skip to main content

Title: Decorating 3D Printed Scaffolds with Electrospun Nanofiber Segments for Tissue Engineering

Repairing large tissue defects often represents a great challenge in clinics due to issues regarding lack of donors, mismatched sizes, irregular shapes, and immune rejection. 3D printed scaffolds are attractive for growing cells and producing tissue constructs because of the intricate control over pore size, porosity, and geometric shape, but the lack of biomimetic surface nanotopography and limited biomolecule presenting capacity render them less efficacious in regulating cell responses. Herein, a facile method for coating 3D printed scaffolds with electrospun nanofiber segments is reported. The surface morphology of modified 3D scaffolds changes dramatically, displaying a biomimetic nanofibrous structure, while the bulk mechanical property, pore size, and porosity are not significantly compromised. The short nanofibers‐decorated 3D printed scaffolds significantly promote adhesion and proliferation of pre‐osteoblasts and bone marrow mesenchymal stem cells (BMSCs). Further immobilization of bone morphogenetic protein‐2 mimicking peptides to nanofiber segments‐decorated 3D printed scaffolds show enhanced mRNA expressions of osteogenic markers Runx2, Alp, OCN, and BSP in BMSCs, indicating the enhancement of BMSCs osteogenic differentiation. Together, the combination of 3D printing and electrospinning is a promising approach to greatly expand the functions of 3D printed scaffolds and enhance the efficacy of 3D printed scaffolds for tissue engineering.

more » « less
Author(s) / Creator(s):
 ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Advanced Biosystems
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    Additive manufacturing is a promising method for producing customized 3D bioactive constructs for regenerative medicine. Here, 3D printed highly osteogenic scaffolds using nanoengineered ionic–covalent entanglement ink (NICE) for bone tissue engineering are reported. This NICE ink consists of ionic–covalent entanglement reinforced with Laponite, a 2D nanosilicate (nSi) clay, allowing for the printing of anatomic‐sized constructs with high accuracy. The 3D printed structure is able to maintain high structural stability in physiological conditions without any significant swelling or deswelling. The presence of nSi imparts osteoinductive characteristics to the NICE scaffolds, which is further augmented by depositing pluripotent stem cell‐derived extracellular matrix (ECM) on the scaffolds. This is achieved by stimulating human induced pluripotent stem cell‐derived mesenchymal stem cells (iP‐hMSCs) with 2‐chloro‐5‐nitrobenzanilide, a PPARγ inhibitor that enhances Wnt pathway, resulting in the deposition of an ECM characterized by high levels of collagens VI and XII found in anabolic bone. The osteoinductive characteristics of these bioconditioned NICE (bNICE) scaffolds is demonstrated through osteogenic differentiation of bone marrow derived human mesenchymal stem cells. A significant increase in the expression of osteogenic gene markers as well as mineralized ECM are observed on bioconditioned NICE (bNICE) scaffolds compared to bare scaffolds (NICE). The bioconditioned 3D printed scaffolds provide a unique strategy to design personalized bone grafts for in situ bone regeneration.

    more » « less
  2. Abstract

    Implantation of stem cells for tissue regeneration faces significant challenges such as immune rejection and teratoma formation. Cell‐free tissue regeneration thus has a potential to avoid these problems. Stem cell derived exosomes do not cause immune rejection or generate malignant tumors. Here, exosomes that can induce osteogenic differentiation of human mesenchymal stem cells (hMSCs) are identified and used to decorate 3D‐printed titanium alloy scaffolds to achieve cell‐free bone regeneration. Specifically, the exosomes secreted by hMSCs osteogenically pre‐differentiated for different times are used to induce the osteogenesis of hMSCs. It is discovered that pre‐differentiation for 10 and 15 days leads to the production of osteogenic exosomes. The purified exosomes are then loaded into the scaffolds. It is found that the cell‐free exosome‐coated scaffolds regenerate bone tissue as efficiently as hMSC‐seeded exosome‐free scaffolds within 12 weeks. RNA‐sequencing suggests that the osteogenic exosomes induce the osteogenic differentiation by using their cargos, including upregulated osteogenic miRNAs (Hsa‐miR‐146a‐5p, Hsa‐miR‐503‐5p, Hsa‐miR‐483‐3p, and Hsa‐miR‐129‐5p) or downregulated anti‐osteogenic miRNAs (Hsa‐miR‐32‐5p, Hsa‐miR‐133a‐3p, and Hsa‐miR‐204‐5p), to activate the PI3K/Akt and MAPK signaling pathways. Consequently, identification of osteogenic exosomes secreted by pre‐differentiated stem cells and the use of them to replace stem cells represent a novel cell‐free bone regeneration strategy.

