Collagen can self-assemble to form fibers with a unique structure and retain a reticular fibrous structure after membrane formation. However, collagen membranes without further modification are easy to tear. In this study, two crosslinkers (linear di-alkynyl poly(ethylene glycol) (DA-PEG) and branched tetra-alkynyl poly(ethylene glycol) (4arm-DA-PEG)) were synthesized, and exogenous crosslinking between collagen fiber bundles through the amino–yne click reaction was studied. Fourier-transform infrared spectroscopy (FT-IR) was performed to confirm the successful synthesis of crosslinkers and the construction of the crosslinked network. Scanning electron microscopy (SEM) showed that the crosslinked collagen membranes (Col/DA-PEG; Col/4arm-DA-PEG) had dense fibrous structures, which was expected to provide a structural foundation for surgical suturing. The denser structures and higher crosslinking degree of Col/4arm-DA-PEG provided good mechanical, optical, and antienzymatic properties. Col/4arm-DA-PEG could withstand 4.6 N/mm suture strength, which enabled it for suturing. Compared with glutaraldehyde-crosslinked membranes, Col/DA-PEG and Col/4arm-DA-PEG showed low cytotoxicity and better biocompatibility, as observed by CCK-8 assay and confocal laser scanning microscopy. These results indicate that alkynyl-terminated PEG systems can be used as ideal collagen crosslinkers to enhance the suture tension of collagen-based materials, especially in corneal repair materials.
Siyuan Liu,Jingxing Liu,Zefen Wang,Zhiqi Wu,Yiliang Wei,Pengru Liu,Xiongdiao Lan,Yexin Liao,Ping Lan
Glucose oxidase (GOx) has a great application potential in the determination of glucose concentration. However, its sensitivity to the environment and poor recyclability limited its broader application. Herein, with the assistance of DA-PEG-DA, a novel immobilized GOx based on amorphous Zn-MOFs (DA-PEG-DA/ [email protected] /PDA) was developed to impart excellent properties to the enzyme. SEM, TEM, XRD, and BET analyses confirmed that GOx was embedded in amorphous ZIF-7 with ∼5 wt% loading. Compared with free GOx, DA-PEG-DA/ [email protected] /PDA exhibited enhanced stability, excellent reusability, and promising potential for glucose detection. After 10 repetitions, the catalytic activity of DA-PEG-DA/ [email protected] /PDA can maintain 95.53 % ± 3.16 %. In understanding the in situ embedding of GOx in ZIF-7, the interaction of zinc ion and benzimidazole with GOx was studied by using molecular docking and multi-spectral methods. Results showed that zinc ions and benzimidazole had multiple binding sites on the enzyme, which induced the accelerated synthesis of ZIF-7 around the enzyme. During binding, the structure of the enzyme changes, but such changes hardly affect the activity of the enzyme. This study provides not only a preparation strategy of immobilized enzyme with high activity, high stability, and low enzyme leakage rate for glucose detection, but also a more comprehensive understanding of the formation of immobilized enzymes using the in situ embedding strategy.
危险品化学品经营许可证（带存储）