Mechanical strength improvement of chitosan/hydroxyapatite scaffolds by coating and cross-linking

Cutting-edge collagen biocomposite reinforced with 2D nano-talc for bone tissue engineering

The advancement of nanobiocomposites reinforced with 2D nano-materials plays a pivotal role in enhancing bone tissue engineering. In this study, we introduce a nanobiocomposite that reinforces bovine collagen with 2D nano-talc, a recently exfoliated nano-mineral. These nanobiocomposites were prepared by blending collagen with varying concentrations of 2D nano-talc, encompassing mono- and few-layers talc from soapstone nanomaterial. Extensive characterization techniques including AFM, XPS, nano-FTIR, s-SNOM nanoimaging, Force Spectroscopy, and PeakForce QNM® were employed. The incorporation of 2D nano-talc significantly enhanced the mechanical properties of the nanobiocomposites, resulting in increased stiffness compared to pristine collagen. In vitro studies supported the growth and proliferation of osteoblasts onto 2D nano-talc-reinforced nanobiocomposites, as well as showed the highest mineralization potential. These findings highlight the substantial potential of the developed nanobiocomposite as a scaffold material for bone tissue engineering applications.

Tunable mechanical properties of chitosan-based biocomposite scaffolds for bone tissue engineering applications: A review

Bone tissue engineering (BTE) aims to develop implantable bone replacements for severe skeletal abnormalities that do not heal. In the field of BTE, chitosan (CS) has become a leading polysaccharide in the development of bone scaffolds. Although CS has several excellent properties, such as biodegradability, biocompatibility, and antibacterial properties, it has limitations for use in BTE because of its poor mechanical properties, increased degradation, and minimal bioactivity. To address these issues, researchers have explored other biomaterials, such as synthetic polymers, ceramics, and CS coatings on metals, to produce CS-based biocomposite scaffolds for BTE applications. These CS-based biocomposite scaffolds demonstrate superior properties, including mechanical characteristics, such as compressive strength, Young's modulus, and tensile strength. In addition, they are compatible with neighboring tissues, exhibit a controlled rate of degradation, and promote cell adhesion, proliferation, and osteoblast differentiation. This review provides a brief outline of the recent progress in making different CS-based biocomposite scaffolds and how to characterize them so that their mechanical properties can be tuned using crosslinkers for bone regeneration.

Techniques, applications and prospects of polysaccharide and protein based biopolymer coatings: A review

The growing relevance of sustainable materials has recently led to the exploration of naturally derived biopolymeric hydrogels as coating materials due to their biodegradability, biocompatibility, ease of fabrication and modification. Although many review articles exist on biopolymeric coatings, they mainly focus on a specific polysaccharide, protein biopolymer, or a particular application- biomedical engineering or food preservation. The current review first summarizes the commonly used polysaccharide and protein-based biopolymers like chitosan, alginate, carrageenan, pectin, cellulose, starch, pullulan, agarose and silk fibroin, gelatin, respectively, with a systematic description of the techniques widely used for physical coating on substrates. Then, broad applications of these biopolymeric coatings on various substrates in biomedical engineering- 3D scaffolds, biomedical implants, and nanoparticles are described in detail. It also entails the application of biopolymeric coatings for food preservation in the form of food packaging and edible coatings. A brief discussion on the newly discovered interest in exploring biopolymers for anticorrosive coating applications is also included. Finally, concluding remarks on the role of biopolymer microstructures in forming homogeneous coatings, prospective alternatives to the currently used biopolymers as coating material and the advent of computer-aided technologies to expedite experimental findings are presented.

