Synthesis and Biomedical Applications of Self-healing Hydrogels

Hydrogels, which are crosslinked polymer networks with high water contents and rheological solid-like properties, are attractive materials for biomedical applications. Self-healing hydrogels are particularly interesting because of their abilities to repair the structural damages and recover the original functions, similar to the healing of organism tissues. In addition, self-healing hydrogels with shear-thinning properties can be potentially used as the vehicles for drug/cell delivery or the bioinks for 3D printing by reversible sol-gel transitions. Therefore, self-healing hydrogels as biomedical materials have received a rapidly growing attention in recent years. In this paper, synthesis methods and repair mechanisms of self-healing hydrogels are reviewed. The biomedical applications of self-healing hydrogels are also described, with a focus on the potential therapeutic applications verified through in vivo experiments. The trends indicate that self-healing hydrogels with automatically reversible crosslinks may be further designed and developed for more advanced biomedical applications in the future

Fabrication of Nanostructured PLGA Scaffolds Using Anodic Aluminum Oxide Templates

PLGA (poly(lactic-co-glycolic acid)) is one of the most used biodegradable and biocompatible materials. Nanostructured PLGA even has great application potentials in tissue engineering. In this research, a fabrication technique for nanostructured PLGA membrane was investigated and developed. In this novel fabrication approach, an anodic aluminum oxide (AAO) film was use as the template ; the PLGA solution was then cast on it ; the vacuum air-extraction process was applied to transfer the nano porous pattern from the AAO membrane to the PLGA membrane and form nanostures on it. The cell culture experiments of the bovine endothelial cells demonstrated that the nanostructured PLGA membrane can double the cell growing rate. Compared to the conventional chemical-etching process, the physical fabrication method proposed in this research not only is simpler but also does not alter the characteristics of the PLGA. The nanostructure of the PLGA membrane can be well controlled by the AAO temperate.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838

Antibacterial properties of silver nanoparticles in three different sizes and their nanocomposites with a new waterborne polyurethane

Silver nanoparticles (AgNPs) are strong bactericidal agents but they are also cytotoxic. Embedding them in a polymer matrix may reduce their cytotoxic effect. In the present study, AgNPs in three average sizes were tested for their antibacterial activities and cytotoxicity. Nanocomposites from a new waterborne polyetherurethane (PEU) ionomer and AgNPs were prepared without the use of any crosslinker. It was observed that the antibacterial activity of AgNPs against Escherichia coli started at the effective concentration of 0.1–1 ppm, while that against Staphylococcus aureus started at higher concentrations of 1–10 ppm. Cytotoxicity of AgNPs was observed at the concentration of 10 ppm. AgNPs with smaller average size showed greater antibacterial activity as well as cytotoxicity. The PEU synthesized in this study showed high tensile strength, and the addition of AgNPs at all sizes further increased its thermal stability. The delicate surface features of nanophases, however, were only observed in nanocomposites with either small-or medium-sized AgNPs. PEU-Ag nanocomposites had a strong bacteriostatic effect on the growth of E. coli and S. aureus. The proliferation of endothelial cells on PEU-Ag nanocomposites was enhanced, whereas the platelet adhesion was reduced. The expression of endothelial nitric oxide synthase gene was upregulated on PEU-Ag containing small-sized AgNPs (30 ppm) or medium-sized AgNPs (60 ppm). This effect was not as remarkable in nanocomposites from large-sized AgNPs. Overall, nanocomposites from the PEU and 60 ppm of the medium-sized (5 nm) AgNPs showed the best biocompatibility and antibacterial activity. Addition of smaller or larger AgNPs did not produce as substantial an effect in PEU, especially for the larger AgNPs

Chittenden County Child Care Providers & Conflict Implementing Sick Child Guidelines

Introduction: Nationwide, 61% of children under age five are enrolled in a form of non-parental care. Problems arise when a child becomes sick and is not able toattend daycare or has to be sent home. Parents must either miss work to care for their child or find someone else to care for them. Since there is stress surrounding taking time off, and because the criteria used to exclude children from child care can be ambiguous, parents may feel that their child doesn’t need to be sent home. Each child care provider has to set up exclusion criteria that meet state licensing requirements. The American Academy of Pediatrics (AAP) developed exclusion guidelines specifically for childcare settings in 2006, but most daycare providers and pediatricians are unaware of its existence. Conflicts occur when there are differences in opinion on the child’s health status between the child care provider and the parents or the child’s pediatrician.https://scholarworks.uvm.edu/comphp_gallery/1023/thumbnail.jp

