Fabrication of graphene/gelatin/chitosan/tricalcium phosphate 3D printed scaffolds for bone tissue regeneration applications

"Biological evaluation of 3D-Printed chitosan-based scaffolds for tissue engineering"

Chitosan is a natural polysaccharide with excellent biocompatibility, biodegradability, and antibacterial capabilities, making it a good candidate for tissue engineering. 3D printing has revolutionized biomaterial fabrication owing to its precision, customization, and ability to create complex structures. This article aims to provide an overview of the current advances in 3D printing techniques for fabricating scaffolds based on chitosan and its derivatives. It also describes various printing methods, including extrusion bioprinting technique, inkjet bioprinting, stereolithography, digital light processing, and indirect 3D printing for controlling porosity, mechanical strength, and biological characteristics of chitosan scaffolds for a variety of tissues, like bone, vascular, cardiac, cartilage, and skin. This review also examines the biological properties of 3D-printed chitosan scaffolds. The advancements in biological performance and 3D printing technology indicate a promising future for developing flexible, customized scaffolds consisting of chitosan.

Graphene-Based Wound Dressings for Wound Healing: Mechanism, Technical Analysis, and Application Status

The development of novel wound dressings is critical in medical care. Graphene and its derivatives possess excellent biomedical properties, making them highly suitable for various applications in medical dressings. This review provides a comprehensive technical analysis and the current application status of graphene-based medical dressings. Initially, we discuss the chemical structure and the fabrication method of graphene and its derivatives. We then provide a detailed summary of the mechanisms by which graphene materials promote wound repair across the four stages of wound healing. Subsequently, we categorize the types of graphene-based wound dressings and analyze corresponding characteristics. Finally, we analyze the challenges encountered at present and propose solutions regarding future development trends. This paper aims to serve as a reference for further research in skin tissue engineering and the development of innovative graphene-based medical dressings.

Study and evaluation of a gelatin- silver oxide nanoparticles releasing nitric oxide production of wound healing dressing for diabetic ulcer

This study aimed to develop a novel Gelatin silver oxide material for releasing nitric oxide bionanocomposite wound dressing with enhanced mechanical, chemical, and antibacterial properties for the treatment of diabetic wounds. The gelatin- silver oxide nanoparticles (Ag2O-NP) bio nanocomposite was prepared using chitosan and gelatin polymers incorporated with silver oxide nanoparticles through the freeze-drying method. The samples were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Results showed that the Ag2O-NP nanoparticles increased porosity, decreased pore size, and improved elastic modulus. The Ag2O-NP wound dressing exhibited the most effective antibacterial properties against Staphylococcus aureus and Escherichia coli. Among the samples, the wound dressing containing silver oxide nanoparticles demonstrated superior physical and mechanical properties, with 48% porosity, a tensile strength of 3.2 MPa, and an elastic modulus of 51.7 MPa. The fabricated wound dressings had a volume ratio of empty space to total volume ranging from 40% to 60%. In parallel, considering the complications of diabetes and its impact on the vascular system, another aspect of the research focused on developing a per2mediated wound dressing capable of releasing nitric oxide gas to regenerate damaged vessels and accelerate diabetic wound healing. Chitosan, a biocompatible and biodegradable polymer, was selected as the substrate for the wound dressing, and beta-glycerophosphate (GPβ), tripolyphosphate (TPP), and per2mediated alginate (AL) were used as crosslinkers. The chitosan-alginate (CS-AL) wound dressing exhibited optimal characteristics in terms of hole count and uniformity in the scanning electron microscope test. It also demonstrated superior water absorption (3854%) and minimal air permeability. Furthermore, the CS-AL sample exhibited an 80% degradation rate after 14 days, indicating its suitability as a wound dressing. The wound dressing was loaded with S-nitrosoglutathione (GSNO) powder, and the successful release of nitric oxide gas was confirmed through the grease test, showing a peak at a wavelength of 540 nm. Subsequent investigations revealed that the treatment of human umbilical vein endothelial cells (HUVECs) with high glucose led to a decrease in the expression of PER2 and SIRT1, while the expression of PER2 increased, which may subsequently enhance the expression of SIRT1 and promote cell proliferation activity. However, upon treatment of the cells with the modified materials, an increase in the expression of PER2 and SIRT1 was observed, resulting in a partial restoration of cell proliferative activity. This comprehensive study successfully developed per2-mediated bio-nanocomposite wound dressings with improved physical, mechanical, chemical, and antibacterial properties. The incorporation of silver oxide nanoparticles enhanced the antimicrobial activity, while the released nitric oxide gas from the dressing demonstrated the ability to mitigate vascular endothelial cell damage induced by high glucose levels. These advancements show promising potential for facilitating the healing process of diabetic wounds by addressing complications associated with diabetes and enhancing overall wound healing.

