Conductive Hydrogel Dressing with High Mechanical Strength for Joint Wound Healing.

Hydrogel wound dressing can accelerate angiogenesis to achieve rapid wound healing, but traditional hydrogel dressings are difficult to meet the repair of joint sites due to their low mechanical strength. Therefore, we constructed the gel system by designing the chemical-physical interpenetrating network structure to achieve high strength and high toughness of the hydrogel. The high-strength double-network hydrogels were synthesized by simple free radical polymerization and low-temperature physicochemical cross-linking in our experiments. The suspension was obtained by green reduction of graphene oxide with carboxymethyl chitosan, followed by the introduction of acrylamide (AM) to form a covalent cross-linked network, which was immersed in ferric chloride solution to form metal ligand bonds, and finally the chemical-physical dual cross-linked network hydrogel wound dressing was prepared. Here, reduced graphene oxide can enhance electrical conductivity and excellent near-infrared photothermal effect to the hydrogel. The cell viability of this novel wound dressing was above 90.0%, its hemolysis rate was below 2.0%, and the electrical conductivity could reach (6.89 ± 0.07 (mS/cm)). In addition, the stress-strain curve demonstrated that the double cross-linked network hydrogel could reach a stress of more than 0.8 MPa at 82.0% strain, and the cyclic compression experiment shows that it can still recover its original shape after five times of repeated compression. This work can provide a reference for the exploitation of high mechanical strength hydrogel wound dressings with good electrical conductivity and near-infrared photothermal effect. This article is protected by copyright. All rights reserved.

Effects of arbuscular mycorrhizal fungus inoculation on the growth and nitrogen metabolism of Catalpa bungei C.A.Mey. under different nitrogen levels.

Evidence suggests that arbuscular mycorrhizal fungi (AMF) may promote the growth of woody plants. However, the effects of AMF on nitrogen (N) metabolism in plants, especially trees, and its regulatory mechanism are rarely reported. Here, the effects of AMF inoculation on the growth and N nutrition status of Catalpa bungei under different N levels were reported. Three N levels (low, medium, high) and two mycorrhizal inoculation treatments (inoculation with Rhizophagus intraradices or not) were used with factorial design. The results showed that medium N could significantly improve the physiological metabolism and growth of C. bungei seedlings. However, when N was excessive, growth was significantly inhibited whether inoculated AMF or not. Compared with non-inoculated treatments, AMF inoculation could promote the absorption of N and P, improve photosynthesis under low to medium N levels, thus promoting the growth of seedlings. AMF changed the biomass allocation in seedlings by reducing the stem mass ratio and root/shoot ratio, and increasing the leaf mass ratio. At medium N levels, compared with non-inoculated treatment, AMF inoculation could significantly promote root growth by changing root hormone levels and improving root architecture and root activity. Under N addition, AMF inoculation could improve the absorption and assimilation of N by regulating the expression of key enzyme genes of N metabolism and nitrate transporter genes (NRT2.4, NRT2.5, NRT2.7) in roots, and enhancing the activities of the key enzyme of N metabolism. This study may provide a reference for the application of AMF in the cultivation and afforestation technology of C. bungei in Northwest China.

Noncontact liquid-solid nanogenerators as self-powered droplet sensors.

Liquid-solid triboelectric nanogenerators (L-S TENGs) can generate corresponding electrical signal responses through the contact separation of droplets and dielectrics and have a wide range of applications in energy harvesting and self-powered sensing. However, the contact between the droplet and the electret will cause the contact L-S TENG's performance degradation or even failure. Here we report a noncontact triboelectric nanogenerator (NCLS-TENG) that can effectively sense droplet stimuli without contact with droplets and convert them into electrical energy or corresponding electrical signals. Since there is no contact between the droplet and the dielectric, it can continuously and stably generate a signal output. To verify the feasibility of NCLS-TENG, we demonstrate the modified murphy's dropper as a smart infusion monitoring system. The smart infusion monitoring system can effectively identify information such as the type, concentration, and frequency of droplets. NCLS-TENG show great potential in smart medical, smart wearable and other fields.

PEG-α-CD/AM/liposome @amoxicillin double network hydrogel wound dressing-Multiple barriers for long-term drug release.

Wound infection and poor wound healing are the major challenges of wound treatment. Antibiotic drug treatment is the effective way to inhibit wound infection. It is necessary to achieve sustained release of antibiotics to get a longer treatment for wound infection. The double network hydrogels based on liposome, polyethylene glycol (PEG), α- cyclodextrin (α-CD) and acrylamide (AM) were developed, in which liposome acts as amoxicillin repository. Because the drug would release from the multiple barriers including two cavities of liposome and α-CD, as well as polyethylene glycol -α- cyclodextrin/acrylamide (PEG-CD/AM) double network, the PEG-α-CD/AM/liposome @amoxicillin double network hydrogels could achieve sustained drug release. The drug release assay showed that the dressing could release amoxicillin continuously until 12 days, than that of 8th day for single-network hydrogel releasing. The antibacterial ratio of the hydrogel could reach above 80%. What's more, the hydrogels present adjustable mechanical strength by changing the ratio of the components. The swelling ratio proved that the hydrogel had potential ability to absorb wound exudates. The cytotoxicity test of the hydrogels demonstrated excellent biocompatibility. These results indicated that this study can provide a new thought for antibacterial wound dressing and has a broad application prospect.

Comfort With Touch and Influencing Factors Among Chinese Midwives: A Cross-sectional Survey.

