Testing Shape Memory of Porous Polymer Tissue Engineering Scaffolds in Compression

2011 ◽  
Author(s):  
Hugh Lippincott ◽  
Daniel F. Schmidt
Keyword(s):  
Tissue Engineering ◽  
Shape Memory ◽  
Test Methods ◽  
The Body ◽  
Porous Polymer ◽  
Small Samples ◽  
Porous Scaffolds ◽  
Tissue Engineering Scaffolds ◽  
Compression Cycle ◽  
Memory Applications

Shape recovery from memory by porous scaffolds for tissue engineering offers easier insertion and self-retention following placement by minimally invasive surgery. Shape memory testing of porous polymer xerogels focuses on the compression cycle and the special aspects of the cycle and equipment used. This contrasts with normal tensile shape memory (SM) testing. In this work a dynamic mechanical analyzer (DMA) was used on small samples to quickly yield measurement of the SM restoration at various stress levels to emulate the forces exerted on the body by a tissue engineering (TE) scaffold returning to its permanent shape. The DMA testing of a hexamethyl diisocyanate trimer crosslinked castor oil (CO) / polycaprolactone (PCL) blend yielded repeated SM with no creep. The porous CO/PCL showed repeated compressive SM at 50% strain with a SM stress-free recovery ratio of 100%. The peak SM recovery work of 6.4 KJ/m3 was measured at 0.5 MPa stress and 6% to 12% strain. In addition to the potential utility of these materials in a tissue engineering setting, the test methods described here are relevant to a broad range of shape memory applications, from medical devices to morphing airframes to self-deploying structures.

scholarly journals Polymeric Scaffolds in Tissue Engineering Application: A Review

2011 ◽  
Vol 2011 ◽  
pp. 1-19 ◽  
Author(s):  
Brahatheeswaran Dhandayuthapani ◽  
Yasuhiko Yoshida ◽  
Toru Maekawa ◽  
D. Sakthi Kumar
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Engineering Application ◽  
Biologically Active ◽  
Porous Scaffolds ◽  
Tissue Engineering Application ◽  
Tissue Engineering Scaffolds ◽  
Matrix Deposition ◽  
Bioactive Agents ◽  
Regenerate Tissue

Current strategies of regenerative medicine are focused on the restoration of pathologically altered tissue architectures by transplantation of cells in combination with supportive scaffolds and biomolecules. In recent years, considerable interest has been given to biologically active scaffolds which are based on similar analogs of the extracellular matrix that have induced synthesis of tissues and organs. To restore function or regenerate tissue, a scaffold is necessary that will act as a temporary matrix for cell proliferation and extracellular matrix deposition, with subsequent ingrowth until the tissues are totally restored or regenerated. Scaffolds have been used for tissue engineering such as bone, cartilage, ligament, skin, vascular tissues, neural tissues, and skeletal muscle and as vehicle for the controlled delivery of drugs, proteins, and DNA. Various technologies come together to construct porous scaffolds to regenerate the tissues/organs and also for controlled and targeted release of bioactive agents in tissue engineering applications. In this paper, an overview of the different types of scaffolds with their material properties is discussed. The fabrication technologies for tissue engineering scaffolds, including the basic and conventional techniques to the more recent ones, are tabulated.

Selective Laser Sintering of Tissue Engineering Scaffolds Using Poly(L-Lactide) Microspheres

2007 ◽  
Vol 334-335 ◽  
pp. 1225-1228 ◽  
Author(s):  
Wen You Zhou ◽  
S.H. Lee ◽  
Min Wang ◽  
W.L. Cheung
Keyword(s):  
Tissue Engineering ◽  
Porous Scaffold ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Porous Scaffolds ◽  
Tissue Engineering Scaffolds ◽  
Water Emulsion ◽  
Bed Temperature ◽  
Oil In Water Emulsion ◽  
Polyamide Powder

This paper reports a study on the modification of a commercial selective laser sintering (SLS) machine for the fabrication of tissue engineering scaffolds from small quantities of poly(L-lactide) (PLLA) microspheres. A miniature build platform was designed, fabricated and installed in the build cylinder of a Sinterstation 2000 system. Porous scaffolds in the form of rectangular prism, 12.7×12.7×25.4 mm3, with interconnected square and round channels were designed using SolidWorks. For initial trials, DuraFormTM polyamide powder was used to build scaffolds with a designed porosity of ~70%. The actual porosity was found to be ~83%, which indicated that the sintered regions were not fully dense. PLLA microspheres in the size range of 5-30 μm were made using an oil-in-water emulsion solvent evaporation procedure and they were suitable for the SLS process. A porous scaffold was sintered from the PLLA microspheres with a laser power of 15W and a part bed temperature of 60oC. SEM examination showed that the PLLA microspheres were partially melted to form the scaffold. This study has demonstrated that it is feasible to build tissue engineering scaffolds from small amounts of biomaterials using a commercial SLS machine with suitable modifications.

