Fabrication Of Tissue Engineering Scaffolds Research Articles

VEGF loading heparinized hyaluronic acid macroporous hydrogels for enhanced 3D endothelial cell migration and vascularization

The formation of robust vascular systems within voluminous scaffolds remains a formidable barrier in the realm of tissue engineering. There is a growing interest in the integration of biomaterial scaffolds with multiple physical and chemical stimuli to augment the process of vascularization. This study aims to investigate the combined impact of macroporous structures and vascular endothelial growth factor (VEGF) on cell migration and vascularization. Heparinized hyaluronic acid (HepHA) macroporous hydrogels with differing pore sizes, composed by methacrylated hyaluronic acid (HAMA) and methacrylated heparin (HepMA), were fabricated by a gelatin microspheres (GMS) template leaching method. After characterization of their physical properties, VEGF was immobilized on the HepHA hydrogels. The in vitro release study indicated that the HepHA hydrogels can provide sustained release of VEGF. Subsequently, cells migration of human umbilical vein endothelial (HUVECs) assessment indicated that HUVECs cultured on VEGF-loaded HepHA hydrogels with larger pores (VEGF@HepHA250) migrated the furthest. Finally, the hydrogels were implanted and evaluated using a dorsal subcutaneous model. The histological analyses conducted in vivo were consistent with the in vitro results, VEGF@HepHA250 hydrogels exhibited the most pronounced vascularization four weeks post-implantation, indicating that hydrogels with expanded pores and an enriched VEGF promoted angiogenesis within the hydrogels. This study sheds light on the synergistic effects of VEGF release on 3D cell migration and vascularization within hydrogels of differing pore sizes, thus providing novel insights into the strategic design and fabrication of tissue-engineered scaffolds that are amenable to vascularization.

Tissue engineering of Cornea via Type 1 Collagen Biomaterials – A perspective

Engineering corneal tissue has advanced significantly in recent years. Engineering a biocompatible, mechanically stable, and optically clear tissue presents significant engineering hurdles. Two fundamental strategies have been explored by scholars to address these issues: cell-based methods for controlling cells their own extracellular matrix and scaffold-based methods for supplying dense, transparent matrices for cell growth. Both approaches have had some level of success. Additionally, new developments in innervating a tissue-engineered construct have been developed. Future research must concentrate on enhancing the mechanical stability of engineered constructions and the host reaction to implantation. Type 1 Collagen Biomaterial has been used for the construction of scaffolds or implantation for the cornea repair. Various methods for fabrication of the scaffolds have been described and mentioned tissue engineering application for cornea repair and regeneration. Given this correspondence, the type 1 collagen was a potential biomaterial for tissue engineering scaffold fabrication for effective regeneration of cornea.

Fabrication of 3D microfibrous composite polycaprolactone/hydroxyapatite scaffolds loaded with piezoelectric poly (lactic acid) nanofibers by sequential near-field and conventional electrospinning for bone tissue engineering

Near-field electrospinning (NFES) has recently gained considerable interest in fabricating tissue engineering scaffolds. This technique combines the advantages of both 3D printing and electrospinning. It allows for the production of fibers with smaller resolution and the ability to make regular structures with suitable pores. In this study, a microfibrous composite scaffold of polycaprolactone (PCL)/hydroxyapatite (HA) was prepared by NFES in the first step. The microfibrous scaffold had a fiber spacing of 414.674 ± 24.9 μm with an average fiber diameter of 94.695 ± 16.149 μm. However, due to the large fiber spacing, the surface area was insufficient for cell adhesion. Therefore, the hybrid scaffold was prepared by adding aligned and random electrospun poly (L-lactic acid) (PLLA) nanofibers to the microfibrous scaffold. Cellular studies showed that cell adhesion to the hybrid scaffold increased by 334 % compared to the microfibrous scaffold. These nanofibers also exhibited piezoelectric properties, which helped stimulate bone regeneration. Aligned nanofibers in the hybrid scaffold enhanced alkaline phosphatase activity and the intensity of alizarin red staining 1.5 and 1.6 times, respectively, compared to the microfibrous scaffold. Furthermore, the elastic modulus and ultimate tensile strength increased by 268 % and 130 %, respectively, by adding aligned nanofibers to the microfibrous scaffold. Therefore, the hybrid microfibrous composite scaffold of PCL/HA containing aligned electrospun PLLA nanofibers with improved properties showed the potential for bone regeneration.

