Scaffolds for Tissue Engineering

MRS Bulletin ◽  
2003 ◽  
Vol 28 (4) ◽  
pp. 301-306 ◽  
Author(s):  
Jeffrey M. Karp ◽  
Paul D. Dalton ◽  
Molly S. Shoichet
Keyword(s):  
Tissue Engineering ◽  
Soft Tissues ◽  
High Water ◽  
Nerve Fibers ◽  
Nerve Tissue ◽  
Tissue Type ◽  
High Water Content ◽  
Tissue Engineering Scaffolds ◽  
High Degree ◽  
Interconnected Pores

AbstractDevices for tissue engineering comprise scaffolds with the appropriate chemistry and architecture to promote cell infiltration and colonization. The scaffold is designed with biology in mind, and thus the architecture and chemistry differ according to tissue type. In this review, we focus on scaffolds for two tissue types—bone and nervous tissue—and describe different approaches used to create them. The appropriate scaffold for a hard tissue such as bone has a high degree of interconnected macroporosity and allows the rapid invasion of cells while maintaining a rigid structure. Several approaches are described for constructing tissue-engineering scaffolds for bone. The appropriate scaffold for soft tissues like nerve fibers (e.g., axons, which conduct nerve impulses) also has a high degree of interconnected pores; however, the pores may require orientation and may be smaller. Homogeneous, high-water-content hydrogels with mechanical properties that match the soft nerve tissue are commonly used as a scaffold, and the methods used to make these are reviewed.

scholarly journals Smart Hydrogels in Tissue Engineering and Regenerative Medicine

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3323 ◽  
Author(s):  
Somasundar Mantha ◽  
Sangeeth Pillai ◽  
Parisa Khayambashi ◽  
Akshaya Upadhyay ◽  
Yuli Zhang ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Regenerative Medicine ◽  
3D Structure ◽  
Cell Immobilization ◽  
Decisive Role ◽  
High Water ◽  
Bioactive Molecules ◽  
High Water Content ◽  
Growth Factor Delivery ◽  
Tissue Engineering Scaffolds

The field of regenerative medicine has tremendous potential for improved treatment outcomes and has been stimulated by advances made in bioengineering over the last few decades. The strategies of engineering tissues and assembling functional constructs that are capable of restoring, retaining, and revitalizing lost tissues and organs have impacted the whole spectrum of medicine and health care. Techniques to combine biomimetic materials, cells, and bioactive molecules play a decisive role in promoting the regeneration of damaged tissues or as therapeutic systems. Hydrogels have been used as one of the most common tissue engineering scaffolds over the past two decades due to their ability to maintain a distinct 3D structure, to provide mechanical support for the cells in the engineered tissues, and to simulate the native extracellular matrix. The high water content of hydrogels can provide an ideal environment for cell survival, and structure which mimics the native tissues. Hydrogel systems have been serving as a supportive matrix for cell immobilization and growth factor delivery. This review outlines a brief description of the properties, structure, synthesis and fabrication methods, applications, and future perspectives of smart hydrogels in tissue engineering.

Hydrogels as Antibacterial Biomaterials

2018 ◽  
Vol 24 (8) ◽  
pp. 843-854 ◽  
Author(s):  
Weiguo Xu ◽  
Shujun Dong ◽  
Yuping Han ◽  
Shuqiang Li ◽  
Yang Liu
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Tissue Engineering ◽  
Water Content ◽  
Oxygen Permeability ◽  
Structural Diversity ◽  
High Water ◽  
Clinical Applications ◽  
High Water Content ◽  
Biomedical Field

Hydrogels, as a class of materials for tissue engineering and drug delivery, have high water content and solid-like mechanical properties. Currently, hydrogels with an antibacterial function are a research hotspot in biomedical field. Many advanced antibacterial hydrogels have been developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs and structural diversity. In this article, an overview is provided on the preparation and applications of various antibacterial hydrogels. Furthermore, the prospects in biomedical researches and clinical applications are predicted.

