Mechanical Properties and In Vitro Evaluation of Thermoplastic Polyurethane and Polylactic Acid Blend for Fabrication of 3D Filaments for Tracheal Tissue Engineering

Surgical reconstruction of extensive tracheal lesions is challenging. It requires a mechanically stable, biocompatible, and nontoxic material that gradually degrades. One of the possible solutions for overcoming the limitations of tracheal transplantation is a three-dimensional (3D) printed tracheal scaffold made of polymers. Polymer blending is one of the methods used to produce material for a trachea scaffold with tailored characteristics. The purpose of this study is to evaluate the mechanical and in vitro properties of a thermoplastic polyurethane (TPU) and polylactic acid (PLA) blend as a potential material for 3D printed tracheal scaffolds. Both materials were melt-blended using a single screw extruder. The morphologies (as well as the mechanical and thermal characteristics) were determined via scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, tensile test, and Differential Scanning calorimetry (DSC). The samples were also evaluated for their water absorption, in vitro biodegradability, and biocompatibility. It is demonstrated that, despite being not miscible, TPU and PLA are biocompatible, and their promising properties are suitable for future applications in tracheal tissue engineering.

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Development of three-dimensional printing filaments based on poly(lactic acid)/hydroxyapatite composites with potential for tissue engineering

Journal of Composite Materials ◽

10.1177/0021998320988568 ◽

2021 ◽

pp. 002199832098856

Author(s):

Marcela Piassi Bernardo ◽

Bruna Cristina Rodrigues da Silva ◽

Luiz Henrique Capparelli Mattoso

Keyword(s):

Tissue Engineering ◽

Lactic Acid ◽

Fused Deposition Modeling ◽

Three Dimensional ◽

Poly Lactic Acid ◽

Scanning Calorimetry ◽

Three Dimensional Printing ◽

Fused Deposition ◽

Deposition Modeling ◽

3D Printed

Injured bone tissues can be healed with scaffolds, which could be manufactured using the fused deposition modeling (FDM) strategy. Poly(lactic acid) (PLA) is one of the most biocompatible polymers suitable for FDM, while hydroxyapatite (HA) could improve the bioactivity of scaffold due to its chemical composition. Therefore, the combination of PLA/HA can create composite filaments adequate for FDM and with high osteoconductive and osteointegration potentials. In this work, we proposed a different approache to improve the potential bioactivity of 3D printed scaffolds for bone tissue engineering by increasing the HA loading (20-30%) in the PLA composite filaments. Two routes were investigated regarding the use of solvents in the filament production. To assess the suitability of the FDM-3D printing process, and the influence of the HA content on the polymer matrix, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were performed. The HA phase content of the composite filaments agreed with the initial composite proportions. The wettability of the 3D printed scaffolds was also increased. It was shown a greener route for obtaining composite filaments that generate scaffolds with properties similar to those obtained by the solvent casting, with high HA content and great potential to be used as a bone graft.

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Three-dimensionally printed polycaprolactone/multicomponent bioactive glass scaffolds for potential application in bone tissue engineering

Biomedical glasses ◽

10.1515/bglass-2020-0006 ◽

2020 ◽

Vol 6 (1) ◽

pp. 57-69

Author(s):

Amirhosein Fathi ◽

Farzad Kermani ◽

Aliasghar Behnamghader ◽

Sara Banijamali ◽

Masoud Mozafari ◽

...

Keyword(s):

Tissue Engineering ◽

3D Printing ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Three Dimensional ◽