Biological and physicochemical characterization of carbonated hydroxyapatite-honeycomb-polyethylene oxide bone scaffold fabricated using the freeze-drying method

In this work, a carbonated hydroxyapatite/honeycomb/polyethylene oxide (CHA/HCB/PEO) scaffold was fabricated using the freeze-drying method. The CHA bioceramic component was synthesized from oyster shells using the precipitation method. HCB and PEO act as reinforcing materials that influence the physicochemical properties of the scaffold and as antibacterial agents on the scaffold. The CHA produced was B-type, confirmed by Fourier transform infrared (FTIR) and x-ray diffractometer (XRD) spectra of the CHA. FTIR analysis of the scaffold demonstrated the presence of functional group vibrations originating from PEO and HCB, affirming the successful application of the freeze-drying method, which preserved the polymer content within the scaffold during the evaporation process, thus facilitating pore formation. The XRD results show that a lower CHA concentration is associated with a smaller size of the scaffold crystallites, potentially inducing dislocations favorable for cellular proliferation. The porosity of the formed scaffold is in the ideal range of >60% with CHA concentration of 5 and 10 wt%. The size of the pores that formed on the scaffold was 3–69 μm, classifying them within the micropore category. The in vitro test results in the form of an antibacterial test revealed that the scaffold could inhibit S. aureus and E. coli bacteria. Notably, a scaffold consisting of 10 wt% of CHA had a larger zone of inhibition diameter, 10.083 ± 0.104 for S. aureus and 10.517 ± 0.247 mm for E. coli. The MTT assay and cell morphology MC3T3E1 results in the scaffold show that the CHA/HCB/PEO scaffold is non-cytotoxic and can facilitate cells to attach and proliferate. The cell viability of the scaffold was 96.23% at the concentration of 31.25 μg ml−1, and the IC50 value was at 16144 μg ml−1. Therefore, CHA/HCB/PEO composites can be an alternative material in scaffold fabrication for bone tissue engineering.

A practical machine learning approach for predicting the quality of 3D (bio)printed scaffolds

3D (Bio)printing is a highly effective method for fabricating tissue engineering scaffolds, renowned for their exceptional precision and control. Artificial intelligence (AI) has become a crucial technology in this field, capable of learning and replicating complex patterns that surpass human capabilities. However, the integration of AI in tissue engineering is often hampered by the lack of comprehensive and reliable data. This study addresses these challenges by providing one of the most extensive datasets on 3D-printed scaffolds. It provides the most comprehensive open-source dataset and employs various AI techniques, from unsupervised to supervised learning. This dataset includes detailed information on 1171 scaffolds, featuring a variety of biomaterials and concentrations-including 60 biomaterials such as natural and synthesized biomaterials, crosslinkers, enzymes, etc.-along with 49 cell lines, cell densities, and different printing conditions. We used over 40 machine learning and deep learning algorithms, tuning their hyperparameters to reveal hidden patterns and predict cell response, printability, and scaffold quality. The clustering analysis using KMeans identified five distinct ones. In classification tasks, algorithms such as XGBoost, Gradient Boosting, Extra Trees Classifier, Random Forest Classifier, and LightGBM demonstrated superior performance, achieving higher accuracy and F1 scores. A fully connected neural network with six hidden layers from scratch was developed, precisely tuning its hyperparameters for accurate predictions. The developed dataset and the associated code are publicly available onhttps://github.com/saeedrafieyan/MLATEto promote future research.

