ABSTRACT
Platelet-rich plasma (PRP) is a volume of autologous plasma that has a higher platelet concentration above baseline. It has already been approved as a new therapeutic modality and investigated in clinics, such as bone repair and regeneration, and oral surgery, with low cost-effectiveness ratio. At present, PRP is mostly prepared using a centrifuge. However, this method has several shortcomings, such as long preparation time (30 min), complexity in operation, and contamination of red blood cells (RBCs). In this paper, a new PRP preparation approach was proposed and tested. Ultrasound waves (4.5 MHz) generated from piezoelectric ceramics can establish standing waves inside a syringe filled with the whole blood. Subsequently, RBCs would accumulate at the locations of pressure nodes in response to acoustic radiation force, and the formed clusters would have a high speed of sedimentation. It is found that the PRP prepared by the proposed device can achieve higher platelet concentration and less RBCs contamination than a commercial centrifugal device, but similar growth factor (i.e., PDGF-ßß). In addition, the sedimentation process under centrifugation and sonication was simulated using the Mason-Weaver equation and compared with each other to illustrate the differences between these two technologies and to optimize the design in the future. Altogether, ultrasound method is an effective method of PRP preparation with comparable outcomes as the commercially available centrifugal products.
Subject(s)
Blood Component Removal/methods , Platelet-Rich Plasma , Ultrasonics/methods , Blood Platelets/cytology , Centrifugation , Erythrocytes/cytology , Humans , Microspheres , Particle Size , Platelet-Rich Plasma/cytology , Platelet-Rich Plasma/physiologyABSTRACT
The design of biomimetic nanomaterials that can directly influence the behavior of cells and facilitate the regeneration of tissues and organs has become an active area of research. Here, the production of materials based on nano-hydroxyapatite composites in scaffolds with nanofibrous and nanoporous topographies, designed to mimic the native bone matrix for applications in bone tissue engineering, is reported. Human mesenchymal stem cells grown on these nanocomposites are stimulated to rapidly produce bone minerals in situ, even in the absence of osteogenic supplements in the cell-culture medium. Nanocomposites comprising type I collagen and nano-hydroxyapatite are found to be especially efficient at inducing mineralization. When subcutaneously implanted into nude mice, this biomimetic nanocomposite is able to form a new bone matrix within only two weeks. Furthermore, when the nanocomposite is enriched with human mesenchymal stem cells before implantation, development of the bone matrix is accelerated to within one week. To the best of the authors' knowledge, this study provides the first clear in vitro and in vivo demonstration of osteoinduction controlled by the material characteristics of a biomimetic nanocomposite. This approach can potentially facilitate the translation of de novo bone-formation technologies to the clinic.
Subject(s)
Biomimetic Materials/chemistry , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/drug effects , Osteogenesis/drug effects , Tissue Engineering/instrumentation , Tissue Scaffolds/chemistry , Animals , Biomimetic Materials/pharmacology , Cell Differentiation/drug effects , Cell Line , Collagen Type I/chemistry , Collagen Type I/pharmacology , Durapatite/chemistry , Durapatite/pharmacology , Humans , Mice , Mice, NudeABSTRACT
This study investigated the adhesive behaviors of normal and abnormal hematopoietic cells on nanotopographical materials. Previously, electrospun nanofiber scaffolds (NFSs) were used to capture and expand hematopoietic stem cells in vitro; here, we demonstrate that NFS could also serve as a useful bioadhesive platform for capturing functionally adherent leukemia cells. Collagen-blended poly(d,l-lactide-co-glycolide) NFS enabled more rapid and efficient capture of K562 leukemia cells than tissue culture polystyrene surfaces with up to 70% improved adhesion and shorter time. Cellular extensions, stronger adhesion, and enhanced cell-cell interactions were observed in K562 cells captured on NFS. While NFS promoted hematopoietic progenitor cell proliferation, it inhibited leukemia cell proliferation and affected cell cycle status by shifting more cells toward the G0/G1 phase. The expression of α-integrins was equally high in both captured and uncaptured leukemia cell populations demonstrating no relation to its adhesive nature. Hematopoietic morphological signatures of NFS captured cells presented no impact on cell differentiation. We conclude that electrospun NFS serves as an excellent platform not only for capturing functionally adherent leukemia cells but also for studying the impact of niche-like structure in the nanoscale.