Layer By Layer ◽

Composite Scaffolds ◽

3D Printed ◽

Co Doped

AbstractOver the last years, three-dimensional (3D) printing has been successfully applied to produce suitable substitutes for treating bone defects. In this work, 3D printed composite scaffolds of polycaprolactone (PCL) and strontium (Sr)- and cobalt (Co)-doped multi-component melt-derived bioactive glasses (BGs) were prepared for bone tissue engineering strategies. For this purpose, 30% of as-prepared BG particles (size <38 μm) were incorporated into PCL, and then the obtained composite mix was introduced into a 3D printing machine to fabricate layer-by-layer porous structures with the size of 12 × 12 × 2 mm3.The scaffolds were fully characterized through a series of physico-chemical and biological assays. Adding the BGs to PCL led to an improvement in the compressive strength of the fabricated scaffolds and increased their hydrophilicity. Furthermore, the PCL/BG scaffolds showed apatite-forming ability (i.e., bioactivity behavior) after being immersed in simulated body fluid (SBF). The in vitro cellular examinations revealed the cytocompatibility of the scaffolds and confirmed them as suitable substrates for the adhesion and proliferation of MG-63 osteosarcoma cells. In conclusion, 3D printed composite scaffolds made of PCL and Sr- and Co-doped BGs might be potentially-beneficial bone replacements, and the achieved results motivate further research on these materials.

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Fabrication, Characterization, and Cytotoxicity of Thermoplastic Polyurethane/Poly(lactic acid) Material Using Human Adipose Derived Mesenchymal Stromal Stem Cells (hASCs)

Polymers ◽

10.3390/polym10101073 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1073 ◽

Cited By ~ 8

Author(s):

Anna Lis-Bartos ◽

Agnieszka Smieszek ◽

Kinga Frańczyk ◽

Krzysztof Marycz

Keyword(s):

Tissue Engineering ◽

Lactic Acid ◽

Thermoplastic Polyurethane ◽

Tensile Tests ◽

In Vitro Assays ◽

Poly Lactic Acid ◽

Scanning Calorimetry ◽

Casting Technique ◽

Wide Range

Thermoplastic polyurethane (TPU) and poly(lactic acid) are types of biocompatible and degradable synthetic polymers required for biomedical applications. Physically blended (TPU+PLA) tissue engineering matrices were produced via solvent casting technique. The following types of polymer blend were prepared: (TPU+PLA) 7:3, (TPU+PLA) 6:4, (TPU+PLA) 4:6, and (TPU+PLA) 3:7. Various methods were employed to characterize the properties of these polymers: surface properties such as morphology (scanning electron microscopy), wettability (goniometry), and roughness (profilometric analysis). Analyses of hydrophilic and hydrophobic properties, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) of the obtained polymer blends were conducted. Tensile tests demonstrated that the blends exhibited a wide range of mechanical properties. Cytotoxicity of polymers was tested using human multipotent stromal cells derived from adipose tissue (hASC). In vitro assays revealed that (TPU+PLA) 3:7 matrices were the most cytocompatible biomaterials. Cells cultured on (TPU+PLA) 3:7 had proper morphology, growth pattern, and were distinguished by increased proliferative and metabolic activity. Additionally, it appeared that (TPU+PLA) 3:7 biomaterials showed antiapoptotic properties. hASC cultured on these matrices had reduced expression of Bax-α and increased expression of Bcl-2. This study demonstrated the feasibility of producing a biocompatible scaffold form based on (TPU+PLA) blends that have potential to be applied in tissue engineering.

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Three-dimensional printed polylactic acid scaffold integrated with BMP-2 laden hydrogel for precise bone regeneration

Biomaterials Research ◽

10.1186/s40824-021-00233-7 ◽

2021 ◽

Vol 25 (1) ◽

Author(s):

Misun Cha ◽

Yuan-Zhe Jin ◽

Jin Wook Park ◽

Kyung Mee Lee ◽

Shi Huan Han ◽

...

Keyword(s):

