Polycaprolactone Scaffolds Fabricated via Bioextrusion for Tissue Engineering Applications

The most promising approach in Tissue Engineering involves the seeding of porous, biocompatible/biodegradable scaffolds, with donor cells to promote tissue regeneration. Additive biomanufacturing processes are increasingly recognized as ideal techniques to produce 3D structures with optimal pore size and spatial distribution, providing an adequate mechanical support for tissue regeneration while shaping in-growing tissues. This paper presents a novel extrusion-based system to produce 3D scaffolds with controlled internal/external geometry for TE applications.The BioExtruder is a low-cost system that uses a proper fabrication code based on the ISO programming language enabling the fabrication of multimaterial scaffolds. Poly(ε-caprolactone) was the material chosen to produce porous scaffolds, made by layers of directionally aligned microfilaments. Chemical, morphological, and in vitro biological evaluation performed on the polymeric constructs revealed a high potential of the BioExtruder to produce 3D scaffolds with regular and reproducible macropore architecture, without inducing relevant chemical and biocompatibility alterations of the material.

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Microscopic Analysis of Porous Biodegradable Scaffolds for Tissue Engineering

Microscopy and Microanalysis ◽

10.1017/s1431927600037430 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 988-989

Author(s):

F. Buevich ◽

S. Pulapura ◽

J. Kohn

Keyword(s):

Tissue Regeneration ◽

Combinatorial Library ◽

Three Dimensional ◽

Microscopic Analysis ◽

Porous Scaffolds ◽

Biodegradable Scaffolds ◽

Condensation Polymers ◽

Scaffold Architecture ◽

Useful Lifetime

Introduction: There is considerable interest in the use of three-dimensional porous scaffolds for tissue regeneration. The presence of an interconnected framework of pores with large surface area facilitates the formation of extracellular matrix and permits cellular ingrowth into implanted structures. For scaffolds to be useful for tissue regeneration, they must maintain good dimensional stability during the lifetime of the implant. While the initial scaffold architecture is often well characterized, a systematic study of the influence of incubation on the scaffold architecture is critical to ensure that the scaffolds retain their interconnected network of pores during their useful lifetime. Herein, we report on the evaluation of the architecture of polyarylate scaffolds and their stability under in vitro conditions using scanning electron microscopy (SEM).The polymers used in this study were selected from a library of degradable polyarylates. This library is the first reported combinatorial library of biodegradable condensation polymers.

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Decellularized bone extracellular matrix in skeletal tissue engineering

Biochemical Society Transactions ◽

10.1042/bst20190079 ◽

2020 ◽

Vol 48 (3) ◽

pp. 755-764

Author(s):

Benjamin B. Rothrauff ◽

Rocky S. Tuan

Keyword(s):

Tissue Engineering ◽

Bone Regeneration ◽

Tissue Regeneration ◽

Animal Studies ◽

Tumor Resection ◽

Regenerative Capacity ◽

Skeletal Tissue ◽

Large Bone

Bone possesses an intrinsic regenerative capacity, which can be compromised by aging, disease, trauma, and iatrogenesis (e.g. tumor resection, pharmacological). At present, autografts and allografts are the principal biological treatments available to replace large bone segments, but both entail several limitations that reduce wider use and consistent success. The use of decellularized extracellular matrices (ECM), often derived from xenogeneic sources, has been shown to favorably influence the immune response to injury and promote site-appropriate tissue regeneration. Decellularized bone ECM (dbECM), utilized in several forms — whole organ, particles, hydrogels — has shown promise in both in vitro and in vivo animal studies to promote osteogenic differentiation of stem/progenitor cells and enhance bone regeneration. However, dbECM has yet to be investigated in clinical studies, which are needed to determine the relative efficacy of this emerging biomaterial as compared with established treatments. This mini-review highlights the recent exploration of dbECM as a biomaterial for skeletal tissue engineering and considers modifications on its future use to more consistently promote bone regeneration.

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Development of Biopolymeric Hybrid Scaffold-Based on AAc/GO/nHAp/TiO2 Nanocomposite for Bone Tissue Engineering: In-Vitro Analysis

Nanomaterials ◽

10.3390/nano11051319 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1319

Author(s):

Muhammad Umar Aslam Khan ◽

Wafa Shamsan Al-Arjan ◽

Mona Saad Binkadem ◽

Hassan Mehboob ◽

Adnan Haider ◽

...

