Osteogenic differentiation of human adipose-derived mesenchymal stem cells in a bisphosphonate-functionalized polycaprolactone/gelatin scaffold

In vitro study of dimethyl glutamate incorporated chitosan/microfibrillated cellulose based matrix in addition of H and Zr on osteoblast cells

Tissue engineering techniques can be utilized to repair or regenerate damaged tissue by promoting the proliferation and differentiation of cells in bone regeneration. A critical component of this process is the scaffold employed, which should ideally support consistent tissue development during bone regeneration. The aim of this study was to evaluate the morphological, physicochemical, and biological characteristics of various scaffolds: S1 (C/MFC), S2 (C/H/MFC), S3 (C/MFC/Zr), S4 (C/MFC/PCL), S5 (C/H/MFC/PCL), S6 (C/PCL/MFC/Zr), and S7 (C/H/MFC/Zr), which are intended for application in bone regeneration. The scaffolds containing microfibrillated cellulose, chitosan, polycaprolactone, zirconium, and hydroxyapatite were fabricated by the freeze-drying method. Conventional methods, including scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis, were used to evaluate morphological and physicochemical properties of composite scaffolds. The fabricated scaffolds (S1-S7) had spongy properties that all functional groups were present in the sponge. Biological properties for cell survival were evaluated by the MTT assay, ALP, and ARS activities, respectively. In physicochemical studies, scaffolds showed tunable water absorption, swelling studies, degradation, sustained drug release, and mechanical properties. In biological studies, the cell proliferation and attachment were shown to significantly increase in scaffolds on MG63 cells. After 7 days of cell culture, ALP and ARS activity indicated the enhancement of extracellular calcium deposition of the MG63 cells on the treated scaffolds. In summary, the scaffolds S7 (C/H/MFC/Zr) treated with dimethyl glutamate revealed favorable effects on bone tissues, implying a potential towards the treatment of bone defects and drug delivery.

Piezoelectric scaffold based on polycaprolactone/thermoplastic polyurethane/barium titanate/cellulose nanocrystal for bone tissue engineering

This study presents the development of a novel piezoelectric scaffold for bone tissue engineering composed of poly(ε-caprolactone) (PCL), thermoplastic polyurethane (TPU), barium titanate (BT), and cellulose nanocrystals (CNC). PCL and TPU are considered advantageous materials because of their ease of processing, versatility in design, and ability to degrade over time; however, their inherent immiscibility poses challenges to achieving optimal porous structures. In this study, porous scaffolds were produced using gas foaming and salt leaching techniques, resulting in highly porous interconnected scaffolds exhibiting considerable elasticity that is suitable for dynamic cell culture while avoiding the use of toxic solvents. Given the piezoelectric nature of bone tissue, incorporating electric biosignals into scaffolds is essential to enhance bone regeneration. Therefore, BT was incorporated as a piezoelectric material. CNC, derived from cotton, assisted in BT distribution and acted as a reinforcing agent, imparting mechanoelectrical signaling properties to the scaffolds. The optimized scaffolds PCL/TPU (75/25) featuring 100 μm pores were integrated with varying BT and CNC ratios and were subjected to multiple analyses. The results showed a measurable electrical output of 1.2 mV and enhanced cell adhesion, viability, and proliferation under dynamic culture conditions, underscoring their potential for bone tissue regeneration.