Photo-Clickable Triazine-Trione Thermosets as Promising 3D Scaffolds for Tissue Engineering Applications.

There is an overwhelming demand for new scaffolding materials for tissue engineering (TE) purposes. Polymeric scaffolds have been explored as TE materials; however, their high glass transition state (Tg) limits their applicability. In this study, a novel materials platform for fabricating TE scaffolds is proposed based on solvent-free two-component heterocyclic triazine-trione (TATO) formulations, which cure at room temperature via thiol-ene/yne photochemistry. Three ester-containing thermosets, TATO-1, TATO-2, and TATO-3, are used for the fabrication of TE scaffolds including rigid discs, elastic films, microporous sponges, and 3D printed objects. After 14 days' incubation the materials covered a wide range of properties, from the soft TATO-2 having a compression modulus of 19.3MPa and a Tg of 30.4°C to the hard TATO-3 having a compression modulus of 411MPa and a Tg of 62.5°C. All materials exhibit micro- and nano-surface morphologies suited for bone tissue engineering, and in vitro studies found them all to be cytocompatible, supporting fast cell proliferation while minimizing cell apoptosis and necrosis. Moreover, bone marrow-derived mesenchymal stem cells on the surface of the materials are successfully differentiated into osteoblasts, adipocytes, and neuronal cells, underlining the broad potential for the biofabrication of TATO materials for TE clinical applications.

Optical Fiber-Assisted Printing: A Platform Technology for Straightforward Photopolymer Resins Patterning and Freeform 3D Printing.

Light-based 3D printing techniques represent powerful tools, enabling the precise fabrication of intricate objects with high resolution and control. An innovative addition to this set of printing techniques is Optical Fiber-Assisted Printing (OFAP) introduced in this article. OFAP is a platform utilizing an LED-coupled optical fiber (LOF) that selectively crosslinks photopolymer resins. It allows change of parameters like light intensity and LOF velocity during fabrication, facilitating the creation of structures with progressive features and multi-material constructs layer-by-layer. An optimized formulation based on allyl-modified gelatin (gelAGE) with food dyes as photoabsorbers is introduced. Additionally, a novel gelatin-based biomaterial, alkyne-modified gelatin (gelGPE), featuring alkyne moieties, demonstrates near-visible light absorption thus fitting OFAP needs, paving the way for multifunctional hydrogels through thiol-yne click chemistry. Besides 2D patterning, OFAP is transferred to embedded 3D printing within a resin bath demonstrating the proof-of-concept as a novel printing technology with potential applications in tissue engineering and biomimetic scaffold fabrication, offering rapid and precise freeform printing capabilities.

Application and Development of Electrospun Nanofiber Scaffolds for Bone Tissue Engineering.

Nanofiber scaffolds have gained significant attention in the field of bone tissue engineering. Electrospinning, a straightforward and efficient technique for producing nanofibers, has been extensively researched. When used in bone tissue engineering scaffolds, electrospun nanofibers with suitable surface properties promote new bone tissue growth and enhance cell adhesion. Recent advancements in electrospinning technology have provided innovative approaches for scaffold fabrication in bone tissue engineering. This review comprehensively examines the utilization of electrospun nanofibers in bone tissue engineering scaffolds and evaluates the relevant literature. The review begins by presenting the fundamental principles and methodologies of electrospinning. It then discusses various materials used in the production of electrospun nanofiber scaffolds for bone tissue engineering, including natural and synthetic polymers, as well as certain inorganic materials. The challenges associated with these materials are also described. The review focuses on novel electrospinning techniques for scaffold construction in bone tissue engineering, such as multilayer nanofibers, multifluid electrospinning, and the integration of electrospinning with other methods. Recent advancements in electrospinning technology have enabled the fabrication of precisely aligned nanofiber scaffolds with nanoscale architectures. These innovative methods also facilitate the fabrication of biomimetic structures, wherein bioactive substances can be incorporated and released in a controlled manner for drug delivery purposes. Moreover, they address issues encountered with traditional electrospun nanofibers, such as mechanical characteristics and biocompatibility. Consequently, the development and implementation of novel electrospinning technologies have revolutionized scaffold fabrication for bone tissue engineering.