Subject(s)
Collagen/chemistry , Leukemia/metabolism , Nanofibers/chemistry , Polyglactin 910/chemistry , Cell Adhesion , G1 Phase , Gene Expression Regulation, Leukemic , Humans , Integrin alpha Chains/biosynthesis , K562 Cells , Leukemia/pathology , Neoplasm Proteins/biosynthesis , Resting Phase, Cell CycleABSTRACT
AIM: Developing 3D scaffolds mimicking the nanoscale structure of the native extracellular matrix is important in tissue regeneration. In this study, we aimed to demonstrate the novelty of 3D nanofibrous scaffolds and compare their efficiency with 2D nanofibrous scaffolds. MATERIALS & METHODS: The 2D poly(L-lactic acid)/collagen nanofibrous scaffolds were 2D meshes fabricated by the conventional electrospinning technique, whereas the 3D poly(L-lactic acid)/collagen nanofibrous scaffolds were fabricated by a modified electrospinning technique using a dynamic liquid support system. The morphology, proliferation and differentiation abilities of human mesenchymal stem cells in osteogenic medium on both scaffolds were investigated. RESULTS & CONCLUSION: Compared with the 2D scaffolds, the 3D scaffolds significantly increased the expression of osteoblastic genes of the stem cells as well as the formation of bone minerals. In addition, the scanning electron microscopic and micro-computed tomographic images showed the dense deposition of bone minerals aligned along the nanofibers of the 3D scaffolds after 14 and 28 days cultured with the mesenchymal stem cells. As such, the 3D electrospun poly(L-lactic acid)/collagen nanofibrous scaffold is a novel bone graft substitute for bone tissue regeneration.
Subject(s)
Cell Differentiation , Nanotechnology , Osteoblasts/cytology , Tissue Scaffolds , Animals , Base Sequence , Cells, Cultured , DNA Primers , Humans , Mesenchymal Stem Cells/cytology , Mice , Microscopy, Electron, Scanning , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Dexamethasone (Dex), a synthetic corticosteroid, was loaded into poly(L-lactic acid) (PLLA) nanofibrous scaffolds with a concentration of 0.333 wt% by electrospinning. The Dex-loaded PLLA nanofibres increased the mechanical strength in comparison with pure PLLA nanofibres. A sustained release profile for over 2 months with an initial burst release after 12 h of 17% was shown. Importantly, the amounts of Dex released from the PLLA nanofibres every 3 days were close to the ones used for the standard osteogenic medium. The sustained osteoinductive environment created by released Dex strongly differentiated human mesenchymal stem cells (hMSCs) cultured in the Ost(-Dex) medium. ALP activity, BSP expression and calcium deposition were significantly higher than those of the cells cultured on the PLLA scaffolds without Dex. A large amount of hydroxyapatite-like minerals was observed on the Dex-loaded PLLA scaffolds after 21 days culture. The cells on these scaffolds also indicated an osteoblastic morphology on the 14th day. Besides, these scaffolds slightly increased the cell proliferation comparing to the scaffolds without Dex. As such, the PLLA nanofibres loaded with 0.333 wt% Dex was an effective osteoinductive scaffold which acts as a promising strategy for bone treatment.