A 3D-Printed Scaffold for Repairing Bone Defects

The treatment of bone defects has always posed challenges in the field of orthopedics. Scaffolds, as a vital component of bone tissue engineering, offer significant advantages in the research and treatment of clinical bone defects. This study aims to provide an overview of how 3D printing technology is applied in the production of bone repair scaffolds. Depending on the materials used, the 3D-printed scaffolds can be classified into two types: single-component scaffolds and composite scaffolds. We have conducted a comprehensive analysis of material composition, the characteristics of 3D printing, performance, advantages, disadvantages, and applications for each scaffold type. Furthermore, based on the current research status and progress, we offer suggestions for future research in this area. In conclusion, this review acts as a valuable reference for advancing the research in the field of bone repair scaffolds.

Preparation and physicochemical characterization of whitlockite/PVA/Gelatin composite for bone tissue regeneration

This work used a straightforward solvent casting approach to synthesize bone whitlockite (WH) based PVA/Gelatin composites. WH nanoparticles (NPs) were synthesized using the wet precipitation method, followed by their addition into the PVA/Gelatin matrix at concentrations from 1% to 10%. The physicochemical characterization of the prepared PVA/Gelatin/WH composite was carried out using ATR-FTIR, Optical profilometry, a Goniometer, a Universal tensile testing machine (UTM), and scanning electron microscopy (SEM) techniques. The ATR-FTIR analysis confirmed the formation of noncovalent interactions between polymeric chains and WH NPs and the incorporation of WH NPs into the polymer cavities. SEM analysis demonstrated increased surface roughness with the addition of WH NPs, supporting the results obtained through optical profilometry analysis. The mechanical properties of the prepared composite showed an increase in the tensile strength with the addition of WH filler up to 7% loading. The prepared composite has demonstrated an excellent swelling ability and surface wettability. The reported results demonstrate the exceptional potential of the prepared composite for bone tissue regeneration.

Synthesis of scale-like nano-hydroxyapatite and preparation of biodegradable woven scaffolds for bone tissue engineering

Bone tissue engineering scaffolds should have bone compatibility, biological activity, porosity, and degradability. In this study, flake-like hydroxyapatite was synthesized by hydrothermal method and mixed with sodium alginate to make a gel, which was injected into a hollow braid. Porous and degradable SA/n-Hap woven scaffolds were prepared by freeze-drying technology. The morphology of hydroxyapatite was characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction. The scaffolds were characterized by an improved liquid replacement method, compression test, and degradation test. The results showed that the hydroxyapatite synthesized at 160 °C had a scaly morphology. The prepared scaffold had a pore size of 5-100 μm, a porosity of 60%-70%, and a swelling rate of more than 300%. After 21 d the degradation rate reached 5.54%, and a cell survival rate of 214.98%. In summary, it is feasible to prepare porous bone scaffolds for potential bone tissue engineering. This study shows the feasibility of applying textile structures to the field of tissue scaffolds and provides a new idea for the application structure of tissue engineering scaffolds.

Antimicrobial and Biodegradable 3D Printed Scaffolds for Orthopedic Infections

In bone tissue engineering, the performance of scaffolds underpins the success of the healing of bone. Microbial infection is the most challenging issue for orthopedists. The application of scaffolds for healing bone defects is prone to microbial infection. To address this challenge, scaffolds with a desirable shape and significant mechanical, physical, and biological characteristics are crucial. 3D printing of antibacterial scaffolds with suitable mechanical strength and excellent biocompatibility is an appealing strategy to surmount issues of microbial infection. The spectacular progress in developing antimicrobial scaffolds, along with beneficial mechanical and biological properties, has sparked further research for possible clinical applications. Herein, the significance of antibacterial scaffolds designed by 3D, 4D, and 5D printing technologies for bone tissue engineering is critically investigated. Materials such as antibiotics, polymers, peptides, graphene, metals/ceramics/glass, and antibacterial coatings are used to impart the antimicrobial features for the 3D scaffolds. Polymeric or metallic biodegradable and antibacterial 3D-printed scaffolds in orthopedics disclose exceptional mechanical and degradation behavior, biocompatibility, osteogenesis, and long-term antibacterial efficiency. The commercialization aspect of antibacterial 3D-printed scaffolds and technical challenges are also discussed briefly. Finally, the discussion on the unmet demands and prevailing challenges for ideal scaffold materials for fighting against bone infections is included along with a highlight of emerging strategies in this field.

