Gelatin-polycaprolactone-nanohydroxyapatite electrospun nanocomposite scaffold for bone tissue engineering

Advances in graphene-based 2D materials for tendon, nerve, bone/cartilage regeneration and biomedicine

Two-dimensional (2D) materials, especially graphene-based materials, have important implications for tissue regeneration and biomedicine due to their large surface area, transport properties, ease of functionalization, biocompatibility, and adsorption capacity. Despite remarkable progress in the field of tissue regeneration and biomedicine, there are still problems such as unclear long-term stability, lack of in vivo experimental data, and detection accuracy. This paper reviews recent applications of graphene-based materials in tissue regeneration and biomedicine and discusses current issues and prospects for the development of graphene-based materials with respect to promoting the regeneration of tendons, neuronal cells, bone, chondrocytes, blood vessels, and skin, as well as applications in sensing, detection, anti-microbial activity, and targeted drug delivery.

Current Perspectives of Protein in Bone Tissue Engineering: Bone Structure, Ideal Scaffolds, Fabrication Techniques, Applications, Scopes, and Future Advances

In view of their exceptional approach, excellent inherent biocompatibility and biodegradability properties, and interaction with the local extracellular matrix, protein-based polymers have received attention in bone tissue engineering, which is a multidisciplinary field that repairs and regenerates fractured bones. Bone is a multihierarchical complex structure, and it performs several essential biofunctions, including maintaining mineral balance and structural support and protecting soft organs. Protein-based polymers have gained interest in developing ideal scaffolds as emerging biomaterials for bone fractured healing and regeneration, and it is challenging to design ideal bone substitutes as perfect biomaterials. Several protein-based polymers, including collagen, keratin, gelatin, serum albumin, etc., are potential materials due to their inherent cytocompatibility, controlled biodegradability, high biofunctionalization, and tunable mechanical characteristics. While numerous studies have indicated the encouraging possibilities of proteins in BTE, there are still major challenges concerning their biodegradability, stability in physiological conditions, and continuous release of growth factors and bioactive molecules. Robust scaffolds derived from proteins can be used to replace broken or diseased bone with a biocompatible substitute; proteins, being biopolymers, provide excellent scaffolds for bone tissue engineering. Herein, recent developments in protein polymers for cutting-edge bone tissue engineering are addressed in this review within 3-5 years, with a focus on the significant challenges and future perspectives. The first section discusses the structural fundamentals of bone anatomy and ideal scaffolds, and the second section describes the fabrication techniques of scaffolds. The third section highlights the importance of proteins and their applications in BTE. Hence, the recent development of protein polymers for state-of-the-art bone tissue engineering has been discussed, highlighting the significant challenges and future perspectives.

Platelet-rich fibrin (PRF) modified nano-hydroxyapatite/chitosan/gelatin/alginate scaffolds increase adhesion and viability of human dental pulp stem cells (DPSC) and osteoblasts derived from DPSC

Bone tissue regeneration strategies have incorporated the use of natural polymers, such as hydroxyapatite (nHA), chitosan (CH), gelatin (GEL), or alginate (ALG). Additionally, platelet concentrates, such as platelet-rich fibrin (PRF) have been suggested to improve scaffold biocompatibility. This study aimed to develop scaffolds composed of nHA, GEL, and CH, with or without ALG and lyophilized PRF, to evaluate the scaffold's properties, growth factor release, and dental pulp stem cells (DPSC), and osteoblast (OB) derived from DPSC viability. Four scaffold variations were synthesized and lyophilized. Then, degradation, swelling profiles, and morphological analysis were performed. Furthermore, PDGF-BB and FGF-B growth factors release were quantified by ELISA, and cytotoxicity and cell viability were evaluated. The swelling and degradation profiles were similar in all scaffolds, with pore sizes ranging between 100 and 250 μm. FGF-B and PDGF-BB release was evidenced after 24 h of scaffold immersion in cell culture medium. DPSC and OB-DPSC viability was notably increased in PRF-supplemented scaffolds. The nHA-CH-GEL-PRF scaffold demonstrated optimal physical-biological characteristics for stimulating DPSC and OB-DPSC cell viability. These results suggest lyophilized PRF improves scaffold biocompatibility for bone tissue regeneration purposes.

Advances in strawberry postharvest preservation and packaging: A comprehensive review

Strawberries spoil rapidly after harvest due to factors such as the ripening process, weight loss, and, most importantly, microbial contamination. Traditionally, several methods are used to preserve strawberries after harvest and extend their shelf life, including thermal, plasma, radiation, chemical, and biological treatments. Although these methods are effective, they are a concern from the perspective of safety and consumer acceptance of the treated food. To address these issues, more advanced environment-friendly technologies have been developed over the past decades, including modified and controlled atmosphere packaging, active biopolymer-based packaging, or edible coating formulations. This method can not only significantly extend the shelf life of fruit but also solve safety concerns. Some studies have shown that combining two or more of these technologies can significantly extend the shelf life of strawberries, which could significantly contribute to expanding the global supply chain for delicious fruit. Despite the large number of studies underway in this field of research, no systematic review has been published discussing these advances. This review aims to cover important information about postharvest physiology, decay factors, and preservation methods of strawberry fruits. It is a pioneering work that integrates, relates, and discusses all information on the postharvest fate and handling of strawberries in one place. Additionally, commercially used techniques were discussed to provide insight into current developments in strawberry preservation and suggest future research directions in this field of study. This review aims to enrich the knowledge of academic and industrial researchers, scientists, and students on trends and developments in postharvest preservation and packaging of strawberry fruits.

Coaxial Electrospun Polycaprolactone/Gelatin Nanofiber Membrane Loaded with Salidroside and Cryptotanshinone Synergistically Promotes Vascularization and Osteogenesis

Background

Salidroside (SAL) is the most effective component of Rhodiola rosea, a traditional Chinese medicine. Cryptotanshinone (CT) is the main fat-soluble extract of Salvia miltiorrhiza, exhibiting considerable potential for application in osteogenesis. Herein, a polycaprolactone/gelatin nanofiber membrane loaded with CT and SAL (PSGC membrane) was successfully fabricated via coaxial electrospinning and characterized.

Methods and Results

This membrane capable of sustained and controlled drug release was employed in this study. Co-culturing the membrane with bone marrow mesenchymal stem cells and human umbilical vein endothelial cells revealed excellent biocompatibility and demonstrated osteogenic and angiogenic capabilities. Furthermore, drug release from the PSGC membrane activated the Wnt/β-catenin signaling pathway and promoted osteogenic differentiation and vascularization. Evaluation of the membrane's vascularization and osteogenic capacities involved transplantation onto a rat's subcutaneous area and assessing rat cranium defects for bone regeneration, respectively. Microcomputed tomography, histological tests, immunohistochemistry, and immunofluorescence staining confirmed the membrane's outstanding angiogenic capacity two weeks post-operation, with a higher incidence of osteogenesis observed in rat cranial defects eight weeks post-surgery.

Conclusion

Overall, the SAL- and CT-loaded coaxial electrospun nanofiber membrane synergistically enhances bone repair and regeneration.

