جستجوی مقالات مرتبط با کلیدواژه "tissue scaffolds" در نشریات گروه "پزشکی"

Natural component-included scaffolds can provide numerous benefits for skin healing and tissue regeneration. Nanofibers (NFs) with intricately intertwined three-dimensional structures afford an exclusive matrix for delivering therapeutics. This research assessed nanofibrous scaffolds loaded with Achillea wilhelmsii extract (5-15 wt%) for skin tissue engineering. 

A. wilhelmsii-loaded scaffolds, composed of poly(vinyl alcohol) (PVA) and chitosan (CS), were fabricated by the electrospinning process. Subsequently, the physicochemical properties of the scaffolds were evaluated through relevant analyses. The antioxidant activity and degradation rate of the scaffolds were also determined. Cell viability and scratch assays on dermal fibroblasts were conducted to assess proliferation and migration activities.  

Electron micrographs revealed interconnected fibers with a nano-scale diameter (> 400 nm) and uniform morphology. Additionally, the intact presence of A. wilhelmsii extract in the polymeric matrix was confirmed without any undesirable interactions. The proposed scaffolds verified favorable mechanical properties, a hydrophilic nature, high volume porosity (>90%), and water absorption capability (<500%). Besides, the findings demonstrated the remarkable radical scavenging ability of A. wilhelmsii extract in the nanofibrous scaffolds, along with controlled degradation kinetics over 72 h. The viability assay proved that the A. wilhelmsii-loaded scaffolds not only exhibited no cytotoxicity but also improved cell proliferation. The scaffolds also significantly accelerated fibroblast migration and complete closure of scratched areas. 

At last, the obtained results revealed that A. wilhelmsii-loaded PVA/CS NFs can be applied as a potential scaffold for skin regeneration and wound healing promotion.

Defects and dysfunctions of temporomandibular joint (TMJ) disc are responsible for the majority of TMJ diseases. Current treatments in this matter are usually short-term and only palliative, thus an alternative treatment that offers long-lasting repair is in great demand. In recent years great attempts have been made to prepare an ideal scaffold which best resembles the native TMJ disc in characteristics such as mechanical, physical and biological properties. This narrative review focuses on developments of the recent ten years in fabrication of scaffolds using decellularized tissues, natural and synthetic biomaterials for regeneration of TMJ disc and compared their properties. PubMed and Google Scholar databases were searched using the following keywords (“TMJ” OR “temporomandibular joint” OR “TMD” OR “temporomandibular disease”) AND (“scaffold” OR “hydrogels”). Randomized controlled trials, randomized clinical trials, case-controls, case reports, and animal studies were included. Comments, systematic reviews, meta-analyses, and non-English papers were excluded. The study concluded that hybrid scaffolds have exhibited favorable cell attachment and proliferation. Synthetic scaffolds have shown promise in providing better control over structural properties; however, additional processes are often required to provide biomimetic cell signaling. While there is still much to learn about the ideal scaffold for TMJ disc regeneration, both natural and synthetic scaffolds have shown promise in achieving the functional, structural, biological, and mechanical properties of a native TMJ disc.

Repair of massive rotator cuff tears remains a challenging process with mixed success. There is agrowing interest in the use of patches to augment the repair construct and the potential to enhance the strength,healing, and associated clinical outcomes. Such patches may be synthetic, xenograft, or autograft/allograft, and avariety of techniques have been tried to biologically enhance their integration and performance. The materials used arerapidly advancing, as is our understanding of their effects on rotator cuff tissue. This article aims to evaluate what wecurrently know about patch augmentation through a comprehensive review of the available literature.

We explore the results of existing clinical trials for each graft type, new manufacturing methods, noveltechniques for biological enhancement, and the histological and biomechanical impact of patch augmentation.

There are promising results in short-term studies, which suggest that patch augmentation has greatpotential to improve the success rate. In particular, this appears to be true for human dermal allograft, while porcinedermal grafts and some synthetic grafts have also had promising results.

However, there remains a need for high-quality, prospective clinical trials directly comparing each type ofgraft and the effect that they have on the clinical and radiological outcomes of rotator cuff repair. 

The esophagus is the gastrointestinal tract’s primary organ that transfers bolus into the stomach with peristaltic motion. Therefore, its lesions cause a significant disturbance in the nutrition and digestive system. Esophageal disease treatment sometimes requires surgical procedures that involve removal and circumferential full-thickness replacement. Unlike other organs, the esophagus has a limited regeneration ability and cannot be transplanted from donors. There are various methods of restoring the esophageal continuity; however, they are associated with certain flaws that lead to a non-functional recovery. As an exponentially growing science, tissue engineering has become a leading technique for the development of tissue replacement to repair damaged esophageal segments. Scaffold plays a significant role in the process of tissue engineering, as it acts as a template for the regeneration of growing tissue. A variety of scaffolds have been studied to replace the esophagus. Due to the many tissue quality challenges, the results are still inadequate and need to be improved. The success of esophageal tissue regeneration will finally depend on the scaffold’s capability to mimic natural tissue properties and provide a qualified environment for regeneration. Thereby, scaffold fabrication techniques are fundamental. This article reviews the recent developments in esophageal tissue engineering for the treatment of circumferential lesions based on scaffold biomaterial engineering approaches.

Objectives

This paper describes the fabrication of a new porous 3D-printed scaffold composed of polycaprolactone (PCL) and polyether-ether ketone (PEEK) micro-particles for bone tissue engineering (BTE) applications.