Wet 3D printing of biodegradable porous scaffolds to enable room-temperature deposition modeling of polymeric solutions for regeneration of articular cartilage

Tissue engineering has emerged as an advanced strategy to regenerate various tissues using different raw materials, and thus it is desired to develop more approaches to fabricate tissue engineering scaffolds to fit specific yet very useful raw materials such as biodegradable aliphatic polyester like poly (lactide-co-glycolide) (PLGA). Herein, a technique of ‘wet 3D printing’ was developed based on a pneumatic extrusion three-dimensional (3D) printer after we introduced a solidification bath into a 3D printing system to fabricate porous scaffolds. The room-temperature deposition modeling of polymeric solutions enabled by our wet 3D printing method is particularly meaningful for aliphatic polyester, which otherwise degrades at high temperature in classic fuse deposition modeling. As demonstration, we fabricated a bilayered porous scaffold consisted of PLGA and its mixture with hydroxyapatite for regeneration of articular cartilage and subchondral bone. Long-term in vitro and in vivo degradation tests of the scaffolds were carried out up to 36 weeks, which support the three-stage degradation process of the polyester porous scaffold and suggest faster degradation in vivo than in vitro. Animal experiments in a rabbit model of articular cartilage injury were conducted. The efficacy of the scaffolds in cartilage regeneration was verified through histological analysis, micro-computed tomography (CT) and biomechanical tests, and the influence of scaffold structures (bilayer versus single layer) on in vivo tissue regeneration was examined. This study has illustrated that the wet 3D printing is an alternative approach to biofabricate tissue engineering porous scaffolds based on biodegradable polymers.

Durotaxis and Topotaxis Orchestrated Guidance on Cell Migration in 3D Printed Scaffold/Hydrogel Composite

Printing three-dimensional (3D) scaffolds with suitable mechanical cues is an effective strategy for guiding tissue regeneration by inducing cell migration and growth. Nevertheless, many studies considered only one type of cue for 3D tissue engineering scaffold fabrication, such as topological cues, which is insufficient. To realize durotaxis- and topotaxis-orchestrated guidance on cell migration, a 3D printed scaffold/hydrogel composite was fabricated in this study. The porous scaffold provided a topological cue (topotaxis), and the combined hydrogel provided a compliance cue (durotaxis). The results indicated that the thin fibers of the scaffold induced cell migration, and the larger pore size and directed fiber number of the scaffold led to more uniform cell orientation (topotaxis). Furthermore, when collagen was cured to cover the scaffold to result in a compliance change, the cells in the collagen still sensed the scaffold topological cue and migrated along it (durotaxis). Collagen also provides a living space and nutrition for cells, thereby significantly increasing their number. The effects of durotaxis and topotaxis synthesis provide a promising solution for tissue engineering scaffold applications.

Three-Dimensional Printing Methods for Bioceramic-Based Scaffold Fabrication for Craniomaxillofacial Bone Tissue Engineering.

Three-dimensional printing (3DP) technology has revolutionized the field of the use of bioceramics for maxillofacial and periodontal applications, offering unprecedented control over the shape, size, and structure of bioceramic implants. In addition, bioceramics have become attractive materials for these applications due to their biocompatibility, biostability, and favorable mechanical properties. However, despite their advantages, bioceramic implants are still associated with inferior biological performance issues after implantation, such as slow osseointegration, inadequate tissue response, and an increased risk of implant failure. To address these challenges, researchers have been developing strategies to improve the biological performance of 3D-printed bioceramic implants. The purpose of this review is to provide an overview of 3DP techniques and strategies for bioceramic materials designed for bone regeneration. The review also addresses the use and incorporation of active biomolecules in 3D-printed bioceramic constructs to stimulate bone regeneration. By controlling the surface roughness and chemical composition of the implant, the construct can be tailored to promote osseointegration and reduce the risk of adverse tissue reactions. Additionally, growth factors, such as bone morphogenic proteins (rhBMP-2) and pharmacologic agent (dipyridamole), can be incorporated to promote the growth of new bone tissue. Incorporating porosity into bioceramic constructs can improve bone tissue formation and the overall biological response of the implant. As such, employing surface modification, combining with other materials, and incorporating the 3DP workflow can lead to better patient healing outcomes.