The aim of this study was to identify comfort with touch (CT) and influencing factors among Chinese midwives. Midwives (N = 252) from 7 hospitals in Guangdong, China, were asked to complete a self-report questionnaire between November 2018 and April 2019. The questionnaire included the Nurses' Comfort with Touch Scale (NCTS), the Nurses' Perceived Professional Benefits (NPPB) Scale, the Maslach Burnout Inventory-General Survey (MBI-GS), and a self-designed demographic questionnaire. Multivariate linear regression was used to identify influencing factors for CT. Mean NCTS total score was 88.90 ± 14.40, and the mean item score was 5.23 ± 0.91, which indicated a respectable score. Within the NCTS, CT was highest in the comfort support category (5.32 ± 0.29) whereas CT was lowest in the physical comfort category (4.28 ± 0.28). Multivariate regression analysis demonstrated that CT among Chinese midwives was associated with positive experiences or feelings surrounding the patient-nurse relationship (B = 3.239, P < .001), perceived professional benefit (PPB, positive professional identity) (B = 0.240, P < .001), emotional exhaustion (B = -0.414, P < .001), depersonalization (negative attitude toward the work setting) (B = -0.773, P < .001), and personal accomplishment (evaluation of self-worth) (B = 0.170, P = .015). Touch training and educational programs are recommended for Chinese midwives to enhance awareness and acceptance of touch care. In addition, promoting positive patient-nurse relationships, improving PPB, and reducing burnout are recommended to enhance CT among Chinese midwives. Because of the size and racial homogeneity of the sample, further studies are recommended to identify CT and influencing factors in a larger, more diverse population of midwives worldwide.

Mussel-inspired in situ forming adhesive hydrogels with anti-microbial and hemostatic capacities for wound healing.

All kinds of commercially available wound dressings are clinically used as fleshly obstacles and therapeutic materials in opposition to microbial incursion. Few researches focused on effective-bleeding and anti-bacteria at the same time. In order to better solve this problem, two hydrogels were synthetized in this study. One is phosphate buffer solution-activated dopamine-modified-γ-poly glutamic acid (PBS-PD) hydrogel, the other one is cirsium setosum extracts-activated dopamine-modified-γ-poly glutamic acid (CSE-PD) hydrogel. The two hydrogels are prepared by applying an enzyme-catalyzed crosslinking means in the presence of horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). The chemical structures were characterized through 1H-NMR and FT-IR. In conclusion, both PBS-PD and CSE-PD hydrogels exhibit superior tissue adhesion properties, and remarkable anti-infection quality. In addition, these two hydrogels manifest prominent hemostatic efficiency. The bio adhesion performance can achieve 30 kPa, meanwhile the CSE-PD hydrogels show good germicidal properties, and the antibacterial rate can reach 98%. The hydrogels could reduce blood loss without any obvious side effect, and present a new prospect in the field of hemostasis rapidly.

Advanced bi-functional CoPi co-catalyst-decorated g-C3N4 nanosheets coupled with ZnO nanorod arrays as integrated photoanodes.

In this work, a CoPi-decorated type II heterojunction composed of one-dimensional (1D) ZnO nanorod arrays (NRAs) coated with two-dimensional (2D) carbon nitride (g-C3N4) was successfully prepared and used as photoanode. CoPi has been speculated to be a mixture of amorphous compound and two cobalt-based compounds: Co3(PO3)6·14H2O and Co(H2PO2)2·6H2O. The advanced bi-functional CoPi acts like a shelter, effectively inhibiting the photocorrosion of CNNS/ZnO NRAs and providing a faster hole transfer channel. Synergistic effects at the interface of the heterojunction efficiently improve the separation of charge carriers from photoexcited g-C3N4 nanosheets to the ZnO nanorods. Photocurrent density is also greatly enhanced by loading CoPi on CNNS/ZnO NRAs heterojunction. The maximum photocurrent density (2.45 mA cm-2 at 1.23 V vs. RHE) generated from CoPi(10)-CNNS(600)/ZnO nanorods is about 10.2 times greater than that of pristine ZnO nanorods (0.24 mA cm-2 at 1.23 V vs. RHE) and 2.5 times higher than that of CNNS(800)/ZnO (0.95 mA cm-2 at 1.23 V vs. RHE). The further increase of photoelectrocatalytic performance may be attributed to CoPi relieving the charge accumulation at the semiconductor/electrolyte, which decreases the electron-hole recombination rate.

Synthesis of cellulose-based double-network hydrogels demonstrating high strength, self-healing, and antibacterial properties.

Novel antibacterial double-network (DN) hydrogels with superior mechanical and self-healing properties are developed via the UV-initiated copolymerization of polyacrylic acid (PAA)-grafted quaternized cellulose (QCE) and polyvinyl alcohol (PVA). The QCE functioned as an antibacterial agent, resulting in excellent antibacterial capability (antibacterial rate >93%). The hydrogels are thus protected from microbial attack in natural environments, prolonging their lifetime. The PVA functioned as a physical cross-linker, resulting in superior mechanical properties. At PVA and QCE contents of 8% and 1.5%, respectively, the strain and stress at break of hydrogel were 465.37% and 1.13MPa, respectively. The hydrogel maintained good self-healing properties owing to ionic bonding between the ferric ions and carboxylic groups, and hydrogen bonding between the PVA molecules. The hydrogel was responsive to pH; its water-holding ability could be controlled by changing the pH. The material is simply prepared and used. Hydrogels with such excellent properties could be applied in various biomedical fields.