Papers by Keyword: Tissue Regeneration

Abstract: In this work, for the first time, chlorogenic acid, a natural phytochemical, was conjugated to a lactoferrin derived antimicrobial peptide sequence RRWQWRMKKLG to develop a self-assembled template. To mimic the components of extracellular matrix, we then incorporated Type I Collagen, followed by a sequence of aggrecan peptide (ATEGQVRVNSIYQDKVSL) onto the self-assembled templates for potential applications in ligament tissue regeneration. Mechanical properties and surface roughness were studied and the scaffolds displayed a Young’s Modulus of 169 MP and an average roughness of 72 nm respectively. Thermal phase changes were studied by DSC analysis. Results showed short endothermic peaks due to water loss and an exothermic peak due to crystallization of the scaffold caused by rearrangement of the components. Biodegradability studies indicated a percent weight loss of 27.5 % over a period of 37 days. Furthermore, the scaffolds were found to adhere to fibroblasts, the main cellular component of ligament tissue. The scaffolds promoted cell proliferation and displayed actin stress fibers indicative of cell motility and attachment. Collagen and proteoglycan synthesis were also promoted, demonstrating increased expression and deposition of collagen and proteoglycans. Additionally, the scaffolds exhibited antimicrobial activity against Staphylococcus epidermis bacteria, which is beneficial for minimizing biofilm formation if potentially used as implants. Thus, we have developed a novel biocomposite that may open new avenues to enhance ligament tissue regeneration.

Abstract: In bone tissue engineering, synthetic scaffolds are commonly used and this should present the following requirements; (i) recapitulate the native three-dimensional (3D) hierarchical fibrous structure, (ii) possess biomimetic surface properties and (iii) demonstrate mechanical integrity. However, some methods of producing scaffolds do not achieve these requirements. The present study aims the application of a composite of poly (L-lactic acid) (PLLA) and Hydroxyapatite (HA) produced by rotary jet spinning, which can be used to obtain scaffolds that meet the above requirements with affordable costs (regarding materials and production). The morphology and thermal properties of the scaffolds were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). For the in vivo tests, 20 Wistar rats, distributed into two groups, in which critical defects were performed in cranial calotte were used. Then scaffolds of PLLA/HA were implanted and compared with the control group that didn’t receive the implant. The results have shown that in the cases where only the defects in cranial caps were performed, bone healing did not occur. In cases where the scaffolds of PLLA/HA were used, rich neovascularization was noted, accompanied by foreign body type reaction and presence of reactive bone around the implants. The evaluation of PLLA/HA scaffolds used in the rat calvarial defect model, according to the criteria surveyed was favorable, showed the implants insurance and that they are suitable materials to be used as substitutes of calvarial bone tissue in these animals.

Abstract: Poly (L-lactide-co-D/L-lactide)-based fiber meshes resembling structural features of the native extracellular matrix have been prepared by electrospinning. Subsequent coating of the electrospun fibers with an ultrathin plasma polymerized allylamine (PPAAm) layer changed the hydrophobic nature of the polylactide surface into a hydrophilic polymer network and provided positively charged amino groups on the fiber surface able to interact with negatively charged pericellular matrix components. Cell experiments in vitro using different types of human epithelial cells (gingiva, uroepithel) revealed that the PPAAm-activated surfaces promoted the occupancy of the meshes by cells accompanied by improved initial cell spreading. An in vivo study in a rat intramuscular implantation model demonstrated that the local inflammatory tissue response did not differ between PPAAm-coated and untreated polylactide meshes.

Abstract: This paper examines challenges and opportunities for the field of bio-ceramics to achieve innovative solutions in two important areas of healthcare; regenerative medicine and personalized versus statistical-based diagnosis and therapy of individual patients. These opportunities are based upon use of new minimally invasive bio-photonics technology that can produce patient specific cell-based data to minimize costs, time and use of animals in developing and testing new bioactive ceramics. Changing the research culture is necessary to achieve significant improvements in the cost/benefit ratio of healthcare for aging populations. The approaches advocated in this paper have potential to achieve this cultural change.