Thermal Processing of Tissue Engineering Scaffolds

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Alisa Morss Clyne
Keyword(s):  
Tissue Engineering ◽  
Thermal Processing ◽  
Three Dimensional ◽  
Processing Parameters ◽  
High Pressure Processing ◽  
Porous Scaffolds ◽  
Tissue Engineering Scaffolds ◽  
Thermally Induced ◽  
Advantages And Disadvantages ◽  
Particulate Leaching

Tissue engineering requires complex three-dimensional scaffolds that mimic natural extracellular matrix function. A wide variety of techniques have been developed to create both fibrous and porous scaffolds out of polymers, ceramics, metals, and composite materials. Existing techniques include fiber bonding, electrospinning, emulsion freeze drying, solvent casting/particulate leaching, gas foaming/particulate leaching, high pressure processing, and thermally induced phase separation. Critical scaffold properties, including pore size, porosity, pore interconnectivity, and mechanical integrity, are determined by thermal processing parameters in many of these techniques. In this review, each tissue engineering scaffold preparation method is discussed, including recent advancements as well as advantages and disadvantages of the technique, with a particular emphasis placed on thermal parameters. Improvements on these existing techniques, as well as new thermal processing methods for tissue engineering scaffolds, will be needed to provide tissue engineers with finer control over tissue and organ development.

APPLICATIONS OF CALCIUM PHOSPHATE NANOPARTICLES IN POROUS HARD TISSUE ENGINEERING SCAFFOLDS

NANO ◽  
2012 ◽  
Vol 07 (04) ◽  
pp. 1230004 ◽  
Author(s):  
ZHE WANG ◽  
ZHURONG TANG ◽  
FANGZHU QING ◽  
YOULIANG HONG ◽  
XINGDONG ZHANG
Keyword(s):  
Tissue Engineering ◽  
Calcium Phosphate ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Three Dimensional ◽  
Porous Scaffolds ◽  
Tissue Engineering Scaffolds ◽  
Important Approach ◽  
Calcium Phosphate Nanoparticles ◽  
Hard Tissue Engineering

To repair bone defects, an important approach is to fabricate tissue engineering scaffolds as substitutions to replace auto-/allologous bones. Currently, processing a biomaterial into three-dimensional porous scaffolds and incorporating the calcium phosphate (Ca–P) nanoparticles into scaffolds profile two main characteristics of bone tissue engineering scaffolds. Based on this fact, in this paper we describe the design principles of the Ca–P nanoparticle-based and porous bone tissue engineering scaffolds. Then we summarize a variety of the Ca–P nanoparticle-based scaffolds, including discussion of the integration of the Ca–P nanoparticles with ceramics and polymers, followed by introduction of safety of the Ca–P nanoparticles in scaffolds.

Monolithic shape memory alloy microgripper for 3D assembly of tissue engineering scaffolds

2001 ◽  
Author(s):  
Han Zhang ◽  
Yves Bellouard ◽  
Thomas C. Sidler ◽  
Etienne Burdet ◽  
Aun-Neow Poo ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Tissue Engineering Scaffolds ◽  
3D Assembly

Biodegradable spirulina extract/polycaprolactone porous scaffolds

2018 ◽  
Vol 42 (19) ◽  
pp. 15830-15838 ◽  
Author(s):  
Bo Shi ◽  
Liming Zhang ◽  
Liang Liang ◽  
Jianfeng Ban
Keyword(s):  
Tissue Engineering ◽  
Porous Scaffolds ◽  
Tissue Engineering Scaffolds

Hydrophilicity, pores with interconnected structures, and degradability are important properties of tissue engineering scaffolds.

Biodegradable Polymer Microfluidics for Tissue Engineering Microvasculature

2002 ◽  
Vol 729 ◽  
Author(s):  
Kevin R. King ◽  
Chiaochun Wang ◽  
Joseph P. Vacanti ◽  
Jeffrey T. Borenstein
Keyword(s):  
Tissue Engineering ◽  
Biodegradable Polymer ◽  
Microfluidic Channels ◽  
Porous Scaffolds ◽  
Scanning Electron Micrographs ◽  
Tissue Engineering Scaffolds ◽  
Bond Interface ◽  
Conventional Photolithography ◽  
Rapid Prototyping And Manufacturing ◽  
Capillary Size

