Chitosan scaffolds with BMP-6 loaded alginate microspheres for periodontal tissue engineering

The aim of this study is to develop an effective growth factor releasing scaffold-microsphere system for promoting periodontal tissue engineering. Bone morphogenetic protein-6 (BMP-6)-loaded alginate microspheres in narrow size distribution were produced by optimising electrospraying conditions. The addition of these microspheres to chitosan gels produced a novel scaffold in which not only the pore sizes and interconnectivity were preserved, but also a controlled release vehicle was generated. Loading capacity was adjusted as 50ng or 100ng BMP-6 for each scaffold and the controlled release behaviour of BMP-6 from chitosan scaffolds was observed during seven days. Cell culture studies were carried out with rat mesenchymal stem cells derived from bone marrow in three groups; chitosan scaffolds, chitosan scaffolds containing BMP-6-loaded alginate microspheres and chitosan scaffolds with free BMP-6 in culture medium. Results showed that controlled delivery of BMP-6 from alginate microspheres has a significant effect on osteogenic differentiation. © 2012 Informa UK Ltd All rights reserved

Delivery systems made of natural-origin polymers for tissue engineering and regenerative medicine applications

There is an emergent need in the development of more specific and effective therapeutic agent carriers to help on the regeneration of a plethora of tissues. The ultimate aim of bioactive factors delivery systems development is to improve the human health with the fewest possible adverse reactions. While there have been many polymeric scaffolds and matrices with different forms and compositions developed to load and deliver bioactive factors, the delivery strategy should be established based on the type of molecules to deliver and mechanisms to control their release. As most bioactive factors such as proteins and genes are water-soluble, natural polymers are more favored than synthetic ones for this purpose. A core-shell structuring of biomaterials (in the cases of particles or fibers) where water-based polymers being placed in the inner core part may be the most common design principal to secure bioactive factors during the processing of synthetic drug delivery scaffolds.(undefined)info:eu-repo/semantics/submittedVersio

Chitosan scaffolds with BMP-6 loaded alginate microspheres for periodontal tissue engineering

The aim of this study is to develop an effective growth factor releasing scaffold-microsphere system for promoting periodontal tissue engineering. Bone morphogenetic protein-6 (BMP-6)-loaded alginate microspheres in narrow size distribution were produced by optimising electrospraying conditions. The addition of these microspheres to chitosan gels produced a novel scaffold in which not only the pore sizes and interconnectivity were preserved, but also a controlled release vehicle was generated. Loading capacity was adjusted as 50ng or 100ng BMP-6 for each scaffold and the controlled release behaviour of BMP-6 from chitosan scaffolds was observed during seven days. Cell culture studies were carried out with rat mesenchymal stem cells derived from bone marrow in three groups; chitosan scaffolds, chitosan scaffolds containing BMP-6-loaded alginate microspheres and chitosan scaffolds with free BMP-6 in culture medium. Results showed that controlled delivery of BMP-6 from alginate microspheres has a significant effect on osteogenic differentiation. © 2012 Informa UK Ltd All rights reserved.National Council for Scientific ResearchThis study was supported by grant (110M345) of the Scientific and Research Council of Turkey (TUBITAK)

Enhanced Osteogenic Activity With Boron-Doped Nanohydroxyapatite-Loaded Poly(Butylene Adipate-Co-Terephthalate) Fibrous 3D Matrix

