Development and characterization of polyvinyl alcohol/chitosan crosslinked malic acid composite films with curcumin encapsulated in ß-cyclodextrin for food packaging application.

Considering that fruits are vulnerable to damage and waste during stockpiling, transport and marketing. Given this, an innovative curcumin inclusion compound (Cur@ß-CD) was devised in this study to introduce oil-soluble curcumin (Cur) into water-soluble polyvinyl alcohol (PVA) materials, thereby fabricating food packaging films endowed with excellent properties. DPPH test manifested that the oxidation resistance for PCOMC-Cur@ß-CD film was 95 % above PVA material. It was ascribed to the fact that the Cur@ß-CD elevated the water solubility of Cur while the increase of water solubility heightened the antioxidant effect for Cur in the film. Additionally, the chitosan (CS) was crosslinked with malic acid (MA), which elevated the barrier property of the film, reduced the amount of oxygen transmission and further retarded the oxidation reaction of the fruits for packaging. The antibacterial test demonstrated that the antibacterial rates of PCOMC-Cur@ß-CD film against E. coli and S. aureus reached 92 % and 95 %, respectively, which was attributed to the slow release of Cur when Cur@ß-CD was dissolved in PVA material and the Schiff base reaction between Cur and amino groups on CS. These findings indicate that the PCOMC-Cur@ß-CD film developed in this work can provide certain insights into the field of food packaging.

Robust and Multifunctional Kirigami Electronics with a Tough and Permeable Aramid Nanofiber Framework.

Kirigami designs are advantageous for the construction of wearable electronics due to their high stretchability and conformability on the 3D dynamic surfaces of the skin. However, suitable materials technologies that enable robust kirigami devices with desired functionality for skin-interfaces remain limited. Here, a versatile materials platform based on a composite nanofiber framework (CNFF) is exploited for the engineering of wearable kirigami electronics. The self-assembled fibrillar network involving aramid nanofibers and poly(vinyl alcohol) combines high toughness, permeability, and manufacturability, which are desirable for the fabrication of hybrid devices. Multiscale simulations are conducted to explain the high fracture resistance of the CNFF-based kirigami structures and provide essential guidance for the design, which can be further generalized to other kirigami devices. Various microelectronic sensors and electroactive polymers are integrated onto a CNFF-based materials platform to achieve electrocardiogram (ECG), electromyogram (EMG), skin-temperature measurements, and measurement of other physiological parameters. These mechanically robust, multifunctional, lightweight, and biocompatible kirigami devices can shed new insights for the development of advanced wearable systems and human-machine interfaces.

Ultrastrong and multifunctional aerogels with hyperconnective network of composite polymeric nanofibers.

Three-dimensional (3D) microfibrillar network represents an important structural design for various natural tissues and synthetic aerogels. Despite extensive efforts, achieving high mechanical properties for synthetic 3D microfibrillar networks remains challenging. Here, we report ultrastrong polymeric aerogels involving self-assembled 3D networks of aramid nanofiber composites. The interactions between the nanoscale constituents lead to assembled networks with high nodal connectivity and strong crosslinking between fibrils. As revealed by theoretical simulations of 3D networks, these features at fibrillar joints may lead to an enhancement of macroscopic mechanical properties by orders of magnitude even with a constant level of solid content. Indeed, the polymeric aerogels achieved both high specific tensile modulus of ~625.3 MPa cm3 g-1 and fracture energy of ~4700 J m-2, which are advantageous for diverse structural applications. Furthermore, their simple processing techniques allow fabrication into various functional devices, such as wearable electronics, thermal stealth, and filtration membranes. The mechanistic insights and manufacturability provided by these robust microfibrillar aerogels may create further opportunities for materials design and technological innovation.

Elastic, Conductive, and Mechanically Strong Hydrogels from Dual-Cross-Linked Aramid Nanofiber Composites.

Recent research on conductive hydrogels has revealed their potential for building advanced soft bioelectronic devices. Their mechanical flexibility, water content, and porosity approach those of biological tissues, providing a compliant interface between the human body and electronic hardware. Conductive hydrogels could be utilized in many soft tools such as neural electrodes, tactile interfaces, soft actuators, and other electroactive devices. However, most of the available conductive hydrogels exhibit weak mechanical properties, which hinders their application in durable biointegrated systems. Here, we report aramid nanofiber-based hydrogels providing a combination of high elasticity, strength, and electrical conductivity. Highly branched aramid nanofibers (ANFs) provide a robust three-dimensional (3D) framework resembling those in load-bearing soft tissues. When interlaced with poly(vinyl alcohol) (PVA) and cross-linked with both noncovalent and covalent interactions, the nanofiber composites exhibit a high water content of ∼76.4 wt %, strength of ∼7.5 MPa, ductility of ∼407%, and shape recovery of ∼99.5% under cyclic tensile stress of 0.3 MPa. Mobile ions impart a conductivity of ∼2 S/m to the hydrogels, enabling large-strain sensors with stable operation. In addition, the embedded silver nanoparticles afford broad-spectrum antimicrobial activities, which is favorable for medical devices. The versatility of aramid nanofiber-based composites suggests their further possibilities for functionalization and scalable fabrication toward sophisticated bioelectronic systems.

[Study on extraction and antigenicity of the outer-membrane-protein of Bordetella avium].

To study the immunogenicity of Bordetella avium OMP, ultrasonic dispersion, TritonX-100 technique were used to extract Bordetella avium OMP. Its content was determined by Bradford method and it was detected by SDS-PAGE. Then OMP immunizing antigen was prepared and 1-day chicken was vaccinated by hypodermic inoculation, with the immunizing does of 0.3mL (OMP90microg), 0.5mL (OMP150microg), 0.8mL (OMP240microg), respectively. Results showed that content of Bordetella avium OMP is 300 g/mL, the best immunizing does is 0.5mL each one and Chickens can be protected against Bordetella avium at fetal dose if antibody titer is over 1:2(8). We can see from the antibody level detected by indirect ELISA that antibody can last long enough to help chickens pass susceptible period, so OMP has good immunogenicity. Results of this study lay good foundation for the development of monoclonal antibody to OMP, rapid diagnosis kit and subunit vaccine.