Abstract: Objective: To explore the effects of the biodegradability of biomaterial scaffolds on skin tissue regeneration and its neovascularization by the animal experiments. Methods: A piece of porous silk fibroin film (SF) of easy biodegradation and a piece of porous polyvinyl alcohol film (PVA) of hard biodegradation were implanted into a same skin wound of adult rat, and the differences in the regenerative blood vessel and tissue at 5, 10, 16, 41 days after surgery were observed by histological methods. Results: (1) at 10 days after surgery, the SF started to degrade, the closed areas without cell infiltration were opened up and the entire material was filled with the regenerative tissue, and there were still the closed areas in the PVA, (2) the new vascular network remodeling in the SF and PVA appeared at 10 days and 41 days after surgery, respectively, and (3) at 16 days after surgery, most of the SF material had degraded and substantially been replaced with the regenerative tissue, and the visible degradation of the PVA appeared at 41 days after surgery. Conclusion: The good biodegradability of the SF was helpful both to all vascularization of the material and to the regenerative blood vessels remodeling, and the regenerative tissue was closer to the normal dermal tissue than in the PVA.

Abstract: FGF-2-apatite and FGF-2-zinc-apatite composite layers were formed on commercially available anodically oxidized Ti external fixation rods using FGF-2-and ZnCl₂-containing supersaturated calcium phosphate solutions. The FGF-2-zinc-apatite composite layers precipitated on the Ti external fixation rods significantly enhanced proliferation of fibroblastic NIH3T3 and osteoblastic MC3T3-E1 cells in vitro.

Abstract: Extracellular matrices (ECM) derived from urinary bladder membrane (UBM) have demonstrated substantial potential for applications in tissue repair and reconstruction. However, these materials are limited by the requirement of suturing following surgery. In this paper, the coalescence of UBM with an advanced surgical adhesive demonstrated a suitable alternative to sutures for wound closure, prevention of fluid leakage and improvement of cell growth. This novel bioadhesive contains favourable characteristics that are suitable for tissue repair, support of cell growth, and influence cellular microenvironments that are biocompatible with peripheral nerve regeneration in the spinal cord.

Abstract: The functionality of tissue scaffolds in vivo plays a critical role in the treatment process. Due to the time dependent nature of the mechanical properties of the constituent phases of the scaffold, a wide range of mechanical property histories may be observed during the treatment process, possibly influencing outcomes. The critical nature of the mechanical properties in load bearing applications indicates a need for the simultaneous modelling of both scaffold degradation and tissue regeneration with time, and the resulting effective properties of the tissue engineering construct. To this end, a review of the literature is conducted to identify the various existing approaches to modelling scaffold degradation, tissue behavior, and the dependency of the two processes on one another.

Abstract: Mesoporous materials synthesized using a polymer templating route have attracted considerable attention in the field of bone tissue regeneration because their unique pore textural properties (high specific surface area, pore volume and controllable mesopore structure) can promote rapid bone formation. In addition, their potential use as a drug delivery system has been highlighted. The scaffolds in bone tissue regeneration should contain 3D interconnected pores ranging in size from 10 to 1000 μm for successful cell migration, nutrient delivery, bone in-growth and vascularization. Meso-sized pores are too small to carry out these roles, even though mesoporous materials have attractive functionalities for bone tissue regeneration. Therefore, a technique linking mesoporous materials with the general scaffolds is required. This paper reviews recent studies relating the development of new porous scaffolds containing mesopores for using in bone tissue regeneration. All the suggested methods, such as a combination of polymer templating methods and rapid prototyping technique can provide hierarchically 3D porous bioactive scaffolds with well interconnected pore structures in the nano to macro size range, good molding capability, biocompatibility, and bioactivity. The new fabrication techniques suggested can potentially be used to design ideal scaffolds in bone tissue regeneration.

Abstract: Carbon nanotubes (CNT) and their derivatives with different structure and compositions have unique features. In the present study, cell proliferation was performed on various nanotubes such as single walled CNTs, multiwalled CNTs and imogolite which is nanotubes of aluminosilicate. SEM observation of the growth of osteoblast-like cells cultured on CNTs showed the morphology fully developed for the whole direction, which was different from that extended to the one direction on the usual scaffold. Numerous filopodia were grown from cell edge, extended far long and combined with CNT meshwork. Apatite precipitation in simulated body fluid, affinity for proteins and saccharides, and nanosize meshwork structure with large porosity would be the properties responsible for these cell adhesion and growth. Imogolite showed the similar properties to CNTs. Nanotubes could be the favorable materials for biomedical applications.