Designing Controllable Porosity for Multifunctional Deformable Tissue Scaffolds

2012 ◽  
Vol 6 (3) ◽  
Author(s):  
AKM Bashirul Khoda ◽  
Bahattin Koc
Keyword(s):  
Tissue Engineering ◽  
Wound Healing ◽  
Negative Impact ◽  
Porous Scaffold ◽  
Three Dimensional ◽  
Effective Porosity ◽  
Free Form ◽  
Porous Scaffolds ◽  
Recent Developments ◽  
Applied Forces

Reconstructing or repairing a damaged tissue with porous scaffolds to restore the mechanical, biological, and chemical functions is one of the major tissue engineering and wound healing strategies. Recent developments in three-dimensional bioprinting techniques and improvements in the biomaterial properties have made fabrication of controlled and interconnected porous scaffold structures possible. Especially, for wound healing or soft tissue engineering, membranes/scaffolds made out of visco-elastic hydrogels, or other soft biomaterials with regular porous structures are commonly used. When the visco-elastic structures are applied onto a wound or damaged area, various forces might act upon these structures. The applied forces caused by bandage or occlusive dressings, contraction, and/or the self-weight could deform the fabricated scaffolds. As a result, the geometry and the designed porosity changes which eventually alters the desired choreographed functionality. To remedy this problem, a denser scaffold providing higher material concentration could be developed. However, denser scaffolds might have a negative impact on cell proliferation and also could block pathways for nutrient and waste transportation. In this work, a novel multifunctional visco-elastic scaffold modeling has been proposed to control the effective porosity of scaffolds. The designed scaffolds are optimized to provide spatial functionality and controlled material concentration under deformed conditions. The proposed methodology has been implemented and illustrative examples are provided in this paper. Effective porosity between the traditional and the proposed scaffold design have been compared by applying both models on the same free-form surface mimicking a wound.

Development of HA-PLGA Scaffold Encapsulating Intact BMP-2 Using Solid Freeform Fabrication Technology

2011 ◽  
Author(s):  
Jin-Hyung Shim ◽  
Jong Young Kim ◽  
Kyung Shin Kang ◽  
Jung Kyu Park ◽  
Sei Kwang Hahn ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Regeneration ◽  
Porous Scaffold ◽  
Solid Freeform Fabrication ◽  
Three Dimensional ◽  
Porous Scaffolds ◽  
Prolonged Release ◽  
Cellular Activity ◽  
Freeform Fabrication

Tissue engineering is an interdisciplinary field that focuses on restoring and repairing tissues or organs. Cells, scaffolds, and biomolecules are recognized as three main components of tissue engineering. Solid freeform fabrication (SFF) technology is required to fabricate three-dimensional (3D) porous scaffolds to provide a 3D environment for cellular activity. SFF technology is especially advantageous for achieving a fully interconnected, porous scaffold. Bone morphogenic protein-2 (BMP-2), an important biomolecule, is widely used in bone tissue engineering to enhance bone regeneration activity. However, methods for the direct incorporation of intact BMP-2 within 3D scaffolds are rare. In this work, 3D porous scaffolds with poly(lactic-co-glycolic acid) chemically grafted hyaluronic acid (HA-PLGA), in which intact BMP-2 was directly encapsulated, were successfully fabricated using SFF technology. BMP-2 was previously protected by poly(ethylene glycol) (PEG), and the BMP-2/PEG complex was incorporated in HA-PLGA using an organic solvent. The HAPLGA/PEG/BMP-2 mixture was dissolved in chloroform and deposited via a multi-head deposition system (MHDS), one type of SFF technology, to fabricate a scaffold for tissue engineering. An additional air blower system and suction were installed in the MHDS for the solvent-based fabrication method. An in vitro evaluation of BMP-2 release was conducted, and prolonged release of intact BMP-2, for up to 28 days, was confirmed. After confirmation of advanced proliferation of pre osteoblasts, a superior differentiation effect of the HA-PLGA/PEG/BMP-2 scaffold was validated by measuring high expression levels of bone-specific markers, such as alkaline phosphatase (ALP) and osteocalcin (OC). We show that our solvent-based fabrication is a non-toxic method for restoring cellular activity. Moreover, the HAPLGA/PEG/BMP-2 scaffold was effective for bone regeneration.