Subject(s)
Dexamethasone/administration & dosage , Glucocorticoids/administration & dosage , Lactic Acid , Nanofibers , Osteogenesis/drug effects , Polymers , Tissue Scaffolds , Actins/metabolism , Calcium/metabolism , Cell Differentiation/drug effects , Cell Differentiation/physiology , Cell Proliferation/drug effects , Cell Proliferation/physiology , Cells, Cultured , Delayed-Action Preparations/chemistry , Dexamethasone/pharmacokinetics , Drug Liberation , Focal Adhesions/metabolism , Focal Adhesions/ultrastructure , Gene Expression/drug effects , Glucocorticoids/pharmacokinetics , Humans , Lactic Acid/chemistry , Materials Testing , Mesenchymal Stem Cells/drug effects , Mesenchymal Stem Cells/physiology , Mesenchymal Stem Cells/ultrastructure , Nanofibers/chemistry , Osteogenesis/physiology , Polyesters , Polymers/chemistry , Tissue Scaffolds/chemistryABSTRACT
The time required for osseointegration with a metal implant having a smooth surface ranges from three to six months. We hypothesized that biomimetic coating surfaces with poly(lactic-co-glycolic acid) (PLGA)/collagen fibers and nano-hydroxyapatite (n-HA) on the implant would enhance the adhesion of mesenchymal stem cells. Therefore, this surface modification of dental and bone implants might enhance the process of osseointegration. In this study, we coated PLGA or PLGA/collagen (50:50 w/w ratio) fiber on Ti disks by modified electrospinning for 5 s to 2 min; after that, we further deposited n-HA on the fibers. PLGA fibers of fiber diameter 0.957 ± 0.357 µm had a contact angle of 9.9 ± 0.3° and PLGA/collagen fibers of fiber diameter 0.378 ± 0.068 µm had a contact angle of 0°. Upon n-HA incorporation, all the fibers had a contact angle of 0° owing to the hydrophilic nature of n-HA biomolecule. The cell attachment efficiency was tested on all the scaffolds for different intervals of time (10, 20, 30 and 60 min). The alkaline phosphatase activity, cell proliferation and mineralization were analyzed on all the implant surfaces on days 7, 14 and 21. Results of the cell adhesion study indicated that the cell adhesion was maximum on the implant surface coated with PLGA/collagen fibers deposited with n-HA compared to the other scaffolds. Within a short span of 60 min, 75% of the cells adhered onto the mineralized PLGA/collagen fibers. Similarly by day 21, the rate of cell proliferation was significantly higher (p ⩽ 0.05) on the mineralized PLGA/collagen fibers owing to enhanced cell adhesion on these fibers. This enhanced initial cell adhesion favored higher cell proliferation, differentiation and mineralization on the implant surface coated with mineralized PLGA/collagen fibers.
Subject(s)
Biomimetic Materials/chemistry , Collagen/chemistry , Durapatite/chemistry , Lactic Acid/chemistry , Mesenchymal Stem Cells/cytology , Osteoblasts/cytology , Polyglycolic Acid/chemistry , Titanium/chemistry , Cell Adhesion , Cell Differentiation , Cell Line , Electroplating/methods , Humans , Mesenchymal Stem Cells/physiology , Osteogenesis/physiology , Polylactic Acid-Polyglycolic Acid Copolymer , Surface Properties , Tissue Engineering/methodsABSTRACT
Nanostructured materials are gaining new impetus owing to the advancements in material fabrication techniques and their unique properties (their nanosize, high surface area-to-volume ratio, and high porosity). Such nanostructured materials mimic the subtleties of extracellular matrix (ECM) proteins, creating artifi cial microenvironments which resemble the native niches in the body. On the other hand, the isolation of mesenchymal stem cells (MSCs) from various tissue sources has resulted in the interest to study the multiple differentiation lineages for various therapeutic treatments. In this review, our focus is tailored towards the potential of biomimetic nanostructured materials as osteoinductive scaffolds for bone regeneration to differentiate MSCs towards osteoblastic cell types without the presence of soluble factors. In addition to mimicking the nanostructure of native bone, the supplement of collagen and hydroxyapatite which mimic the main components of the ECM also brings signifi cant advantages to these materials.
Subject(s)
Biomimetics/methods , Mesenchymal Stem Cells , Nanostructures , Osteogenesis , Tissue Engineering/methods , Biomimetics/instrumentation , Bone Transplantation , Collagen Type I , Extracellular Matrix , Humans , Tissue Engineering/instrumentationABSTRACT
UNLABELLED: Using scaffolds with autologous stem cells is a golden strategy for the treatment of bone defects. In this strategy, human mesenchymal stem cells (hMSCs) have often been isolated and expanded in vitro on a plastic surface to obtain a sufficient cell number before seeding on a suitable scaffold. MATERIALS & METHODS: Investigating the influence of serial passages (from passage two to passage eight) on the abilities of proliferation and osteogenic differentiation of hMSCs on 24-well tissue culture polystyrene plates and poly L-lactic acid electrospun nanofibrous scaffolds was performed to determine how prolonged culture affected these cellular abilities and how the nanofibrous scaffolds supported the osteogenic differentiation potential of hMSCs. RESULTS & CONCLUSION: Serial passage caused adverse changes in hMSCs characteristics, which were indicated by the decline in both proliferation and osteogenic differentiation abilities. Interestingly, the poly L-lactic acid nanofibrous scaffolds showed a significant support in recovering the osteogenic abilities of hMSCs, which had been severely affected by prolonged culture.