Keyword(s):

Mechanical Properties ◽

Tissue Engineering ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Guar Gum ◽

Porous Scaffolds ◽

Vitro Assay ◽

Vitro Analysis ◽

Nanocomposite Scaffolds

Bone tissue engineering is an advanced field for treatment of fractured bones to restore/regulate biological functions. Biopolymeric/bioceramic-based hybrid nanocomposite scaffolds are potential biomaterials for bone tissue because of biodegradable and biocompatible characteristics. We report synthesis of nanocomposite based on acrylic acid (AAc)/guar gum (GG), nano-hydroxyapatite (HAp NPs), titanium nanoparticles (TiO2 NPs), and optimum graphene oxide (GO) amount via free radical polymerization method. Porous scaffolds were fabricated through freeze-drying technique and coated with silver sulphadiazine. Different techniques were used to investigate functional group, crystal structural properties, morphology/elemental properties, porosity, and mechanical properties of fabricated scaffolds. Results show that increasing amount of TiO2 in combination with optimized GO has improved physicochemical and microstructural properties, mechanical properties (compressive strength (2.96 to 13.31 MPa) and Young’s modulus (39.56 to 300.81 MPa)), and porous properties (pore size (256.11 to 107.42 μm) and porosity (79.97 to 44.32%)). After 150 min, silver sulfadiazine release was found to be ~94.1%. In vitro assay of scaffolds also exhibited promising results against mouse pre-osteoblast (MC3T3-E1) cell lines. Hence, these fabricated scaffolds would be potential biomaterials for bone tissue engineering in biomedical engineering.

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Light Cross-Linkable Marine Collagen for Coaxial Printing of a 3D Model of Neuromuscular Junction Formation

Biomedicines ◽

10.3390/biomedicines9010016 ◽

2020 ◽

Vol 9 (1) ◽

pp. 16

Author(s):

Borja Sanz ◽

Ane Albillos Sanchez ◽

Bonnie Tangey ◽

Kerry Gilmore ◽

Zhilian Yue ◽

...

Keyword(s):

Tissue Engineering ◽

Neuromuscular Junction ◽

Disease Transmission ◽

Low Cost ◽

Attractive Alternative ◽

Waste Products ◽

Environmentally Sustainable ◽

Zoonotic Disease Transmission ◽

And Migration

Collagen is a major component of the extracellular matrix (ECM) that modulates cell adhesion, growth, and migration, and has been utilised in tissue engineering applications. However, the common terrestrial sources of collagen carry the risk of zoonotic disease transmission and there are religious barriers to the use of bovine and porcine products in many cultures. Marine based collagens offer an attractive alternative and have so far been under-utilized for use as biomaterials for tissue engineering. Marine collagen can be extracted from fish waste products, therefore industry by-products offer an economical and environmentally sustainable source of collagen. In a handful of studies, marine collagen has successfully been methacrylated to form collagen methacrylate (ColMA). Our work included the extraction, characterization and methacrylation of Red Snapper collagen, optimisation of conditions for neural cell seeding and encapsulation using the unmodified collagen, thermally cross-linked, and the methacrylated collagen with UV-induced cross-linking. Finally, the 3D co-axial printing of neural and skeletal muscle cell cultures as a model for neuromuscular junction (NMJ) formation was investigated. Overall, the results of this study show great potential for a novel NMJ in vitro 3D bioprinted model that, with further development, could provide a low-cost, customizable, scalable and quick-to-print platform for drug screening and to study neuromuscular junction physiology and pathogenesis.

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In Vitro Degradation of β-TCP/PLLA Scaffolds with Different Proportions of β-TCP

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1545 ◽

2007 ◽

Vol 336-338 ◽

pp. 1545-1548

Author(s):

Lin Luo ◽

Guang Fu Yin ◽

Yun Zhang ◽

Ya Dong Yao ◽

Wei Zhong Yang ◽

...

Keyword(s):

Degradation Rate ◽

Porous Scaffolds ◽

Carbonate Apatite ◽

Tissue Formation ◽

Cellular Attachment ◽

Biodegradable Scaffolds ◽

Scaffold Structure ◽

Mechanical Strengths

Porous biodegradable scaffolds are widely used in bone tissue engineering to provide temporary templates for cellular attachment and matrix synthesis. Ideally, the degradation rate in vivo may be similar or slightly less than that of tissue formation, allowing for the maintenance of the scaffold structure and the mechanical support during early stages of tissue formation. Eventually, the 3-D spaces occupied by the porous scaffolds will be replaced by newly formed tissue. In this work, β-tricalcium phosphate/Poly-L lactide (β-TCP/PLLA) scaffolds with different proportions of β-TCP to PLLA were investigated. The effects of β-TCP proportions on degradation rate and mechanical strengths of the scaffolds were evaluated in simulated body fluid (SBF) at 37°C up to 42 days. Results show that: different proportions of β-TCP to PLLA have significant influence on degradation behaviors of the scaffolds, and mechanical strengths of the scaffolds with weight proportion of β-TCP to PLLA being 2 to 1 are much higher than those of the others during the degradation period. And in this period, the scaffolds biodegrade slowly, and Hydroxyl Carbonate Apatite (HCA) forms in the surface of the material.

