جستجوی مقالات مرتبط با کلیدواژه « مهندسی بافت » در نشریات گروه « مواد و متالورژی »

Skin, as the largest body organ, performs several functions namely creating a protective barrier against microorganisms and regulating body temperature. For this reason, maintenance of skin integrity and health is of high importance. This tissue can repair itself in limited damages; however, under some conditions such as severe burns, extensive and deep damage, and chronic wounds, skin loses its ability to completely repair itself. For this reason, the products that help repair the wound are needed. Such skin products are prepared through skin tissue engineering. In this respect, extensive research has been done, and natural and synthetic materials with different potentials were used to prepare wound dressings. One of these materials is the eggshell membrane which is a fibrous structure between the inner layer of the mineral shell and the egg white. This membrane has attracted a number of researchers’ attention due to its porous structure, biocompatibility, availability, non-contamination, containing natural proteins and compounds similar to the extracellular matrix, and low cost. It has many applications in medicine, among which is preparation of wound dressings and wound healing products with promising results. In this study, eggshell membrane is introduced as a natural biomaterial. Further, its application in wound healing and preparation of wound dressings are reviewed.

The most important strategy in tissue engineering is the relationship between the three components of biomaterials, living cells, and biologically active molecules suitable for tissue regeneration. To be clinically effective, these environments must replicate, as closely as possible, the main characteristics of the native Extracellular Matrix (ECM) on a cellular scale. Tissue engineering is generally employed to create hybrid scaffolding to support cartilage tissue regeneration using fabrication 3D printing techniques. The current study designed a three-dimensional scaffold using FDA-approved Polycaprolactone/Poly Lactic-co-Glycolic Acid (PCL/PLGA) polymers. Then, 40 and 45 (w/w) alginate nanoparticles were added to the bio-ink to improve the printability, mechanical properties, and biocompatibility of the scaffolds. Finally, 3D-printed scaffolds were evaluated using mechanical properties, surface hydrophilicity, water absorption, biodegradability, surface morphology, and cell viability. The results showed that increasing the percentage of alginate nanoparticles in the bio-ink would increase the percentage of porosity, surface hydrophilicity, mechanical properties, cell viability, and printability. In addition, water absorption and compression modules of PCL/PLGA 3D-printed scaffolds containing 45 % alginate were optimized, compared to those of other groups, hence used as bio-ink in 3D printing of scaffolds in tissue engineering defects.

Development of bioactive ceramic composite scaffold materials with enhanced mechanical strength has been a topic of great interest in bone tissue engineering. In the present study, β-tricalcium phosphate scaffolds with various amounts of bredigite and an interconnected pore network suitable for bone regeneration were fabricated by the space holder method. The effect of high concentrations of bredigite on the structure, mechanical properties (compressive strength), and in vitro bioactivity was investigated. According to the results, immersion in simulated body fluid (SBF) led to the apatite formation on the surface of the scaffold, but increasing the bredigite content caused the agglomeration of the bredigite phase at the grain boundaries and deteriorated the mechanical properties.

Biodegradable porous scaffold polymers are good candidates for tissue engineering. In this research, a three-dimensional porous poly-lactic acid (PLA) scaffold was prepared using a Fused Deposition Modeling (FDM) including about 70% porosity. The study of the phases of primary filament and scaffold using the X-ray diffraction (XRD) test shows that no significant phase difference has been created due to the manufacturing process and the polymer retains its phases properties. The results of the mechanical properties evaluation by the compression test show that the mechanical properties of the scaffold are different in both the parallel and perpendicular directions of the Z axis during the printing, and the mechanical properties of the scaffold are of anisotropic property. Microstructural study by Scanning Electron Microscope (SEM) also shows that the morphology of scaffold porosities is different in two directions, and this is the main cause of anisotropic mechanical properties. Anisotropy of the mechanical properties of FDM produced scaffolds should be considered during load bearing applications in vivo.