New Generation of Osteoinductive and Antimicrobial Polycaprolactone-Based Scaffolds in Bone Tissue Engineering: A Review

With respect to other fields, bone tissue engineering has significantly expanded in recent years, leading not only to relevant advances in biomedical applications but also to innovative perspectives. Polycaprolactone (PCL), produced in the beginning of the 1930s, is a biocompatible and biodegradable polymer. Due to its mechanical and physicochemical features, as well as being easily shapeable, PCL-based constructs can be produced with different shapes and degradation kinetics. Moreover, due to various development processes, PCL can be made as 3D scaffolds or fibres for bone tissue regeneration applications. This outstanding biopolymer is versatile because it can be modified by adding agents with antimicrobial properties, not only antibiotics/antifungals, but also metal ions or natural compounds. In addition, to ameliorate its osteoproliferative features, it can be blended with calcium phosphates. This review is an overview of the current state of our recent investigation into PCL modifications designed to impair microbial adhesive capability and, in parallel, to allow eukaryotic cell viability and integration, in comparison with previous reviews and excellent research papers. Our recent results demonstrated that the developed 3D constructs had a high interconnected porosity, and the addition of biphasic calcium phosphate improved human cell attachment and proliferation. The incorporation of alternative antimicrobials-for instance, silver and essential oils-at tuneable concentrations counteracted microbial growth and biofilm formation, without affecting eukaryotic cells' viability. Notably, this challenging research area needs the multidisciplinary work of material scientists, biologists, and orthopaedic surgeons to determine the most suitable modifications on biomaterials to design favourable 3D scaffolds based on PCL for the targeted healing of damaged bone tissue.

Electrospun medicated gelatin/polycaprolactone Janus fibers for photothermal-chem combined therapy of liver cancer

Liver cancer is a common cancer in the world, and core-shell nanoparticles as a commonly used combination therapy for local tumor ablation, have many shortcomings. In this study, photothermal Janus nanofibers were prepared using a electrospinning technology for tumor treatment, and the products were characterized and in vitro photothermal performance investigated. The micromorphology analysis showed that the photothermic agent CuS and electrospun fibers (loaded with CuS and anticancer drug dihydromyricetin) were successfully prepared, with diameters of 11.58 ± 0.27 μm and 1.19 ± 0.01 μm, respectively. Water contact angle and tensile test indicated that the fiber membranes has a certain hydrophilic adhesion and excellent mechanical strength. The fiber membranes has 808 nm near-infrared laser photothermal heating performance and photothermal stability, and it also has a strong response to the laser that penetrates biological tissue. In addition, in vitro cell culture and in vivo implantation study showed that the fiber membranes could kill HepG2 hepatocellular carcinoma cells combined with photothermal-chem and could be enriched in the implantation area, respectively. Hence, the Janus membranes may be a potential cancer treatment material.

Potential use of a bone tissue engineering scaffold based on electrospun poly (ɛ-caprolactone) - Poly (vinyl alcohol) hybrid nanofibers containing modified cockle shell nanopowder

Today, the construction of scaffolds promoting the differentiation of stem cells is an intelligent innovation that accelerates the differentiation toward the target tissue. The use of calcium and phosphate compounds is capable of elevating the precision and efficiency of the osteogenic differentiation of stem cells. In this research, osteoconductive electrospun poly (ɛ-caprolactone) (PCL) - poly (vinyl alcohol) (PVA) hybrid nanofibrous scaffolds containing modified cockle shell (CS) nanopowder were prepared and investigated. In this regard, the modified CS nanopowder was prepared by grinding and modifying with phosphoric acid, and it was then added to PVA nanofibers at different weight percentages. Based on the SEM images, the optimum content of the modified CS nanopowder was set at 7 wt %, since reaching the threshold of agglomeration restricted this incorporation. In the second step, the PVA-CS7 nanofibrous sample was hybridized with different PCL ratios. Concerning the hydrophilicity and mechanical strength, the sample named PCL50-PVA50-CS7 was ultimately selected as the optimized and suitable candidate scaffold for bone tissue application. The accelerated hydrolytic degradation of the sample was also studied by FTIR and SEM analyses, and the results confirmed that the mineral deposits of CS are available approximately 7 days for mesenchymal stem cells. Moreover, Alizarin red staining illustrated that the presence of CS in the PCL50-PVA50-CS7 hybrid nanofibrous scaffold may potentially lead to an increase in calcium deposits with high precipitates, authenticating the differentiation of stem cells towards osteogenic cells.

Biomimetic gradient scaffolds for the tissue engineering and regeneration of rotator cuff enthesis

Rotator cuff tear is one of the most common musculoskeletal disorders, which often results in recurrent shoulder pain and limited movement. Enthesis is a structurally complex and functionally critical interface connecting tendon and bone that plays an essential role in maintaining integrity of the shoulder joint. Despite the availability of advanced surgical procedures for rotator cuff repair, there is a high rate of failure following surgery due to suboptimal enthesis healing and regeneration. Novel strategies based on tissue engineering are gaining popularity in improving tendon-bone interface (TBI) regeneration. Through incorporating physical and biochemical cues into scaffold design which mimics the structure and composition of native enthesis is advantageous to guide specific differentiation of seeding cells and facilitate the formation of functional tissues. In this review, we summarize the current state of research in enthesis tissue engineering highlighting the development and application of biomimetic scaffolds that replicate the gradient TBI. We also discuss the latest techniques for fabricating potential translatable scaffolds such as 3D bioprinting and microfluidic device. While preclinical studies have demonstrated encouraging results of biomimetic gradient scaffolds, the translation of these findings into clinical applications necessitates a comprehensive understanding of their safety and long-term efficacy.

Biodegradable electrospun poly(L-lactide-co-ε-caprolactone)/polyethylene glycol/bioactive glass composite scaffold for bone tissue engineering

The field of tissue engineering has witnessed significant advancements in recent years, driven by the pursuit of innovative solutions to address the challenges of bone regeneration. In this study, we developed an electrospun composite scaffold for bone tissue engineering. The composite scaffold is made of a blend of poly(L-lactide-co-ε-caprolactone) (PLCL) and polyethylene glycol (PEG), with the incorporation of calcined and lyophilized silicate-chlorinated bioactive glass (BG) particles. Our investigation involved a comprehensive characterization of the scaffold's physical, chemical, and mechanical properties, alongside an evaluation of its biological efficacy employing alveolar bone-derived mesenchymal stem cells. The incorporation of PEG and BG resulted in elevated swelling ratios, consequently enhancing hydrophilicity. Thermal gravimetric analysis confirmed the efficient incorporation of BG, with the scaffolds demonstrating thermal stability up to 250°C. Mechanical testing revealed enhanced tensile strength and Young's modulus in the presence of BG; however, the elongation at break decreased. Cell viability assays demonstrated improved cytocompatibility, especially in the PLCL/PEG+BG group. Alizarin red staining indicated enhanced osteoinductive potential, and fluorescence analysis confirmed increased cell adhesion in the PLCL/PEG+BG group. Our findings suggest that the PLCL/PEG/BG composite scaffold holds promise as an advanced biomaterial for bone tissue engineering.