Bioinspired nanostructured hydroxyapatite/collagen three-dimensional porous scaffolds for bone tissue engineering

RSC Advances ◽  
2015 ◽  
Vol 5 (46) ◽  
pp. 36175-36184 ◽  
Author(s):  
Junjie Guan ◽  
Jun Yang ◽  
Junqi Dai ◽  
Yunhao Qin ◽  
Yang Wang ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Porous Scaffold ◽  
Three Dimensional ◽  
Porous Scaffolds ◽  
Needle Punching

A needle punching and bioinspired mineralization strategy has been developed to fabricate a collagen/hydroxyapatite porous scaffold for bone tissue engineering.

scholarly journals Macroporous chitosan/methoxypoly(ethylene glycol) based cryosponges with unique morphology for tissue engineering applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pradeep Kumar ◽  
Viness Pillay ◽  
Yahya E. Choonara
Keyword(s):  
Tissue Engineering ◽  
Polymer Network ◽  
Three Dimensional ◽  
Hysteresis Loops ◽  
Interpenetrating Polymer Network ◽  
Morphological Data ◽  
Porous Scaffolds ◽  
Morphological Variations ◽  
Molecular Stability ◽  
The Matrix

AbstractThree-dimensional porous scaffolds are widely employed in tissue engineering and regenerative medicine for their ability to carry bioactives and cells; and for their platform properties to allow for bridging-the-gap within an injured tissue. This study describes the effect of various methoxypolyethylene glycol (mPEG) derivatives (mPEG (-OCH3 functionality), mPEG-aldehyde (mPEG-CHO) and mPEG-acetic acid (mPEG-COOH)) on the morphology and physical properties of chemically crosslinked, semi-interpenetrating polymer network (IPN), chitosan (CHT)/mPEG blend cryosponges. Physicochemical and molecular characterization revealed that the –CHO and –COOH functional groups in mPEG derivatives interacted with the –NH2 functionality of the chitosan chain. The distinguishing feature of the cryosponges was their unique morphological features such as fringe thread-, pebble-, curved quartz crystal-, crystal flower-; and canyon-like structures. The morphological data was well corroborated by the image processing data and physisorption curves corresponding to Type II isotherm with open hysteresis loops. Functionalization of mPEG had no evident influence on the macro-mechanical properties of the cryosponges but increased the matrix strength as determined by the rheomechanical analyses. The cryosponges were able to deliver bioactives (dexamethasone and curcumin) over 10 days, showed varied matrix degradation profiles, and supported neuronal cells on the matrix surface. In addition, in silico simulations confirmed the compatibility and molecular stability of the CHT/mPEG blend compositions. In conclusion, the study confirmed that significant morphological variations may be induced by minimal functionalization and crosslinking of biomaterials.

scholarly journals A Review on Hydrogels with Photothermal Effect in Wound Healing and Bone Tissue Engineering

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2100
Author(s):  
Xu Zhang ◽  
Bowen Tan ◽  
Yanting Wu ◽  
Min Zhang ◽  
Jinfeng Liao
Keyword(s):  
Tissue Engineering ◽  
Wound Healing ◽  
Bone Regeneration ◽  
Controlled Drug Release ◽  
Multidrug Resistant ◽  
Future Application ◽  
Photothermal Effect ◽  
Resistant Bacteria ◽  
Promote Cell Proliferation ◽  
Recent Developments

Photothermal treatment (PTT) is a promising strategy to deal with multidrug-resistant bacteria infection and promote tissue regeneration. Previous studies demonstrated that hyperthermia can effectively inhibit the growth of bacteria, whereas mild heat can promote cell proliferation, further accelerating wound healing and bone regeneration. Especially, hydrogels with photothermal properties could achieve remotely controlled drug release. In this review, we introduce a photothermal agent hybrid in hydrogels for a photothermal effect. We also summarize the potential mechanisms of photothermal hydrogels regarding antibacterial action, angiogenesis, and osteogenesis. Furthermore, recent developments in photothermal hydrogels in wound healing and bone regeneration applications are introduced. Finally, future application of photothermal hydrogels is discussed. Hydrogels with photothermal effects provide a new direction for wound healing and bone regeneration, and this review will give a reference for the tissue engineering.

scholarly journals Porous Geometry Guided Micro-mechanical Environment Within Scaffolds for Cell Mechanobiology Study in Bone Tissue Engineering

2021 ◽  
Vol 9 ◽  
Author(s):  
Feihu Zhao ◽  
Yi Xiong ◽  
Keita Ito ◽  
Bert van Rietbergen ◽  
Sandra Hofmann
Keyword(s):  
Porous Scaffold ◽  
Mechanical Strain ◽  
Three Dimensional ◽  
Pore Geometry ◽  
Cell Physiology ◽  
Porous Scaffolds ◽  
Mechanical Environment ◽  
Functional Features ◽  
Future Work