Towards a sustainable chitosan-based composite scaffold derived from Scylla serrata crab chitosan for bone tissue engineering

Bone tissue engineering offers a novel therapy for repairing bone defects or fractures. However, it is becoming increasingly challenging because an ideal scaffold should possess a similar porous structure, high biocompatibility, and mechanical properties that match those of natural bone. To fabricate such a scaffold, biodegradable polymers are often preferred due to their degradability and tailored structure. This study involved the isolation of chitosan from crab shells (Scylla serrata) waste to use as a biomaterial in combination with hydroxyapatite (HAP) and collagen I (COL I) to mimic the extracellular matrix (ECM) composition of bone. After being cast and freeze-dried, it resulted in an interconnected porous scaffold with a porosity of 51.44% ± 2.28% and a pore diameter of 109.88 μm ± 49.84 μm. The swelling ratio of the crab scaffold was measured at 358.31% ± 25.23%, 363.04% ± 1.56%, and 370.11% ± 3.7% at 1, 3, and 6 h, respectively. Consequently, the scaffold exhibited a degradation ratio of 8.17% ± 2.59%, 21.62% ± 5.43%, 22.59% ± 14.23%, and 23.12% ± 6.28% over the course of 1 to 4 weeks. It demonstrated excellent biocompatibility with MG-63 osteosarcoma cells. Although the compression strength was lower than 2-12 MPa, the crab scaffold can still be applied effectively for non-load-bearing bone defects. Crab shell waste emerges as a promising source of chitosan for tissue engineering applications.

Anti-Photoaging Effects of Nanocomposites of Amphiphilic Chitosan/18β-Glycyrrhetinic Acid

Improving the transdermal absorption of weakly soluble drugs for topical use can help to prevent and treat skin photoaging. Nanocrystals of 18β-glycyrrhetinic acid (i.e., NGAs) prepared by high-pressure homogenization and amphiphilic chitosan (ACS) were used to form ANGA composites by electrostatic adsorption, and the optimal ratio of NGA to ACS was 10:1. Dynamic light scattering analysis and zeta potential analysis were used to evaluate the nanocomposites' suspension, and the results showed that mean particle size was 318.8 ± 5.4 nm and the zeta potential was 30.88 ± 1.4 mV after autoclaving (121 °C, 30 min). The results of CCK-8 showed that the half-maximal inhibitory concentration (IC50) of ANGAs (71.9 μg/mL) was higher than that of NGAs (51.6 μg/mL), indicating that the cytotoxicity of ANGAs was weaker than that of NGAs at 24 h. After the composite had been prepared as a hydrogel, the vertical diffusion (Franz) cells were used to investigate skin permeability in vitro, and it was shown that the cumulative permeability of the ANGA hydrogel increased from 56.5 ± 1.4% to 75.3 ± 1.8%. The efficacy of the ANGA hydrogel against skin photoaging was studied by constructing a photoaging animal model under ultraviolet (UV) irradiation and staining. The ANGA hydrogel improved the photoaging characteristics of UV-induced mouse skin significantly, improved structural changes (e.g., breakage and clumping of collagen and elastic fibers in the dermis) significantly, and improved skin elasticity, while it inhibited the abnormal expression of matrix metalloproteinase (MMP)-1 and MMP-3 significantly, thereby reducing the damage caused by UV irradiation to the collagen-fiber structure. These results indicated that the NGAs could enhance the local penetration of GA into the skin and significantly improve the photoaging of mouse skin. The ANGA hydrogel could be used to counteract skin photoaging.

Chitosan-Based Smart Biomaterials for Biomedical Applications: Progress and Perspectives

Over the past decade, smart and functional biomaterials have escalated as one of the most rapidly emerging fields in the life sciences because the performance of biomaterials could be improved by careful consideration of their interaction and response with the living systems. Thus, chitosan could play a crucial role in this frontier field because it possesses many beneficial properties, especially in the biomedical field such as excellent biodegradability, hemostatic properties, antibacterial activity, antioxidant properties, biocompatibility, and low toxicity. Furthermore, chitosan is a smart and versatile biopolymer due to its polycationic nature with reactive functional groups that allow the polymer to form many interesting structures or to be modified in various ways to suit the targeted applications. In this review, we provide an up-to-date development of the versatile structures of chitosan-based smart biomaterials such as nanoparticles, hydrogels, nanofibers, and films, as well as their application in the biomedical field. This review also highlights several strategies to enhance biomaterial performance for fast growing fields in biomedical applications such as drug delivery systems, bone scaffolds, wound healing, and dentistry.