Exploring the frontiers: The potential and challenges of bioactive scaffolds in osteosarcoma treatment and bone regeneration

The standard treatment for osteosarcoma combines surgery with chemotherapy, yet it is fraught with challenges such as postoperative tumor recurrence and chemotherapy-induced side effects. Additionally, bone defects after surgery often surpass the body's regenerative ability, affecting patient recovery. Bioengineering offers a novel approach through the use of bioactive scaffolds crafted from metals, ceramics, and hydrogels for bone defect repair. However, these scaffolds are typically devoid of antitumor properties, necessitating the integration of therapeutic agents. The development of a multifunctional therapeutic platform incorporating chemotherapeutic drugs, photothermal agents (PTAs), photosensitizers (PIs), sound sensitizers (SSs), magnetic thermotherapeutic agents (MTAs), and naturally occurring antitumor compounds addresses this limitation. This platform is engineered to target osteosarcoma cells while also facilitating bone tissue repair and regeneration. This review synthesizes recent advancements in integrated bioactive scaffolds (IBSs), underscoring their dual role in combating osteosarcoma and enhancing bone regeneration. We also examine the current limitations of IBSs and propose future research trajectories to overcome these hurdles.

A review of computational optimization of bone scaffold architecture: methods, challenges, and perspectives

The design and optimization of bone scaffolds are critical for the success of bone tissue engineering (BTE) applications. This review paper provides a comprehensive analysis of computational optimization methods for bone scaffold architecture, focusing on the balance between mechanical stability, biological compatibility, and manufacturability. Finite element method (FEM), computational fluid dynamics (CFD), and various optimization algorithms are discussed for their roles in simulating and refining scaffold designs. The integration of multiobjective optimization and topology optimization has been highlighted for developing scaffolds that meet the multifaceted requirements of BTE. Challenges such as the need for consideration of manufacturing constraints and the incorporation of degradation and bone regeneration models into the optimization process have been identified. The review underscores the potential of advanced computational tools and additive manufacturing techniques in evolving the field of BTE, aiming to improve patient outcomes in bone tissue regeneration. The reliability of current optimization methods is examined, with suggestions for incorporating non-deterministic approaches andin vivovalidations to enhance the practical application of optimized scaffolds. The review concludes with a call for further research into artificial intelligence-based methods to advance scaffold design and optimization.

Alginate-gelatin based nanocomposite hydrogel scaffold incorporated with bioactive glass nanoparticles and fragmented nanofibers promote osteogenesis: From design to in vitro studies

The current study proposes fragmented nanofibers of polycaprolactone (FNF) with bioactive glass nanoparticles (nBG) incorporated into a polymeric matrix of alginate-gelatin for the creation of a hydrogel scaffold. Four groups were prepared: control, bioactive glass containing scaffold (BG), fragmented nanofibers with bioactive glass scaffold (FNF(PCL) + BG), and fragmented composite nanofibers scaffold (FNF (PCL + BG)). FNF (PCL + BG) scaffolds revealed a more controlled degradation rate, with approximately 20 % degradation occurring after 28 compared. The FNF(PCL) + BG scaffolds had the highest compressive strength in both dry and wet states. Following 14 days of incubation in simulated body fluid, hydroxyapatite formation had occurred on the surface of scaffolds containing nBG, and after 28 days on other groups tested. Cell studies revealed that the FNF(PCL) + BG scaffolds had superior cell viability without inhibiting cell proliferation. The FNF(PCL) + BG and FNF(PCL + BG) scaffolds had the highest alkaline phosphatase (ALP) activity and FNF(PCL) + BG scaffolds showed to support osteogenic differentiation.

Fabrication and characterization of nanohydroxyapatite/chitosan/decellularized placenta scaffold for bone tissue engineering applications

Novel biomaterials are necessary to fabricate biomimetic scaffolds for bone tissue engineering. In the present experiment, we aimed to fabricate and evaluate the osteogenic properties of nanohydroxyapatite/chitosan/decellularized placenta (nHA.Cs.dPL) composite scaffolds. The human placenta was decellularized (dPL), characterized, and digested in pepsin to form the hydrogel. nHA.Cs.dPL scaffolds were fabricated using salt leaching/freeze drying and evaluated for their morphology, chemical composition, swelling, porosity, degradation, mechanical strength, and biocompatibility. Saos-2 cells were seeded on scaffolds, and their osteogenic properties were investigated by evaluating alkaline phosphatase (ALP), osteocalcin (OCN), collagen type 1 (COL I) expression, and calcium deposition under osteogenic differentiation. The dPL was prepared with minimized DNA content and a well-preserved porous structure. Scaffolds were highly porous with interconnected pores and exhibited appropriate swelling and degradation rates supporting saos-2 cell attachment and proliferation. dPL improved scaffold physicochemical features and increased cell proliferation, ALP, OCN, COL I expression, and calcium deposition under osteogenic differentiation induction. nHA.Cs.dPL composite scaffolds provide a 3D microenvironment with superior physicochemical features that support saos-2 cell adhesion, proliferation, and osteogenic differentiation.

