In a previous study, we demonstrated the feasibility of retaining poly(N-isopropylacrylamide) (pNIPAAm) on hydroxylated surfaces by spin-coating a blend of pNIPAAm with a small amount of 3-aminopropyltriethoxysilane (APTES), an organosilane, followed by thermal annealing. In this study, we detail the conditions for retaining pNIPAAm films by APTES. Our results show that the difference in surface energy between pNIPAAm and APTES in the blended film resulted in the segregation of APTES molecules to the film/substrate interface, as verified by XPS, during annealing, and the segregated APTES molecules cross-linked to form the APTES network, thus entrapping pNIPAAm. The retained pNIPAAm films (25–35 nm) exhibited thermo-responsive behavior, determined by water contact angles and film thickness in water at temperatures above and below the lower critical solution temperature of pNIPAAm, as well as good cell attachment and rapid detachment (<10 minutes). The gained insights would allow a better design of these thermo-responsive surfaces for cell sheet engineering and other relevant applications.
Objectives:To assess Saudi mother’s preferences regarding Saudi children’s physicians’ attire, and its influence on the parents’ level of trust and confidence.Methods:A cross-sectional survey was conducted from January to April 2014. Our sample comprised mothers of pediatric patients in both inpatient and outpatient settings at National Guard Hospital, Riyadh, Kingdom of Saudi Arabia. Mothers answered multiple questions, including their preferences regarding male and female pediatric physicians’ attire, their preferences regarding their children’s physician’s gender, and the impact of physician’s appearance on mothers’ confidence.Results:There were 259 female participants. Of all caregivers, 51.4% were 32-years-old or younger. Of those, 170 (65.6%) were educated (had completed high school or higher). Forty-four percent preferred that male physicians wear scrubs, while 5.4% preferred formal attire (tie, shirt, and trousers) and 27.8% preferred Saudi national attire (Thobe and shemagh). Most caregivers (57.9%) preferred that female physicians wear long skirts. Most caregivers (87.6%) preferred physicians to wear a white coat. Most (89.2%) believed that a physician’s appearance is very important.Conclusion:Gender of the treating physician is insignificant to mothers. However, the level of trust in a physician is related to his/her external appearance. Most mothers prefer their children’s physicians to wear scrubs.
A negatively charged hydrophilic low fouling film was prepared by thermally cross-linking a blend consisting of polystyrene sulfonic acid (PSS) and polyethylene glycol (PEG). The film was found to be stable by dip-washing. The fouling resistance of this material towards bacterial (Escherichia coli) and colloidal (polystyrene particles) attachment, non-specific protein (fibronectin) adsorption and cell (3T3 NIH) adhesion was evaluated and was compared with glass slides modified with polyethylene glycol (PEG) brushes, oxidized 3-mercaptopropyltrimethoxysilane (sulfonic acid, SA), and n-octadecyltrichlorosilane (OTS). The extended Derjaguin-Landau- Verwey-Overbeek (XDLVO) theory and thermodynamic models based on surface energy were used to explain the interaction behaviors of E. coli/polystyrene particles–substrate and protein–substrate interactions, respectively. The cross-linked PSS-PEG film was found to be slightly better than SA and PEG towards resisting non-specific protein adsorption, and showed comparable low attachment results as those of PEG towards particle, bacterial and NIH-3T3 cells adhesion. The low-fouling performance of PSS-PEG, a cross-linked film by a simple thermal curing process, could allow this material to be used for applications in aqueous environments, where most low fouling hydrophilic polymers, such as PSS or PEG, could not be easily retained.
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