Development and Evaluation of Biodegradable Core-Shell Microfibrous and Nanofibrous Scaffolds for Tissue Engineering Applications

Tissue engineering scaffolds as three-dimensional substrates may serve as ideal templates for tissue regeneration by simulating the structure of the extracellular matrix (ECM). Many biodegradable synthetic polymers, either hydrophobic, like Poly-ε-caprolactone (PCL), or hydrophilic, like Poly(Vinyl Alcohol) (PVA), are widely used as candidate bioactive materials for fabricating tissue engineering scaffolds. However, a combination of good cytocompatibility of hydrophilic polymers with good biomechanical performance of hydrophobic polymers could be beneficial for the in vivo performance of the scaffolds. In this study, we aimed to fabricate biodegradable fibrous scaffolds by combining the properties of hydrophobic PCL with those of hydrophilic PVA and evaluate their properties in comparison with pristine PCL scaffolds. Therefore, single-layered PCL scaffolds, sequential tri-layered (PVA/PCL/PVA), and core-shell (PVA as shell and PCL as core) composite scaffolds were developed utilizing the electrospinning technique. The material structural and biomechanical properties of the electrospun scaffolds, before and after their hydrolytic degradation over a seven-month period following storage in phosphate-buffered saline (PBS) at 37 °C, were comprehensively compared. In addition, human embryonic kidney cells (HEK-293) were cultured on the scaffolds to investigate potential cell attachment, infiltration, and proliferation. The results demonstrated the long-term efficacy of core-shell biodegradable fibrous scaffolds in comparison to single-layers PCL and tri-layers PVA/PCL/PVA, not only due to its superior morphological characteristics and mechanical properties, but also due to its ability to promote homogeneous cell distribution and proliferation, without any external chemical or physical stimuli.Graphical

Biomimetic hydroxyapatite and strontium-doped derivatives from crab shells and their ingenious scaffold fabrication for bone tissue engineering

The success of the most commonly used bio-ceramics in current medicine, hydroxyapatite (HAp), is due to its similar chemical and structural properties with the human bone tissue. The current research aims to calcine crab shells, a bio-waste source, to synthesize HAp, and dope it with strontium (Sr) to use it as a sustainable and economical source for bone tissue engineering. Different temperatures (900°, 1000°, and 1100 °C) were used for the calcination process. FE-SEM analysis showed the importance of temperature for morphology. The variance in the Ca/P ratio was revealed by EDX analysis. The higher the calcination temperature, the more pronounced were the peaks of HAp and (β-Tricalcium Phosphate) β-TCP were revealed by X-Ray Diffraction (XRD) analysis. Moreover, as the concentration of Sr2+ increased, both the crystallite size and crystallinity index (CI) of HAp decreased, as confirmed by XRD analysis. ATR-FTIR analysis showed the best-defined bond types (O-H, P-O, etc.). TGA and DSC analysis revealed the loss of adsorbed water and the appearance of endothermic peaks, respectively. To create a possible bone transplant substitute, scaffolds from HAp and strontium-doped HAp (Sr-HAp) were prepared utilising the foam replica method. At a Sr2+ doping of 1% (w/w) and a calcination temperature of 1100 °C, the highest percent cell viability was obtained, as determined by the MTT test. These results indicate that the concentration of the dopant (Sr2+) have a significant influence on the properties of the final material suitable for bone regeneration in situ.

MXene and Xene: promising frontier beyond graphene in tissue engineering and regenerative medicine.