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Bioengineered Teeth from Cultured Rat Tooth Bud Cells

Journal of Dental Research ◽

10.1177/154405910408300703 ◽

2004 ◽

Vol 83 (7) ◽

pp. 523-528 ◽

Cited By ~ 259

Author(s):

M.T. Duailibi ◽

S.E. Duailibi ◽

C.S. Young ◽

J.D. Bartlett ◽

J.P. Vacanti ◽

...

Keyword(s):

Tissue Engineering ◽

Stem Cells ◽

Mesenchymal Stem Cells ◽

Engineering Applications ◽

Adult Rat ◽

Dental Tissues ◽

Biodegradable Scaffolds ◽

Bioengineered Tooth ◽

Tooth Tissue

The recent bioengineering of complex tooth structures from pig tooth bud tissues suggests the potential for the regeneration of mammalian dental tissues. We have improved tooth bioengineering methods by comparing the utility of cultured rat tooth bud cells obtained from three- to seven-day post-natal (dpn) rats for tooth-tissue-engineering applications. Cell-seeded biodegradable scaffolds were grown in the omenta of adult rat hosts for 12 wks, then harvested. Analyses of 12-week implant tissues demonstrated that dissociated 4-dpn rat tooth bud cells seeded for 1 hr onto PGA or PLGA scaffolds generated bioengineered tooth tissues most reliably. We conclude that tooth-tissue-engineering methods can be used to generate both pig and rat tooth tissues. Furthermore, our ability to bioengineer tooth structures from cultured tooth bud cells suggests that dental epithelial and mesenchymal stem cells can be maintained in vitro for at least 6 days.

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Scaffolds in tissue engineering of blood vessels

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y10-073 ◽

2010 ◽

Vol 88 (9) ◽

pp. 855-873 ◽

Cited By ~ 60

Author(s):

Divya Pankajakshan ◽

Devendra K. Agrawal

Keyword(s):

Tissue Engineering ◽

Extracellular Matrix ◽

Blood Vessels ◽

Vascular Tissue ◽

Small Diameter ◽

Biological Scaffolds ◽

Hemodynamic Forces ◽

Biodegradable Scaffolds

Tissue engineering of small diameter (<5 mm) blood vessels is a promising approach for developing viable alternatives to autologous vascular grafts. It involves in vitro seeding of cells onto a scaffold on which the cells attach, proliferate, and differentiate while secreting the components of extracellular matrix that are required for creating the tissue. The scaffold should provide the initial requisite mechanical strength to withstand in vivo hemodynamic forces until vascular smooth muscle cells and fibroblasts reinforce the extracellular matrix of the vessel wall. Hence, the choice of scaffold is crucial for providing guidance cues to the cells to behave in the required manner to produce tissues and organs of the desired shape and size. Several types of scaffolds have been used for the reconstruction of blood vessels. They can be broadly classified as biological scaffolds, decellularized matrices, and polymeric biodegradable scaffolds. This review focuses on the different types of scaffolds that have been designed, developed, and tested for tissue engineering of blood vessels, including use of stem cells in vascular tissue engineering.

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Tuning the Properties of PNIPAm-Based Hydrogel Scaffolds for Cartilage Tissue Engineering

Polymers ◽

10.3390/polym13183154 ◽

2021 ◽

Vol 13 (18) ◽

pp. 3154

Author(s):

Md Mohosin Rana ◽

Hector De la Hoz Siegler

Keyword(s):

Tissue Engineering ◽

Physical Properties ◽

Tissue Regeneration ◽

Structural Integrity ◽

Cartilage Tissue ◽

Design Parameters ◽

Comprehensive Overview ◽

Hydrogel Scaffolds ◽

Design Variables

Poly(N-isopropylacrylamide) (PNIPAm) is a three-dimensional (3D) crosslinked polymer that can interact with human cells and play an important role in the development of tissue morphogenesis in both in vitro and in vivo conditions. PNIPAm-based scaffolds possess many desirable structural and physical properties required for tissue regeneration, but insufficient mechanical strength, biocompatibility, and biomimicry for tissue development remain obstacles for their application in tissue engineering. The structural integrity and physical properties of the hydrogels depend on the crosslinks formed between polymer chains during synthesis. A variety of design variables including crosslinker content, the combination of natural and synthetic polymers, and solvent type have been explored over the past decade to develop PNIPAm-based scaffolds with optimized properties suitable for tissue engineering applications. These design parameters have been implemented to provide hydrogel scaffolds with dynamic and spatially patterned cues that mimic the biological environment and guide the required cellular functions for cartilage tissue regeneration. The current advances on tuning the properties of PNIPAm-based scaffolds were searched for on Google Scholar, PubMed, and Web of Science. This review provides a comprehensive overview of the scaffolding properties of PNIPAm-based hydrogels and the effects of synthesis-solvent and crosslinking density on tuning these properties. Finally, the challenges and perspectives of considering these two design variables for developing PNIPAm-based scaffolds are outlined.