IKVAV functionalized oriented PCL/Fe3O4 scaffolds for magnetically modulating DRG growth behavior

The re-bridging of the deficient nerve is the main problem to be solved after the functional impairment of the peripheral nerve. In this study, a directionally aligned polycaprolactone/triiron tetraoxide (PCL/Fe3O4) fiber scaffolds were firstly prepared by electrospinning technique, and further then grafted with IKVAV peptide for regulating DRG growth and axon extension in peripheral nerve regeneration. The results showed that oriented aligned magnetic PCL/Fe3O4 composite scaffolds were successfully prepared by electrospinning technique and possessed good mechanical properties and magnetic responsiveness. The PCL/Fe3O4 scaffolds containing different Fe3O4 concentrations were free of cytotoxicity, indicating the good biocompatibility and low cytotoxicity of the scaffolds. The IKVAV-functionalized PCL/Fe3O4 scaffolds were able to guide and promote the directional extension of axons, the application of external magnetic field and the grafting of IKVAV peptides significantly further promoted the growth of DRGs and axons. The ELISA test results showed that the AP-10 F group scaffolds promoted the secretion of nerve growth factor (NGF) from DRG under a static magnetic field (SMF), thus promoting the growth and extension of axons. Importantly, the IKVAV-functionalized PCL/Fe3O4 scaffolds could significantly up-regulate the expression of Cntn2, PCNA, Sox10 and Isca1 genes related to adhesion, proliferation and magnetic receptor function under the stimulation of SMF. Therefore, IKVAV-functionalized PCL/Fe3O4 composite oriented scaffolds have potential applications in neural tissue engineering.

Chitosan-chelated carbon dots-based nanozyme of extreme stability with super peroxidase activity and antibacterial ability for wound healing

Bacterial infection often leads to failed wound healing, causing one-third of death cases globally. However, antibacterial nanomaterials and natural enzymes face limitations including low antibacterial efficiency, lack of catalytic performance, low safety, and instability. Therefore, a new Fe/N-doped chitosan-chelated carbon dot-based nanozyme CS@Fe-N CDs was developed, which showed multiple advantages such as highly efficient antibacterial activity, excellent peroxidase-like activity, high stability, and high biocompatibility, shortening the wound healing time. The ultra-small (6.14 ± 3.38 nm) CS@Fe-N CDs nanozyme accelerated the H2O2 to ·OH conversion, exhibiting excellent antibacterial performance against Staphylococcus aureus. The antibacterial activity was increased by over 2000-fold after catalysis. The CS@Fe-N CDs nanozyme also displayed outstanding peroxidase activity (Vmax/Km = 1.77 × 10-6/s), 8.8-fold higher than horseradish peroxidase. Additionally, the CS@Fe-N CDs nanozyme exhibited high stability at broad pH values (pH 1-12) and temperature ranges (20-90 °C). In vitro evaluation of cell toxicity proved that the CS@Fe-N CDs nanozyme had negligible cytotoxicity. In vivo, wound healing experiments demonstrated that the CS@Fe-N CDs could shorten the healing time of rat wounds by at least 4 days, and even had a better curative effect than penicillin. In conclusion, this therapeutic platform provides an effective antibacterial and biologically safe healing strategy for skin wounds.