The emergence of 2D nanomaterials (2D NMs), which was initiated by the isolation of graphene (G) in 2004, revolutionized various biomedical applications, including bioimaging and -sensing, drug delivery, and tissue engineering, owing to their unique physicochemical and biological properties. Building on the success of G, a novel class of monoelemental 2D NMs, known as Xenes, has recently emerged, offering distinct advantages in the fields of tissue engineering and regenerative medicine. In this review, we focus on the comparison of G and Xene materials for use in fabricating tissue engineering scaffolds. After a brief introduction to the basic physicochemical properties of these materials, recent representative studies are classified in terms of the engineered tissue, i.e., bone, cartilage, neural, muscle, and skin tissues. We analyze several methods of improving the clinical potential of Xene-laden scaffolds using state-of-the-art fabrication technologies and innovative biomaterials. Despite the considerable advantages of Xene materials, critical concerns, such as biocompatibility, biodistribution and regulatory challenges, should be considered. This review and collaborative efforts should advance the field of Xene-based tissue engineering and enable innovative, effective solutions for use in future tissue regeneration.

Scaffold fabrication for tissue engineering based on radiation copolymerization of polymer blends: (I) Zein/poly (vinyl butyral) blends

AbstractThe main objective of this work is to fabricate scaffold material for tissue engineering and using Vero (monkey kidney cells)/Paulownia tomentosa cells as model cells. For this objective, copolymer blends of poly(vinyl butyral) (PVB) and Zein, the main constituent, have been fabricated as thin films. Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), and x‐ray diffraction (XRD) were used to characterize the copolymer blends. The findings showed that Zein component degradation caused the gel fraction percentage to decrease with higher irradiation doses. Zein's thermal characteristics are also decreased by the addition of PVB polymer, but they are improved by irradiation to 10 kGy through promoting phase adhesion and the generation of free radicals at boundary surfaces. Vero (Monkey kidney) cells proliferate more rapidly in the blend Zein/PVB (85/15%) irradiated to 45 kGy than in the unirradiated one. On the other hand, the Paulownia tomentosa cells proliferation was died.Highlights Copolymer blends of Zein and PVB were prepared by gamma irradiation. The copolymers were fabricated as scaffold material for tissue engineering using monkey kidney cells. PVB and Zein copolymer were characterized by FT‐IR, SEM, DSC, and XRD. The Zein/PVB (85/15%)—45 kGy has monkey kidney cells proliferation better than unirradiated one.

Feasibility of caffeic acid as a crosslinking agent in modifying acellular extracellular matrices

Acellular extracellular matrices (aECM) are commonly utilized, both experimentally and clinically, in the regenerative medicine field. However, some disadvantages such as rapid degradation, poor mechanical properties, chronic inflammatory reactions and low antioxidant activity have limited their further application. In this study the feasibility of caffeic acid as a crosslinking agent in fixing small intestinal submucosa (SIS) was evaluated. The ninhydrin assay, swelling ratio and FTIR spectra indicated that caffeic acid can efficiently react with free amino groups to crosslink SIS and the highest crosslinking index reached 21.60 ± 1.37%. Moreover, the shrinkage temperature of SIS remarkably increased from 59 °C to about 80 °C and the degradation rate of CA-SIS was all lower than 6%, demonstrating their improved biostability and hydrothermal stability. Importantly, the antioxidant activity of CA-SIS ranged from 55% to 90%, statistically higher than that of native SIS (37.33 ± 2.94%). Additionally the cytotoxicity test presented that the cytotoxicity grade of CA-SIS was 1 or 0, whilst large numbers of living HUVECs were attached to the surface of the material and exhibited high cell viability. These results indicated their excellent cytocompatibility. The data of subcutaneous implant displayed that the number of inflammatory cells in 2%- and 2.5%CA-SIS groups remained at a low level (below 100 cells/field) while that of the native SIS group continued increasing, finally reaching 142.33 ± 30.92 cells/field. In conclusion, caffeic acid is a promising candidate for modifying aECM and may play a vital role in the design and fabrication of tissue engineering scaffolds.