Subject(s)
Cell Differentiation/physiology , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/metabolism , Osteogenesis/physiology , Tissue Scaffolds/chemistry , Alkaline Phosphatase/metabolism , Calcium/metabolism , Cell Proliferation , Cells, Cultured , Humans , Lactic Acid/chemistry , Mesenchymal Stem Cells/ultrastructure , Microscopy, Electron, Scanning , Polyesters , Polymers/chemistry , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Acute full-thickness skin wounds (FTSW) caused by extensive burns or high-energy trauma are not adequately addressed by current clinical treatments. This study hypothesized that biomimetic nanofiber scaffolds (NFSs) functionalized with rich attachment of bone-marrow-derived mesenchymal stem cells (BM-MSCs) can promote wound healing in acute FTSW. Results in a rat model showed that both NFS and BM-MSCs contributed to the wound healing. Wounds in NFS group with a higher density of BM-MSCs achieved complete closure 8 days earlier than the control group. Implanted BM-MSCs were found to promote epithelial edge ingrowth and collagen synthesis. The colocation of BM-MSCs (tagged with quantum-dots) with the expression of keratin 10 and filaggrin indicated the participation of BM-MSCs in epidermal differentiation at early and intermediate stages under the local wounding environment. Overall, this study suggests a great potential of using NFS/BM-MSC composites for the treatment of acute FTSW.
Subject(s)
Bone Marrow Cells/metabolism , Burns/therapy , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/metabolism , Nanofibers , Skin/injuries , Wound Healing , Animals , Biomimetic Materials , Burns/metabolism , Cell Differentiation , Filaggrin Proteins , Humans , Intermediate Filament Proteins , Keratin-10 , Male , Quantum Dots , Rats , Rats, Sprague-Dawley , Skin/metabolism , Transplantation, HeterologousABSTRACT
The regenerative potential of injured adult tissue suggests the physiological existence of cells capable of participating in the reparative process. Recent studies indicate that stem-like cells residing in tissues contribute to tissue repair and are replenished by precursor bone marrow-derived cells. Mesenchymal stromal cells (MSC) are among the candidates for reparative cells. These cells can potentially be mobilized into the circulation in response to injury signals and exert their reparative effects at the site of injury. Current therapies for musculoskeletal injuries pose unavoidable risks which can impede full recovery. Trafficking of MSC to the injury site and their subsequent participation in the regenerative process is thought to be a natural healing response that can be imitated or augmented by enhancing the endogenous MSC pool with exogenously administered MSC. Therefore, a promising alternative to the existing strategies employed in the treatment of musculoskeletal injuries is to reinforce the inherent reparative capacity of the body by delivering MSC harvested from the patient's own tissues to the site of injury. The aim of this review is to inform the reader of studies that have evaluated the intrinsic homing and regenerative abilities of MSC, with particular emphasis on the repair of musculoskeletal injuries. Research that supports the direct use of MSC (without in vitro differentiation into tissue-specific cells) will also be reported. Based on accruing evidence that the natural healing mechanism involves the recruitment of MSC and their subsequent reparative actions at the site of injury, as well as documented therapeutic response after the exogenous administration of MSC, the feasibility of the emerging strategy of instant stem-cell therapy will be proposed.