In order to improve the compatibility of the reinforcing PEEK powder with polycaprolactone, the PEEK powder was surface-modified by an amino-silane coupling agent. After modification, Fourier-transform infrared spectrometry (FTIR) and differential scanning calorimetry (DSC) were used to investigate the chemical reaction between PEEK and silane coupling agent. In order to increase the compressive modulus of the 3D printed PCL scaffold, 10% silane-modified PEEK was incorporated into the PCL polymeric matrix. Scanning electron microscopy (SEM) was used for cell morphology and attachment evaluation.

The results indicated that the silane coupling agent was successfully grafted onto the particle surface. The compressive modulus of PCL scaffold increased by incorporating the silane-modified PEEK, despite having higher porosity, compared with the pure PCL scaffolds. Addition of amino-silane had a positive impact on cell response, and that surface modification led to improved particle dispersion.

In conclusion, it seems that the incorporation of surface-modified PEEK micro-particles into the PCL porous scaffold could enhance its mechanical properties, and may be applicable for the management of large bone defects.Keywords Polyetheretherketone; Polycaprolactone; Amino-propyl-triethoxysilane; Tissue Scaffolds; Printing, Three-Dimensional

Background:

Periodontal regeneration is an essential goal of periodontal therapy. Acellular dermal matrix (ADM) has been recommended as an alternative to autogenous grafts. However, since it is devoid of cells and vasculature, there are concerns regarding the biological behavior of cells on ADM. This study aimed to assess the effects of two commonly used ADMs on biological behavior, i.e., attachment and proliferation, of human gingival fibroblasts (HGFs).

Methods:

This in vitro, experimental study was conducted on explanted and cultured HGFs. ADM types 1 and 2 (n=26; measuring 10×15 mm) were rinsed with saline solution, adapted to the bottom of 52 wells, exposed to HGFs with a cell density of 16,000 cells/mL, and incubated at 37°C for 12, 24, and 84 hours and seven days. Cell attachment was assessed 12 hours after incubation using 4›,6-diamidino-2-phenylindole (DAPI) and methyl-thiazol-diphenyl-tetrazolium (MTT) assay under a fluorescence microscope. Cell viability was assessed at 24 and 84 hours and one week using the MTT assay. Cells were then platinum-coated, and their morphology was evaluated under a scanning electron microscope (SEM). Data were analyzed using ANOVA.

Results:

 HGFs were evaluated in 60 samples in three groups (n=20). Cell attachment was the same in the three groups, as shown by the MTT assay and DAPI test (P=0.6). Cell viability at one week was 3.73±0.02, 2.88±0.29, and 2.13±0.24 in the control, ADM 1, and ADM 2 groups, respectively. The difference was statistically significant (P=0.01).

Conclusion:

Both scaffolds were the same in terms of attachment of HGFs. However, ADM 1 was superior to ADM2 in terms of cell viability and morphology at one week. It was concluded that the quality of acellular dermal scaffolds could significantly influence cellular behaviors and tissue maturation.

Tissue engineering is a relatively novel field that has been intensely developing during recent years and has shown to be excessively promising when used for cartilage regeneration. Scaffolds represent important components for tissue engineering.

The Poly Lactic-Co-Glycolic Acid (PLGA) impregnated with fibrin and hyaluronic acid (HA) produce hybrid scaffolds. human adipose-derived stem cells (hADSCs) were seeded in scaffolds and cultured in chondrogenic media. The viability of cells in different groups was assessed by MTT. The expression of chondrogenic related genes [Sox9, type II collagen (Col II), Aggrecan(AGG)] and type X collagen (Col X) was quantified by real-time polymerase chain reaction.

The results of the real-time PCR showed SOX9, AGG and Col X gene expression in the control groups being significantly lower than the other groups (p≤0.05). It also demonstrated Col II gene expression in the control group being significantly lower than the PLGA/Fibrin and PLGA/Fibrin/HA groups (p≤0.05). The Col X gene expression of cells in PLGA/HA and PLGA/Fibrin/HA groups significantly decreased in comparison with the PLGA/Fibrin group (p≤0.05).

These conclusions indicate that administration of PLGA/ Fibrin and PLGA/HA scaffolds, particularly PLGA/Fibrin/ HA, motivates chondrogenesis in hADSCs. This can be diminished by decreasing hypertrophic markers and increasing characteristic markers of hyaline cartilage.

Endodontic treatment of necrotic immature teeth is quite challenging. Current concepts for revitalization of these teeth known as regenerative endodontic treatment (RET) is based on key elements necessary for tissue engineering including stem cells, three-dimensional (3D) scaffolds, and growth factors. Utilizing an applicable scaffold for narrow root canal space with adequate properties is essential for successful outcome. Fibrin-based products are materials with various advantages as a scaffold. This review article aims to discuss the properties of different types of fibrin-based products and debates whether they are appropriate scaffolds for RET or not?

An electronic search was performed using databases such as Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus. Keywords such as (“scaffold”) AND (“fibrin gel” OR “fibrin sealant” OR “fibrin glue” OR “fibrin tissue adhesive” OR “fibrin hydrogel” OR “platelet concentrate”) AND (“tooth” OR “teeth”) AND/OR (“regenerative endodontics” OR “dentistry”) were used. Exclusion criteria included studies published in a language other than English and abstracts from congress.

Fibrin gel is a protein-based natural polymer hydrogel scaffold which can be easily used in the root canal. Platelet concentrates are autologous fibrin-based products used as scaffolds for RET with various favorable properties especially due to containing various growth factors.

It seems that fibrin gel and platelet concentrates have adequate properties for use in RET; however, more evidence is required regarding the clinical outcome of applying these products as scaffolds for RET.