Laser-assisted synthesis of nano-hydroxyapatite and functionalization with bone active molecules for bone regeneration

The main goal of bone tissue engineering research is to replace the allogenic and autologous bone graft substitutes that can promote bone repair. Owing to excellent biocompatibility and osteoconductivity, hydroxyapatite is in extensive research and high demand for both medical and non-medical applications. Although various methods have been developed for the synthesis of hydroxyapatite, in the present study we have shown the use of nanosecond laser energy in the wet precipitation method of nano-hydroxyapatite (nHAP) synthesis without using ammonium solution or any other chemicals for pH maintenance. Here, the present study aimed to fabricate the nanohydroxyapatite using a nanosecond laser. The X-ray diffraction and Fourier transform infrared spectroscopy have confirmed the hydroxyapatite formation under laser irradiation in less time without aging. A transmission electron microscopy confirmed the nano size of synthesized nHAP, which is comparable to conventional nHAP. The length and width of the laser-assisted nHAP were found to be in the range of 50-200 nm and 15-20 nm, respectively, at various laser parameters. The crystallite size obtained by Debye Scherrer formulae was found to be in the range of ∼ 16-36 nm. In addition, laser-assisted nHAP based composite cryogel (nanohydroxyapatite/gelatin/collagen I) was synthesized and impregnated with bioactive molecules (bone morphogenic protein and zoledronic acid) that demonstrated significant osteogenic potential both in vitro in cell experiment and in vivo rat muscle pouch model (abdomen and tibia muscles). Dual-energy X-ray analysis, micro-CT, and histological analysis confirmed ectopic bone regeneration. Micro-CT based histomorphometry showed a higher amount (more than 10-fold) of mineralization for animal groups implanted with composite cryogels loaded with bioactive molecules compared to only composite cryogels groups. Our findings thus demonstrate a controlled and rapid synthetic method for the synthesis of nHAP with various physical, chemical, and biological properties exhibited as comparable to conventionally synthesized nHAP.

In Vitro Evaluation of Pore Size Graded Bone Scaffolds with Different Material Composition

The demand for biomimetic and biocompatible scaffolds in equivalence of structure and material composition for the regeneration of bone tissue is relevantly high. This article is investigating a novel three-dimensional (3D) printed porous structure called bone bricks with a gradient pore size mimicking the structure of the bone tissue. Poly-ɛ-caprolactone (PCL) combined with ceramics such as hydroxyapatite (HA), β-tricalcium phosphate (TCP), and bioglass 45S5 were successfully mixed using a melt blending method and fabricated with the use of screw-assisted extrusion-based additive manufacturing system. Bone bricks containing the same material concentration (20 wt%) were biologically characterized through proliferation and differentiation tests. Scanning electron microscopy (SEM) was used to investigate the morphology of cells on the surface of bone bricks, whereas energy dispersive X-ray (EDX) spectroscopy was used to investigate the element composition on the surface of the bone bricks. Confocal imaging was used to investigate the number of differentiated cells on the surface of bone bricks. Proliferation results showed that bone bricks containing PCL/HA content are presenting higher proliferation properties, whereas differentiation results showed that bone bricks containing PCL/Bioglass 45S5 are presenting higher differentiation properties. Confocal imaging results showed that bone bricks containing PCL/Bioglass 45S5 are presenting a higher number of differentiated cells on their surface compared with the other material contents.

Nanoengineered oxygen-releasing polymeric scaffold with sustained release of dexamethasone for bone regeneration

Maintaining the continuous oxygen supply and proper cell growth before blood vessel ingrowth at the bone defect site are considerably significant issues in bone regeneration. Oxygen-producing scaffolds can supply oxygen and avoid hypoxia leading to expedited bone regeneration. Herein, first oxygen-producing calcium peroxide nanoparticles (CPO NPs) are synthesized, and subsequently, the various amounts of synthesized CPO NPs (0.1, 0.5, and 1 wt/v%) loaded in the scaffold composite, which is developed by simple physical blending of chitosan (CS) and polycaprolactone (PCL) polymers. To deliver the synergistic therapeutic effect, dexamethasone (DEX), known for its potential anti-inflammatory and osteogenic properties, is loaded into the nanocomposite scaffolds. The extensive physicochemical characterizations of nanocomposite scaffolds confirm the successful loading of CPO NPs, adequate porous morphology, pore size, hydrophilicity, and biodegradability.In vitro, biological studies support the antibacterial, hemocompatible, and cytocompatible (MG-63 and MC3T3-E1 cells) nature of the material when tested on respective cells. Field emission scanning electron microscopy and energy-dispersive x-ray spectroscopy confirm the successful biomineralization of the scaffolds. Scaffolds also exhibit the sustained release of DEX and efficient protein adsorption. This study revealed that a nanoengineered scaffold loaded with CPO NPs (PCL/CS/DEX/CPO 3) is a suitable candidate for bone tissue regeneration.

Characterization and in vitro bioactivity evaluation of polyvinyl alcohol incorporated electro spun chitosan/ fluor apatite nanofibrous scaffold for bone tissue engineering

In this study, polyvinyl alcohol/chitosan/fluor apatite scaffolds with different concentrations of polyvinyl alcohol of 0.075 g ml-1 and 0.1 g ml-1, respectively named A and B fabricated by electrospinning method to use in tissue engineering. By examining the scaffolds by FE-SEM, an appetite layer formation which was on the scaffold surface was clearly observable. Increasing the concentration of polyvinyl alcohol from 0.075 g ml-1 to 0.1 g ml-1 in the nanofibrous scaffolds improved degradation characteristic with an optimized value of 26 ± 2 and 42 ± 1 % after 28 days, respectively. The mean diameter of fibers both scaffolds was 405 nm and 212 nm, respectively. Furthermore, the percentage of porosity in both scaffolds was calculated as 84% and 91%, separately. The level of hydrophilicity of the scaffolds was measured by the dynamic contact angle method. Moreover, the increase in the percentage of polyvinyl alcohol led to the decrease in the average contact angle in scaffold A and scaffold B from 90° to 70°, respectively. The results of bone marrow culture test with MG-63 (NCBI C555) cell on the surface of scaffolds demonstrated not cytotoxicity in the resulting scaffolds as well as a suitable substrate for the adhesion and growth of the cells. According to our findings, the electrospun fluorapatite-incorporated-chitosan/polyvinyl alcohol scaffold could provide a new nanocomposite for biomedical applications.

A comprehensive review on nanocomposite biomaterials based on gelatin for bone tissue engineering

The creation of a suitable scaffold is a crucial step in the process of bone tissue engineering (BTE). The scaffold, acting as an artificial extracellular matrix, plays a significant role in determining the fate of cells by affecting their proliferation and differentiation in BTE. Therefore, careful consideration should be given to the fabrication approach and materials used for scaffold preparation. Natural polypeptides such as gelatin and collagen have been widely used for this purpose. The unique properties of nanoparticles, which vary depending on their size, charge, and physicochemical properties, have demonstrated potential in solving various challenges encountered in BTE. Therefore, nanocomposite biomaterials consisting of polymers and nanoparticles have been extensively used for BTE. Gelatin has also been utilized in combination with other nanomaterials to apply for this purpose. Composites of gelatin with various types of nanoparticles are particularly promising for creating scaffolds with superior biological and physicochemical properties. This review explores the use of nanocomposite biomaterials based on gelatin and various types of nanoparticles together for applications in bone tissue engineering.

Ethyl cellulose/gelatin/β-cyclodextrin/curcumin nanofibrous membrane with antibacterial and formaldehyde adsorbable capabilities for lightweight and high-performance air filtration

Functionalization of bio-based nanofibers is the development tendency of high-performance air filter. However, the conventional structural optimization strategy based on high solution conductivity greatly hinders the development of fully bio-based air filter, and not conducive to sustainable development. This work fabricated fully bio-based nanofibrous membrane with formaldehyde-adsorbable and antibacterial capabilities by electrospinning low-conductivity solution for high-performance air filtration and applied to lightweight mask. The "water-like" ethyl cellulose (EC) was selected as the base polymer to "nourish" functional materials of gelatin (GE), β-cyclodextrin (βCD), and curcumin (Cur), thus forming a solution system with high binding energy differences and electrospinning into ultrafine bimodal nanofibers. The filtration efficiency for 0.3 μm NaCl particles, pressure drop, and quality factor were 99.25 %, 53 Pa, and 0.092 Pa-1, respectively; the bacteriostatic rates against Escherichia coli and Staphylococcus aureus were 99.9 % and 99.4 %, respectively; the formaldehyde adsorption capacity was 442 μg/g. This is the first report on antibacterial and formaldehyde-adsorbable high-performance air filter entirely made from bio-based materials. This simple strategy will greatly broaden the selection of materials for preparing high-performance multifunctional air filter, and promote the development of bio-based air filter.

