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Poultry feather is hydrolyzed into peptides and amino acids in sub-critical water without any acid or alkali as catalyst under microwave-assisted heating to produce protein-based surfactant. The optimal hydrolysis condition is as follows: temperature 200 °C, time 60 min, and the yield of peptides and amino acids 84.31%. The critical micelle concentration (CMC) and surface tension of the product of peptides and amino acids are 2.6 g/L and 48.2 mN/m. In order to increase lipophilicity, subsequently anionic protein-based surfactant was synthesized by acylation reaction between the hydrolysis product of peptides and amino acidsand oleoyl chloride. The CMC and surface tension decreased greatly with linkage with oleoyl. The synthesized anionic surfactant with weight ratios of 10% (wt.%) hydrolysis liquid/oleoyl chloride of 3:1, 4.5:1 and 6:1 are 0.5, 0.7 and 0.8 g/L and corresponding surface tension are 30.1, 34.0 and 35.7mN/m.

Stem cell-based tissue engineering shows enormous potential for regenerative medicine. Three-dimensional (3D) stem cell culture is the most basic aspect of tissue engineering. However, achievement of a perfect scaffold for highly efficient 3D cell culture is currently still limited. Herein, a new hyaluronic acid hydrogel dual-enzymatically crosslinked by horseradish peroxidase and choline oxidase is developed as a 3D stem cell culture system. This hydrogel possesses superior stability over two months, controllable biodegradability with hyaluronidases, a high swelling ratio exceeding 6000%, and excellent cytocompatibility in vitro and biocompatibility in vivo. More importantly, a long-time and highly cellular activity 3D culture of bone marrow-derived mesenchymal stem cells was achieved in vitro over 20 days. All these encouraging results highlight the great potential of this new hydrogel for 3D culture and tissue engineering.

A new three-dimensional cellular system based on the elongated octahedron model [1] is analyzed and discussed mathematically for its compressibility properties. It is shown that there exists negative linear and area compressibility for some certain conformations in this model. In addition, when compared with the octahedral structure, it can be found that this structure has better negative compression effect in the horizontal direction.