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Additive Manufacturing of Biopolymers for Tissue Engineering and Regenerative Medicine: An Overview, Potential Applications, Advancements, and Trends

International Journal of Polymer Science ◽

10.1155/2021/4907027 ◽

2021 ◽

Vol 2021 ◽

pp. 1-20 ◽

Cited By ~ 2

Author(s):

Dhinakaran Veeman ◽

M. Swapna Sai ◽

P. Sureshkumar ◽

T. Jagadeesha ◽

L. Natrayan ◽

...

Keyword(s):

Tissue Engineering ◽

Additive Manufacturing ◽

3D Printing ◽

Regenerative Medicine ◽

Tissue Regeneration ◽

Three Dimensional ◽

Porous Scaffolds ◽

Wide Range ◽

Potential Applications ◽

Pharmaceutical Industries

As a technique of producing fabric engineering scaffolds, three-dimensional (3D) printing has tremendous possibilities. 3D printing applications are restricted to a wide range of biomaterials in the field of regenerative medicine and tissue engineering. Due to their biocompatibility, bioactiveness, and biodegradability, biopolymers such as collagen, alginate, silk fibroin, chitosan, alginate, cellulose, and starch are used in a variety of fields, including the food, biomedical, regeneration, agriculture, packaging, and pharmaceutical industries. The benefits of producing 3D-printed scaffolds are many, including the capacity to produce complicated geometries, porosity, and multicell coculture and to take growth factors into account. In particular, the additional production of biopolymers offers new options to produce 3D structures and materials with specialised patterns and properties. In the realm of tissue engineering and regenerative medicine (TERM), important progress has been accomplished; now, several state-of-the-art techniques are used to produce porous scaffolds for organ or tissue regeneration to be suited for tissue technology. Natural biopolymeric materials are often better suited for designing and manufacturing healing equipment than temporary implants and tissue regeneration materials owing to its appropriate properties and biocompatibility. The review focuses on the additive manufacturing of biopolymers with significant changes, advancements, trends, and developments in regenerative medicine and tissue engineering with potential applications.

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Suture Fiber Reinforcement of a 3D Printed Gelatin Scaffold for Its Potential Application in Soft Tissue Engineering

International Journal of Molecular Sciences ◽

10.3390/ijms222111600 ◽

2021 ◽

Vol 22 (21) ◽

pp. 11600

Author(s):

Dong Jin Choi ◽

Kyoung Choi ◽

Sang Jun Park ◽

Young-Jin Kim ◽

Seok Chung ◽

...

Keyword(s):

Tissue Engineering ◽

Mechanical Strength ◽

Physical Properties ◽

Dimensional Stability ◽

3D Structure ◽

Biological Properties ◽

Dermal Fibroblasts ◽

3D Scaffolds ◽

3D Printed

Gelatin has excellent biological properties, but its poor physical properties are a major obstacle to its use as a biomaterial ink. These disadvantages not only worsen the printability of gelatin biomaterial ink, but also reduce the dimensional stability of its 3D scaffolds and limit its application in the tissue engineering field. Herein, biodegradable suture fibers were added into a gelatin biomaterial ink to improve the printability, mechanical strength, and dimensional stability of the 3D printed scaffolds. The suture fiber reinforced gelatin 3D scaffolds were fabricated using the thermo-responsive properties of gelatin under optimized 3D printing conditions (−10 °C cryogenic plate, 40–80 kPa pneumatic pressure, and 9 mm/s printing speed), and were crosslinked using EDC/NHS to maintain their 3D structures. Scanning electron microscopy images revealed that the morphologies of the 3D printed scaffolds maintained their 3D structure after crosslinking. The addition of 0.5% (w/v) of suture fibers increased the printing accuracy of the 3D printed scaffolds to 97%. The suture fibers also increased the mechanical strength of the 3D printed scaffolds by up to 6-fold, and the degradation rate could be controlled by the suture fiber content. In in vitro cell studies, DNA assay results showed that human dermal fibroblasts’ proliferation rate of a 3D printed scaffold containing 0.5% suture fiber was 10% higher than that of a 3D printed scaffold without suture fibers after 14 days of culture. Interestingly, the supplement of suture fibers into gelatin biomaterial ink was able to minimize the cell-mediated contraction of the cell cultured 3D scaffolds over the cell culture period. These results show that advanced biomaterial inks can be developed by supplementing biodegradable fibers to improve the poor physical properties of natural polymer-based biomaterial inks.

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