Preparation of Porous Multi-Channeled Chitosan Conduits for Nerve Tissue Engineering

2005 ◽  
Vol 288-289 ◽  
pp. 27-30 ◽  
Author(s):  
Q. Ao ◽  
A.J. Wang ◽  
W.L. Cao ◽  
C. Zhao ◽  
Ya Dong Gong ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Stainless Steel ◽  
Spinal Cord Injuries ◽  
Neuroblastoma Cells ◽  
Nerve Tissue ◽  
Tissue Engineering Scaffolds ◽  
Nerve Conduits ◽  
Porous Chitosan ◽  
Nerve Tissue Engineering ◽  
Chitosan Gel

A new method to fabricate porous chitosan nerve conduits with multi-channels was described. A uniquely designed mold was composed of 7-50 stainless steel needles and a set of plastic pedestals. Porous or imperforate chitosan tubes with 2-5mm inner diameter and 0.2-1.0 mm wall thickness were made firstly. The chitosan tubes were injected with 3% chitosan gel. The stainless steel needles longitudinally perforated through the chitosan tubes filled with chitosan gel, and the plastic pedestals were used to fix the needles. Lyophilization was used to finish fabrication. The diameter of channels was 0.2-0.4mm. Swelling property and biodegradability of Multi-channeled chitosan conduits were investigated. Wright’s staining and scanning electron microscope (SEM) were used to observe spread and proliferation of Neuroblastoma cells (N2A, mouse) on the conduits. It is promising that the porous chitosan nerve conduits with multi-channels are used as nerve tissue engineering scaffolds in repair of peripheral nerve and spinal cord injuries.

Engineering of nanometer-sized cross-linked hydrogels for biomedical applications

2010 ◽  
Vol 88 (3) ◽  
pp. 173-184 ◽  
Author(s):  
Jung Kwon Oh
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Tissue Engineering ◽  
Water Content ◽  
Biomedical Applications ◽  
Drug Delivery Systems ◽  
High Water ◽  
Delivery Systems ◽  
High Water Content ◽  
Surface Areas

Microgels/nanogels (micro/nanogels) are promising drug-delivery systems (DDS) because of their unique properties, including tunable chemical and physical structures, good mechanical properties, high water content, and biocompatibility. They also feature sizes tunable to tens of nanometers, large surface areas, and interior networks. These properties demonstrate the great potential of micro/nanogels for drug delivery, tissue engineering, and bionanotechnology. This mini-review describes the current approaches for the preparation and engineering of effective micro/nanogels for drug-delivery applications. It emphasizes issues of degradability and bioconjugation, as well as loading/encapsulation and release of therapeutics from customer-designed micro/nanogels.

scholarly journals Designing robust chitosan-based hydrogels for stem cell nesting under oxidative stress

Bioimpacts ◽  
2021 ◽  
Author(s):  
Zahra Olfat Noubari ◽  
Asal Golchin ◽  
Marziyeh Fathi ◽  
Ailar Nakhlband
Keyword(s):  
Oxidative Stress ◽  
Tissue Engineering ◽  
Stem Cells ◽  
Porous Structure ◽  
High Water ◽  
High Water Content ◽  
Dapi Staining ◽  
Antioxidant Genes ◽  
Wide Range ◽  
The Impact

Introduction: Hydrogels are unique candidates for a wide range of biomedical applications including drug delivery and tissue engineering. The present investigation was designed to consider the impact of chitosan-based hydrogels as a scaffold on the proliferation of human bone marrow mesenchymal stem cells (hBM-MSCs) besides neutralization of oxidative stress in hBM-MSCs. Methods: Chitosan (CS) and CS-gelatin hydrogels were fabricated through ionic crosslinking using β-glycerophosphate. The hBM-MSCs were cultured on the prepared matrices and their proliferation was evaluated using DAPI staining and MTT assay. Furthermore, the effect of hydrogels on oxidative stress was assessed by measuring the expression of NQO1, Nrf2, and HO-1 genes using real-time PCR. Results: The developed hydrogels indicated a porous structure with high water content. The toxicity studies showed that the prepared hydrogels have a high biocompatibility/cytocompatibility. The expression of intracellular antioxidant genes was studied to ensure that stress is not imposed by the scaffold on the nested cells. The results showed that Nrf2 as a super transcription factor of antioxidant genes and its downstream antioxidant gene, NQO1 were downregulated. Unexpectedly, the upregulation of HO-1 was detected in the current study. Conclusion: The prepared CS-based hydrogels with desired properties including porous structure, high swelling ability, and cytocompatibility did not show oxidative stress for the nesting of stem cells. Therefore, they could be attractive scaffolds to support stem cells for successful tissue engineering purposes.