In Vitro Investigation of Gelatin/Polycaprolactone Nanofibers in Modulating Human Gingival Mesenchymal Stromal Cells

The aesthetic constancy and functional stability of periodontium largely depend on the presence of healthy mucogingival tissue. Soft tissue management is crucial to the success of periodontal surgery. Recently, synthetic substitute materials have been proposed to be used for soft tissue augmentation, but the tissue compatibility of these materials needs to be further investigated. This study aims to assess the in vitro responses of human gingival mesenchymal stromal cells (hG-MSCs) cultured on a Gelatin/Polycaprolactone prototype (GPP) and volume-stable collagen matrix (VSCM). hG-MSCs were cultured onto the GPP, VSCM, or plastic for 3, 7, and 14 days. The proliferation and/or viability were measured by cell counting kit-8 assay and resazurin-based toxicity assay. Cell morphology and adhesion were evaluated by microscopy. The gene expression of collagen type I, alpha1 (COL1A1), α-smooth muscle actin (α-SMA), fibroblast growth factor (FGF-2), vascular endothelial growth factor A (VEGF-A), transforming growth factor beta-1 (TGF-β1), focal adhesion kinase (FAK), integrin beta-1 (ITG-β1), and interleukin 8 (IL-8) was investigated by RT-qPCR. The levels of VEGF-A, TGF-β1, and IL-8 proteins in conditioned media were tested by ELISA. GPP improved both cell proliferation and viability compared to VSCM. The cells grown on GPP exhibited a distinct morphology and attachment performance. COL1A1, α-SMA, VEGF-A, FGF-2, and FAK were positively modulated in hG-MSCs on GPP at different investigation times. GPP increased the gene expression of TGF-β1 but had no effect on protein production. The level of ITG-β1 had no significant changes in cells seeded on GPP at 7 days. At 3 days, notable differences in VEGF-A, TGF-β1, and α-SMA expression levels were observed between cells seeded on GPP and those on VSCM. Meanwhile, GPP showed higher COL1A1 expression compared to VSCM after 14 days, whereas VSCM demonstrated a more significant upregulation in the production of IL-8. Taken together, our data suggest that GPP electrospun nanofibers have great potential as substitutes for soft tissue regeneration in successful periodontal surgery.

Resorbable GBR Scaffolds in Oral and Maxillofacial Tissue Engineering: Design, Fabrication, and Applications

Guided bone regeneration (GBR) is a promising technique in bone tissue engineering that aims to replace lost or injured bone using resorbable scaffolds. The promotion of osteoblast adhesion, migration, and proliferation is greatly aided by GBR materials, and surface changes are critical in imitating the natural bone structure to improve cellular responses. Moreover, the interactions between bioresponsive scaffolds, growth factors (GFs), immune cells, and stromal progenitor cells are essential in promoting bone regeneration. This literature review comprehensively discusses various aspects of resorbable scaffolds in bone tissue engineering, encompassing scaffold design, materials, fabrication techniques, and advanced manufacturing methods, including three-dimensional printing. In addition, this review explores surface modifications to replicate native bone structures and their impact on cellular responses. Moreover, the mechanisms of bone regeneration are described, providing information on how immune cells, GFs, and bioresponsive scaffolds orchestrate tissue healing. Practical applications in clinical settings are presented to underscore the importance of these principles in promoting tissue integration, healing, and regeneration. Furthermore, this literature review delves into emerging areas of metamaterials and artificial intelligence applications in tissue engineering and regenerative medicine. These interdisciplinary approaches hold immense promise for furthering bone tissue engineering and improving therapeutic outcomes, leading to enhanced patient well-being. The potential of combining material science, advanced manufacturing, and cellular biology is showcased as a pathway to advance bone tissue engineering, addressing a variety of clinical needs and challenges. By providing this comprehensive narrative, a detailed, up-to-date account of resorbable scaffolds' role in bone tissue engineering and their transformative potential is offered.

Biocomposite-based strategies for dental bone regeneration

OBJECTIVE

Because of the anatomical complexity of the oral and maxillofacial sites, repairing bone defects in these regions is very difficult. This review article aims to consider the application of biocomposites-based strategies for dental bone regeneration.

STUDY DESIGN

Research papers related to the topic, published over the last 20 years, were selected using the Web of Science, Pubmed, Scopus, and Google Scholar databases.

RESULTS

The strategies of monophasic, biphasic/multiphasic scaffolds, and biopolymer-based nanocomposite scaffolds containing nanomaterials compared with traditional methods used for bone regeneration, such as autografts, allografts, xenografts, and alloplasts are found to be superior because of their ability to overcome the issues (e.g., limited bone sources, pain, immune responses, high cost) related to the applications of the traditional methods.

CONCLUSIONS

In addition, additive manufacturing technologies were found to be highly advantageous for improving the efficacy of biocomposite scaffolds for treating dental bone defects.

Dual cross-linked gellan gum/gelatin-based multifunctional nanocomposite hydrogel scaffold for full-thickness wound healing

Biological macromolecules are excellent materials for wound dressing owing to their similar structure to the extracellular matrix and adjustable physicochemical properties. This research focuses on fabricating biological macromolecule-based hydrogel with desirable antibacterial, antioxidant, controlled drug release, cytocompatibility, and wound healing properties. Herein, different concentrations of nanoceria (NC) and flurbiprofen (FLU) drug-loaded gellan gum/gelatin (GG/Ge) based dual crosslinked (Ionic and EDC/NHS coupling) hydrogels were engineered. All fabricated hydrogels were hydrophilic, biodegradable, good strength, porous, antioxidant, hemocompatible and cytocompatible. Among all, hydrogel loaded with 500 μg/ml NC (GG/Ge/NC@FLU) exhibited desirable antioxidant, antibacterial (killed Staphylococcus aureus and Escherichia coli within 12 h), hemocompatible, cytocompatible, supports oxidative-stressed L929 cell growth and acted as a controlled release matrix for FLU, following Fickian diffusion, Peppas Sahlin and Korsmeyer-Peppas drug release models. Furthermore, nanocomposite hydrogel (GG/Ge/NC@FLU)-treated wounds of rats on day 14 demonstrated significantly higher collagen synthesis, nearly 100 % wound contractions, and efficiently decreased the expression of TNF-α and IL-1 while increasing the production of IL-10 and TNF-ß3, indicating antiinflammatory activity, and effectively reduced the expression of VEGF gene indicating effective angiogenesis than all other controls. In conclusion, the fabricated multifunctional GG/Ge/NC@FLU nanocomposite hydrogel shows promising potential for effectively treating full-thickness wound healing in a rat model.