Tissue-engineering scaffolds provide biological and mechanical frameworks for cell adhesion, growth, and differentiation. Nanofibrous scaffolds mimic the native extracellular matrix (ECM) and play a significant role in formation and remodeling of tissues and/or organs . One way to mimic the desired properties of fibrous ECM is adding nanoparticles into the polymer matrix. In the current study, the uniform fibers of poly (ε-caprolactone) (PCL) enriched with different layered double hydroxide (LDH) contents (ranging from 0.1 wt.% to 10 wt.%) were successfully fabricated by electrospinning method. The LDH nano particles were randomly dispersed in the fibers, as confirmed by Energy Dispersive X-ray analysis (EDX). Scaffolds were analyzed from morphological, physical and mechanical view. Biological assessments of scaffolds in terms of cellular attachment and adipogenic differentiation of mouse adipose derived stem cells (mADSCs) were performed. The results showed that inclusion of LDH nanoparticles reduced the average fiber diameter and enhanced the tensile strength and elongation at break values of the PCL scaffold. The LDH-enriched electrospun PCL scaffolds had remarkable effects on cell adhesion. Moreover, a significant increase in adipogenic differentiation of mADSCs was observed. The PCL/LDH nanofibrous scaffolds showed great potential in application for soft tissue engineering.

In recent years, nanoceramics have been used in scaffolds to emulate the nanocomposite with a three-dimensional structure of natural bone tissue. In this regard, polycaprolactone biopolymer is widely used as a scaffold in bone tissue engineering. The goal of this research is to produce porous scaffolds of polycaprolactone - zeolite biocomposite with suitable mechanical, bioactive and biological properties  for bone tissue engineering applications. The nanocomposite scaffolds were synthesized by solvent casting/particulate leaching and freeze-drying approaches. Microscopic investigations showed generation of pores with an average size of 200-400μm after addition of ceramic phase. Energy dispersive X-ray analysis confirmed uniform distribution of ceramic phase in polycaprolactone matrix. FTIR results determined the binding type of zeolite nanoparticles to the polycaprolactone matrix as physical bonding. The results of mechanical tests showed the increase in young’s modulus after addition of ceramic phase (from 0.04 to 0.3 and 3 to 7 MPa, respectively). The hydrophilicity of polycaprolactone increased after adding nanozeolite and more weight loss was observed for scaffold containing 20% zeolite (53.52 6 1.6%) with an increase in the rate of hydroxyapatite formation. The results showed that the prepared scaffolds have potential for cancellous bone tissue engineering application.

Albumin is a protein macromolecule that it has been attractive since the early 20th century and has several therapeutic applications. Albumin is an aboundant serum with good biocompatibility, hematopoiesis and biodegradability in blood. The existence of multiple functional groups makes it possible to carry significant amounts of therapeutic and diagnostic factors, as well as targeting factors. This protein, on the one hand, has therapeutic uses and, on the other hand, is used in various formulations to carry pharmaceutical and diagnostic agents. There are many benefits to albumin-based nanocomposites in facilitating their clinical applications in a variety fields, including drug release, imaging, teranostic, tissue engineering, and coatings.

Recently، composite scaffolds prepared by electrospinning have shown desirable properties for tissue engineering applications. In this study، first the nBGs were prepared via the sol-gel technique، then، the electrospun PHB/nBG nanocomposite scaffolds (with 7. 5، 10 and 15 wt% of nBGs) were fabricated. The nanoparticles and scaffolds were characterized by Scanning Electron Microscopy (SEM)، X-ray diffraction spectrometer (XRD)، X-rayfluorescence spectroscopy (XRF)، Fourier transform infrared spectroscopy (FTIR). Results showed that nanoparticles with an amorphous structure mainly had a particle size of less than 70 nm. All the nano-fibrous scaffolds had a uniform distribution of interconnected porosities with fiber diameters ranging from 326. 1 nm to 1. 276 micrometer. Composite scaffolds having nanoparticle concentrations higher than 7. 5 wt%، tend to agglomerate. In addition، the FTIR results showed a favorable interaction between the polymer and nBGs. Therefore، the proposed PHB/nBG scaffolds prepared in this study can be considered as good candidates for bone tissue engineering applications.