Bone Regeneration ◽

Polylactic Acid ◽

Three Dimensional ◽

Burst Release ◽

Defect Model ◽

Ectopic Ossification ◽

Significant Difference ◽

3D Printed

Abstract Background Critical bone defects remain challenges for clinicians, which cannot heal spontaneously and require medical intervention. Following the development of three-dimensional (3D) printing technology is widely used in bone tissue engineering for its outstanding customizability. The 3D printed scaffolds were usually accompanied with growth factors, such as bone morphometric protein 2 (BMP-2), whose effects have been widely investigated on bone regeneration. We previously fabricated and investigated the effect of a polylactic acid (PLA) cage/Biogel scaffold as a carrier of BMP-2. In this study, we furtherly investigated the effect of another shape of PLA cage/Biogel scaffold as a carrier of BMP-2 in a rat calvaria defect model and an ectopic ossification (EO) model. Method The PLA scaffold was printed with a basic commercial 3D printer, and the PLA scaffold was combined with gelatin and alginate-based Biogel and BMP-2 to induce bone regeneration. The experimental groups were divided into PLA scaffold, PLA scaffold with Biogel, PLA scaffold filled with BMP-2, and PLA scaffold with Biogel and BMP-2 and were tested both in vitro and in vivo. One-way ANOVA with Bonferroni post-hoc analysis was used to determine whether statistically significant difference exists between groups. Result The in vitro results showed the cage/Biogel scaffold released BMP-2 with an initial burst release and followed by a sustained slow-release pattern. The released BMP-2 maintained its osteoinductivity for at least 14 days. The in vivo results showed the cage/Biogel/BMP-2 group had the highest bone regeneration in the rat calvarial defect model and EO model. Especially, the bone regenerated more regularly in the EO model at the implanted sites, which indicated the cage/Biogel had an outstanding ability to control the shape of regenerated bone. Conclusion In conclusion, the 3D printed PLA cage/Biogel scaffold system was proved to be a proper carrier for BMP-2 that induced significant bone regeneration and induced bone formation following the designed shape.

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3D Bioprinting of Vascularized Tissues for in vitro and in vivo Applications

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.664188 ◽

2021 ◽

Vol 9 ◽

Author(s):

Earnest P. Chen ◽

Zeren Toksoy ◽

Bruce A. Davis ◽

John P. Geibel

Keyword(s):

Tissue Engineering ◽

Drug Testing ◽

Rapid Development ◽

Three Dimensional ◽

3D Bioprinting ◽

Vascular Networks ◽

Main Challenge ◽

3D Printed

With a limited supply of organ donors and available organs for transplantation, the aim of tissue engineering with three-dimensional (3D) bioprinting technology is to construct fully functional and viable tissue and organ replacements for various clinical applications. 3D bioprinting allows for the customization of complex tissue architecture with numerous combinations of materials and printing methods to build different tissue types, and eventually fully functional replacement organs. The main challenge of maintaining 3D printed tissue viability is the inclusion of complex vascular networks for nutrient transport and waste disposal. Rapid development and discoveries in recent years have taken huge strides toward perfecting the incorporation of vascular networks in 3D printed tissue and organs. In this review, we will discuss the latest advancements in fabricating vascularized tissue and organs including novel strategies and materials, and their applications. Our discussion will begin with the exploration of printing vasculature, progress through the current statuses of bioprinting tissue/organoids from bone to muscles to organs, and conclude with relevant applications for in vitro models and drug testing. We will also explore and discuss the current limitations of vascularized tissue engineering and some of the promising future directions this technology may bring.

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Microstructure design and degradation performance in vitro of three-dimensional printed bioscaffold for bone tissue engineering

Advances in Mechanical Engineering ◽

10.1177/1687814019883784 ◽

2019 ◽

Vol 11 (10) ◽

pp. 168781401988378 ◽

Cited By ~ 2

Author(s):

Hongyu Jin ◽

Yue Zhuo ◽

Yang Sun ◽

Hongya Fu ◽

Zhenyu Han

Keyword(s):

Mechanical Properties ◽

Tissue Engineering ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Polylactic Acid ◽