Influence of mechanochemically fabricated nano-hardystonite reinforcement in polycaprolactone scaffold for potential use in bone tissue engineering: Synthesis and characterization

Bone tissue engineering (BTE) has gained significant attention for the regeneration of bone tissue, particularly for critical-size bone defects. The aim of this research was first to synthesize nanopowders of hardystonite (HT) through ball milling and then to manufacture composite scaffolds for BTE use out of polycaprolactone (PCL) containing 0, 3, 5, and 10 wt% HT by electrospinning method. The crystallite size of the synthesized HT nanopowders was 42.8 nm. including up to 5 wt% HT into PCL scaffolds resulted in significant improvements, such as a reduction in the fiber diameter from 186.457±15.74 to 150.021±21.99 nm, a decrease in porosity volume from 85.2±2.5 to 80.3±3.3 %, an improvement in the mechanical properties (ultimate tensile strength: 5.7±0.2 MPa, elongation: 47.5±3.5 %, tensile modulus: 32.7±0.9 MPa), an improvement in the hydrophilicity, and biodegradability. Notably, PCL/5%HT exhibited the maximum cell viability (194±14 %). Additionally, following a 4-week of submersion in simulated body fluid (SBF), the constructed PCL/HT composite scaffolds showed a remarkable capacity to stimulate the development of hydroxyapatite (HA), which increased significantly for the 5 wt% HT scaffolds. However, at 10 wt% HT, nanopowder agglomeration led to an increase in the fiber diameter and a decrease in the mechanical characteristics. Collectively, the PCL/5%HT composite scaffolds can therefore help with the regeneration of the critical-size bone defects and offer tremendous potential for BTE applications.

Controlling differentiation of stem cells via bioactive disordered cues

Ideal bone tissue engineering is to induce bone regeneration through the synergistic integration of biomaterial scaffolds, bone progenitor cells, and bone-forming factors. Biomimetic scaffolds imitate the native extracellular matrix (ECM) and are often utilized in vitro as analogues of the natural ECM to facilitate investigations of cell-ECM interactions and processes. In vivo, the cellular microenvironment has a crucial impact on regulating cell behavior and functions. A PET surface was activated and then functionalized with mimetic peptides to promote human mesenchymal stem cell (hMSC) adhesion and differentiation into an osteogenic lineage. Spray technology was used to randomly micropattern peptides (RGD and BMP-2 mimetic peptides) on the PET surface. The distribution of the peptides grafted on the surface, the roughness of the surfaces and the chemistry of the surfaces in each step of the treatment were ascertained by atomic force microscopy, fluorescence microscopy, time-of-flight secondary ion mass spectrometry, Toluidine Blue O assay, and X-ray photoelectron spectroscopy. Subsequently, cell lineage differentiation was evaluated by quantifying the expression of immunofluorescence markers: osteoblast markers (Runx-2, OPN) and osteocyte markers (E11, DMP1, and SOST). In this article, we hypothesized that a unique combination of bioactive micro/nanopatterns on a polymer surface improves the rate of morphology change and enhances hMSC differentiation. In DMEM, after 14 days, disordered micropatterned surfaces with RGD and BMP-2 led to a higher osteoblast marker expression than surfaces with a homogeneous dual peptide conjugation. Finally, hMSCs cultured in osteogenic differentiation medium (ODM) showed accelerated cell differentiation. In ODM, our results highlighted the expression of osteocyte markers when hMSCs were seeded on PET surfaces with random micropatterns.

Investigation of osteogenesis and angiogenesis in perfusion bioreactors using improved multi-layer PCL-nHA-nZnO electrospun scaffolds

PURPOSE

Bone tissue engineering aims to create a three-dimensional, matured, angiogenic scaffold with a suitable thickness that resembles a natural bone matrix. On the other hand, electrospun fibers, which researchers have considered due to their good biomimetic properties, are considered 2D structures. Due to the highly interwoven network and small pore size, achieving the desired thickness for bone lesions has always been challenging. In bone tissue engineering, bioreactors are crucial for achieving initial tissue maturity and introducing certain signals as flow parameters for differentiation.

METHODS

In the present study, Human bone marrow mesenchymal stem cells (hBMSCs) and human umbilical vein endothelial cells (HUVECs) were co-cultured in a perfusion bioreactor on treated (improved pore size by gelatin sacrification and subsequent ultrasonication) 5-layer polycaprolactone-nano hydroxyapatite-nano zinc oxide (T-PHZ) scaffolds to investigate osteogenesis and angiogenesis simultaneously. The flow parameters and stresses on the cells were studied using two patterns of parallel and vertical scaffolds relative to the flow of the culture medium. In dynamic vertical flow (DVF), the culture medium flows perpendicular to the scaffolds, and in dynamic parallel flow (DPF), the culture medium flows parallel to the scaffolds. In all evaluations, static samples (S) served as the control group.

RESULTS

Live/dead, and MTT assays demonstrated the biocompatibility of the 5-layer scaffolds and the suitability of the bioreactor's functional conditions. ALP activity, EDAX analysis, and calcium content measurements exhibited greater osteogenesis for T-PHZ scaffolds in DVF conditions. Calcium content increased by a factor of 2.2, 1.8, and 1.6 during days 7 to 14 of culture under DVF, DPF and S conditions, respectively. After 21 days of co-culturing, an immunohistochemistry (IHC) test was performed to investigate angiogenesis and osteogenesis. Five antibodies were investigated in DVF, CD31, VEGFA, and VEGFR2 for angiogenesis, osteocalcin, and RUNX2 for osteogenesis. Compressive stress applied in DVF mode has increased osteogenic activity compared to DPF.

CONCLUSION

The results indicated the development of ideal systems for osteogenesis and angiogenesis on the treated multilayer electrospun scaffolds in the perfusion bioreactor.

Static adsorption and photocatalytic degradation of amoxicillin using titanium dioxide/hydroxyapatite nanoparticles based on sea scallop shells

The objective of this study is to investigate the efficiency of two processes for the amoxicillin removal through static (batch) adsorption and photocatalytic degradation onto the prepared samples. Three solid materials as photocatalyst and/or adsorbent were synthesized viz. nanotitanium dioxide (NT) prepared by the sol-gel method, scallop shells-based nanohydroxyapatite (NP), and nanotitanium dioxide/nanohydroxyapatite composite (NTP). The physicochemical and morphological properties of the prepared samples were tested by TGA, XRD, DRS, ATR-FTIR, nitrogen adsorption/desorption isotherm, zeta potential, SEM, and TEM. The major operational conditions were optimized for catalyst or adsorbent mass, pH, shaking time, initial amoxicillin (AMX) concentration, power of UV lamp, and temperature. The results illuminated that NTP achieved the highest adsorption capacity (88.46 mg/g) at 20 ℃ and AMX adsorption onto all the solid materials was well applied by Langmuir, Temkin, pseudo-second order, and Elovich models. The maximum desorption percent (98%) was attained by acetone. The degradation percent of AMX reached 85.3 and 99.5% for NT and NTP, respectively, using 0.9 g/L of catalyst dosage through 90 min. AMX photodegradation onto the catalysts' surface was well fitted by Langmuir-Hinshelwood, Arrhenius, and Eyring-Polanyi models with endothermic, physical, and nonspontaneous nature of photocatalysis process. NTP acts as a promising adsorbent and photocatalyst for the antibiotics' removal in wastewater.