3D Printing Type 1 Bovine Collagen Scaffolds for Tissue Engineering Applications-Physicochemical Characterization and In Vitro Evaluation.

Collagen, an abundant extracellular matrix protein, has shown hemostatic, chemotactic, and cell adhesive characteristics, making it an attractive choice for the fabrication of tissue engineering scaffolds. The aim of this study was to synthesize a fibrillar colloidal gel from Type 1 bovine collagen, as well as three dimensionally (3D) print scaffolds with engineered pore architectures. 3D-printed scaffolds were also subjected to post-processing through chemical crosslinking (in N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide) and lyophilization. The scaffolds were physicochemically characterized through Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis, Differential Scanning Calorimetry, and mechanical (tensile) testing. In vitro experiments using Presto Blue and Alkaline Phosphatase assays were conducted to assess cellular viability and the scaffolds' ability to promote cellular proliferation and differentiation. Rheological analysis indicated shear thinning capabilities in the collagen gels. Crosslinked and lyophilized 3D-printed scaffolds were thermally stable at 37 °C and did not show signs of denaturation, although crosslinking resulted in poor mechanical strength. PB and ALP assays showed no signs of cytotoxicity as a result of crosslinking. Fibrillar collagen was successfully formulated into a colloidal gel for extrusion through a direct inkjet writing printer. 3D-printed scaffolds promoted cellular attachment and proliferation, making them a promising material for customized, patient-specific tissue regenerative applications.

A novel eco-friendly abrasive media based abrasive flow machining of 3D printed PLA parts using IGWO and ANN

PurposeThree-dimensional (3D) printed parts usually have poor surface quality due to layer manufacturing’s “stair casing/stair-stepping”. So post-processing is typically needed to enhance its capabilities to be used in closed tolerance applications. This study aims to examine abrasive flow finishing for 3D printed polylactic acid (PLA) parts.Design/methodology/approachA new eco-friendly abrasive flow machining media (EFAFM) was developed, using paper pulp as a base material, waste vegetable oil as a liquid synthesizer and natural additives such as glycine to finish 3D printed parts. Characterization of the media was conducted through thermogravimetric analysis and Fourier transform infrared spectroscopy. PLA crescent prism parts were produced via fused deposition modelling (FDM) and finished using AFM, with experiments designed using central composite design (CCD). The impact of process parameters, including media viscosity, extrusion pressure, layer thickness and finishing time, on percentage improvement in surface roughness (%ΔRa) and material removal rate were analysed. Artificial neural network (ANN) and improved grey wolf optimizer (IGWO) were used for data modelling and optimization, respectively.FindingsThe abrasive media developed was effective for finishing FDM printed parts using AFM, with SEM images and 3D surface profile showing a significant improvement in surface topography. Optimal solutions were obtained using the ANN-IGWO approach. EFAFM was found to be a promising method for improving finishing quality on FDM 3D printed parts.Research limitations/implicationsThe present study is focused on finishing FDM printed crescent prism parts using AFM. Future research may be done on more complex shapes and could explore the impact of different materials, such as thermoplastics and composites for different applications. Also, implication of other techniques, such as chemical vapour smoothing, mechanical polishing may be explored.Practical implicationsIn the biomedical field, the use of 3D printing has revolutionized the way in which medical devices, implants and prosthetics are designed and manufactured. The biodegradable and biocompatible properties of PLA make it an ideal material for use in biomedical applications, such as the fabrication of surgical guides, dental models and tissue engineering scaffolds. The ability to finish PLA 3D printed parts using AFM can improve their biocompatibility, making them more suitable for use in the human body. The improved surface quality of 3D printed parts can also facilitate their sterilization, which is critical in the biomedical field.Social implicationsThe use of eco-friendly abrasive flow finishing for 3D printed parts can have a positive impact on the environment by reducing waste and promoting sustainable manufacturing practices. Additionally, it can improve the quality and functionality of 3D printed products, leading to better performance and longer lifespans. This can have broader economic and societal benefits.Originality/valueThis AFM media constituents are paper pulp, waste vegetable oil, silicon carbide as abrasive and the mixture of “Aloe Barbadensis Mill” – “Cyamopsis Tetragonoloba” powder and glycine. This media was then used to finish 3D printed PLA crescent prism parts. The study also used an IGWO to optimize experimental data that had been modelled using an ANN.

