No abstract

D-Pantonohydrolase has attracted increasing attention as a biocatalyst for stereospecific production of D-pantoic acid. The Fusarium moniliforme D-pantonohydrolase was selected for directed evolution through error-prone Polymerase Chain Reaction (PCR) combined with DNA shuffling for improved activity and pH stability using a convenient two-step high-throughput screening method based on the product formation and pH indicator. After three sequential error-prone PCRs and two rounds of DNA shuffling followed by screening, about 60 positive mutants were produced and a best mutant, Mut H-1287, with improved activity and pH stability was obtained. As compared to wild-type D-pantonohydrolase, Mut H-1287 showed a 10.5-fold higher specific activity; moreover, it could retain 85% of its original activity after incubation under low pH. Gene analysis indicated that the Mut H-1287 had D63H, K118Q, and V241I substitutions. The wild-type and evolved D-pantonohydrolase (Mut H-1287) was purified in three steps. The activities and characteristics of purified wild-type and evolved D-pantonohydrolase were also studied and compared.

We fabricated graphene-thermopolyurethane (G-TPU) flexible conductive film by a blending method and systematically investigated the electrical, thermal and self-healing properties of the G-TPU flexible conductive film by infrared light and electricity. The experimental results demonstrate that the G-TPU composite films have good conductivity and thermal conductivity in the appropriate mass content of graphene in the composite film. The composite films have the good electro-thermal and infrared light thermal response performances and electro-thermal response performance is closely related to the mass content of graphene in the composite film, but the infrared light thermal response performance is not. The scratch on the composite film can be completely healed, using electricity or infrared light. The healing efficiency of the composite film healed using infrared light is higher than that of using the electricity, while the healing time of the composite film is shorter. Regardless of the self-healing method, the temperature of the self-healing is a very important factor. The self-healing conductive composite film still exhibits a good conductivity.Nanomaterials 2020, 10, 753 2 of 16 of the material can be automatically healed to improve the safety, lifetime, and environmental impact of man-made materials [16][17][18][19][20][21]. To obtain self-healing materials, many strategies have been explored, such as micro-containers containing healing agent and microvascular networks in the matrix, dynamic chemical bonds or weak interaction [22][23][24][25][26][27]. These self-healing materials can realize self-healing by using a large number of healing agents [28,29]. In theory, they can realize multiple self-healing of the damaged materials with the assistance of external light, heat, and electric field, et al. Although, great progress has been made in the research of the self-healing materials and techniques, there are still some critical problems that restrict their applications, such as low mechanical properties after healing, high cost, time-consuming, and low efficiency. Therefore, it is significant to fabricate a self-healing polymer and composites based on new materials, and then explore their potential applications, as well as new healing method.Graphene (G), a novel two-dimensional material, possesses large specific surface area, superior mechanical property, as well as being an excellent conductor of both heat and electricity, and having a good microwave and infrared absorbing capacity, so they have strong response to electricity and electromagnetic waves and infrared radiation (IR) [30][31][32][33][34]. Graphene is often used as fillers in preparing functional composites. Based on these properties, researchers fabricated graphene-based self-healing polymer composites by introducing graphene into the polymer [34,35]. Kim et al. reported, for the first time, self-healable PU nanocomposites, containing modified graphene by the near IR absorption of graphene [36]. Huang et al. prepared TPU containing few layers of g...

In prior work we have shown that titanium oxide (Ti-O) thin films have good blood compatibility. However, as well as being hemocompatible, biomaterials used in contact with blood should be cell compatible also. In the work described here, Ti-O films were synthesized using unbalanced magnetron sputtering (UBMS) and were modified by immobilizing laminin on the film surface for improving human umbilical vein endothelial cell (HUVEC) adhesion and growth. Scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR) and contact-angle measurements were used to investigate the surface characteristics of the Ti-O films and the modified Ti-O films. The results suggest that Laminin can be biochemically immobilized on the Ti-O film surface. The modified layer of Laminin can improve the hydrophilicity and wettability of Ti-O films. In vitro HUVEC investigations reveal that Laminin immobilized on the film surface greatly enhances cell adhesion and growth on Ti-O films.