scholarly journals IN VITRO AGGREGATION OF MIXED EMBRYONIC KIDNEY AND NERVE CELLS

1971 ◽  
Vol 50 (2) ◽  
pp. 457-468 ◽  
Author(s):  
Judith Medoff ◽  
Jerome Gross
Keyword(s):  
Lactic Dehydrogenase ◽  
Nerve Fibers ◽  
Nerve Cells ◽  
Nerve Tissue ◽  
Mixed Cell ◽  
Mixed Aggregates ◽  
Cell Stability ◽  
High Level ◽  
High Degree

The possible role of nerve on growth of embryonic parenchymal organs such as kidney was explored by measuring macromolecular synthesis (DNA, RNA, and protein and three enzymes) in aggregates of mixed suspensions of cells from dissociated chick embryo kidney and nerve tissue. One and one-half to threefold increments in net synthesis of the three different types of macromolecules were observed in the mixed aggregates of kidney and nerve cells as compared with those of single organs or mixtures of kidney with nonneural cells. The addition of nerve-growth factor (NGF) did not significantly affect the results. Increased incorporation of label was paralleled by increases in chemically measured DNA and protein, suggesting an increase in growth in the mixed kidney-nerve aggregates compared with those of single tissues. Measurements of survival rate did not indicate increased cell stability in the mixed aggregates. The activities of three enzymes, acid phosphatase, alkaline phosphatase, and lactic dehydrogenase, were also enhanced two to four times in cultures of kidney plus nerve cells. Morphologic studies indicated a high degree of reorganization of tubular structures within the reaggregates of kidney cells alone or in those mixed with nerve. In addition, radioautographs of thymidine-3H-labeled cells in the aggregates showed a high level of DNA synthesis in the reformed tubular cells. Electron micrographs revealed the presence of large numbers of nerve fibers containing microtubules in the mixed cell aggregates. The data suggest a significant role for nerve in the growth processes of embryonic parenchymal organs.

A Structural Model for the Flexural Mechanics of Nonwoven Tissue Engineering Scaffolds

2006 ◽  
Vol 128 (4) ◽  
pp. 610-622 ◽  
Author(s):  
George C. Engelmayr ◽  
Michael S. Sacks
Keyword(s):  
Tissue Engineering ◽  
Soft Tissues ◽  
Structural Model ◽  
Fiber Diameter ◽  
Polyglycolic Acid ◽  
Mechanical Effect ◽  
Effective Stiffness ◽  
Tissue Formation ◽  
Functional Requirements ◽  
Tissue Engineering Scaffolds

The development of methods to predict the strength and stiffness of biomaterials used in tissue engineering is critical for load-bearing applications in which the essential functional requirements are primarily mechanical. We previously quantified changes in the effective stiffness (E) of needled nonwoven polyglycolic acid (PGA) and poly-L-lactic acid (PLLA) scaffolds due to tissue formation and scaffold degradation under three-point bending. Toward predicting these changes, we present a structural model for E of a needled nonwoven scaffold in flexure. The model accounted for the number and orientation of fibers within a representative volume element of the scaffold demarcated by the needling process. The spring-like effective stiffness of the curved fibers was calculated using the sinusoidal fiber shapes. Structural and mechanical properties of PGA and PLLA fibers and PGA, PLLA, and 50:50 PGA/PLLA scaffolds were measured and compared with model predictions. To verify the general predictive capability, the predicted dependence of E on fiber diameter was compared with experimental measurements. Needled nonwoven scaffolds were found to exhibit distinct preferred (PD) and cross-preferred (XD) fiber directions, with an E ratio (PD/XD) of ∼3:1. The good agreement between the predicted and experimental dependence of E on fiber diameter (R2=0.987) suggests that the structural model can be used to design scaffolds with E values more similar to native soft tissues. A comparison with previous results for cell-seeded scaffolds (Engelmayr, G. C., Jr., et al., 2005, Biomaterials, 26(2), pp. 175–187) suggests, for the first time, that the primary mechanical effect of collagen deposition is an increase in the number of fiber-fiber bond points yielding effectively stiffer scaffold fibers. This finding indicated that the effects of tissue deposition on needled nonwoven scaffold mechanics do not follow a rule-of-mixtures behavior. These important results underscore the need for structural approaches in modeling the effects of engineered tissue formation on nonwoven scaffolds, and their potential utility in scaffold design.

