Osteogenic differentiation and mineralization on compact multilayer nHA-PCL electrospun scaffolds in a perfusion bioreactor

Background: Monolayer electrospun scaffolds have already been used in bone tissue engineering due to their high surface-tovolume ratio, interconnectivity, similarity to natural bone extracellular matrix [ECM], and simple production

Objectives: The aim of this study was to evaluate the dynamic culture effect on osteogenic differentiation and mineralizationi into a compact cellular multilayer nHA-PCL electrospun construct. The dynamic culture was compared with static culture

Materials and Methods: The calcium content, alkaline phosphatase [ALP] activity and cell viability were investigated on days 3 and 7

Results: When the dynamic culture compared to static culture, the mineralization and ALP activity were increased in dynamic culture. After 7 days, calcium contents were 41.24 and 20.44 micro g.[cm[3]][-1], and also normalized ALP activity were 0.32 and 0.19 U.mg[-1] in dynamic and static culture, respectively. Despite decreasing the cell viability until day 7, the scanning electron microscopy [SEM] results showed that, due to higher mineralization, a larger area of the construct was covered with calcium deposition in dynamic culture

Conclusions: The dynamic flow could improve ALP activity and mineralization into the compact cellular multilayer construct cultured in the perfusion bioreactor after 7 days. Fluid flow of media helped to facilitate the nutrients transportation into the construct and created uniform cellular construct with high mineralization. This construct can be applied for bone tissue engineering

[Formulation and optimization of controlled release of olanzapine by glycerol monooleate]

Background and Objectives: In situ gel formation of Glycerol Monooleate [GMO] has been utilized to release many drugs. The aim of this research was to optimize, and in-vitro characterization of the controlled release and formulation of the matrices containing Olanzapine [OZ], GMO and Polyethylene glycol [PEG 300]

Methods and Materials: Response surface methodology [RSM] is a combination of mathematical and statistical techniques. In this study, Design-Expert software with Box-Behnken response surface methodology has been used to determine the relationships between variables and responses. GMO/water weight ratio [w/w] different and PEG 300/GMO [w/w] were in the range of 2-4% and 2-6% respectively. Percentage of loading; and release at 12 th and 168 th hr were calculated. In-vitro release studies of OZ from prepared gels were conducted in PBS [pH 6.8] and then analyzed by spectrophotometer at 265 nm

Results: The optimum formulation was obtained at weight ratio of water/GMO [w/w] and PEG [300]/GMO [w/w] at 0.28 and 0.2 respectively, and percentage of OZ was at 4%. The observed and predicted values for EE % were 86.8 %, 90.31% respectively those parameters for release at 12th hr were 16.1% and 15% and for release at 168th hr, were 59.8 % and 63.56% respectively

Conclusion: In this study we performed kinetic release profile of OZ with several models, from which Higuchi model showed the best fitting and correlation

Aligned and random nanofibrous nanocomposite scaffolds for bone tissue engineering

Biological effects of MSCs on aligned and random nanofibrous scaffolds of PCL/PVA/nHA were investigated in this study. Aligned and random nanocomposite nanofibrous scaffolds were electrospun from polycaprolactone [PCL], poly [vinyl alcohol] [PVA] and hydroxyapatite nanoparticles [nHA]. The morphology and mechanical characteristics of the nanofibers were evaluated using scanning electron microscopy and tensile testing, respectively. Scanning electron microscopy revealed fibers with an average diameter of 123 +/- 32 nm and 339 +/- 107 nm for aligned and random nanofibers, respectively. The mechanical data indicated the higher tensile strength and elastic modulus of aligned nanofibers. The in vitro biocompatibility of aligned and random nanofibrous scaffolds was also assessed by growing mesenchymal stem cells [MSCs], and investigating the proliferation and alkaline phosphatase activity [ALP] on different nanofibrous scaffolds. Our findings showed that the alignment orientation of nanofibers enhanced the osteogenic differentiation of stem cells. The in vitro results showed that the aligned biocomposite nanofibrous scaffolds of PCL/nHA/PVA could be a potential substrate for tissue engineering applications, especially in the field of artificial bone implant

Production of recombinant human granulocyte-colony stimulating factor by Pichia pastoris

Human granulocyte-colony stimulating factor [hGCSF] cDNA was expressed in the methylotrophic yeast Pichia pastoris under the control of the alcohol oxidase [AOX1] promoter. An expression vector for hG-CSF secretion was constructed using pPIC9 vector. Higher levels of hG-CSF was obtained using a P. pastoris Mut+ [methanol utilization fast] phenotype. The effects of environmental factors such as, temperature and pH on the P. pastoris cell growth and hGCSF production during fermentation were investigated. Cell growth and hG-CSF production were found to be optimal at 28C and pH 6.0. A fed-batch fermentation process was also developed to obtain high cell density and higher levels of protein expression. Using a high cell density cultivation method, cell dry weight and hGCSF concentration reached 100 g/l and 35 mg/l, respectively

Hydrogen oxidizing bacteria as poly [hydroxybutyrate] producers

Batch culture of Ralstonia eutropha using the recycled gas closed circuit culture system was conducted in order to develop a practical fermentation system for industrial autotrophic culture for poly [hydroxybutrate] production. The gas phase of the culture system consisted of substrate gas so that gases in this culture could be recycled as long as the amount of the gas consumed would be replenished. All gases supplied into this system could be completely used without any loss as exhaust. Studies on the effect of oxygen concentration showed that high concentration of this gas suppressed the specific growth rate while a low oxygen concentration promoted it