Surface Characteristics Of Scaffolds Research Articles

Promotion of osteogenic differentiation by non-thermal biocompatible plasma treated chitosan scaffold

Non-thermal biocompatible plasma (NBP) has recently emerged as an attractive tool for surface modification of biomaterials in tissue engineering. Three dimensional chitosan scaffolds have been widely used in bone tissue engineering due to biodegradable and biocompatible properties. The present study aimed to evaluate osteogenic potential of NBP treated chitosan scaffold. The surface characteristics of scaffolds were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), cell proliferation and differentiation was tested with osteoprogenitor cell line MC3T3-E1. The results show that NBP modified scaffold increase cell metabolic by MTT assay and live/dead assay. More importantly, we evidenced enhancement of osteogenic differentiation on NBP treated scaffolds by an increase of alkaline phosphatase (ALP) activity, high degree of extracellular mineralization and up-regulated osteogenic marker genes expression level. The findings in our study highlighted NBP as the innovative method to modified chitosan scaffold and to fine-tuning the scaffold a more suitable and beneficial biomaterial for in vivo bone tissue engineering and clinical bone defects therapies.

The Effects of Carbon and Gold Ion Implanted Surfaces on Neuronal Stem Cells’ Functions

Biomaterials have been used in medicine for decades to improve the functions of tissues and organs. They are also used as prosthesis and implants which are designed to substitute functions of a lacking organ or tissue. Carbon (C) and Gold (Au) were particularly chosen due to their biocompatibility and applied as implants for decades. Carbon and gold were great ion sources for medical applications, as well. In this study, polystyrene dishes were modified using gold and carbon ions via ion implantation technique. Using this surface modification method, it was aimed to improve surface characteristics and achieve a bioactive surface for neural stem cells. Even though the integration of stem cells was promising, neural stem cell studies still have many milestones to reach. Neuro-regeneration was the most desired function for people who suffer from neural system diseases. Changing surface characteristics of scaffolds was a way to promote regeneration and ion implantation was one of the methods to modify surface properties which play a huge role in enhancing the proliferation and integration of cells. In this study, it was observed that the ion implantation stimulated the neural proliferation and the implantation of different ions on cell culture surfaces was essential to determine the effects of this technique on adhesion, proliferation, differentiation and apoptosis properties of cells in details.

Multiple approaches to predicting oxygen and glucose consumptions by HepG2 cells on porous scaffolds in an axial-flow bioreactor.

In this study, the distribution of oxygen and glucose was evaluated along with consumption by hepatocytes using three different approaches. The methods include (i) Computational Fluid Dynamics (CFD) simulation, (ii) residence time distribution (RTD) analysis using a step-input coupled with segregation model or dispersion model, and (iii) experimentally determined consumption by HepG2 cells in an open-loop. Chitosan-gelatin (CG) scaffolds prepared by freeze-drying and polycaprolactone (PCL) scaffolds prepared by salt leaching technique were utilized for RTD analyses. The scaffold characteristics were used in CFD simulations i.e. Brinkman's equation for flow through porous medium, structural mechanics for fluid induced scaffold deformation, and advection-diffusion equation coupled with Michaelis-Menten rate equations for nutrient consumption. With the assumption that each hepatocyte behaves like a micro-batch reactor within the scaffold, segregation model was combined with RTD to determine exit concentration. A flow rate of 1 mL/min was used in the bioreactor seeded with 0.6 × 10(6) HepG2 cells/cm(3) on CG scaffolds and oxygen consumption was measured using two flow-through electrodes located at the inlet and outlet. Glucose in the spent growth medium was also analyzed. RTD results showed distribution of nutrients to depend on the surface characteristics of scaffolds. Comparisons of outlet oxygen concentrations between the simulation results, and experimental results showed good agreement with the dispersion model. Outlet oxygen concentrations from segregation model predictions were lower. Doubling the cell density showed a need for increasing the flow rate in CFD simulations. This integrated approach provide a useful strategy in designing bioreactors and monitoring tissue regeneration.