3D printing of 'green' thermo-sensitive chitosan-hydroxyapatite bone scaffold based on lyophilized platelet-rich fibrin

The critical bone defect is still an urgent problem in the field of bone repair. Here, we reported a new type of chitosan (CS)-hydroxyapatite (HAP) scaffolds based on lyophilized platelet-rich fibrin (L-PRF) for releasing abundant growth factors to realize their respective functions. It also has strong mechanical properties to maintain the stability of the bone repair environment. However, acid-soluble CS hydrogels often contain toxic and organic solvents. Moreover, chemical agents may be used for cross-linking for better mechanical properties, further increasing cytotoxicity. In this study, we used an alkali/urea dissolution system to dissolve CS, which improved its mechanical properties and made it thermo-sensitive. Finally, the L-PRF-CS-HAP (P-C-H) composite scaffold was constructed by extrusion-based printing. The results showed that the printing ink had desirable printability and temperature sensitivity. The compressive properties of the scaffolds exhibited a trend of decline with L-PRF content increasing, but all of them could meet the strength of cancellous bone. Meanwhile, the scaffolds had high hydrophilicity, porosity, and could be degraded stablyin vitro. The antibacterial properties of the scaffolds were also verified, greatly reducing the risk of infection during bone repair. It was also demonstrated that the release time of growth factor from L-PRF was significantly prolonged, and growth factor could still be detected after 35 d of sustained release. The capacity of cells to proliferate increased as the number of L-PRF components increased, indicating that L-PRF still exhibited biological activity after 3D printing.

Mechanical and biological characteristics of 3D fabricated clay mineral and bioceramic composite scaffold for bone tissue applications

3D printing technology provides a platform to fabricate a wide range of structures and complex geometry-based scaffolds through computer-aided design (CAD). This study investigates the possibility of developing Bentonite(BEN)/Hydroxyapatite(HAP) scaffold with different HAP wt% (25, 50, 75) using a 3D printing technique (Robocasting) for potential bone tissue applications. Thermal stability of the composites was characterized in TGA and rheological properties of slurries were observed to have different viscosity and shear stress, especially BEN-HAP 50 wt% achieves all criteria for high-quality printing. The fabricated scaffolds were subjected to sintering from 200 °C to 1000 °C for proper densification and attained a maximum compression strength of 52 MPa at 1000 °C for the printed structures. Changes in crystallinity and functional groups were observed as well with respective sintering temperatures. In this study, we also discussed the extrusion and rheological properties of the composite slurry. Porosity, water absorption, degradation and density were studied to understand the physical properties of the sintered scaffolds. The biological characteristics of the scaffold were studied using MG63 cell lines In vitro biocompatibility study and expressed 91% of viability for the 1000 °C sintered samples under controlled culture conditions.

Application Progress of Modified Chitosan and Its Composite Biomaterials for Bone Tissue Engineering

In recent years, bone tissue engineering (BTE), as a multidisciplinary field, has shown considerable promise in replacing traditional treatment modalities (i.e., autografts, allografts, and xenografts). Since bone is such a complex and dynamic structure, the construction of bone tissue composite materials has become an attractive strategy to guide bone growth and regeneration. Chitosan and its derivatives have been promising vehicles for BTE owing to their unique physical and chemical properties. With intrinsic physicochemical characteristics and closeness to the extracellular matrix of bones, chitosan-based composite scaffolds have been proved to be a promising candidate for providing successful bone regeneration and defect repair capacity. Advances in chitosan-based scaffolds for BTE have produced efficient and efficacious bio-properties via material structural design and different modifications. Efforts have been put into the modification of chitosan to overcome its limitations, including insolubility in water, faster depolymerization in the body, and blood incompatibility. Herein, we discuss the various modification methods of chitosan that expand its fields of application, which would pave the way for future applied research in biomedical innovation and regenerative medicine.