Magnesium-Rich Calcium Phosphate Derived from Tilapia Bone Has Superior Osteogenic Potential.

We extracted magnesium-rich calcium phosphate bioceramics from tilapia bone using a gradient thermal treatment approach and investigated their chemical and physicochemical properties. X-ray diffraction showed that tilapia fish bone-derived hydroxyapatite (FHA) was generated through the first stage of thermal processing at 600-800 °C. Using FHA as a precursor, fish bone biphasic calcium phosphate (FBCP) was produced after the second stage of thermal processing at 900-1200 °C. The beta-tricalcium phosphate content in the FBCP increased with an increasing calcination temperature. The fact that the lattice spacing of the FHA and FBCP was smaller than that of commercial hydroxyapatite (CHA) suggests that Mg-substituted calcium phosphate was produced via the gradient thermal treatment. Both the FHA and FBCP contained considerable quantities of magnesium, with the FHA having a higher concentration. In addition, the FHA and FBCP, particularly the FBCP, degraded faster than the CHA. After one day of degradation, both the FHA and FBCP released Mg2+, with cumulative amounts of 4.38 mg/L and 0.58 mg/L, respectively. Furthermore, the FHA and FBCP demonstrated superior bone-like apatite formation; they are non-toxic and exhibit better osteoconductive activity than the CHA. In light of our findings, bioceramics originating from tilapia bone appear to be promising in biomedical applications such as fabricating tissue engineering scaffolds.

3D Bioprinting of a Bioactive Composite Scaffold for Cell Delivery in Periodontal Tissue Regeneration.

Hydrogels have been widely applied to the fabrication of tissue engineering scaffolds via three-dimensional (3D) bioprinting because of their extracellular matrix-like properties, capacity for living cell encapsulation, and shapeable customization depending on the defect shape. However, the current hydrogel scaffolds show limited regeneration activity, especially in the application of periodontal tissue regeneration. In this study, we attempted to develop a novel multi-component hydrogel that possesses good biological activity, can wrap living cells for 3D bioprinting and can regenerate periodontal soft and hard tissue. The multi-component hydrogel consisted of gelatin methacryloyl (GelMA), sodium alginate (SA) and bioactive glass microsphere (BGM), which was first processed into hydrogel scaffolds by cell-free 3D printing to evaluate its printability and in vitro biological performances. The cell-free 3D-printed scaffolds showed uniform porous structures and good swelling capability. The BGM-loaded scaffold exhibited good biocompatibility, enhanced osteogenic differentiation, apatite formation abilities and desired mechanical strength. The composite hydrogel was further applied as a bio-ink to load with mouse bone marrow mesenchymal stem cells (mBMSCs) and growth factors (BMP2 and PDGF) for the fabrication of a scaffold for periodontal tissue regeneration. The cell wrapped in the hydrogel still maintained good cellular vitality after 3D bioprinting and showed enhanced osteogenic differentiation and soft tissue repair capabilities in BMP2- and PDGF-loaded scaffolds. It was noted that after transplantation of the cell- and growth factor-laden scaffolds in Beagle dog periodontal defects, significant regeneration of gingival tissue, periodontal ligament, and alveolar bone was detected. Importantly, a reconstructed periodontal structure was established in the treatment group eight weeks post-transplantation of the scaffolds containing the cell and growth factors. In conclusion, we developed a bioactive composite bio-ink for the fabrication of scaffolds applicable for the reconstruction and regeneration of periodontal tissue defects.