Recent advances on 3D-printed PCL-based composite scaffolds for bone tissue engineering

Population ageing and various diseases have increased the demand for bone grafts in recent decades. Bone tissue engineering (BTE) using a three-dimensional (3D) scaffold helps to create a suitable microenvironment for cell proliferation and regeneration of damaged tissues or organs. The 3D printing technique is a beneficial tool in BTE scaffold fabrication with appropriate features such as spatial control of microarchitecture and scaffold composition, high efficiency, and high precision. Various biomaterials could be used in BTE applications. PCL, as a thermoplastic and linear aliphatic polyester, is one of the most widely used polymers in bone scaffold fabrication. High biocompatibility, low cost, easy processing, non-carcinogenicity, low immunogenicity, and a slow degradation rate make this semi-crystalline polymer suitable for use in load-bearing bones. Combining PCL with other biomaterials, drugs, growth factors, and cells has improved its properties and helped heal bone lesions. The integration of PCL composites with the new 3D printing method has made it a promising approach for the effective treatment of bone injuries. The purpose of this review is give a comprehensive overview of the role of printed PCL composite scaffolds in bone repair and the path ahead to enter the clinic. This study will investigate the types of 3D printing methods for making PCL composites and the optimal compounds for making PCL composites to accelerate bone healing.

Overview of Electrospinning for Tissue Engineering Applications

Tissue engineering (TE) is an emerging field of study that incorporates the principles of biology, medicine, and engineering for designing biological substitutes to maintain, restore, or improve tissue functions with the goal of avoiding organ transplantation. Amongst the various scaffolding techniques, electrospinning is one of the most widely used techniques to synthesise a nanofibrous scaffold. Electrospinning as a potential tissue engineering scaffolding technique has attracted a great deal of interest and has been widely discussed in many studies. The high surface-to-volume ratio of nanofibres, coupled with their ability to fabricate scaffolds that may mimic extracellular matrices, facilitates cell migration, proliferation, adhesion, and differentiation. These are all very desirable properties for TE applications. However, despite its widespread use and distinct advantages, electrospun scaffolds suffer from two major practical limitations: poor cell penetration and poor load-bearing applications. Furthermore, electrospun scaffolds have low mechanical strength. Several solutions have been offered by various research groups to overcome these limitations. This review provides an overview of the electrospinning techniques used to synthesise nanofibres for TE applications. In addition, we describe current research on nanofibre fabrication and characterisation, including the main limitations of electrospinning and some possible solutions to overcome these limitations.

PCL and DMSO2 Composites for Bio-Scaffold Materials

Polycaprolactone (PCL) has been one of the most popular biomaterials in tissue engineering due to its relatively low melting temperature, excellent thermal stability, and cost-effectiveness. However, its low cell attraction, low elastic modulus, and long-term degradation time have limited its application in a wide range of scaffold studies. Dimethyl sulfone (DMSO₂) is a stable and non-hazardous organosulfur compound with low viscosity and high surface tension. PCL and DMSO₂ composites may overcome the limitations of PCL as a biomaterial and tailor the properties of biocomposites. In this study, PCL and DMSO₂ composites were investigated as a new bio-scaffold material to increase hydrophilicity and mechanical properties and tailor degradation properties in vitro. PCL and DMSO₂ were physically mixed with 10, 20, and 30 wt% of DMSO₂ to evaluate thermal, hydrophilicity, mechanical, and degradation properties of the composites. The water contact angle of the composites for hydrophilicity decreased by 15.5% compared to pure PCL. The experimental results showed that the mechanical and degradation properties of PCL and DMSO₂ were better than those of pure PCL, and the properties can be tuned by regulating DMSO2 concentration in the PCL matrix. The elastic modulus of the composite with 30 wt% of DMSO2 showed 532 MPa, and its degradation time was 18 times faster than that of PCL.

Surgical cotton microfibers loaded with proteins and apatite: A potential platform for bone tissue engineering

Tissue engineering has emerged as the best alternative to replacing damaged tissue/organs. However, the cost of scaffold materials continues to be a significant obstacle; thus, developing inexpensive scaffolds is strongly encouraged. In this study, cellulose microfibers (C), gelatin (G), egg white (EW), and nanohydroxyapatite (nHA) were assembled into a quaternary scaffold using EDC-NHS crosslinking, followed by freeze-drying method. Cellulose microfibers as a scaffold have only received a limited amount of research due to the absence of an intrinsic three-dimensional structure. Gelatin, more likely to interact chemically with collagen, was used to provide a stable structure to the cellulose microfibers. EW was supposed to provide the scaffold with numerous cell attachment sites. nHA was chosen to enhance the scaffold's bone-bonding properties. Physico-chemical, mechanical, and biological characterization of scaffolds were studied. In-vitro using MG-63 cells and in-ovo studies revealed that all scaffolds were biocompatible. The results of the DPPH assay demonstrate the ability of CGEWnHA to reduce free radicals. The CGEWnHA scaffold exhibits the best properties with 56.84 ± 28.45 μm average pore size, 75 ± 1.4 % porosity, 39.23 % weight loss, 109.19 ± 0.98 kPa compressive modulus, and 1.72 Ca/P ratio. As a result, the constructed CGEWnHA scaffold appears to be a viable choice for BTE applications.

Fabrication, characterization and biological properties evaluation of bioactive scaffold based on mineralized carbon nanofibers

Tissue engineering as an innovative approach aims to combine engineering, biomaterials and biomedicine to eliminate the drawbacks of conventional bone defect treatment. In the current study, we fabricated bioengineered electroactive and bioactive mineralized carbon nanofibers as the scaffold for bone tissue engineering applications. The scaffold was fabricated using the sol-gel method and thoroughly characterized by SEM imaging, EDX analysis and a 4-point probe. The results showed that the CNFs have a diameter of 200 ± 19 nm and electrical conductivity of 1.02 ± 0.12 S cm-1. The in vitro studies revealed that the synthesized CNFs were osteoactive and supported the mineral crystal deposition. The hemolysis study confirmed the hemocompatibility of the CNFs and cell viability/proliferation sassy using an MTT assay kit showed the proliferative activities of mineralized CNFs. In conclusion, this study revealed that the mineralized CNFs synthesized by the combination of sol-gel and electrospinning techniques were electroactive, osteoactive and biocompatible, which can be considered an effective bone tissue engineering scaffold.Communicated by Ramaswamy H. Sarma.

Gelatin/monetite electrospun scaffolds to regenerate bone tissue: Fabrication, characterization, and in-vitro evaluation

This work is dedicated to combining nanotechnology with bone tissue engineering to prepare and characterize electrospun gelatin/monetite nanofibrous scaffold with improved physicochemical, mechanical, and biological properties. Nanofibrous scaffolds possessing fiber diameter in the range of 242-290 nm were prepared after incorporating varying content of monetite nanoparticles up to 7 wt % into the gelatin matrix using the electrospinning technique. Cross-linking of gelatin chains in the scaffold was performed using 0.25 wt% glutaraldehyde as indicated by imine (-CN-) bond formation in the FTIR analysis. With an increase in monetite addition up to 7 wt%, a decrease in swelling ratio and bio-degradability of cross-linked gelatin scaffolds was observed. Gelatin scaffold with 7 wt% monetite content registered the highest values of tensile strength and tensile modulus of 18.8 MPa and 170 MPa, as compared to 0% and 5 wt% monetite containing scaffolds respectively. Cell viability and differentiation were studied after culturing MG-63 cells onto the scaffolds from confocal microscopy of live and dead cells images, MTT assay, and alkaline phosphatase assay for a cell culture period of up to 21 days. It was observed that 7 wt % monetite containing gelatin scaffold exhibited better MG-63 cell adhesion, proliferation, higher biomineralization, and ALP activity compared to 0% and 5 wt% monetite containing electrospun scaffolds studied here.