Tribological Properties and Physiochemical Analysis of Polymer-Ceramic Composite Coatings for Bone Regeneration

The biomaterial coatings for bone tissue regeneration described in this study promote bioactivity. The ceramic-polymer composite coatings deposited on polylactide (PLA) plates contain polymers, namely polyvinylpyrrolidone (PVP)/polyethylene glycol (PEG), while the ceramic phase is hydroxyapatite (HA). Additionally, collagen (COL) and glutathione (GSH) are components of high biological value. Bone tissue materials requires additionally demanding tribological properties, which are thoroughly described in this research. These findings, presented herein for the first time, characterize this type of highly specific composite coating material and their indicate possible application in bone regeneration implants. Implementation of the collagen in the PVP/PEG/HA composite matrix can tailor demanding tribological performance, e.g., anti-wear and friction reduction. The addition of the ceramic phase in too high a content (15%) leads to the decreased swelling ability of materials and slower liquid medium absorption by composite coatings, as well as strong surface roughening and loosening tribological properties. In consequence, small particles of HA from the very rough composite crumble, having a strong abrasive effect on the sample surface. In conclusion, sample C composed of PVP/PEG/GSH/COL/HA (5%) exhibits high bioactivity, strong mechanical and tribological properties, the highest free surface energy, porosity, and accepted roughness to be implemented as a material for bone regeneration.

A Novel Bionic Extracellular Matrix Polymer Scaffold Enhanced by Calcium Silicate for Bone Tissue Engineering

A novel porous calcium silicate (CS)-enhanced small intestinal submucosa (SIS) scaffold was prepared by freeze-drying to mimic the natural extracellular matrix environment for bone tissue engineering. The micro-morphology, physicochemical properties, biological characteristics, and effects on osteogenic differentiation in vitro were explored; the effects on promoting bone formation in vivo were evaluated. The composite scaffold had an ideal three-dimensional porous structure. The amount of calcium silicate played a significant role in improving mechanical properties and promoting osteogenic differentiation. The SIS/2CS scaffold promoted proliferation and osteogenic differentiation in human bone marrow mesenchymal stem cells; it also significantly increased osteogenesis in vivo. This novel composite polymer scaffold has potential applications in bone tissue engineering.

Aspects of In Vitro Biodegradation of Hybrid Fibrin-Collagen Scaffolds

The success of the regenerative process resulting from the implantation of a scaffold or a tissue-engineered structure into damaged tissues depends on a series of factors, including, crucially, the biodegradability of the implanted materials. The selection of a scaffold with appropriate biodegradation characteristics allows for synchronization of the degradation of the construct with the processes involved in new tissue formation. Thus, it is extremely important to characterize the biodegradation properties of potential scaffold materials at the stage of in vitro studies. We have analyzed the biodegradation of hybrid fibrin–collagen scaffolds in both PBS solution and in trypsin solution and this has enabled us to describe the processes of both their passive and enzymatic degradation. It was found that the specific origin of the collagen used to form part of the hybrid scaffolds could have a significant effect on the nature of the biodegradation process. It was also established, during comparative studies of acellular scaffolds and scaffolds containing stem cells, that the cells, too, make a significant contribution to changes in the biodegradation and structural properties of such scaffolds. The study results also provided evidence indicating the dependency between the pre-cultivation period for the cellular scaffolds and the speed and extent of their subsequent biodegradation. Our discussion of results includes an attempt to explain the mechanisms of the changes found. We hope that the said results will make a significant contribution to the understanding of the processes affecting the differences in the biodegradation properties of hybrid, biopolymer, and hydrogel scaffolds.

Fabrication and applications of bioactive chitosan-based organic-inorganic hybrid materials: A review

Organic-inorganic hybrid materials like bone, shells, and teeth can be found in nature, which are usually composed of biomacromolecules and nanoscale inorganic ingredients. Synergy of organic-inorganic components in hybrid materials render them outstanding and versatile performance. Chitosan is commonly used organic materials in bionic hybrid materials since its bioactive properties and could be controllable tailored by various means to meet complex conditions in different applications. Among these fabrication means, hybridization was favored for its convenience and efficiency. This review discusses three kinds of chitosan-based hybrid materials: hybridized with hydroxyapatite, calcium carbonate, and clay respectively, which are the representative of phosphate, carbonate, and hydrous aluminosilicates. Here, we reported the latest developments of the preparation methods, composition, structure and applications of these bioactive hybrid materials, especially in the biomedical field. Despite the great progress was made in bioactive organic-inorganic hybrid materials based on chitosan, some challenges and specific directions are still proposed for future development in this review.

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.