Effect of double growth factor release on cartilage tissue engineering

The effects of double release of insulin-like growth factor I (IGF-I) and growth factor β1 (TGF-β1) from nanoparticles on the growth of bone marrow mesenchymal stem cells and their differentiation into cartilage cells were studied on PLGA scaffolds. The release was achieved by using nanoparticles of poly(lactic acid-co-glycolic acid) (PLGA) and poly(N-isopropylacrylamide) (PNIPAM) carrying IGF-I and TGF-β1, respectively. On tissue culture polystyrene (TCPS), TGF-β1 released from PNIPAM nanoparticles was found to have a significant effect on proliferation, while IGF-I encouraged differentiation, as shown by collagen type II deposition. The study was then conducted on macroporous (pore size 200-400μm) PLGA scaffolds. It was observed that the combination of IGF-I and TGF-β1 yielded better results in terms of collagen type II and aggrecan expression than GF-free and single GF-containing applications. It thus appears that gradual release of a combination of growth factors from nanoparticles could make a significant contribution to the quality of the engineered cartilage tissue. © 2011 John Wiley & Sons, Ltd

Construction of a bioraactor for the degradation of the pesticide, aldicarb

Water soluble derivatives of cellulose are widely used in various biomedical and biotechnological applications. Sodium carboxymethyl cellulose (25 ml, 1-4% w/v) was insolubilized in the form of microspheres using aluminum chloride (150 ml, 0.2-2.0 M) as the crosslinking agent. Microspheres were activated by epichlorohydrin. Methylophilus, a Gram negative bacteria capable of degrading aldicarb, a carbamate pesticide, was immobilized Methylophilus was determined by feeding in aqueous aldicarb solutions (10-400 ppm) at a rate of 20 ml/h. The degradative capability was found to be quite stable for ca. 48 h, and ca. 10% of the aldicarb was degradative capability was found to be quite stable for ca. 48 h, and ca. 10% of the aldicarb was found to be metabolized in the packed bed approach with a single pass application. © 1997 Elsevier B.V. All rights reserved.Consejo Nacional de Investigaciones Científicas y Técnicas: TBAG-DPT-27 Orta Doğu Teknik ÜniversitesiThe authors appreciate the support by the Scientific and Technical Research Council of Turkey (Grant No: TBAG-DPT-27) and by the Middle East Technical University, Graduate School of Natural and Applied Sciences (assistantship to F.N.K.)

Controlled release of Aldicarb from carboxymethylcellulese microcapsules

Sodium carboxymethyl cellulose was converted into microspheres by crosslinking with aluminum chloride. Various microsheres with different amounts of crosslinker, biopolymer of various concentrations and molecular weights, and with different pesticide (Aldicarb) contents and pesticide to polymer ratios were prepared. The pesticide encapsulation efficiencies and aldicarb release kinetics of the resultant microcapsules were investigated. It was possible to modify the release behaviour by varying the above parameters and to have drug release with half-lives longer than 100 hours in aqueous media. The release kinetics were described by first order and zero order kinetics

Controlled release of aldicarb from carboxymethyl cellulose microspheres: In vitro and field applications

Aldicarb is a carbamate pesticide that is widely used throughout the world in the protection of crops (eg cotton, nuts, potatoes, onion, tobacco, sugar beet and sugar cane). In Turkey, especially in the Cukurova region, it is used for the control of the cotton white fly (Bernisia tabaci) which attacks cotton plants cultivated in this region. Aldicarb contamination in surface and ground water is a serious problem in several countries, partly due to its high water solubility. It is also highly toxic to mammals. In order to overcome these problems, microspheres of aldicarb were prepared using carboxymethyl cellulose (CMC) as the biodegradable support material cross-linked with aluminium chloride. A strong hysteresis behaviour was observed upon drying and reswelling. Encapsulation efficiency was in the range 12-23% and aldicarb contents of 5.7-10.3 mg per 100 mg of microspheres was achieved. In vitro release was distinctly Fickian, and Higuchi constants were very close to 0.5. Release in pots revealed that only one sample had a release capability for more than four weeks. In the cotton plot much longer durations of release (more than seven weeks) were observed while a commercial granular formulation released its content immediately. It was thus possible to construct a controlled pesticide release system that prolonged the bioavailability to about eight weeks

Effect of double growth factor release on cartilage tissue engineering

PubMedID: 22081628The effects of double release of insulin-like growth factor I (IGF-I) and growth factor ß1 (TGF-ß1) from nanoparticles on the growth of bone marrow mesenchymal stem cells and their differentiation into cartilage cells were studied on PLGA scaffolds. The release was achieved by using nanoparticles of poly(lactic acid-co-glycolic acid) (PLGA) and poly(N-isopropylacrylamide) (PNIPAM) carrying IGF-I and TGF-ß1, respectively. On tissue culture polystyrene (TCPS), TGF-ß1 released from PNIPAM nanoparticles was found to have a significant effect on proliferation, while IGF-I encouraged differentiation, as shown by collagen type II deposition. The study was then conducted on macroporous (pore size 200-400µm) PLGA scaffolds. It was observed that the combination of IGF-I and TGF-ß1 yielded better results in terms of collagen type II and aggrecan expression than GF-free and single GF-containing applications. It thus appears that gradual release of a combination of growth factors from nanoparticles could make a significant contribution to the quality of the engineered cartilage tissue. © 2011 John Wiley & Sons, Ltd