Fabrication of Electrospun Double Layered Biomimetic Collagen-Chitosan Polymeric Membranes with Zinc-Doped Mesoporous Bioactive Glass Additives.

Several therapeutic approaches have been developed to promote bone regeneration, including guided bone regeneration (GBR), where barrier membranes play a crucial role in segregating soft tissue and facilitating bone growth. This study emphasizes the importance of considering specific tissue requirements in the design of materials for tissue regeneration, with a focus on the development of a double-layered membrane to mimic both soft and hard tissues within the context of GBR. The hard tissue-facing layer comprises collagen and zinc-doped bioactive glass to support bone tissue regeneration, while the soft tissue-facing layer combines collagen and chitosan.

Facile modification of polycaprolactone nanofibers with egg white protein.

Synthetic polymers remain to be a major choice for scaffold fabrication due to their structural stability and mechanical strength. However, the lack of functional moieties limits their application for cell-based therapies which necessitate modification and functionalization. Blending synthetic polymers with natural components is a simple and effective way to achieve the desired biological properties for a scaffold.

A combinatorial approach for spinal cord injury repair using multifunctional collagen-based matrices: development, characterization and impact on cell adhesion and axonal growth.

Spinal cord injury is a devastating condition of the central nervous system, in which traditional treatments are largely ineffective due to the complex nature of the injured tissue. Therefore, biomaterial-based systems have been developed as possible alternative strategies to repair the damaged tissue. In the present study, we aimed to design bioactive agent loaded scaffolds composed of two layers with distinct physical properties to improve tissue regeneration.

Design of a new dual mesh with an absorbable nanofiber layer as a potential implant for abdominal hernia treatment.

Dual meshes are often preferred in the treatment of umbilical and incisional hernias where the abdominal wall defect is large. These meshes are generally composed of either two nonabsorbable layers or a nonabsorbable layer combined with an absorbable one that degrades within the body upon healing of the defect. The most crucial point in the design of a dual mesh is to produce the respective layers based on the structure and requirements of the recipient site.

Osteogenic differentiation of mesenchymal stem cells cultured on PLLA scaffold coated with Wharton's Jelly.

Poly-L-lactic acid (PLLA) electrospun nanofiber scaffold is one of the most commonly used synthetic polymer scaffolds for bone tissue engineering application. However, PLLA is hydrophobic in nature, hence does not maintain proper cell adhesion and tissue formation, moreover, it cannot provide the osteo-inductive environment due to inappropriate surface characteristic and the lack of surface motives participating in the first cellular events. To modify these shortcomings different approaches have been used, among those the most commonly used one is coating of the surface of the electrospun nanofiber with natural materials.

Bio-engineered synovial membrane to prevent tendon adhesions in rabbit flexor tendon model.

During tendon injuries, the tendon sheath is also damaged. This study aims to test effectiveness of engineered tendon synovial cell biomembrane on prevention of adhesions. Forty New Zealand Rabbits enrolled into four study groups.

Influence of scaffold composition over in vitro osteogenic differentiation of hBMSCs and in vivo inflammatory response.

To understand the role of chitosan in chitosan-poly(butylene succinate) scaffolds (50% wt), 50%, 25%, and 0% of chitosan were used to produce different scaffolds. These scaffolds were in vitro seeded and cultured with human bone marrow stromal cells in osteogenic conditions, revealing that higher percentage of chitosan showed enhanced cell viability over time, adhesion, proliferation, and osteogenic differentiation. Scaffolds were also implanted in cranial defects and iliac submuscular region in Wistar rats, and the results evidenced that chitosan-containing scaffolds displayed mild inflammatory response and good integration with surrounding tissues, showed by connective tissue colonization and the presence of new blood vessels.

Enzymatic degradation behavior and cytocompatibility of silk fibroin-starch-chitosan conjugate membranes.

The objective of this study was to investigate the influence of silk fibroin and oxidized starch conjugation on the enzymatic degradation behavior and the cytocompatability of chitosan based biomaterials. The tensile stress of conjugate membranes, which was at 50 Megapascal (MPa) for the lowest fibroin and starch composition (10 weight percent (wt.%)), was decreased significantly with the increased content of fibroin and starch.

