The effect of zinc oxide doping on mechanical and biological properties of 3D printed calcium sulfate based scaffolds

AbstractThis study evaluates the suitability of 3D printed biodegradable mats to load and deliver the topical antibiotic, neomycin, for up to 3 weeks in vitro. A 3D printer equipped with a hot melt extruder was used to print bandage-like wound coverings with porous sizes appropriate for cellular attachment and viability. The semicrystalline polyester, poly-l-lactic acid (PLLA) was used as the base polymer, coated (post-printing) with polyethylene glycols (PEGs) of MWs 400 Da, 6 kDa, or 20 kDa to enable manipulation of physicochemical and biological properties to suit intended applications. The mats were further loaded with a topical antibiotic (neomycin sulfate), and cumulative drug-release monitored for 3 weeks in vitro. Microscopic imaging as well as Scanning Electron Microscopy (SEM) studies showed pore dimensions of 100 × 400 µm. These pore dimensions were achieved without compromising mechanical strength; because of the “tough” individual fibers constituting the mat (Young’s Moduli of 50 ± 20 MPa and Elastic Elongation of 10 ± 5%). The in vitro dissolution study showed first-order release kinetics for neomycin during the first 20 h, followed by diffusion-controlled (Fickian) release for the remaining duration of the study. The release of neomycin suggested that the ability to load neomycin on to PLLA mats increases threefold, as the MW of the applied PEG coating is lowered from 20 kDa to 400 Da. Overall, this study demonstrates a successful approach to using a 3D printer to prepare porous degradable mats for antibiotic delivery with potential applications to dermal regeneration and tissue engineering.

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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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Strategies for inclusion of growth factors into 3D printed bone grafts

Essays in Biochemistry ◽

10.1042/ebc20200130 ◽

2021 ◽

Author(s):

Alessia Longoni ◽

Jun Li ◽

Gabriella C.J. Lindberg ◽

Jelena Rnjak-Kovacina ◽

Lyn M. Wise ◽

...

Keyword(s):

Growth Factors ◽

Bone Regeneration ◽

New Technologies ◽

Healing Process ◽

Bone Grafts ◽

Biological Properties ◽

3 Dimensional ◽

3D Printed ◽

Physical And Chemical ◽

Large Bone

Abstract There remains a critical need to develop new technologies and materials that can meet the demands of treating large bone defects. The advancement of 3-dimensional (3D) printing technologies has allowed the creation of personalized and customized bone grafts, with specific control in both macro- and micro-architecture, and desired mechanical properties. Nevertheless, the biomaterials used for the production of these bone grafts often possess poor biological properties. The incorporation of growth factors (GFs), which are the natural orchestrators of the physiological healing process, into 3D printed bone grafts, represents a promising strategy to achieve the bioactivity required to enhance bone regeneration. In this review, the possible strategies used to incorporate GFs to 3D printed constructs are presented with a specific focus on bone regeneration. In particular, the strengths and limitations of different methods, such as physical and chemical cross-linking, which are currently used to incorporate GFs to the engineered constructs are critically reviewed. Different strategies used to present one or more GFs to achieve simultaneous angiogenesis and vasculogenesis for enhanced bone regeneration are also covered in this review. In addition, the possibility of combining several manufacturing approaches to fabricate hybrid constructs, which better mimic the complexity of biological niches, is presented. Finally, the clinical relevance of these approaches and the future steps that should be taken are discussed.