Subject(s)
Mesenchymal Stem Cells/cytology , Stromal Cells/cytology , Animals , Bone and Bones/cytology , Cartilage/cytology , Humans , Tissue Engineering/methods , Wound Healing/physiologyABSTRACT
Biodegradable nanofibers have become a popular candidate for tissue engineering scaffolds because of their biomimetic structure that physically resembles the extracellular matrix. For certain tissue regeneration applications, prolonged in vitro culture time for cellular reorganization and tissue remodeling may be required. Therefore, extensive understanding of cellular effects on scaffold degradation is needed. There are only few studies on the degradation of nanofibers, and also the studies on degradation throughout cell culture are rare. In this study, polyglycolide (PGA), poly(DL-lactide-co-glycolide) (PLGA) and poly(L-lactide-co-epsilon-caprolactone) [P(LLA-CL)] were electrospun into nanofibrous meshes. The nanofibers were cultured with porcine smooth muscle cells for up to 3 months to evaluate their degradation behavior and cellular response. The results showed that the degradation rates are in the order of PGA >> PLGA > P(LLA-CL). PGA nanofibers degraded in 3 weeks and supported cell growth only in the first few days. PLGA nanofiber scaffolds facilitated cell growth during the first 30 days after seeding, but cell growth was slow thereafter. P(LLA-CL) nanofibers facilitated long-term (1-3 months) cell growth. mRNA quantification using real-time polymerase chain reaction revealed that some smooth muscle cell markers (alpha-actinin and calponin) and extracellular matrix genes (collagen and integrin) seemed to be downregulated with increased cell culture time. Cell culture significantly increased the degradation rate of PGA nanofibers, whereas the effect on PLGA and P(LLA-CL) nanofibers was limited. We found that the molecular weight of P(LLA-CL) and PLGA nanofibers decreased linearly for up to 100 days. Half lives of PLGA and P(LLA-CL) nanofibers were shown to be 80 and 110 days, respectively. In summary, this is the first study to our knowledge to evaluate long-term polymeric nanofiber degradation in vitro with cell culture. Cell culture accelerated the nanofibrous scaffold degradation to a limited extent. P(LLA-CL) nanofibers could be a good choice as scaffolds for long-term smooth muscle cell culture.
Subject(s)
Absorbable Implants , Biomimetic Materials , Extracellular Matrix , Lactic Acid , Myocytes, Smooth Muscle/ultrastructure , Nanofibers , Polyesters , Polyglycolic Acid , Animals , Cell Culture Techniques , Cells, Cultured , Extracellular Matrix Proteins/biosynthesis , Gene Expression Regulation , Myocytes, Smooth Muscle/metabolism , Polylactic Acid-Polyglycolic Acid Copolymer , Swine , Time Factors , Tissue Engineering/methodsABSTRACT
BACKGROUND: A wealth of evidences have shown the participation and benefits of bone marrow-derived mesenchymal stem cells (BM-MSCs) in wound healing and skin tissue repair in vivo. However, their role in epidermal development and reconstitution is not clearly investigated. OBJECTIVE: Here we examine the quantitative effect of human BM-MSCs on epidermal regeneration in vitro. METHOD: Human keratinocytes and BM-MSCs are cultured at ratios from 0% to 100% on top of a fibroblast-embedded collagen gel in a three-dimensional organotypic co-culture model at an air-liquid interface up to 20 days and analyzed by histochemical and immunochemical staining of filaggrin, involucrin and keratin 10 on days 14 and 20. Human BM-MSCs were tracked with quantum dots in organotypic co-cultures. RESULTS: It was found that epidermal development is strongly influenced by the percentage of co-cultured BM-MSCs. A strong chemotactic effect between keratinocytes and MSCs was seen in the group with 50% of BM-MSCs, which resulted in an impaired epidermal development, whereas at a low percentage of BM-MSCs (10%), a stratified epidermal structure resembling native skin was established on day 14 of culture. Moreover, the immunostaining studies revealed that BM-MSCs in the low percentage (10%) participated in the basal periphery of reconstructed epidermis and a similar pattern characteristic of native epidermis was demonstrated in this experimental group, which was superior to all other experimental groups in terms of the thickness of stratum corneum and the expression profile of epidermal differentiation markers. CONCLUSION: This study indicates the advantage of using a new skin equivalent model incorporating a small fraction of MSCs to develop biologically useful tissues for maintaining homeostasis during skin regeneration and wound healing process.
