Gas Bubbles Stabilized by Janus Particles with Varying Hydrophilic–Hydrophobic Surface Characteristics

Micrometer-sized polymer-grafted gold–silica (Au-SiO₂) Janus particles were fabricated by vacuum evaporation followed by polymer grafting. The Janus particle diameter, diameter distribution, morphology, surface chemistry, and water wettability were characterized by optical microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and contact angle measurements. The optical microscopy results showed that the polystyrene (PS)-grafted Au-SiO₂ Janus particles exhibited monolayer adsorption at the air–water interface and could stabilize bubbles, preventing their coalescence for more than 1 month. The hydrophobic PS-grafted Au and hydrophilic SiO₂ surfaces were exposed to the air and water phases, respectively. Bare Au-SiO₂ and poly­(2-(per­fluoro­butyl)­ethyl meth­acrylate) (PPFBEM)-grafted Au-SiO₂ Janus particles could also stabilize bubbles for up to 2 weeks. By contrast, bare silica particles did not stabilize bubbles and were dispersed in water. The bubbles that formed in the PS-grafted Janus particle system were more stable than those formed in the bare Au-SiO₂ Janus particles, PPFBEM-grafted Au-SiO₂ Janus particles, and SiO₂ particle systems because of the high adsorption energy of the PS-grafted particles at the air–water interface

Micrometer-Sized Gold–Silica Janus Particles as Particulate Emulsifiers

Micrometer-sized gold–silica Janus particles act as an effective stabilizer of emulsions by adsorption at the oil–water interface. The Janus particles were adsorbed at the oil–water interface as a monolayer and stabilized near-spherical and nonspherical oil droplets that remained stable without coalescence for longer than one year. Gold and silica surfaces have hydrophobic and hydrophilic features; these surfaces were exposed to oil and water phases, respectively. In contrast, bare silica particles cannot stabilize stable emulsion, and completed demulsification occurred within 2 h. Greater stability of the emulsion for the Janus particle system compared to the silica particle system was achieved by using the adsorption energy of the Janus particles at the oil–water interface; the adsorption energy of the Janus particles is more than 3 orders of magnitude greater than that of silica particles. Suspension polymerization of Janus particle-stabilized vinyl monomer droplets in the absence of any molecular-level emulsifier in aqueous media led to nonspherical microspheres with Janus particles on their surface. Furthermore, polymer microspheres carrying Au femtoliter cups on their surfaces were successfully fabricated by removal of the silica component from the Janus-particle stabilized microspheres

Correlation with dROMs levels.

<p>Correlation with dROMs levels.</p

Correlation with Log Fstl1 levels.

<p>Correlation with Log Fstl1 levels.</p

Correlation between plasma Fstl1 levels and clinical parameters.

<p>Correlation of plasma Log Fstl1 levels with Log fasting immune-reactive insulin (FIRI), Log high sensitive CRP (hsCRP) and derivatives of reactive oxidative metabolites (dROMs) was analyzed.</p

Correlation with Log hsCRP levels.

<p>Correlation with Log hsCRP levels.</p

Clinical characteristics of all subjects.

<p>Clinical characteristics of all subjects.</p

Ablation of KLF15 by siRNA reduces adipolin expression in adipocytes.

<p>KLF15, adipolin (APL) and adiponectin (APN) mRNA levels were determined by quantitative RT-PCR method. <b>A</b>, KLF15 mRNA levels in 3T3-L1 adipocytes at 48 h after transfection with siRNA targeting KLF15 (si-KLF15) (20 nM) or non-targeting control siRNA (si-Control) (20 nM). N = 3 in each group. <b>B</b>, mRNA levels of APL and APN in 3T3-L1 adipocytes transfected with si-KLF15 (20 nM) or si-Control (20 nM). N = 3 in each group.</p

Overexpression of KLF15 rescues the reduction of adipolin expression caused by TNFα.

<p>Quantitative RT-PCR method was used for measurement of mRNA levels. <b>A</b>, Adipolin mRNA levels treated with adenovirus expressing KLF9 (Ad-KLF9), KLF15 (Ad-KLF15) or β-galactosidase (Ad-β-gal) at 150 moi for 24 h in 3T3-L1 adipocytes. 3T3-L1 adipocytes were treated with TNFα (10 ng/ml) or vehicle for 24 h. N = 3 in each group. <b>B</b>, Adiponectin mRNA levels treated with Ad-KLF15 or Ad-β-gal at 150 moi for 24 h in 3T3-L1 adipocytes. 3T3-L1 adipocytes were treated with TNFα (10 ng/ml) or vehicle for 24 h. N = 3 in each group.</p

Expression of KLF15 augments the promoter activity of adipolin.

<p><b>A and B</b>, Effect of KLF15 and KLF9 on the promoter activity of adipolin. Protein levels of KLF15 (A) and KLF9 (B) in HEK293 cells transfected with pShuttle vector expressing KLF15 tagged with FLAG, KLF9 tagged with FLAG or empty vector (MOCK). Expression of KLF15 and KLF9 was evaluated by Western blot analyses using anti-FLAG antibody. HEK293 cells were transfected with pShuttle vector expressing KLF15, KLF9 or MOCK, along with pGL3-basic vectors containing adipolin promoter region (−66/−1 or −111/−1) or empty pGL3 vector in the presence of pRL-SV40. Promoter activity was assessed by luciferase reporter assay. Results are normalized relative to the values of empty pShuttle vectors (MOCK). N = 6 in each group. <b>C</b>, Luciferase assay for determination of adipolin promoter activity in 3T3-L1 adipocytes. 3T3-L1 adipocytes were transfected with pGL3-basic vectors containing adipolin promoter (−66/−1 or −111/−1) or empty pGL3 vector in the presence of pRL-SV40. N = 6 in each group.</p