ABSTRACT
Background: collagen, the most abundant protein in the human body, and as an extracellular matrix protein, has an important role in the fiber formation. This feature of the collagen renders establishment of the structural skeleton in tissues. Regarding specific features associated with the collagen, such as, formation of the porous structure, permeability and hydrophilicity, it can also be used as a biocompatible matrix in the enzyme engineering
Objectives: the aim of the present study was to investigate the application of the type I collagen as a matrix for alkaline phosphatase immobilization using cross-linking method
Material and Methods: the Alkaline phosphatase was covalently immobilized on collagen matrix by using 1-ethyl-3-[dimethylaminopropyl] carbodiimide hydrochloride [EDC]. The source of the alkaline phosphatase was from the bovine intestinal mucous. After that, the activity of the immobilized enzyme was assayed under different experimental conditions
Results: the optimum pH was similar to that of the free enzyme, whereas the optimum temperature and thermal stability were shown some increments. The surface topography of the collagen matrix containing immobilized enzyme and ALP [Alkaline phosphatase] deficient was investigated by Atomic-force microscopy [AFM]. Images that have been obtained applying AFM show significant differences between uncovered and immobilized enzyme- matrix surface topography
Conclusions: our findings suggest that type I collagen can be utilized as a matrix for alkaline phosphatase immobilization via cross-linking method
ABSTRACT
Characteristics of differentiated osteoblasts from adipose derived stem cells [ADSCs] in compared with isolated osteoblasts from normal bone such as calvaria are unknown. The aim of this study was determination and comparison of phenotypic characterization between differentiated osteoblasts from stem cells and calvaria osteoblasts in vitro. In this study, mesenchymal stem cells were isolated from adipose tissue of human by enzymatic digestion and were differentiated into osteoblasts using osteogenic medium. Characteristics of these cells at first, second, third and fourth weeks were comprised with calvaria osteoblasts that were isolated from human calvaria by explanation culture method. To screen the characteristics of both calvaria and the differentiated osteoblasts, we used western blot to identify protein levels, von Kossa staining for mineral matrix detection and alkaline phosphatase [ALP] assay kit [Sigma] for ALP activity measurement. Difference between calvaria and differentiated osteoblast cells were analyzed by one-way ANOVA and P < 0.05 was considered as statistically significant. Alkaline phosphatase activity, collagen and mineral material production in differentiated osteoblasts at third week were more significantly than calvaria cells [P < 0.05]. Our results indicated that there was no significant different in osteocalcin [OC] production between differentiated osteoblast at first, second and third weeks and calvaria cells but declined at fourth week [P < 0.05]. Our survey showed that cellular traits of differentiated osteoblasts presented better than calvaria osteoblasts in vitro conditions. Therefore, we suggest that ADSCs could be used in next studies for bone tissue engineering