Mechanobiology research is for understanding the role of mechanics in cell physiology and pathology. It will have implications for studying bone physiology and pathology and to guide the strategy for regenerating both the structural and functional features of bone. Mechanobiological studies in vitro apply a dynamic micro-mechanical environment to cells via bioreactors. Porous scaffolds are commonly used for housing the cells in a three-dimensional (3D) culturing environment. Such scaffolds usually have different pore geometries (e.g. with different pore shapes, pore dimensions and porosities). These pore geometries can affect the internal micro-mechanical environment that the cells experience when loaded in the bioreactor. Therefore, to adjust the applied micro-mechanical environment on cells, researchers can tune either the applied load and/or the design of the scaffold pore geometries. This review will provide information on how the micro-mechanical environment (e.g. fluid-induced wall shear stress and mechanical strain) is affected by various scaffold pore geometries within different bioreactors. It shall allow researchers to estimate/quantify the micro-mechanical environment according to the already known pore geometry information, or to find a suitable pore geometry according to the desirable micro-mechanical environment to be applied. Finally, as future work, artificial intelligent – assisted techniques, which can achieve an automatic design of solid porous scaffold geometry for tuning/optimising the micro-mechanical environment are suggested.

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

2021 ◽  
Vol 2021 ◽  
pp. 1-20 ◽  
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.

Development of Scaffold Building Units and Assembly for Tissue Engineering Using Fused Deposition Modelling

2009 ◽  
Vol 83-86 ◽  
pp. 269-274 ◽  
Author(s):  
Syed H. Masood ◽  
Kadhim Alamara
Keyword(s):  
Tissue Engineering ◽  
Pore Size ◽  
Fused Deposition Modeling ◽  
Porous Scaffold ◽  
Cell Structure ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Unit Cells

In tissue engineering (TE), a porous scaffold structure of biodegradable material is required as a template to guide the proliferation, growth and development of cells appropriately in three dimensions. The scaffold must meet design requirements of appropriate porosity, pore size and interconnected structure to allow cell proliferation and adhesion. This paper presents a methodology for design and manufacture of TE scaffolds with varying porosity by employing open structure building units and Fused Deposition Modeling (FDM) rapid prototyping technique. A computer modeling approach for constructing and assembly of three-dimensional unit cell structure is presented to provide a solution of scaffolds design that can potentially meet the diverse requirements of TE applications. A parametric set of open polyhedral unit cells is used to assist the user in designing the required micro-architecture of the scaffold with required porosity and pore size and then the Boolean operation is used to create the scaffold of a given CAD model from the designed microstructure. The procedure is verified by fabrication of physical scaffolds using the commercial FDM system.

Preparation and Characterization of Ha/Gel/β-TCP Microspheres Composite Porous Scaffold

2018 ◽  
Vol 782 ◽  
pp. 103-115
Author(s):  
Yang Zi Zhao ◽  
You Fa Wang
Keyword(s):  
Tissue Engineering ◽  
Compressive Strength ◽  
Hyaluronic Acid ◽  
Pore Size ◽  
Porous Scaffold ◽  
Three Dimensional ◽  
Swelling Ratio ◽  
Cell Compatibility ◽  
Hydrogel Scaffolds

Being one of the three elements of tissue engineering, three-dimensional porous structure scaffold plays an important role in tissue engineering. As it not only prvovide cells for the life, but also serves as a template to guide tissue regeneration and control of organizational structure and other functions. In this study, hyaluronic acid and gelatin are successfully cross-linked by 1-ethyl- (3-dimethylaminopropyl) -carbodiimide hydrochloride (EDC) , and compound β-TCP microspheres to prepare porous hydrogel scaffolds. The microspheres were analyzed by X-ray diffraction (XRD). The scaffolds were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). At the same time, the compressive strength, swelling ratio, degradation of the scaffold were tested. To assess the in vitro cell compatibility of the scaffolds, mouse L929 fibroblasts were seeded onto scaffolds for cell morphology and cell viability studies. The results showed that the pore size of the porous scaffold can be adjusted by changing the ratio of gelatin to hyaluronic acid (HA), increasing the proportion of hyaluronic acid in a certain range, pore size will be significantly increased. With the increase of the proportion of hyaluronic acid in the scaffold, the swelling ratio and the degradation rate also increased. The compressive strength of the scaffold increased with the increase of the proportion of gelatin. The appropriate ratio of β-TCP can promote cell growth and proliferation.

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