Recent advances on bioactive baghdadite ceramic for bone tissue engineering applications: 20 years of research and innovation (a review)

Various artificial bone graft substitutes based on ceramics have been developed over the last 20 years. Among them, calcium-silicate-based ceramics, which are osteoconductive and can attach directly to biological organs, have received great attention for bone tissue engineering applications. However, the degradation rate of calcium-silicate and bone formation is often out of balance, resulting in stress shielding (osteopenia). A new strategy to improve the drawbacks of these ceramics is incorporating trace elements such as Zn, Mg, and Zr into their lattice structures, enhancing their physical and biological properties. Recently, baghdadite (Ca₃ZrSi₂O₉) ceramic, one of the most appealing calcium-silicate-based ceramics, has demonstrated high bioactivity, biocompatibility, biodegradability, and cell interaction. Because of its physical, mechanical, and biological properties and ability to be shaped using various fabrication techniques, baghdadite has found high potential in various biomedical applications such as coatings, fillers, cement, scaffolds, and drug delivery systems. Undoubtedly, there is a high potential for this newly developed ceramic to contribute significantly to therapies to provide a tremendous clinical outcome. This review paper aims to summarize and discuss the most relevant studies performed on baghdadite-based ceramics and composites by focusing on their behavior in vivo and in vitro.

Design strategies for composite matrix and multifunctional polymeric scaffolds with enhanced bioactivity for bone tissue engineering

Over the past few decades, various bioactive material-based scaffolds were investigated and researchers across the globe are actively involved in establishing a potential state-of-the-art for bone tissue engineering applications, wherein several disciplines like clinical medicine, materials science, and biotechnology are involved. The present review article's main aim is to focus on repairing and restoring bone tissue defects by enhancing the bioactivity of fabricated bone tissue scaffolds and providing a suitable microenvironment for the bone cells to fasten the healing process. It deals with the various surface modification strategies and smart composite materials development that are involved in the treatment of bone tissue defects. Orthopaedic researchers and clinicians constantly focus on developing strategies that can naturally imitate not only the bone tissue architecture but also its functional properties to modulate cellular behaviour to facilitate bridging, callus formation and osteogenesis at critical bone defects. This review summarizes the currently available polymeric composite matrices and the methods to improve their bioactivity for bone tissue regeneration effectively.

Frontiers of Hydroxyapatite Composites in Bionic Bone Tissue Engineering

Bone defects caused by various factors may cause morphological and functional disorders that can seriously affect patient's quality of life. Autologous bone grafting is morbid, involves numerous complications, and provides limited volume at donor site. Hence, tissue-engineered bone is a better alternative for repair of bone defects and for promoting a patient's functional recovery. Besides good biocompatibility, scaffolding materials represented by hydroxyapatite (HA) composites in tissue-engineered bone also have strong ability to guide bone regeneration. The development of manufacturing technology and advances in material science have made HA composite scaffolding more closely related to the composition and mechanical properties of natural bone. The surface morphology and pore diameter of the scaffold material are more important for cell proliferation, differentiation, and nutrient exchange. The degradation rate of the composite scaffold should match the rate of osteogenesis, and the loading of cells/cytokine is beneficial to promote the formation of new bone. In conclusion, there is no doubt that a breakthrough has been made in composition, mechanical properties, and degradation of HA composites. Biomimetic tissue-engineered bone based on vascularization and innervation show a promising future.

Fabrication and investigating in vivo wound healing property of coconut oil loaded nanofiber/hydrogel hybrid scaffold

Obtaining a sustainable drug delivery system is a challenging issue in biomedical science. This became even more important in the wound regeneration process due to its long treatment process. In this study, the calcium alginate (CaAlg) hydrogel is coated on the surface of polycaprolactone (PCL)/gelatin (Gel) nanofibers containing coconut oil (CO) using the impregnation method. The physical, chemical, and morphological properties of produced samples are investigated using different characterization techniques to verify the influence of hydrogel. Water contact angle, swelling ratio, and water vapor permeability measurements are used to evaluate the effect of hydrogel on the hydrophilicity of the proposed system. The cell viability test showed that the nanocomposite hydrogel is biocompatible and could improve wound healing. According to drug release studies, hydrogel addition to the nanofiber system plays an essential role in controlling CO release rate in the first 250 h. In vivo studies also indicated faster skin regeneration.

Dexamethasone loaded injectable, self-healing hydrogel microspheresbased on UPy-functionalized Gelatin/ZnHAp physical network promotes bone regeneration

Biopolymer-based injectable hydrogels provide great potential as bone tissue engineering (BTE) scaffolds on account of biocompatibility, and pore interconnectivity that enables delivery of cells and/or signaling molecules for bone repair. Recently, Gelatin hydrogels based on H-bonds were considered in response to concerns around the chemical crosslinking agents. In this study, a self-healing gelatin hydrogel with remarkable compressive and self-healing properties was prepared via formation of quadruple hydrogen bonds between ureidopyrimidinon functional groups, which were substituted on NH₂ groups of gelatin(GelUPy). Degree of substitution controls properties of the resulting hydrogel from a shape- memory hydrogel (100% substitution), to a hydrogel (about 80%), to this self-healing hydrogel (about 40%). We report a strategy that adopts an emulsion synthesis approach to delivery of dexamethasone and Ca/Zn ions from injectable self-healing GelUPy hydrogel (GelUPy-ZnHApUPy-DEX), to induce osteogenic differentiation of adipose-derived stem cells, in vitro, and enhance bone regeneration in a cranial bone defect in a rat model. We show that key properties of the composite hydrogels, including mechanical properties, and release behavior of DEX are a match to the requirements of BTE. Overall, our results demonstrate that this self-healing gelatin approach is a promising strategy to enhance bone regeneration through a minimally invasive procedure.

Gelatin-hydroxyapatite Fibrous Nanocomposite for Regenerative Dentistry and bone Tissue Engineering

Aims:

This study aimed to prepare and physicochemically evaluate as well as assess the cytotoxicity and stimulation of early osteogenic differentiation of dental pulp stem cells of gelatin-hydroxyapatite (Gel-HA) fibrous nanocomposite scaffold.

Background:

Recently, the electrospinning approach in nanotechnology has been considered due to its application in the preparation of biomimetic nanofibers for tissue engineering.

Objective:

The main objective of this study was to evaluate Gel-HA fibrous nanocomposite for regenerative dentistry and bone tissue engineering material.

Methods:

The nano-scaffold was prepared via the electrospinning method. Then, the physicochemical properties (particle size, surface charge, morphology, hydrophilicity, specific surface area, crystalline state and the characterization of functional groups) and the proliferative effects of nano-scaffolds on dental pulp stem cells were assessed. The alkaline phosphatase activity was assessed for evaluation of early osteogenic differentiation of dental pulp stem cells.

Results:

The prepared nano-scaffolds had a negative surface charge (-30 mv±1.3), mono-dispersed nano-scale diameter (98 nm±1.2), crystalline state and fibrous uniform morphology without any bead (structural defects). The nanofibrous scaffold showed increased hydrophobicity compared to gelatin nanofibers. Based on Brunauer-Emmett-Teller analysis, the specific surface area, pore volume and pore diameter of Gel-HA nanofibers decreased compared to gelatin nanofibers. The Gel-HA nano-fibers showed the proliferative effect and increased the alkaline phosphatase activity of cells significantly (P<0.05).

Conclusion:

The prepared Gel-HA nanofibers can be considered potential candidates for application in bone tissue engineering and regenerative dentistry.

Other:

Gel-HA nanofibers could be a potential material for bone regeneration and regenerative dentistry in the near future.