Tricalcium Phosphate ◽

Three Dimensional ◽

Spherical Pore ◽

And Topology

In bone tissue engineering, three-dimensional printed biological scaffolds play an important role in the development of bone regeneration. The ideal scaffolds should have the ability to match the bone degradation rate and osteogenic ability. This article optimizes the unit cell model of the microstructure including spherical pore, gyroid, and topology to explore degradation performance of scaffolds. Boolean operation of array microstructure unit cells and selected part of a computer-aided design (CAD) femur model are adopted to create a reconstructed scaffold model. Polylactic acid/[Formula: see text]-tricalcium phosphate/hydroxyapatite scaffolds with spherical pore, gyroid, and topology-optimized structures are manufactured by three-dimensional printing utilizing the composition of bio-ink including polylactic acid, [Formula: see text]-tricalcium phosphate, and hydroxyapatite. After degradation of the scaffolds in vitro for several days, the mechanical properties are analyzed to study the effects of different microstructures on the degradation properties. The results show that the gyroid scaffolds with favorable degradability still maintain excellent mechanical properties after degradation. Mechanical properties of the scaffolds with topology-optimized structure and spherical pore microstructure scaffolds have a significant decrease after degradation.

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Performance comparison of the 3D-printed and injection-molded PLA and its elastomer blend and fiber composites

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705718772867 ◽

2018 ◽

Vol 32 (4) ◽

pp. 501-520 ◽

Cited By ~ 14

Author(s):

Cevdet Kaynak ◽

S Deniz Varsavas

Keyword(s):

3D Printing ◽

Mechanical Performance ◽

Thermoplastic Polyurethane ◽

Three Dimensional ◽

Performance Comparison ◽

Reinforced Composites ◽

Scanning Calorimetry ◽

Photographic Images ◽

3D Printed ◽

Injection Molded

The purpose of this study was to compare the performance of polylactide (PLA)-based materials shaped by the traditional injection molding technique versus three-dimensional (3D)-printing additive manufacturing. Comparisons were performed not only for neat PLA but also for its thermoplastic polyurethane elastomer (TPU) blend and for its E-glass fiber (GF)-reinforced composites. Performance comparison of the injection-molded and 3D-printed specimens was especially conducted to compare their mechanical properties (strength–modulus–toughness) by tensile, flexural, and fracture toughness tests. Other comparisons such as their macro-level appearances, fracture surface morphology, and thermal behavior were also performed by photographic images, scanning electron microscopy, differential scanning calorimetry, and thermogravimetric analysis. It can be concluded that the use of 3D-printing in the shaping of neat PLA and PLA/TPU blend was generally very beneficial; on the other hand, due to the differences in the orientation of the GF reinforcements, there could be certain reductions in the mechanical performance of PLA/GF and PLA/TPU/GF composite specimens.

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Three-Dimensional-Printed Scaffolds for Meniscus Tissue Engineering: Opportunity for the Future in the Orthopaedic World

Journal of Functional Biomaterials ◽

10.3390/jfb12040069 ◽

2021 ◽

Vol 12 (4) ◽

pp. 69

Author(s):

Angelo V. Vasiliadis ◽

Nikolaos Koukoulias ◽

Konstantinos Katakalos

Keyword(s):

Tissue Engineering ◽

Three Dimensional ◽

In Vivo Studies ◽

Cell Based Therapy ◽

Meniscus Tissue ◽

The Future ◽

Healthy Knee ◽

3D Printed

The meniscus is a critical component of a healthy knee joint. It is a complex and vital fibrocartilaginous tissue that maintains appropriate biomechanics. Injuries of the meniscus, particularly in the inner region, rarely heal and usually progress into structural breakdown, followed by meniscus deterioration and initiation of osteoarthritis. Conventional therapies range from conservative treatment, to partial meniscectomy and even meniscus transplantation. All the above have high long-term failure rates, with recurrence of symptoms. This communication presents a brief account of in vitro and in vivo studies and describes recent developments in the field of 3D-printed scaffolds for meniscus tissue engineering. Current research in meniscal tissue engineering tries to combine polymeric biomaterials, cell-based therapy, growth factors, and 3D-printed scaffolds to promote the healing of meniscal defects. Today, 3D-printing technology represents a big opportunity in the orthopaedic world to create more specific implants, enabling the rapid production of meniscal scaffolds and changing the way that orthopaedic surgeons plan procedures. In the future, 3D-printed meniscal scaffolds are likely to be available and will also be suitable substitutes in clinical applications, in an attempt to imitate the complexity of the native meniscus.

