PCL fibrous membrane by electrospinning which exhibit excellent hydrophilicity, mechanical properties and biocompatibility. In addition, we investigated its regulatory effect on polarization of macrophages and facilitating the regeneration of periodontal tissue both in vivo and in vitro. These findings showed the 0.5%TPG/PLGA/PCL may inhibit the polarization of RAW 264.7 into M1 phenotype by suppressing the PI3K/AKT and NF-κB signaling pathways. Furthermore, it directly up-regulated the expression of cementoblastic differentiation markers (CEMP-1 and CAP) in periodontal ligament stem cells (hPDLSCs), and indirectly up-regulated the expression of cementoblastic (CEMP-1 and CAP) and osteoblastic (ALP, RUNX2, COL-1, and OCN) differentiation markers by inhibiting the polarization of M1 macrophage. Upon implantation into a periodontal bone defect rats model, histological assessment revealed that the 0.5%TPG/PLGA/PCL membrane could regenerate oriented collagen fibers and structurally intact epithelium. Micro-CT (BV/TV) and the expression of immunohistochemical markers (OCN, RUNX-2, COL-1, and BMP-2) ultimately exhibited satisfactory regeneration of alveolar bone, periodontal ligament. Overall, 0.5%TPG/PLGA/PCL did not only directly promote osteogenic effects on hPDLSCs, but also indirectly facilitated cementoblastic and osteogenic differentiation through its immunomodulatory effects on macrophages. These findings provide a novel perspective for the development of materials for periodontal tissue regeneration.

Functionalized microporous sulfonated polyetheretherketone: Osteogenesis and anti-osteoclastogenesis effects via ROS and NLRP3-mediated pyroptosis in macrophages

The treatment of osteoporotic implant failures tends to be challenging due to an imbalance in bone homeostasis. Recently, the accumulation of intracellular reactive oxygen species (ROS) and activation of the inflammasome containing nucleotide-binding oligomerization domain-like-receptor family pyrin domain-containing 3 (NLRP3) protein have been shown to indirectly affect osteogenesis and osteoclastogenesis. Owing to the release of multi-metal ions from laponite (LAP), we fabricated a multifunctional LAP coating on a three-dimensional microporous sulfonated polyetheretherketone (SPEEK) surface via polydopamine (PDA) modification (SPEEK@PDA-LAP). The balance between osteogenesis and osteoclastogenesis was examined using macrophages in an osteo-immune microenvironment. Employing in vitro assays, we showed that the SPEEK@PDA-LAP alleviated intracellular ROS accumulation and inhibited the activation of NLRP3 inflammasome-mediated pyroptosis in macrophages, creating an osteoimmunomodulatory microenvironment to stimulate osteogenesis and inhibit osteoclastogenesis. The micro-computed tomography and histological results of in vivo experiments indicated that SPEEK@PDA-LAP implants reversed the balance between osteogenesis and osteoclastogenesis to promote the formation of new bone around the implant even under osteoporotic conditions. The results indicate that inhibiting the NLRP3 inflammasome and regulating intracellular ROS in macrophages can be an effective therapy for osteoporosis. These results highlight the potential of functional PEEK materials for bone regeneration in patients with osteoporosis.

Advances in Polysaccharides for Cartilage Tissue Engineering Repair: A Review.

Cartilage repair has been a significant challenge in orthopedics that has not yet been fully resolved. Due to the absence of blood vessels and the almost cell-free nature of mature cartilage tissue, the limited ability to repair cartilage has resulted in significant socioeconomic pressures. Polysaccharide materials have recently been widely used for cartilage tissue repair due to their excellent cell loading, biocompatibility, and chemical modifiability. They also provide a suitable microenvironment for cartilage repair and regeneration. In this Review, we summarize the techniques used clinically for cartilage repair, focusing on polysaccharides, polysaccharides for cartilage repair, and the differences between these and other materials. In addition, we summarize the techniques of tissue engineering strategies for cartilage repair and provide an outlook on developing next-generation cartilage repair and regeneration materials from polysaccharides. This Review will provide theoretical guidance for developing polysaccharide-based cartilage repair and regeneration materials with clinical applications for cartilage tissue repair and regeneration.

Direct inkjet writing of polylactic acid/β-tricalcium phosphate composites for bone tissue regeneration: A proof-of-concept study.

There is an ever-evolving need of customized, anatomic-specific grafting materials for bone regeneration. More specifically, biocompatible and osteoconductive materials, that may be configured dynamically to fit and fill defects, through the application of an external stimulus. The objective of this study was to establish a basis for the development of direct inkjet writing (DIW)-based shape memory polymer-ceramic composites for bone tissue regeneration applications and to establish material behavior under thermomechanical loading. Polymer-ceramic (polylactic acid [PLA]/β-tricalcium phosphate [β-TCP]) colloidal gels were prepared of different w/w ratios (90/10, 80/20, 70/30, 60/40, and 50/50) through polymer dissolution in acetone (15% w/v). Cytocompatibility was analyzed through Presto Blue assays. Rheological properties of the colloidal gels were measured to determine shear-thinning capabilities. Gels were then extruded through a custom-built DIW printer. Space filling constructs of the gels were printed and subjected to thermomechanical characterization to measure shape fixity (Rf) and shape recovery (Rr) ratios through five successive shape memory cycles. The polymer-ceramic composite gels exhibited shear-thinning capabilities for extrusion through a nozzle for DIW. A significant increase in cellular viability was observed with the addition of β-TCP particles within the polymer matrix relative to pure PLA. Shape memory effect in the printed constructs was repeatable up to 4 cycles followed by permanent deformation. While further research on scaffold macro-/micro-geometries, and engineered porosities are warranted, this proof-of-concept study suggested suitability of this polymer-ceramic material and the DIW 3D printing workflow for the production of customized, patient specific constructs for bone tissue engineering.