A new method for the production of gelatin microparticles for controlled protein release from porous polymeric scaffolds.

Tissue engineering using scaffolds and growth factors is a crucial approach in bone regeneration and repair. The combination of bioactive agents carrying microparticles with porous scaffolds can be an efficient solution when controlled release of bio-signalling molecules is required. The present study was based on a recent approach using a biodegradable scaffold and protein-loaded microparticles produced in an innovative manner in which protein loss is minimized during the loading process.

Thermoresponsive poly(N-isopropylacrylamide)-g-methylcellulose hydrogel as a three-dimensional extracellular matrix for cartilage-engineered applications.

Recent advances in tissue engineering and regenerative medicine fields can offer alternative solutions to the existing techniques for cartilage repair. In this context, a variety of materials has been proposed, and the injectable hydrogels are among the most promising alternatives. The aim of this work is to explore the ability of poly(N-isopropylacrylamide)-g-methylcellulose (PNIPAAm-g-MC) thermoreversible hydrogel as a three-dimensional support for cell encapsulation toward the regeneration of articular cartilage through a tissue engineering approach.

Microchannel-patterned and heparin micro-contact-printed biodegradable composite membranes for tissue-engineering applications.

Microchannel-patterned starch-poly(capro-lactone)/hydydroxyapatite (SPCL-HA) and starch-poly(lactic acid) (SPLA) composite membranes were produced for use as a laminated tissue-engineering scaffold that incorporates both physical and biochemical patterns. For this purpose, SPCL (30% starch) blended with inorganic hydroxyl apatite (50%) and SPLA (50% starch) membranes were made with compressive moulding. Consequently, the microchannel structures (width 102 µm, 174 µm intervals) were developed on the composite membranes by means of micro-patterned metal mould(s) and hydraulic pressing.

Design of nano- and microfiber combined scaffolds by electrospinning of collagen onto starch-based fiber meshes: a man-made equivalent of natural extracellular matrix.

Mimicking the structural organization and biologic function of natural extracellular matrix has been one of the main goals of tissue engineering. Nevertheless, the majority of scaffolding materials for bone regeneration highlights biochemical functionality in detriment of mechanical properties. In this work we present a rather innovative construct that combines in the same structure electrospun type I collagen nanofibers with starch-based microfibers.

In vivo short-term and long-term host reaction to starch-based scaffolds.

The implantation of biomaterials may elicit a host response to this foreign body, and the magnitude of that reaction depends on the host and on the implanted material. The aim of this study was to compare the inflammatory response induced by the implantation of starch-based (SPCL) scaffolds in two implantation rat models: subcutaneous (SC) and intramuscular (IM). Moreover, two methodologies, wet spinning (WS) and fibre-bonding (FB), were used to prepare the scaffolds.

Incorporation of a sequential BMP-2/BMP-7 delivery system into chitosan-based scaffolds for bone tissue engineering.

The aim of this study was to develop a 3-D construct carrying an inherent sequential growth factor delivery system. Poly(lactic acid-co-glycolic acid) (PLGA) nanocapsules loaded with bone morphogenetic protein BMP-2 and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanocapsules loaded with BMP-7 made the early release of BMP-2 and longer term release of BMP-7 possible. 3-D fiber mesh scaffolds were prepared from chitosan and from chitosan-PEO by wet spinning.

A new route to produce starch-based fiber mesh scaffolds by wet spinning and subsequent surface modification as a way to improve cell attachment and proliferation.

This study proposes a new route for producing fiber mesh scaffolds from a starch-polycaprolactone (SPCL) blend. It was demonstrated that the scaffolds with 77% porosity could be obtained by a simple wet-spinning technique based on solution/precipitation of a polymeric blend. To enhance the cell attachment and proliferation, Ar plasma treatment was applied to the scaffolds.

Preparation and characterization of starch-poly-epsilon-caprolactone microparticles incorporating bioactive agents for drug delivery and tissue engineering applications.