Scaffolds in the microbial resistant era: Fabrication, materials, properties and tissue engineering applications

Due to microbial infections dramatically affect cell survival and increase the risk of implant failure, scaffolds produced with antimicrobial materials are now much more likely to be successful. Multidrug-resistant infections without suitable prevention strategies are increasing at an alarming rate. The ability of cells to organize, develop, differentiate, produce a functioning extracellular matrix (ECM) and create new functional tissue can all be controlled by careful control of the extracellular microenvironment. This review covers the present state of advanced strategies to develop scaffolds with antimicrobial properties for bone, oral tissue, skin, muscle, nerve, trachea, cardiac and other tissue engineering applications. The review focuses on the development of antimicrobial scaffolds against bacteria and fungi using a wide range of materials, including polymers, biopolymers, glass, ceramics and antimicrobials agents such as antibiotics, antiseptics, antimicrobial polymers, peptides, metals, carbon nanomaterials, combinatorial strategies, and includes discussions on the antimicrobial mechanisms involved in these antimicrobial approaches. The toxicological aspects of these advanced scaffolds are also analyzed to ensure future technological transfer to clinics. The main antimicrobial methods of characterizing scaffolds' antimicrobial and antibiofilm properties are described. The production methods of these porous supports, such as electrospinning, phase separation, gas foaming, the porogen method, polymerization in solution, fiber mesh coating, self-assembly, membrane lamination, freeze drying, 3D printing and bioprinting, among others, are also included in this article. These important advances in antimicrobial materials-based scaffolds for regenerative medicine offer many new promising avenues to the material design and tissue-engineering communities.

A Review of Recent Advances in Natural Polymer-Based Scaffolds for Musculoskeletal Tissue Engineering

The musculoskeletal (MS) system consists of bone, cartilage, tendon, ligament, and skeletal muscle, which forms the basic framework of the human body. This system plays a vital role in appropriate body functions, including movement, the protection of internal organs, support, hematopoiesis, and postural stability. Therefore, it is understandable that the damage or loss of MS tissues significantly reduces the quality of life and limits mobility. Tissue engineering and its applications in the healthcare industry have been rapidly growing over the past few decades. Tissue engineering has made significant contributions toward developing new therapeutic strategies for the treatment of MS defects and relevant disease. Among various biomaterials used for tissue engineering, natural polymers offer superior properties that promote optimal cell interaction and desired biological function. Natural polymers have similarity with the native ECM, including enzymatic degradation, bio-resorb and non-toxic degradation products, ability to conjugate with various agents, and high chemical versatility, biocompatibility, and bioactivity that promote optimal cell interaction and desired biological functions. This review summarizes recent advances in applying natural-based scaffolds for musculoskeletal tissue engineering.

An Overview of Extracellular Matrix-Based Bioinks for 3D Bioprinting

As a microenvironment where cells reside, the extracellular matrix (ECM) has a complex network structure and appropriate mechanical properties to provide structural and biochemical support for the surrounding cells. In tissue engineering, the ECM and its derivatives can mitigate foreign body responses by presenting ECM molecules at the interface between materials and tissues. With the widespread application of three-dimensional (3D) bioprinting, the use of the ECM and its derivative bioinks for 3D bioprinting to replicate biomimetic and complex tissue structures has become an innovative and successful strategy in medical fields. In this review, we summarize the significance and recent progress of ECM-based biomaterials in 3D bioprinting. Then, we discuss the most relevant applications of ECM-based biomaterials in 3D bioprinting, such as tissue regeneration and cancer research. Furthermore, we present the status of ECM-based biomaterials in current research and discuss future development prospects.

Antiviral performance of graphene-based materials with emphasis on COVID-19: A review

Coronavirus disease-2019 has been one of the most challenging global epidemics of modern times with a large number of casualties combined with economic hardships across the world. Considering that there is still no definitive cure for the recent viral crisis, this article provides a review of nanomaterials with antiviral activity, with an emphasis on graphene and its derivatives, including graphene oxide, reduced graphene oxide and graphene quantum dots. The possible interactions between surfaces of such nanostructured materials with coronaviruses are discussed. The antiviral mechanisms of graphene materials can be related to events such as the inactivation of virus and/or the host cell receptor, electrostatic trapping and physico-chemical destruction of viral species. These effects can be enhanced by functionalization and/or decoration of carbons with species that enhances graphene-virus interactions. The low-cost and large-scale preparation of graphene materials with enhanced antiviral performances is an interesting research direction to be explored.

Chitosan-based 3D-printed scaffolds for bone tissue engineering

Despite the spontaneous regenerative properties of autologous bone grafts, this technique remains dilatory and restricted to fractures and injuries. Conventional grafting strategies used to treat bone tissue damage have several limitations. This highlights the need for novel approaches to overcome the persisting challenges. Tissue-like constructs that can mimic natural bone structurally and functionally represent a promising strategy. Bone tissue engineering (BTE) is an approach used to develop bioengineered bone with subtle architecture. BTE utilizes biomaterials to accommodate cells and deliver signaling molecules required for bone rejuvenation. Among the various techniques available for scaffold creation, 3D-printing technology is considered to be a superior technique as it enables the design of functional scaffolds with well-defined customizable properties. Among the biomaterials obtained from natural, synthetic, or ceramic origins, naturally derived chitosan (CS) polymers are promising candidates for fabricating reliable tissue constructs. In this review, the physicochemical-biological properties and applications of CS-based 3D-printed scaffolds and their future perspectives in BTE are summarized.

Current achievements in 3D bioprinting technology of chitosan and its hybrids

Chitosan and its hybrids, as an appropriate bioink in 3D printing technology, for the fabrication of engineered constructions.