In this study, three dimensional (3D) poly(butylene adipate-co-terephthalate) (PBAT) fibrous scaffolds with more than 90% porosity were fabricated via wet electrospinning method. Amorphous hydroxyapatite (HAp) and boron (B) doped hydroxyapatite (B-HAp) nanoparticles were produced by microwave-assisted biomimetic precipitation and encapsulated into PBAT fibres with the ratio of 5% (w/w) in order to enhance osteogenic activity of the scaffolds. Cell culture studies were carried out with human bone marrow derived stem cells (hBMSCs) and they showed that alkaline phosphatase (ALP) activity and the amounts of collagen and calcium were higher on B containing PBAT (B-HAp-PBAT) scaffolds during the 28-day culture period than that of the PBAT scaffolds. Moreover, hBMSCs cultivated on B-HAp-PBAT scaffolds showed significantly higher expression levels of both early and late stage osteogenic genes e.g. ALP, collagen I (COL-I), osteocalcin (OCN) and osteopontin (OPN) at day 28 than that of the PBAT scaffolds. Scanning electron microscope (SEM) photographs and energy dispersive X-ray (EDX) analysis indicated that hBMSCs produced high amounts of mineralized extracellular matrix (ECM) mainly on the surface of the 3D matrices. This study demonstrates that boron-containing 3D nanofibrous PBAT scaffolds with their osteoinductive and osteoconductive properties can be used as alternative constructs for bone tissue engineering.WoSScopu

In vitro chondrogenesis by BMP6 gene therapy

In this study, the promotion of in vitro chondrogenesis was investigated by using chitosan scaffolds and rat bone marrow-derived mesenchymal stem cells (rBMSCs) which are transfected by BMP6 (bone morphogenetic protein-6) encoding gene. For this purpose, plasmid DNA (pShuttle-rBMP6), the expression vector consisting of the coding sequence of the BMP6 was obtained, and then, it was entrapped in chitosan scaffolds to obtain a gene-activated matrix (GAM). The chitosan scaffolds performed the controlled and sustained release of plasmid DNA, thus they continuously provided the modification of rBMSCs to induce chondrogenic differentiation. In addition, the cells were transfected by lipid-based agent (Lipofectamine) and then, these modified cells were inoculated into the chitosan scaffolds. Furthermore, a group of chitosan scaffolds with nontransfected rBMSCs with recombinant BMP6 free in culture medium was used as control. Comparative results showed that, mitochondrial activities of modified rBMSCs by Lipofectamine and chitosan GAM were significantly higher than those of nontransfected rBMSCs. The observations from scanning electron microscopy analysis confirmed that BMP6 gene-modified rBMSCs differentiated to the chondrogenic phenotype. Highest amount of glycosaminoglycan contents of rBMSCs on GAM concluded that BMP6 gene-activated chitosan scaffold has a potential in the application of cartilage regeneration. © 2012 Wiley Periodicals, Inc

Encapsulated boron as an osteoinductive agent for bone scaffolds

The aim of this study was to develop boron (B)-releasing polymeric scaffold to promote regeneration of bone tissue. Boric acid-doped chitosan nanoparticles with a diameter of approx. 175. nm were produced by tripolyphosphate (TPP)-initiated ionic gelation process. The nanoparticles strongly attached via electrostatic interactions into chitosan scaffolds produced by freeze-drying with approx. 100. µm pore diameter. According to the ICP-OES results, following first 5. h initial burst release, fast release of B from scaffolds was observed for 24. h incubation period in conditioned medium. Then, slow release of B was performed over 120. h. The results of the cell culture studies proved that the encapsulated boron within the scaffolds can be used as an osteoinductive agent by showing its positive effects on the proliferation and differentiation of MC3T3-E1 preosteoblastic cells. © 2015 Elsevier GmbH

GRGDS-conjugated and curcumin-loaded magnetic polymeric nanoparticles for the hyperthermia treatment of glioblastoma cells

