Degradable Cell-Adhesive Hybrid Hydrogels by Cross-Linking of Gelatin with Poly(2-isopropenyl-2-oxazoline).

This study focused on the cross-linking of poly(2-isopropenyl-2-oxazoline) (PiPOx) with gelatin to obtain strong, degradable hybrid hydrogels with good cell adhesion. The molecular weight and concentration of PiPOx and the PiPOx-to-gelatin ratio were varied to adjust the mechanical and swelling properties of the hybrid hydrogels. The swelling degree of PiPOx-gelatin hydrogels in water ranged between 1260 and 810%, with the corresponding Young's compressive moduli ranging from 77 to 215 kPa. Rheological measurements demonstrated the mechanical stability of the hydrogels. The hydrogels exhibited substantial degradation in Dulbecco's phosphate-buffered saline (DPBS) and cell culture medium within several weeks, indicating their degradability and responsiveness. The cell adhesion assay with primary human foreskin fibroblasts revealed the hybrid hydrogels are noncytotoxic and support cell attachment and proliferation. These strong hydrogels thus show excellent potential as biomedical cell scaffolds, combining the tunability and strength of PiPOx hydrogels with gelatin's cell-interactive properties while the ester-containing cross-links provide tunable degradability.

Analysis of soluble proteins during flowering of Petunia hybrida.

Soluble proteins were extracted from the leaves of Petunia hybrida when flower differentiation was induced. The results showed that 4 special proteins, with molecular weight of 49.45 kD (a), 35.45 kD (b), 17.98 kD (c) and 11.74 kD(d), are related to blossoming of flowers after photoperiod induction. Without proteins a and d only floral buds were formed which were never blossomed. There were flowers when all the 4 special proteins appeared together. Proteins c and d disappeared after blossoming. Proteins in different tissues were different when the plant was induced to blossom. Thus, for example, protein c and d were absent from stem throughout the process.