    more » « less
  3. Three-dimensional (3D) printing was utilized for the fabrication of a composite scaffold of poly(ε-caprolactone) (PCL) and calcium magnesium phosphate (CMP) bioceramics for bone tissue engineering application. Four groups of scaffolds, that is, PMC-0, PMC-5, PMC-10, and PMC-15, were fabricated using a custom 3D printer. Rheology analysis, surface morphology, and wettability of the scaffolds were characterized. The PMC-0 scaffolds displayed a smoother surface texture and an increase in the ceramic content of the composite scaffolds exhibited a rougher structure. The hydrophilicity of the composite scaffold was significantly enhanced compared to the control PMC-0. The effect of ceramic content on the bioactivity of fibroblast NIH/3T3 cells in the composite scaffold was investigated. Cell viability and toxicity studies were evaluated by comparing results from lactate dehydrogenase (LDH) and Alamar Blue (AB) colorimetric assays, respectively. The live-dead cell assay illustrated the biocompatibility of the tested samples with more than 100% of live cells on day 3 compared to the control one. The LDH release indicated that the composite scaffolds improved cell attachment and proliferation. In this research, the fabrication of a customized composite 3D scaffold not only mimics the rough textured architecture, porosity, and chemical composition of natural bone tissue matrices but also serves as a source for soluble ions of calcium and magnesium that are favorable for bone cells to grow. These 3D-printed scaffolds thus provide a desirable microenvironment to facilitate biomineralization and could be a new effective approach for preparing constructs suitable for bone tissue engineering. 
    more » « less
  4. Babski-Reeves, K ; Eksioglu, B ; Hampton, D. (Ed.)
    Traditional static cell culture methods don't guarantee access to medium inside areas or through the scaffolds because of the complex three-dimensional nature of the 3D bio-printed scaffolds. The bioreactor provides the necessary growth medium encapsulated and seeded cells in 3D bioprinted scaffolds. The constant flow of new growing medium could promote more viable and multiplying cells. Therefore, we created a specialized perfusion bioreactor that dynamically supplies the growth medium to the cells implanted or encapsulated in the scaffolds. A redesigned configuration of our developed bioreactor may enhance the in vivo stimuli and circumstances, ultimately improving the effectiveness of tissue regeneration. This study investigated how different scaffold pore shapes and porosities affect the flow. We employed a simulation technique to calculate fluid flow turbulence across several pore geometries, including uniform triangular, square, circular, and honeycomb. We constructed a scaffold with changing pore diameters to examine the fluid movement while maintaining constant porosity. The impact of fluid flow was then determined by simulating and mimicking the architecture of bone tissue. The best scaffold designs were chosen based on the findings. 
    more » « less
  5. Abstract

    Due to the three-dimensional nature of the 3D bio-printed scaffolds, typical stagnant cell culturing methods don’t ensure entering medium inside areas or passing through the scaffolds. The bioreactor has frequently provided the required growth medium to encapsulated- and seeded-cells in 3D bio-printed scaffolds. To address this issue, we developed a customized perfusion bioreactor to supply the growth medium dynamically to the cells encapsulated or seeded in the scaffolds. The dynamic supply of fresh growth medium may help improve cell viability and proliferation. Because of its uniform nutrition distribution and flow-induced shear stress within the tissue-engineering scaffold, perfusion bioreactors have been used in a variety of tissue engineering applications. Including a modified setup of our designed bioreactor may improve the in vivo stimuli and conditions, eventually enhancing the overall performance of tissue regeneration. In this paper, we explored the response of fluid flow to certain types of scaffold pore geometries and porosities. We used a simulation technique to determine fluid flow turbulence through various pore geometries such as uniform triangular, square, diamond, circular, and honeycomb. We used variable pore sizes of the scaffold maintaining constant porosity to analyze the fluid flow. Based on the results, optimum designs for scaffolds were determined.

    more » « less