Microbial Deterioration in Stored Fresh Fruit and Vegetables

1986 ◽  
Vol 15 (4) ◽  
pp. 160-166 ◽  
Author(s):  
R. T. Burchill ◽  
R. B. Maude
Keyword(s):  
Soft Tissues ◽  
High Water ◽  
Fruit And Vegetables ◽  
High Water Content ◽  
Stored Products ◽  
Microbial Infection ◽  
Low Temperature Storage ◽  
Single Form ◽  
Physical Treatments ◽  
Temperature Storage

Effort devoted to increased productivity in the field can be nullified by deterioration in storage before marketing. Because of their relatively high water content and soft tissues fruit and vegetables are particularly prone to deterioration due to invasion by microorganisms. Although a variety of chemical and physical treatments have been developed for the control of microbial infection of stored products, low temperature storage is probably the most effective single form of treatment.

scholarly journals Fabrication of poly(ε-caprolactone) tissue engineering scaffolds with fibrillated and interconnected pores utilizing microcellular injection molding and polymer leaching

RSC Advances ◽  
2017 ◽  
Vol 7 (69) ◽  
pp. 43432-43444 ◽  
Author(s):  
An Huang ◽  
Yongchao Jiang ◽  
Brett Napiwocki ◽  
Haoyang Mi ◽  
Xiangfang Peng ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Injection Molding ◽  
Three Dimensional ◽  
Tissue Engineering Scaffolds ◽  
Microcellular Injection Molding ◽  
Interconnected Pores ◽  
Porous Poly

Three-dimensional fibrillated interconnected porous poly(ε-caprolactone) scaffolds were prepared by microcellular injection molding and polymer leaching.

Study on Tissue Engineering Scaffolds of Silk Fibroin-Chitosan/ Nano-Hydroxyapatite Composite

2007 ◽  
Vol 330-332 ◽  
pp. 971-975 ◽  
Author(s):  
Guang Wu Wen ◽  
Jing Wang ◽  
Mu Qin Li ◽  
Xiang Cai Meng
Keyword(s):  
Tissue Engineering ◽  
Silk Fibroin ◽  
Porous Scaffolds ◽  
High Porosity ◽  
Tissue Engineering Scaffolds ◽  
Component Structure ◽  
X Ray ◽  
Hydroxyapatite Composite ◽  
Ray Diffusion ◽  
Interconnected Pores

The porous scaffolds of silk fibroin-chitosan /nano-hydroxyapatite (SF-CS / n-HA) were fabricated through the freeze- drying technique. Component, structure and morphology of scaffolds were studied by infrared (IR), X-ray diffusion (XRD) and scanning electron microscope (SEM), and the mechanical properties of the scaffolds were measured. The simulated body fluid (SBF) experiments were conducted to assess the bioactivity of the scaffolds. Results indicate that chemical binding is formed between HA and organics, the macropore diameter of the scaffolds varies from 150 to 400μm. The porous scaffolds with interconnected pores possess a high porosity of 78%-91% and compressive strength of 0.26 -1.96MPa, which can be controlled by adjusting the concentration of organic phases and prefreezing temperature. In the SBF tests, a layer of randomly oriented bone-like apatite crystals formed on the scaffold surface, which suggested that the composite material had good bioactivity. Studies suggest the feasibility of using SF-CS /n-HA composite scaffolds for bone tissue engineering.

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