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Enhancing X-ray Attenuation of 3D Printed Gelatin Methacrylate (GelMA) Hydrogels Utilizing Gold Nanoparticles for Bone Tissue Engineering Applications

Polymers ◽

10.3390/polym11020367 ◽

2019 ◽

Vol 11 (2) ◽

pp. 367 ◽

Cited By ~ 9

Author(s):

Nehar Celikkin ◽

Simone Mastrogiacomo ◽

X. Walboomers ◽

Wojciech Swieszkowski

Keyword(s):

Tissue Engineering ◽

Gold Nanoparticles ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Biological Properties ◽

Proof Of Concept ◽

New Bone Formation ◽

X Ray ◽

3D Printed ◽

Low Toxicity

Bone tissue engineering is a rapidly growing field which is currently progressing toward clinical applications. Effective imaging methods for longitudinal studies are critical to evaluating the new bone formation and the fate of the scaffolds. Computed tomography (CT) is a prevailing technique employed to investigate hard tissue scaffolds; however, the CT signal becomes weak in mainly-water containing materials, which hinders the use of CT for hydrogels-based materials. Nevertheless, hydrogels such as gelatin methacrylate (GelMA) are widely used for tissue regeneration due to their optimal biological properties and their ability to induce extracellular matrix formation. To date, gold nanoparticles (AuNPs) have been suggested as promising contrast agents, due to their high X-ray attenuation, biocompatibility, and low toxicity. In this study, the effects of different sizes and concentrations of AuNPs on the mechanical properties and the cytocompatibility of the bulk GelMA-AuNPs scaffolds were evaluated. Furthermore, the enhancement of CT contrast with the cytocompatible size and concentration of AuNPs were investigated. 3D printed GelMA and GelMA-AuNPs scaffolds were obtained and assessed for the osteogenic differentiation of mesenchymal stem cells (MSC). Lastly, 3D printed GelMA and GelMA-AuNPs scaffolds were scanned in a bone defect utilizing µCT as the proof of concept that the GelMA-AuNPs are good candidates for bone tissue engineering with enhanced visibility for µCT imaging.

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Comparative Study of Biological (Phoenix loureiroi Fruit) and Chemical Synthesis of Chitosan-Encapsulated Zinc Oxide Nanoparticles and their Biological Properties

Arabian Journal for Science and Engineering ◽

10.1007/s13369-019-04174-1 ◽

2019 ◽

Vol 45 (1) ◽

pp. 15-28 ◽

Cited By ~ 1

Author(s):

Murugan Rajan ◽

Allen Joseph Anthuvan ◽

Kasipandi Muniyandi ◽

Naveen Kumar Kalagatur ◽

Saravanan Shanmugam ◽

...

Keyword(s):

Zinc Oxide ◽

Chemical Synthesis ◽

Comparative Study ◽

Zinc Oxide Nanoparticles ◽

Biological Properties ◽

Oxide Nanoparticles

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Influence of Topography on 3D printed Titanium Foot and Ankle Implants

Foot & Ankle Orthopaedics ◽

10.1177/2473011420s00016 ◽

2020 ◽

Vol 5 (4) ◽

pp. 2473011420S0001

Author(s):

Bijan Abar ◽

Cambre N. Kelly ◽

Nicholas B. Allen ◽

Helena Barber ◽

Alexander P. Kelly ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Testing ◽