One limitation associated with the delivery of bioactive agents concerns the short half-life of these molecules when administered intravenously, which results in their loss from the desired site. Incorporation of bioactive agents into depot vehicles provides a means to increase their persistence at the disease site. Major issues are involved in the development of a proper carrier system able to deliver the correct drug, at the desired dose, place and time.

Biodegradable polymeric fiber structures in tissue engineering.

Tissue engineering offers a promising new approach to create biological alternatives to repair or restore function of damaged or diseased tissues. To obtain three-dimensional tissue constructs, stem or progenitor cells must be combined with a highly porous three-dimensional scaffold, but many of the structures purposed for tissue engineering cannot meet all the criteria required by an adequate scaffold because of lack of mechanical strength and interconnectivity, as well as poor surface characteristics. Fiber-based structures represent a wide range of morphological and geometric possibilities that can be tailored for each specific tissue-engineering application.

Endothelial cell colonization and angiogenic potential of combined nano- and micro-fibrous scaffolds for bone tissue engineering.

Presently the majority of tissue engineering approaches aimed at regenerating bone relies only on post-implantation vascularization. Strategies that include seeding endothelial cells (ECs) on biomaterials and promoting their adhesion, migration and functionality might be a solution for the formation of vascularized bone. Nano/micro-fiber-combined scaffolds have an innovative structure, inspired by extracellular matrix (ECM) that combines a nano-network, aimed to promote cell adhesion, with a micro-fiber mesh that provides the mechanical support.

A novel enzymatically-mediated drug delivery carrier for bone tissue engineering applications: combining biodegradable starch-based microparticles and differentiation agents.

In many biomedical applications, the performance of biomaterials depends largely on their degradation behavior. For instance, in drug delivery applications, the polymeric carrier should degrade under physiological conditions slowly releasing the encapsulated drug. The aim of this work was, therefore, to develop an enzymatic-mediated degradation carrier system for the delivery of differentiation agents to be used in bone tissue engineering applications.

Formation of bone-like apatite layer on chitosan fiber mesh scaffolds by a biomimetic spraying process.

Bone-like apatite coating of polymeric substrates by means of biomimetic process is a possible way to enhance the bone bonding ability of the materials. The created apatite layer is believed to have an ability to provide a favorable environment for osteoblasts or osteoprogenitor cells. The purpose of this study is to obtain bone-like apatite layer onto chitosan fiber mesh tissue engineering scaffolds, by means of using a simple biomimetic coating process and to determine the influence of this coating on osteoblastic cell responses.

Influence of porosity and fibre diameter on the degradation of chitosan fibre-mesh scaffolds and cell adhesion.

The state of the art approaches for tailoring the degradation of chitosan scaffolds are based on altering the chemical structure of the polymer. Nevertheless, such alterations may lead to changes in other properties of scaffolds, such as the ability to promote cell adhesion. The aim of this study was to investigate the influence of physical parameters such as porosity and fibre diameter on the degradation of chitosan fibre-mesh scaffolds, as a possible way of tailoring the degradation of such scaffolds.

Nano- and micro-fiber combined scaffolds: a new architecture for bone tissue engineering.

One possible interesting way of designing a scaffold for bone tissue engineering is to base it on trying to mimic the biophysical structure of natural extracellular matrix (ECM). This work was developed in order to produce scaffolds for supporting bone cells. Nano and micro fiber combined scaffolds were originally produced from starch based biomaterials by means of a fiber bonding and a electrospinning, two step methodology.

Production and characterization of chitosan fibers and 3-D fiber mesh scaffolds for tissue engineering applications.

This study reports on the production of chitosan fibers and 3-D fiber meshes for the use as tissue engineering scaffolds. Both structures were produced by means of a wet spinning technique. Maximum strain at break and tensile strength of the developed fibers were found to be 8.

Multichannel mould processing of 3D structures from microporous coralline hydroxyapatite granules and chitosan support materials for guided tissue regeneration/engineering.

A three-dimensional composite material was produced from microporous coralline origin hydroxyapatite (HA) microgranules, chitosan fibers and chitosan membrane. Cylindrical HA microgranules were oriented along channel direction within multichannel mould space and aligned particles were supported with fibers and a chitosan membrane. The positive replica of mould channels was clasp fixed to produce thicker scaffolds.