Design of bio-scaffold conjugated with chitosan-PEG nano-carriers containing bio-macromolecules of Verbascum sinuatum L. to differentiate human adipose-derived stem cells into dermal keratinocytes

Regenerative medicine and drug delivery systems provide promising approaches for the treatment of skin lesions. However, the design of engineered substrates containing therapeutic agents for cell proliferation and its differentiation into skin cells, with skin-like patterns, is the major challenge. Here, to overcome this problem, a hybrid scaffold conjugated with nanoparticles containing the extract of Verbascum sinuatum L. flowers (HE) was designed. To this end, (chitosan-PEG)-based nanocarriers (Chi-PEG) were first prepared in the volume ratios of 90:10, 80:20, 70:30, and 50:50 v/v. The results indicated that the 70:30 ratio possessed better physical/morphologic properties along with more suitable stability than other nanoparticles (encapsulation-efficiency:86.34 %, zeta-potential:21.2 mV, and PDI:0.30). Afterward, PCL-collagen biologic scaffold (PCL-Coll) were prepared by the lyophilization method, then conjugated with selected nanoparticles(Chi-PEG70:30-HE). Notably, in addition to PCL-Coll/Chi-PEG-HE, two scaffolds of PCL-Coll and PCL-Coll/Chi-PEG were prepared to evaluate the role of conjugation in the release behavior of herbal bio-macromolecules. Based on the results, the conjugation process was led to a more stable release, compared to unconjugated nanoparticles. The mentioned process also created an integrated network along with better physicomechanical properties [modulus:12.31 MPa, tensile strength:4.44 MPa, smaller pore size(2 μm), and better swelling (100.27 %) with a symmetrical wettability on the surface]. PCL-Coll/Chi-PEG-HE scaffold was also resulted in higher expression levels of K10 and K14 keratinocytes with biomimetic patterns than PCL-Coll/Chi-PEG scaffold. This could be due to the active ingredients of V. sinuatum extract like alkaloids, flavonoids, and triterpenoids which imparts the wound healing (anti-inflammatory, anti-bacterial, anti-oxidant) properties to this scaffold. It seems that the use of bioactive materials like herbal extracts, in the form of encapsulated into polymeric nanocarriers, in the structure of engineered scaffolds can be a promising option for regenerating damaged skin without scarring. Hence, this study can provide innovative insights into the combination of two techniques of drug delivery and tissue engineering to design bio-scaffolds containing bioactive molecules with better therapeutic approaches.

Emulsion template fabricated gelatin-based scaffold functionalized by dialdehyde starch complex with antibacterial antioxidant properties for accelerated wound healing

Gelatin and starch are considered as promising sustainable materials for their abundant production and good biodegradability. Efforts have been made to explore their medical application. Herein, scaffolds based on gelatin and starch with a preferred microstructure and antibacterial antioxidant property were fabricated by the emulsion template method. The dialdehyde starch was firstly combined with silver nanoparticles and curcumin to carry out the efficient hybrid antibacterial agent. Then, the gelatin microsphere of appropriate size was prepared by emulsification and gathered by the above agent to obtain gelatin-based scaffolds. The prepared scaffolds showed porous microstructures with high porosity of over 74 % and the preferred pore sizes of ∼65 μm, which is conducive to skin regeneration. Moreover, the scaffolds possessed a good swelling ability of over 640 %, good degradability of over 18 days, excellent blood compatibility, and cell compatibility. The promising antibacterial and antioxidant properties came from the hybrid antibacterial agent were affirmed. As expected, the gelatin-based scaffolds fabricated by the emulsion template method with a preferred microstructure can facilitate more adhered fibroblasts. In summary, gelatin-based scaffolds functionalized by starch-based complex expanded the application of abundant sustainable materials in the biomedical field, especially as antibacterial antioxidant wound dressings.