Thermally responsive and ligand-mediated drug delivery systems have the potential to improve the treatment of brain tumors, especially, most lethal one, glioblastoma multiform (GBM). Magnetic nanoparticle-mediated hyperthermia becomes one of the most promising alternative therapy for GBM treatment in cases where localized heating and targeted delivery of a therapeutic drug can be achieved on the tumor site. In this study, it is aimed to increase the therapeutic efficiency of multi-functionalized nanoparticles (NPs) in combination with radiofrequency hyperthermia (RF-HT) on GBM cells. For this purpose, firstly, a low-cost and portable home-built RFHT system suitable for in vitro/in vivo studies was successfully implemented and tested at 13.56 MHz frequency with power up to approximately 400 W. Subsequently, the highly monodispersed superparamagnetic iron oxide nanoparticles (SPIONs), which could interact with the RF magnetic field, were synthesized with the mean particle size of 5.6 +/- 0.9 nm. The obtained SPIONs were coated with poly (lactic-co-glycolic acid)-poly (ethylene glycol) di-block copolymer (PLGA-b-PEG). Most of the SPIONs were uniformly distributed in such a well-defined spherical-shaped polymeric NP. Moreover, curcumin (Cur), a potential agent for GBM treatment, was loaded into the magnetic polymeric nanoparticles (m-PNPs) with a loading capacity of 8% (w/w, Cur/NPs) and a mean diameter of Cur-loaded m-PNPs (Cur-m-PNPs) was 142 +/- 70 nm. To increase cellular uptake and targeting ability of NPs, glycine-arginine-glycine-aspartic acid-serine (GRGDS) peptide was immobilized on the Cur-m-PNPs and the amount of GRGDS was detected as 37 mu g/mg NPs. In vitro cytotoxicity studies revealed that the presence of GRGDS on Cur-m-PNPs (GRGDS-Cur-m-PNPs) improved the cytotoxic efficiency of Cur-m-PNPs by 6-fold in GBM-cells for all incubation times (24, 48 and 72 h). Furthermore, NPs with RF treatment exhibited higher antitumor activity than that of NPs without RF on GBM cells. This result may be attributed to the thermal (SPIONs) or non thermal (cellular membrane) effects or both of them on cells. Overall, this study showed that RF-HT in combination with GRGDS-Cur-m-PNPs could provide a feasible approach to improve GBM treatment.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [SBAG-118S027, SBAG119S137]This study was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) , Grant no: SBAG-118S027 and SBAG119S137. We are sincerely grateful for the assistance of the Cell and Tissue Engineering Research Group at Hacettepe University. We are also thankful to Dr. Anl Sera Cakmak for the support of cell culture studies.WOS:00065741860000

Biological nerve conduit model with de-epithelialized human amniotic membrane and adipose-derived mesenchymal stem cell sheet for repair of peripheral nerve defects

In this study, a biological conduit, consisting of an adipocyte-derived mesenchymal stem cell (AdMSCs) sheet and amniotic membrane (AM), was designed for the reconstruction of peripheral nerve defects. To evaluate the effect of the produced conduit on neural regeneration, a 10-mm sciatic nerve defect was created in rats, and experiments were carried out on six groups, i.e., sham control group (SC), negative control group (NC), nerve autograft group (NG), the biological conduit (AdMSCs + AM) group, the commercial PGA tube conduit (PGA) group, and the conduit only consisting of AM (AM) group. The effects of different nerve repair methods on the peripheral nerve and gastrocnemius muscle were evaluated by functional, histological, and immunohistochemical tests. When the number of myelinated axons was compared between the groups of AdMSCs + AM and PGA, it was higher in the AdMSCs + AM group (p < 0.05). The percentage of gastrocnemius collagen bundle area of AdMSCs + AM group was found to be statistically lower than the PGA group (p < 0.05). The muscle fiber diameter of AdMSCs + AM group was lower than that of the NG group, but significantly higher than that of the PGA group and the AM group (p < 0.001). Muscle weight index was significantly higher in the AdMSCs + AM group compared to the PGA group (p < 0.05). It was observed that nerve regeneration was faster in the AdMSCs + AM group, and there was an earlier improvement in pin-prick score and sciatic functional index compared to the PGA group and the AM group. In conclusion, the biological conduit prepared from the AdMSCs sheet and AM is regarded as a new biological conduit that can be used as an alternative treatment method to nerve autograft in clinical applications.TUBITAK; [119S133]The authors acknowledge the support gained from TUBITAK (the Scientific and Technological Research Council of Turkey) (Grant No: 119S133) for this stud