Yuan Yinghai

Degradation behavior and compatibility of micro, nanoHA/chitosan scaffolds with interconnected spherical macropores

Hydroxyapatite/Chitosan (HA/CS) composite have significant application in biomedical especially for bone replacement. Inorganic particle shape and size of composite affect the scaffold mechanical property, biological property, and degradation. The aim of this study was to fabricate HA/CS scaffold with good pore connectivity and analyze their biological, degradation properties. Microhydroxyapatite/chitosan (mHA/CS) and nanohydroxyapatite/chitosan (nHA/CS) composite scaffolds with interconnected spherical pore architectures were fabricated. Composite scaffolds structure parameters were analyzed using micro CT. Cell proliferation and morphology were tested and compared between two scaffolds using mouse osteoblastic cell line MC3T3-E1. To research the composite degradation in lysozyme PBS solution, degradation rate and reducing sugar content were tested, and scaffolds morphology were observed by SEM. The results showed that microHA and nanoHA were fabricated by being calcined and synthesis methods, and their infrared spectra are very similar. EDAX composition analysis demonstrated that both of microHA and nanoHA were calcium deficiency HA. Micro-CT results demonstrated the scaffolds had interconnected spherical pores, and the structure parameters were similar. Cell viabilities were significant increased with cultured time, but there were no significant difference between microHA/CS and nanoHA/CS scaffolds. Scaffold structure was gradually destroyed and inorganic composition HA particles are more prominent with degradation time. SIGNIFICANCE (1) Inorganic particle shape and size of composite affect the scaffold mechanical property, biological property, and degradation. NanoHA/CS and microHA/CS scaffolds with good pore connectivity were fabricated and their biological, degradation properties were studied in this manuscript. (2) The scaffold with interconnected porosity construct provides the necessary support for cells to proliferate and maintain their differentiated function, and its architecture related to the structure and morphology of new bone. Polymer scaffolds were fabricated by the technique of compression molding and particulate leaching method, and paraffin microspheres were used as the porogen. (3) MicroHA/CS and nanoHA/CS composite scaffolds are potential materials for use in bone tissue engineering.

Component Analysis of Enriched Oxygen Gas from a Small-Size PSA Medical Oxygen Generator

This paper studied on the component of enriched oxygen gas from a self-developed small-size PSA medical oxygen generator. Through gas chromatography each concentration group of oxygen, nitrogen, argon, carbon dioxide and total hydrocarbon with different outlet flow was investigated, and the fluctuation of each group during continuous operation of 48 h was also measured. The result showed that the key factor to constrain the increase of oxygen purity was micro argon in the air, which can reach to 5.1101% in oxygen-rich gas and didn’t change with the variation of zeolite utilization or the increase of operating time, indicating the invalid of current molecular sieve materials. Another major gas nitrogen declined significantly with the improvement of the molecular sieve utilization, which was only account for 0.4643%. Other trace amount of impurity gas such as total hydrocarbon and carbon dioxide were only in ppm level.