Subject(s)
Bone Marrow Cells/physiology , Epidermis/physiology , Keratinocytes/physiology , Mesenchymal Stem Cells/physiology , Regeneration , Bone Marrow Cells/cytology , Coculture Techniques , Epidermal Cells , Filaggrin Proteins , Homeostasis/physiology , Humans , Intermediate Filament Proteins/metabolism , Keratin-10/metabolism , Keratinocytes/cytology , Mesenchymal Stem Cells/cytology , Models, Biological , Organ Culture Techniques , Protein Precursors/metabolism , Quantum DotsABSTRACT
Biodegradable materials are widely used in the biomedical field because there is no postoperative surgery after implantation. Widely used synthetic biodegradable materials are polyesters, especially those used in tissue engineering. Advances in the tissue engineering field have brought much attention in terms of scaffold fabrication, such as with biodegradable polyester nanofibers. The rationale for using nanofibers for tissue engineering is that the nonwoven polymeric meshwork is a close representation of the nanoscale protein fiber meshwork in native extracellular matrix (ECM). Electrospinning technique is a promising way to fabricate controllable continuous nanofiber scaffold mimicking the ECM structure. Electrospun nanofibers provide high surface-to-volume ratio and high porosity as a promising scaffold for tissue engineering. Because the degradation behaviors of scaffolds significantly affect new tissue regeneration, the degradation of the material becomes one of the crucial factors when considering using polyester nanofibers as scaffolds in tissue engineering. In this review paper, we focus on the degradation studies of several bioresorbable polyester nanofibrous scaffolds used in tissue engineering. The degradable properties of nanofibers were compared with the corresponding degradable materials in macroscale. The factors that might affect the degradation behaviors were analyzed.
Subject(s)
Absorbable Implants , Biocompatible Materials/chemistry , Nanostructures/chemistry , Polyesters/chemistry , Tissue Engineering/methods , Animals , Humans , Nanostructures/ultrastructureABSTRACT
A bioabsorbable nanofibrous scaffold was developed for early adhesion of mesenchymal stem cells (MSCs). Collagen nanofibers with diameters of 430 +/- 170 nm were fabricated by electrospinning. Over 45% of the MSC population adhered to this collagen nanofiber after 30 min at room temperature. Remarkably, collagen-coated P(LLA-CL) electrospun nanofibers were almost as efficient as collagen nanofibers whereas collagen cast film did not enhance early capture when it was applied on cover slips. The adhesive efficiency could be further increased to over 20% at 20 min and over 55% at 30 min when collagen nanofibers were grafted with monoclonal antibodies recognizing CD29 or CD49a. These data demonstrate that the early adhesive behavior is highly dependent on both the surface texture and the surface chemistry of the substrate. These findings have potential applications for early capture of MSCs in an ex vivo setting under time constraints such as in a surgical setting.
Subject(s)
Biocompatible Materials/chemistry , Bone Marrow Cells/cytology , Bone Marrow Cells/physiology , Collagen/chemistry , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/physiology , Cell Adhesion , Cell Differentiation , Cells, Cultured , Electrochemistry/methods , Humans , Materials Testing , Rotation , Surface PropertiesABSTRACT
Mineralized type I collagen (collagen I) nanofibers and their nanofibril bundles make up the microstructure of natural bone tissue, which range from nanometers to micrometers. However, attempts to achieve this hierarchically assembled structure in vitro have been unsuccessful. In this study, we added osteonectin into the collagen I solution, either at a high or low weight ratio (osteonectin: collagen I = 1:30 or 1:90) before co-precipitation. Results indicated that spindle-like nano-hydroxyapatite (nano-HA) was deposited on collagen/osteonectin and pure osteonectin (control) groups. Furthermore, transmission electron microscope (TEM) and scanning electron microscope (SEM) results showed that the assembled mineralized fiber bundles were formed randomly at different levels from 50 nm, 250 nm to 1100 nm. However, when we replaced collagen I with collagen II, osteonectin addition did not induce the formation of mineralized fiber bundles. The participation of osteonectin in the assembly of the mineralized fibers could provide new insights into the novel mineralization function of osteonectin for bone development in vivo and advancing new biomimetic methods for bone graft applications.