Self-adaptable calcium-based bioactive phosphosilicate-infused gelatin-hyaluronic hydrogel for orthopedic regeneration

Bone regeneration is a critical and intricate process vital for healing fractures, defects, and injuries. Although conventional bone grafts are commonly used, they may fall short of optimal outcomes, thereby driving the need for alternative therapies. This research endeavors to explore synergistically designed Hyalo Glass Gel (HGG), and its explicitly for bone tissue engineering and regenerative medicine. The HGG composite comprises a modifiable calcium-based bioactive phosphosilicates-incorporated/crosslinked gelatin-hyaluronic scaffold showcasing promising functional characteristics. The study underscores the distinct attributes of each constituent (gelatin (Gel), hyaluronic acid (HA), and 45S5 calcium sodium phosphosilicates (BG)), and their cooperative influences on the scaffold's performance. Careful manipulation of crosslinking methods facilitates customization of HGG's mechanical attributes, degradation kinetics, and structural features, aligning them with the requisites of bone tissue engineering applications. Moreover, the integration of BG augments the scaffold's bioactivity, thereby expediting tissue regenerative processes. This comprehensive evaluation encompasses HGG's physicochemical aspects, mechanical traits rooted in viscoelasticity, as well as its biodegradability, in-vitro bioactivity, and interactions with stem cells. The result obtained underscores the viscoelastic nature of HGG, substantiating its capacity to foster mesenchymal stem cell viability, proliferation, and differentiation. Significantly, HGG manifests biocompatibility and adjustable attributes, exhibits pronounced drug (vancomycin) retention abilities, rendering it apt for wound healing, drug delivery, and bone regeneration. Its distinctive composition, tailored attributes, and mimicry of bone tissue's extracellular matrix (ECM) due to its bioactive nature, collectively situate its potential as a versatile biomaterial for subsequent research and development endeavors with compelling prospects in bone tissue engineering and regenerative medicine.

Development of cobalt-incorporated chitosan scaffold for regenerative potential in human dental pulp stem cells: An in vitro study

The aim of the study was to comparatively evaluate chitosan and Cobalt incorporated chitosan (CoCH) scaffold at varying concentrations in terms of their material characteristics, cytotoxicity and cell adhesion potential. In the present study, cobalt incorporated chitosan scaffolds at varying concentrations were prepared and dried. The synthesised scaffolds were characterised using XRD, FTIR, SEM-EDX and BET which revealed amorphous, porous surface of CoCH scaffolds and FTIR analysis showed the complexation confirming the chelation of cobalt with chitosan. The experimental scaffolds proved to be non-cytotoxic when compared to chitosan scaffolds on XTT analysis. Cell-seeding assay revealed enhanced adherence of hDPSCs to CoCH scaffold at 1:1 ratio in the concentration of 100 mL of 100 μmol/L cobalt chloride solution in 100mL of 2% chitosan solution, when compared to other groups. The results highlighted that 100 μmol/L concentration of cobalt chloride when incorporated in 1:1 ratio into 2 % CH solution yields a promising porous, biocompatible scaffold with enhanced cellular adhesion for dentin-pulp regeneration.

Vitamin D3-incorporated chitosan/collagen/fibrinogen scaffolds promote angiogenesis and endothelial transition via HIF-1/IGF-1/VEGF pathways in dental pulp stem cells

Effective vascularization during wound healing remains a critical challenge in the regeneration of skin tissue. On the other hand, mesenchymal stem cell (MSC) to endothelial phenotype transition (MEnDoT) is a potential phenomenon grossly underexplored in vascularized skin tissue engineering. Vitamin D3 has a proven role in promoting MEnDoT. Hence, a D3-incorporated scaffold made with biocompatible materials such as chitosan, collagen and fibrinogen should be able to promote endothelial lineage transition in vitro for tissue engineering purposes. In this study, we developed vitamin D3 incorporated chitosan-collagen-fibrinogen (CCF-D3) scaffolds physically crosslinked under UV and conducted thorough physicochemical and biological assays on it compared to a control scaffold without vitamin D3. Our study for the first time reports the potential vascularization property of the CCF-D3 scaffold by inducing the transitions of dental pulp MSC to endothelial lineage via the HIF-1/IGF-1/VEGF pathways. MSC seeded on UV-exposed CCF-D3 scaffolds had higher cell viability and transitioned towards endothelial lineage was observed by elevated proliferative and endothelial-specific gene expressions and flow cytometric analysis of SCA-1+ antibody. The difference in VEGF-A and α-SMA expressions was also observed in the D3-CCF scaffold compared to the scaffolds without D3.