Technology-Enhanced Learning for Graduate Students: Exploring the Correlation of Media Richness and Creativity of Computer-Mediated Communication and Face-to-Face Communication

The objective of the research was to explore and compare the differences in potential creative thinking that media richness had on learners in creativity training through two different types of communication formats; computer-mediated communication, and face-to-face communication. The results indicated that the computer-mediated communication format performed better than the face-to-face in terms of the fluency, flexibility, and originality dimensions of creative thinking. The computer-mediated communication format also had a greater level of media richness perception (i.e., use of multiple cues, language diversity, and personal focus of the medium) than the face-to-face format. In terms of the combined effectiveness of computer-mediated communication, and face-to-face formats, the use of multiple cues, language variety of perception of media richness had direct effects on the fluency of creativity. There was also a positive correlation between the elaboration of creativity and the use of multiple cues, language variety, and personal focus of the medium in the perception of media richness. Furthermore, language variety was correlated with creativity and flexibility. The research findings highlighted the importance of the availability of immediate feedback on media richness, whereas creativity cognition should focus on the breadth and depth of the information, which contributes to enhancing the creativity of individuals or a group of employees

Efficacy and safety of nanohybrids comprising silver nanoparticles and silicate clay for controlling Salmonella infection

Developing effective and safe drugs is imperative for replacing antibiotics and controlling multidrug-resistant microbes. Nanoscale silicate platelet (NSP) and its nanohybrid, silver nanoparticle/NSP (AgNP/NSP), have been developed, and the nanohybrids show a strong and general antibacterial activity in vitro. Here, their efficacy for protecting Salmonella-infected chicks from fatality and septicemia was evaluated. Both orally administrated NSP and AgNP/NSP, but not AgNPs alone, effectively reduced the systemic Salmonella infection and mortality. In addition, quantitative Ag analyses demonstrated that Ag deposition from AgNP/NSP in the intestines was less than that from conventional AgNPs, indicating that the presence of NSP for immobilizing AgNPs reduced Ag accumulation in tissue and improved the safety of AgNPs. These in vivo results illustrated that both NSP and AgNP/NSP nanohybrid represent potential agents for controlling enteric bacterial infections

Effectiveness and Limitations of Hand Hygiene Promotion on Decreasing Healthcare–Associated Infections

BACKGROUND: Limited data describe the sustained impact of hand hygiene programs (HHPs) implemented in teaching hospitals, where the burden of healthcare-associated infections (HAIs) is high. We use a quasi-experimental, before and after, study design with prospective hospital-wide surveillance of HAIs to assess the cost effectiveness of HHPs. METHODS AND FINDINGS: A 4-year hospital-wide HHP, with particular emphasis on using an alcohol-based hand rub, was implemented in April 2004 at a 2,200-bed teaching hospital in Taiwan. Compliance was measured by direct observation and the use of hand rub products. Poisson regression analyses were employed to evaluate the densities and trends of HAIs during the preintervention (January 1999 to March 2004) and intervention (April 2004 to December 2007) periods. The economic impact was estimated based on a case-control study in Taiwan. We observed 8,420 opportunities for hand hygiene during the study period. Compliance improved from 43.3% in April 2004 to 95.6% in 2007 (p<.001), and was closely correlated with increased consumption of the alcohol-based hand rub (r = 0.9399). The disease severity score (Charlson comorbidity index) increased (p = .002) during the intervention period. Nevertheless, we observed an 8.9% decrease in HAIs and a decline in the occurrence of bloodstream, methicillin-resistant Staphylococcus aureus, extensively drug-resistant Acinetobacter baumannii, and intensive care unit infections. The intervention had no discernable impact on HAI rates in the hematology/oncology wards. The net benefit of the HHP was US$5,289,364, and the benefit-cost ratio was 23.7 with a 3% discount rate. CONCLUSIONS: Implementation of a HHP reduces preventable HAIs and is cost effective