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Recycled algae-based carbon materials as electroconductive 3D printed skeletal muscle tissue engineering scaffolds

Journal of Materials Science Materials in Medicine ◽

10.1007/s10856-021-06534-6 ◽

2021 ◽

Vol 32 (7) ◽

Author(s):

Selva Bilge ◽

Emre Ergene ◽

Ebru Talak ◽

Seyda Gokyer ◽

Yusuf Osman Donar ◽

...

Keyword(s):

Skeletal Muscle ◽

Tissue Engineering ◽

Electrical Stimulation ◽

Muscle Tissue ◽

Carbonaceous Material ◽

Hydrothermal Carbonization ◽

Skeletal Muscle Tissue ◽

Myotube Formation ◽

3D Printed

AbstractSkeletal muscle is an electrically and mechanically active tissue that contains highly oriented, densely packed myofibrils. The tissue has self-regeneration capacity upon injury, which is limited in the cases of volumetric muscle loss. Several regenerative therapies have been developed in order to enhance this capacity, as well as to structurally and mechanically support the defect site during regeneration. Among them, biomimetic approaches that recapitulate the native microenvironment of the tissue in terms of parallel-aligned structure and biophysical signals were shown to be effective. In this study, we have developed 3D printed aligned and electrically active scaffolds in which the electrical conductivity was provided by carbonaceous material (CM) derived from algae-based biomass. The synthesis of this conductive and functional CM consisted of eco-friendly synthesis procedure such as pre-carbonization and multi-walled carbon nanotube (MWCNT) catalysis. CM obtained from biomass via hydrothermal carbonization (CM-03) and its ash form (CM-03K) were doped within poly(ɛ-caprolactone) (PCL) matrix and 3D printed to form scaffolds with aligned fibers for structural biomimicry. Scaffolds were seeded with C2C12 mouse myoblasts and subjected to electrical stimulation during the in vitro culture. Enhanced myotube formation was observed in electroactive groups compared to their non-conductive counterparts and it was observed that myotube formation and myotube maturity were significantly increased for CM-03 group after electrical stimulation. The results have therefore showed that the CM obtained from macroalgae biomass is a promising novel source for the production of the electrically conductive scaffolds for skeletal muscle tissue engineering.

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Fabrication of 3D-Printed Interpenetrating Hydrogel Scaffolds for Promoting Chondrogenic Differentiation

Polymers ◽

10.3390/polym13132146 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2146

Author(s):

Jian Guan ◽

Fu-zhen Yuan ◽

Zi-mu Mao ◽

Hai-lin Zhu ◽

Lin Lin ◽

...

Keyword(s):

Tissue Engineering ◽

Elastic Modulus ◽

Chondrogenic Differentiation ◽

Marker Genes ◽

Self Healing ◽

Polyethylene Glycol Diacrylate ◽

3D Microenvironment ◽

3D Printed

The limited self-healing ability of cartilage necessitates the application of alternative tissue engineering strategies for repairing the damaged tissue and restoring its normal function. Compared to conventional tissue engineering strategies, three-dimensional (3D) printing offers a greater potential for developing tissue-engineered scaffolds. Herein, we prepared a novel photocrosslinked printable cartilage ink comprising of polyethylene glycol diacrylate (PEGDA), gelatin methacryloyl (GelMA), and chondroitin sulfate methacrylate (CSMA). The PEGDA-GelMA-CSMA scaffolds possessed favorable compressive elastic modulus and degradation rate. In vitro experiments showed good adhesion, proliferation, and F-actin and chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the scaffolds. When the CSMA concentration was increased, the compressive elastic modulus, GAG production, and expression of F-actin and cartilage-specific genes (COL2, ACAN, SOX9, PRG4) were significantly improved while the osteogenic marker genes of COL1 and ALP were decreased. The findings of the study indicate that the 3D-printed PEGDA-GelMA-CSMA scaffolds possessed not only adequate mechanical strength but also maintained a suitable 3D microenvironment for differentiation, proliferation, and extracellular matrix production of BMSCs, which suggested this customizable 3D-printed PEGDA-GelMA-CSMA scaffold may have great potential for cartilage repair and regeneration in vivo.

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