Subject(s)
Bone Substitutes , Collagen/chemistry , Durapatite/chemistry , Osteonectin/chemistry , Biomimetics , Bone Regeneration , Bone and Bones/metabolism , Humans , Microscopy, Electron, Scanning/methods , Microscopy, Electron, Transmission/methods , Nanostructures/chemistry , Nanotechnology/methods , Spectroscopy, Fourier Transform Infrared , Tissue Engineering/instrumentation , Tissue Engineering/methods , X-Ray DiffractionABSTRACT
Bone is a nanocomposite consisting of two main components, nano-hydroxyapatite (n-HA) and Type I collagen (Col). The aim is to exploit the nano-scale functional and material characteristics of natural bone in order to modulate cellular functions for optimal bone repair in bone graft systems. Here, we present an effective and novel technique in obtaining n-HA in cognate with native apatite on electrospun nanofibers within minutes without any pre-treatment. Using an alternate calcium and phosphate (Ca-P) solution dipping method, n-HA was formed on poly(lactide-co-glycolide) acid (PLGA) and blended PLGA/Col nanofibers. The presence of the functional groups of collagen significantly hastened n-HA deposition closed to nine-fold. The quantity of n-HA impinged upon the specific surface area, whereby mineralized PLGA/Col had a greater surface area than non-mineralized PLGA/Col, whereas n-HA did not significantly improve the specific surface area of mineralized PLGA compared to pure PLGA. The novelty of the process was that n-HA on PLGA had a positive modulation on early osteoblast capture (within minutes) compared to pure PLGA. Contrary, cell capture on mineralized PLGA/Col was comparable to pure PLGA/Col. Interestingly, although n-HA impeded proliferation during the culture period (days 1, 4 and 7), the cell functionality such as alkaline phosphatase (ALP) and protein expressions were ameliorated on mineralized nanofibers. The amount of n-HA appeared to have a greater effect on the early stages of osteoblast behavior (cell attachment and proliferation) rather than the immediate/late stages (proliferation and differentiation).
Subject(s)
Bone and Bones/metabolism , Collagen/chemistry , Durapatite/chemistry , Lactic Acid/chemistry , Nanocomposites/chemistry , Osteoblasts/cytology , Polyglycolic Acid/chemistry , Tissue Engineering , Alkaline Phosphatase/metabolism , Calcification, Physiologic , Cells, Cultured , Elasticity , Humans , Nanocomposites/ultrastructure , Osteoblasts/enzymology , Osteoblasts/ultrastructure , Polylactic Acid-Polyglycolic Acid Copolymer , Spectroscopy, Fourier Transform Infrared , Temperature , Time Factors , Tissue Scaffolds , X-Ray DiffractionABSTRACT
The interactions of bone marrow-derived mesenchymal stem cells (MSCs) and their engrafted microenvironment are an integral part of signaling control of stem cell lineage commitment. We attempted to induce bone marrow-derived MSCs to undergo epidermal lineage differentiation by manipulating the biochemical, environmental and physical properties of culture conditions in an organotypic coculture model to simulate a skin-specific microenvironment. The induction medium was optimized by varying different biomolecular supplements in a basic stratification medium. A multi-layered epidermis-like structure was established when MSCs were cultured in an optimized induction medium on a contractible fibroblast-embedded collagen gel with an air-liquid interface. The commitment into epidermal lineage was further confirmed by the expression of early and intermediate epidermalization markers - keratin 10 and filaggrin in 90.67% and 80.51% of MSCs, respectively. This study not only highlights the possibility of in vitro control of MSCs into epidermal lineage, but also suggests the therapeutic potential of bone marrow-derived MSCs for skin regeneration.
Subject(s)
Bone Marrow Cells/physiology , Cell Differentiation/physiology , Epidermal Cells , Mesenchymal Stem Cells/physiology , Tissue Culture Techniques , Animals , Biomarkers/metabolism , Bone Marrow Cells/cytology , Cell Lineage , Cell Proliferation , Cell Survival/physiology , Cells, Cultured , Coculture Techniques , Filaggrin Proteins , Humans , Intermediate Filament Proteins/metabolism , Keratin-10/metabolism , Mesenchymal Stem Cells/cytology , Mice , Regeneration/physiologyABSTRACT
Chemical guiding cues are being exploited to stimulate neuron adhesion and neurite outgrowth. In this study, an amino-functioned PLLA, lysine-capped PLLA [K-(CH(2))(n)-PLLA (n=2, 5, 8)], was synthesized with different length of linking spaces between lysine molecule and PLLA backbone. Drop-cast films were fabricated from K-(CH(2))(n)-PLLA/PLLA blends (10/90, w/w) and amino groups were detected on the surfaces of the resultant films. More amine groups were detected on the surface and the hydrophilicity of the films was obviously improved by annealing the films in water. The representative atomic force microscopy (AFM) images indicated that incorporation of lysine-capped PLLA into PLLA matrix increased the roughness of the films and resulted in a phase separation with distinct two nano-domains which may correspond to the hydrophilic and hydrophobic domains. Furthermore, the laminin-derived peptides, CYIGSR (Cys-Tyr-Ile-Gly-Ser-Arg) and CSIKVAV (Cys-Ser-Ile-Lys-Val-Ala-Val), were jointly tethered to the amine groups of lysine-capped PLLA by a linking reagent sulfo-succinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (Sulfo-SMCC). The neonatal mouse cerebellum C17.2 stem cells were seeded on the peptides-grafted K-(CH(2))(n)-PLLA/PLLA (n=2, 5, 8) films and pure PLLA films were used as controls. Improved viability and longer neurites were obtained on the peptide-grafted films than PLLA film over the cultivation period, especially for K-(CH(2))(5)-PLLA/PLLA, which had the highest peptide density of 0.28+/-0.03 microg/cm(2). This study highlights the potential of using the lysine-capped PLLA with laminin-derived peptides for promoting nerve regeneration.