Evolution of Electrospinning in Liver Tissue Engineering

The major goal of liver tissue engineering is to reproduce the phenotype and functions of liver cells, especially primary hepatocytes ex vivo. Several strategies have been explored in the recent past for culturing the liver cells in the most apt environment using biological scaffolds supporting hepatocyte growth and differentiation. Nanofibrous scaffolds have been widely used in the field of tissue engineering for their increased surface-to-volume ratio and increased porosity, and their close resemblance with the native tissue extracellular matrix (ECM) environment. Electrospinning is one of the most preferred techniques to produce nanofiber scaffolds. In the current review, we have discussed the various technical aspects of electrospinning that have been employed for scaffold development for different types of liver cells. We have highlighted the use of synthetic and natural electrospun polymers along with liver ECM in the fabrication of these scaffolds. We have also described novel strategies that include modifications, such as galactosylation, matrix protein incorporation, etc., in the electrospun scaffolds that have evolved to support the long-term growth and viability of the primary hepatocytes.

Polysaccharide-based nanocomposites for biomedical applications: a critical review

Polysaccharides (PSA) have taken specific position among biomaterials for advanced applications in medicine. Nevertheless, poor mechanical properties are known as the main drawback of PSA, which highlights the need for PSA modification. Nanocomposites PSA (NPSA) are a class of biomaterials widely used as biomedical platforms, but despite their importance and worldwide use, they have not been reviewed. Herein, we critically reviewed the application of NPSA by categorizing them into generic and advanced application realms. First, the application of NPSA as drug and gene delivery systems, along with their role in the field as an antibacterial platform and hemostasis agent is discussed. Then, applications of NPSA for skin, bone, nerve, and cartilage tissue engineering are highlighted, followed by cell encapsulation and more critically cancer diagnosis and treatment potentials. In particular, three features of investigations are devoted to cancer therapy, i.e., radiotherapy, immunotherapy, and photothermal therapy, are comprehensively reviewed and discussed. Since this field is at an early stage of maturity, some other aspects such as bioimaging and biosensing are reviewed in order to give an idea of potential applications of NPSA for future developments, providing support for clinical applications. It is well-documented that using nanoparticles/nanomaterials above a critical concentration brings about concerns of toxicity; thus, their effect on cellular interactions would become critical. We compared nanoparticles used in the fabrication of NPSA in terms of toxicity mechanism to shed more light on future challenging aspects of NPSA development. Indeed, the neutralization mechanisms underlying the cytotoxicity of nanomaterials, which are expected to be induced by PSA introduction, should be taken into account for future investigations.

Biomaterials for Tissue Engineering Applications and Current Updates in the Field: A Comprehensive Review

Tissue engineering has emerged as an interesting field nowadays; it focuses on accelerating the auto-healing mechanism of tissues rather than organ transplantation. It involves implanting an In Vitro cultured initiative tissue or a scaffold loaded with tissue regenerating ingredients at the damaged area. Both techniques are based on the use of biodegradable, biocompatible polymers as scaffolding materials which are either derived from natural (e.g. alginates, celluloses, and zein) or synthetic sources (e.g. PLGA, PCL, and PLA). This review discusses in detail the recent applications of different biomaterials in tissue engineering highlighting the targeted tissues besides the in vitro and in vivo key findings. As well, smart biomaterials (e.g. chitosan) are fascinating candidates in the field as they are capable of elucidating a chemical or physical transformation as response to external stimuli (e.g. temperature, pH, magnetic or electric fields). Recent trends in tissue engineering are summarized in this review highlighting the use of stem cells, 3D printing techniques, and the most recent 4D printing approach which relies on the use of smart biomaterials to produce a dynamic scaffold resembling the natural tissue. Furthermore, the application of advanced tissue engineering techniques provides hope for the researchers to recognize COVID-19/host interaction, also, it presents a promising solution to rejuvenate the destroyed lung tissues.

Near-Infrared Responsive Synergistic Chemo-Phototherapy from Surface-Functionalized Poly(ε-caprolactone)-Poly(d,l-lactic-co-glycolic acid) Composite Nanofibers for Postsurgical Cancer Treatment

The combination of hyperthermia and chemotherapy has attracted significant attention in local cancer treatment following surgical resection. Pyrrole is a potent photothermal agent that can induce a temperature rise at different concentrations in the surrounding medium by absorbing near-infrared radiation (NIR). In this study, poly(ε-caprolactone) (PCL) and poly (d,l-lactic-co-glycolic acid) (PLGA) were used to make nanofibers using the electrospinning process. Then, pyrrole in different concentrations of (0.2, 0.4, and 0.6) M was attached to the surface of PCL-PLGA fiber mats by in situ polymerization, which was confirmed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) analysis. A concentration-dependent local temperature rise was observed using a FLIR camera under near-infrared (NIR) laser irradiation. For the hyperthermia effect, pyrrole concentration (0.06 M) was used for in vitro drug release studies and cell viability assays because under NIR irradiation (2 W/cm², 3 min), it increased the local temperature to around 45 °C. In vitro drug release studies confirmed that NIR irradiation increased the diffusion rate of doxorubicin (DOX) by increasing the environmental temperature above the glass transition temperature of PLGA. In vitro cytotoxicity experiments further confirmed that PCL-PLGA-DOX/PPy fiber mats showed an enhanced inhibitory effect against CT26 and MCF7 cells by the combination of hyperthermia and chemotherapy.

Recent advances in 3D-printed polylactide and polycaprolactone-based biomaterials for tissue engineering applications

The three-dimensional printing (3DP) also known as the additive manufacturing (AM), a novel and futuristic technology that facilitates the printing of multiscale, biomimetic, intricate cytoarchitecture, function-structure hierarchy, multi-cellular tissues in the complicated micro-environment, patient-specific scaffolds, and medical devices. There is an increasing demand for developing 3D-printed products that can be utilized for organ transplantations due to the organ shortage. Nowadays, the 3DP has gained considerable interest in the tissue engineering (TE) field. Polylactide (PLA) and polycaprolactone (PCL) are exemplary biomaterials with excellent physicochemical properties and biocompatibility, which have drawn notable attraction in tissue regeneration. Herein, the recent advancements in the PLA and PCL biodegradable polymer-based composites as well as their reinforcement with hydrogels and bio-ceramics scaffolds manufactured through 3DP are systematically summarized and the applications of bone, cardiac, neural, vascularized and skin tissue regeneration are thoroughly elucidated. The interaction between implanted biodegradable polymers, in-vivo and in-vitro testing models for possible evaluation of degradation and biological properties are also illustrated. The final section of this review incorporates the current challenges and future opportunities in the 3DP of PCL- and PLA-based composites that will prove helpful for biomedical engineers to fulfill the demands of the clinical field.

Functionalization of Electrospun Nanofiber for Bone Tissue Engineering

Bone-tissue engineering is an alternative treatment for bone defects with great potential in which scaffold is a critical factor to determine the effect of bone regeneration. Electrospun nanofibers are widely used as scaffolds in the biomedical field for their similarity with the structure of the extracellular matrix (ECM). Their unique characteristics are: larger surface areas, porosity and processability; these make them ideal candidates for bone-tissue engineering. This review briefly introduces bone-tissue engineering and summarizes the materials and methods for electrospining. More importantly, how to functionalize electrospun nanofibers to make them more conducive for bone regeneration is highlighted. Finally, the existing deficiencies of functionalized electrospun nanofibers for promoting osteogenesis are proposed. Such a summary can lay the foundation for the clinical practice of functionalized electrospun nanofibers.