AbstractIn this work, we present for the first time, the fabrication of a fully biodegradable microfluidic device with features of micron-scale precision. This implantable MEMS device is a transition from poorly defined porous scaffolds to reproducible precision scaffolds with built-in convective conduits. First, conventional photolithography is used to create a master mold by bulk micromachining silicon. Next, polydimethylsiloxane (PDMS) silicone elastomer is replica molded to form a flexible inverse mold. The commonly used biodegradable polymer Poly-lactic-co-glycolic acid (PLGA 85:15) is then compression micromolded onto the PDMS to form micropatterned films of the biodegradable polymer. Finally, a thermal fusion bonding process is used to seal the biodegradable PLGA films, forming closed microfluidic channels at the capillary size-scale. Film thicknesses from 100μm-1mm are demonstrated with features having 2μm resolution and 0.2μm precision. Scanning electron micrographs of bonded biodegradable films reveal no observable bond interface and no significant pattern deformation. Bonded microfluidic channels are capable of supporting more than 30psi during flow studies, and we have used the processes to develop complex microfluidic networks for cell culture and implantation as well as simple channels to verify the fluid dynamics in the degradable microchannels. The processes described here are high resolution and fully biodegradable. In addition, they are fast, inexpensive, reproducible, and scalable, making them ideal for both rapid prototyping and manufacturing of tissue engineering scaffolds.

Improving Bioactivity of Porous β-TCP Ceramics by Forming Bone-Like Apatite Layer on the Surfaces of Pore Walls

2012 ◽  
Vol 512-515 ◽  
pp. 1815-1820
Author(s):  
Qing Feng Zan ◽  
Yuan Zhuang ◽  
Li Min Dong ◽  
Chen Wang ◽  
Ning Wen ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Cell Attachment ◽  
Apatite Layer ◽  
Porous Scaffolds ◽  
Tissue Engineering Scaffolds ◽  
Naoh Solution ◽  
Pre Treatment ◽  
Cells Cultured

Bone tissue engineering provides a new way to repair the bone defect in orthopaedics. The scaffolds, porous materials with excellent biocompatibility, bioactivity and biodegradability, play an important role in bone tissue engineering. Furthermore, the bioactivity of the pore interior surfaces is very important for cell attachment, differentiation and growth, as well as new bone tissue ingrowth into pores. In this paper, β-TCP was selected as materials of scaffolds, and its bioactivity was improved by activating the interior surfaces of pore walls. The porous β-TCP scaffolds with about 50~300μm of pore size and above 80% of porosity were obtained by 3D-gel-laminated processing. Their surfaces of the scaffolds were easily covered by a low crystallized bone-like apatite layer, which determined by XRD and FTIR, after immersing in 1.5SBF solution following pre-treatment by NaOH solution. MTT and ALP assays were performed after cells cultured on the porous scaffolds with bone-like structure, and the results showed higher proliferation rate and differentiation level than that on the scaffolds without treatment, which indicated that the porous β-TCP scaffolds with bone-like apatite layer on surfaces of pore walls possess higher bioactivity. Therefore, the bioactivity of tissue engineering scaffolds could be improved by deposited bone-like apatite layer on their surfaces.

Design and 3D Printing of Hierarchical Tissue Engineering Scaffolds Based on Mechanics and Biology Perspectives

2016 ◽  
Author(s):  
Paul Egan ◽  
Stephen J. Ferguson ◽  
Kristina Shea
Keyword(s):  
Tissue Engineering ◽  
Surface Area ◽  
Structural Integrity ◽  
The Body ◽  
Cellular Growth ◽  
Design Parameters ◽  
Tissue Engineering Scaffolds ◽  
Structural Support ◽  
Trade Offs ◽  
Design Alternatives

Continued scientific research is crucial for developing new biomedical products, such as tissue engineering scaffolds, that are difficult to optimize due to the complexity of interfacing mechanical and biological systems. In this paper, mechanical and biological perspectives are used to propose and implement an approach for designing hierarchical scaffolds that provide structural support in the body as tissue regenerates. Three sequential steps are proposed for defining design needs, generating design alternatives, and fabricating design prototypes. Design needs are determined by considering mechanical and biological performance requirements, experimental procedures, and fabrication constraints. The primary mechanical requirement is a scaffold’s need to maintain structural integrity, while biologically the scaffold should promote cellular growth. Scaffold design alternatives of four topology types are generated by altering design parameters that describe a scaffold’s structure. Trade-offs are revealed for scaffold porosity and surface area properties that are known to influence mechanical and biological scaffold performance. Scaffolds of each topology type are designed with 80% porosity and fabricated, which enables their potential use in scientific experiments to measure how property trade-offs influence scaffold performance. On the basis of currently available knowledge, a to-scale spinal scaffold implant is designed and fabricated with a graphically maximized surface area to porosity ratio for a hierarchical scaffold, which represents a potentially high performing design from both mechanical and biological perspectives. These results demonstrate the importance of multidisciplinary approaches for designing complex biomedical tissue scaffolds that could significantly improve healthcare through the development of new clinical products.

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