Subject(s)
Cerebellum/cytology , Laminin/pharmacology , Lysine/pharmacology , Peptides/pharmacology , Polyesters/pharmacology , Stem Cells/cytology , Stem Cells/drug effects , Amino Acid Sequence , Animals , Animals, Newborn , Cell Adhesion/drug effects , Cell Line , Cell Shape/drug effects , Cell Survival/drug effects , Laminin/chemistry , Lysine/chemistry , Magnetic Resonance Spectroscopy , Mice , Microscopy, Atomic Force , Microscopy, Confocal , Molecular Sequence Data , Neurites/drug effects , Neurites/metabolism , Peptides/chemistry , Polyesters/chemical synthesis , Polyesters/chemistry , Solvents , Stem Cells/ultrastructure , Surface Properties/drug effects , Temperature , WaterABSTRACT
The concept of bone tissue engineering, which began in the early 1980s, has seen tremendous growth in the numbers of research studies. One of the key areas of research has been in the field of mesenchymal stem cells, where the challenge is to produce the perfect tissue-engineered bone construct. This practical review summarizes basic and applied state-of-the-art research in the area of mesenchymal stem cells, and highlights the important translational research that has already been initiated. The topics that will be covered include the sources of stem cells in use, scaffolds, gene therapy, clinical applications in nonunions, tumors, osteonecrosis, revision arthroplasties, and spine fusion. Although significant challenges remain, there exists an exceptional opportunity to translate basic research in mesenchymal stem cell technologies into viable clinical treatments for bone regeneration.
Subject(s)
Bone Regeneration/physiology , Cell- and Tissue-Based Therapy/methods , Mesenchymal Stem Cells/physiology , Animals , Clinical Trials as Topic , Genetic Therapy , Guided Tissue Regeneration , Humans , Tissue Engineering/methods , Tissue ScaffoldsABSTRACT
Poly-L-lactic acid (PLLA) and PLLA/collagen (50% PLLA+50% collagen; PLLA/Col) nanofibers were fabricated using electrospinning. Mineralization of these nanofibers was processed using a modified alternating soaking method. The structural properties and morphologies of mineralized PLLA and PLLA/Col nanofibers were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and contact angle measurements. Human bone-derived osteoblasts were cultured on the materials for up to 1 week to assess the biological properties of the nanofibrous composites. Cell attachment on these nanocomposites was also tested within 1 h of culture at room temperature. The mechanical properties of the cell-nanocomposite constructs were determined using tensile testing. From our results, the bone-like nano-hydroxyapatite (n-HA) was successfully deposited on the PLLA and PLLA/Col nanofibers. We observed that the formation of n-HA on PLLA/Col nanofibers was faster and significantly more uniform than on pure PLLA nanofibers. The n-HA significantly improved the hydrophilicity of PLLA/Col nanofibers. From the results of cell attachment studies, n-HA deposition enhanced the cell capture efficacy at the 20-minute time point for PLLA nanofibers. The E-modulus values for PLLA+n-HA with cells (day 1 and day 4) were significantly higher than for PLLA+n-HA without cells. Based on these observations, we have demonstrated that n-HA deposition on nanofibers is a promising strategy for early cell capture.