Cellular Proliferation ◽

Quantitative Polymerase Chain Reaction ◽

Biological Properties ◽

Titanium Implants ◽

Foot And Ankle ◽

Cell Viability Assay ◽

Osseous Integration ◽

3D Printed

Category: Basic Sciences/Biologics; Ankle; Trauma Introduction/Purpose Foot and ankle etiologies such as traumatic fractures, Charcot Arthropathy, nonunion after high risk arthrodesis and infectious debridement can result in critical sized bone defect (CSD). CSD is defined as bone loss greater than 1-2 cm in length or greater than 50% loss in circumference of bone. CSD remain a significant challenge in Orthopaedics. Custom 3D printed porous Titanium implants are currently being implemented when allograft is not an option. However, in a subset of cases, Titanium implants need to be removed due to infection or poor osseous integration where surrounding bone does not grow onto or through the scaffold. There is no one clear reason for poor osseous integration. This study explores effects of 3D printed topography on mechanical and biological properties. Methods: Titanium dog bones and discs were printed via laser powder bed fusion. Roughness groups were polished, blasted, as built, sprouts and rough sprouts. Roughness was measured with line measurement using a confocal microscope. To assess mechanical properties, tensile testing of samples from each roughness group produced stress strain curves. MC3T3 preosteoblast were seeded on discs. Samples were analyzed at 0, 2, and 4 weeks. A cell viability assay and confocal florescent microscopy assessed cell growth. Alkaline Phosphatase (ALP) assay and Quantitative Polymerase Chain Reaction (qPCR) examined cell differentiation. Extracellular matrix (ECM) was stained for collagen and calcium. Scanning Electron Microcopy (SEM) was done on sputter coated discs. Results: Rz, maximum peak to valley distance of the sample profile, for the polished, blasted, as built, sprouts and rough sprouts were 2.6, 22.6, 33.0, 41.4 and 65.1 µm respectively. The addition of printed roughness in the sprouts and rough sprouts group significantly diminished ductility resulting in early strain to failure during tensile testing. Cells adhered and proliferated on discs regardless of roughness group. There was no statically difference in ALP activity, but qPCR showed that rough groups (sprouts and rough sprouts) had diminished Osteocalcin gene expression at week 2 and 4. The ECM observed with SEM in the rough groups was more resistant to repeated washes and was more extensive compared to the less rough groups. Conclusion: The addition of 3D printed artificial roughness leads to inferior mechanical properties and confers no clear benefit regarding cellular proliferation. Printed topography increases the initiation of fractures resulting in diminished tensile strength and ductility. Concurrently, the resolution of LBF is not fine enough at this time to create surface features that enhance cell behavior. Therefore, data in this study suggest that artificially printing roughness is not an effective strategy to enhance osseous integration into Titanium implants for critical sized defects.

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Composite System of 3D-Printed Polymer and Acellular Matrix Hydrogel to Repair Temporomandibular Joint Disc

Frontiers in Materials ◽

10.3389/fmats.2021.621416 ◽

2021 ◽

Vol 8 ◽

Author(s):

Ping Yi ◽

Jiadi Liang ◽

Futing Huang ◽

Zuodong Zhao ◽

Xiaohui Zhou ◽

...

Keyword(s):

Tissue Engineering ◽

Temporomandibular Joint ◽

Photoelectron Spectroscopy ◽

Biomechanical Testing ◽

Biomechanical Properties ◽

Biological Properties ◽

Cell Counting ◽

Structural And Functional Properties ◽

Tmj Disc ◽

3D Printed

Tissue engineering is a promising approach to restore or replace a damaged temporomandibular joint (TMJ) disc. However, constructing a scaffold that can mimic biomechanical and biological properties of the natural TMJ disc remains a challenge. In this study, three-dimensional (3D) printing technology was used to fabricate polycaprolactone (PCL)/polyurethane (PU) scaffolds and PU scaffolds to imitate the region-specific biomechanical properties of the TMJ disc. The scaffolds were coated with polydopamine (PDA) and combined with a decellularized matrix (dECM). Then, rat costal chondrocytes and mouse L929 fibroblasts, respectively, were suspended on the composite scaffolds and the biological functions of the cells were studied. The properties of the scaffolds were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), contact angle analysis, and biomechanical testing. To verify the biocompatibility of the scaffolds, the viability, proliferation, and extracellular matrix (ECM) production of the cells seeded on the scaffolds were assessed by LIVE/DEAD staining, Cell Counting Kit-8 assay, biochemical content analysis, immunofluorescence staining, and qRT-PCR. The functionalized hybrid scaffolds were then implanted into the subcutaneous space of nude mice for 6 weeks, and the regenerated tissue was evaluated by histological staining. The biomechanical properties of PCL/PU and PU scaffolds were comparable to that of the central and peripheral zones, respectively, of a native human TMJ disc. The PDA-coated scaffolds displayed superior biomechanical, structural, and functional properties, creating a favorable microenvironment for cell survival, proliferation, ECM production, and tissue regeneration. In conclusion, 3D-printed polymer scaffolds coated with PDA and combined with dECM hydrogel were found to be a promising substitute for TMJ disc tissue engineering.

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