Sumecton reinforced gelatin-based scaffolds for cell-free bone regeneration

Bone tissue engineering has risen to tackle the challenges of the current clinical need concerning bone fractures that is already considered a healthcare system problem. Scaffold systems for the repair of this tissue have yielded different combinations including biomaterials with nanotechnology or biological agents. Herein, three-dimensional porous hydrogels were engineered based on gelatin as a natural biomaterial and reinforced with synthetic saponite nanoclays. Scaffolds were biocompatible and shown to enhance the inherent properties of pristine ones, in particular, proved to withstand pressures similar to load-bearing tissues. Studies with murine mesenchymal stem cells found that scaffolds had the potential to proliferate and promote cell differentiation. In vivo experiments were conducted to gain insight about the ability of these cell-free scaffolds to regenerate bone, as well as to determine the role that these nanoparticles in the scaffold could play as a drug delivery system. SDF-1 loaded scaffolds showed the highest percentage of bone formation, which was corroborated by osteogenic markers and new blood vessels. Albeit a first attempt in the field of synthetic nanosilicates, these results suggest that the designed constructs may serve as delivery platforms for biomimetic agents to mend bony defects, circumventing high doses of therapeutics and cell-loading systems.

Novel scaffold platforms for simultaneous induction osteogenesis and angiogenesis in bone tissue engineering: a cutting-edge approach

Despite the recent advances in the development of bone graft substitutes, treatment of critical size bone defects continues to be a significant challenge, especially in the elderly population. A current approach to overcome this challenge involves the creation of bone-mimicking scaffolds that can simultaneously promote osteogenesis and angiogenesis. In this context, incorporating multiple bioactive agents like growth factors, genes, and small molecules into these scaffolds has emerged as a promising strategy. To incorporate such agents, researchers have developed scaffolds incorporating nanoparticles, including nanoparticulate carriers, inorganic nanoparticles, and exosomes. Current paper provides a summary of the latest advancements in using various bioactive agents, drugs, and cells to synergistically promote osteogenesis and angiogenesis in bone-mimetic scaffolds. It also discusses scaffold design properties aimed at maximizing the synergistic effects of osteogenesis and angiogenesis, various innovative fabrication strategies, and ongoing clinical studies.

Cell unit-inspired natural nano-based biomaterials as versatile building blocks for bone/cartilage regeneration

The regeneration of weight-bearing bone defects and critical-sized cartilage defects remains a significant challenge. A wide range of nano-biomaterials are available for the treatment of bone/cartilage defects. However, their poor compatibility and biodegradability pose challenges to the practical applications of these nano-based biomaterials. Natural biomaterials inspired by the cell units (e.g., nucleic acids and proteins), have gained increasing attention in recent decades due to their versatile functionality, compatibility, biodegradability, and great potential for modification, combination, and hybridization. In the field of bone/cartilage regeneration, natural nano-based biomaterials have presented an unparalleled role in providing optimal cues and microenvironments for cell growth and differentiation. In this review, we systematically summarize the versatile building blocks inspired by the cell unit used as natural nano-based biomaterials in bone/cartilage regeneration, including nucleic acids, proteins, carbohydrates, lipids, and membranes. In addition, the opportunities and challenges of natural nano-based biomaterials for the future use of bone/cartilage regeneration are discussed.