Micropreparative Gel Electrophoresis for Purification of Nanoscale Bioconjugates.

Conventional techniques for purifying macromolecular conjugates often require complex and costly installments that are inaccessible to most laboratories. In this work, we develop a one-step micropreparative method based on a trilayered polyacrylamide gel electrophoresis (MP-PAGE) setup to purify biological samples, synthetic nanoparticles, as well as biohybrid complexes. We apply this method to recover DNA from a ladder mixture with yields of up to 90%, compared to the 58% yield obtained using the conventional crush-and-soak method. MP-PAGE was also able to isolate enhanced yellow fluorescence protein (EYFP) from crude cell extract with 90% purity, which is comparable to purities achieved through a more complex two-step purification procedure involving size exclusion and immobilized metal-ion affinity chromatography. This technique was further extended to demonstrate size-dependent separation of a commercial mixture of graphene quantum dots (GQDs) into three different fractions with distinct optical properties. Finally, MP-PAGE was used to isolate DNA-EYFP and DNA-GQD bioconjugates from their reaction mixture of DNA and EYFP and GQD precursors, samples that otherwise could not be effectively purified by conventional chromatography. MP-PAGE thus offers a rapid and versatile means of purifying biological and synthetic nanomaterials without the need for specialized equipment.

Durable superhydrophobic/superoleophilic melamine foam based on biomass-derived porous carbon and multi-walled carbon nanotube for oil/water separation.

In the present study, fabrications of two eco-friendly superhydrophobic/superoleophilic recyclable foamy-based adsorbents for oil/water mixture separation were developed. Hierarchically biomass (celery)-derived porous carbon (PC) and multi-walled carbon nanotube (MWCNT) were firstly synthesized and loaded on pristine melamine foam (MF) by the simple dip-coating approach by combining silicone adhesive to create superhydrophobic/superoleophilic, recyclable, and reusable three-dimensional porous structure. The prepared samples have a large specific surface area of 240 m2/g (MWCNT), 1126 m2/g (PC), and good micro-mesoporous frameworks. The water contact angle (WCA) values of the as-prepared foams, PC/MF and MWCNT/MF, not only were 159.34° ± 1.9° and 156.42° ± 1.6°, respectively but also had oil contact angle (OCA) of equal to 0° for a wide range of oils and organic solvents. Therefore, PC/MF and MWCNT/MF exhibited superhydrophobicity and superoleophilicity properties, which can be considered effective adsorbents in oil/water mixture separations. In this context, superhydrophobic/superoleophilic prepared foams for kind of different oils and organic solvents were shown to have superior separation performance ranges of 54-143 g/g and 46-137 g/g for PC/MF and MWCNT/MF, respectively, suggesting a new effective porous material for separating oil spills. Also, outstanding recyclability and reusability of these structures in the ten adsorption-squeezing cycles indicated that the WCA and sorption capacity has not appreciably changed after soaking into acidic (pH = 2) and alkaline (pH = 12) as well as saline (3.5% NaCl) solutions. More importantly, the reusability and chemical durability of the superhydrophobic samples made them good opportunities for use in different harsh conditions for oil-spill cleanup.

Investigation of grafting silane coupling agents on superhydrophobicity of carbonyl iron/SiO2 particles for efficient oil/water mixture and emulsion separation.

The present study demonstrated the wettability properties of grafting silane coupling agents on carbonyl iron (CI)/SiO2 particles for efficient oil/water mixture and emulsion separation. CI particles were first reacted with Tetraethoxysilane (TEOS) to create a magnetic component. Then, CI/SiO2 particles were altered by 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS) and Hexamethyldisilazane (HDMS) to create magnetic superhydrophobic/superoleophilic, recyclable, and reusable sorbent powders. The water contact angle (WCA) values of the as-prepared particles, CI, CI/SiO2, CI/SiO2@FAS, and CI/SiO2@HMDS, were 5.4° ± 1.3°, 6.4° ± 1.4°, 151.9° ± 2.1°, and 170.1° ± 1.1°, respectively. In addition, the oil contact angles (OCAs) of a variety of oils were found to be equivalent to 0°. Hence, superhydrophobic/superoleophilic particles for kind of different oils were shown sorption capacities of 1.7-3.1 g/g and 2.5-4.3 g/g for CI/SiO2@FAS, and CI/SiO2@HMDS, respectively. Besides, for 1%w/w hexane/water emulsion separation efficiency higher than 99%, the lowest mass was obtained at 50 and 200 mg for CI/SiO2@HDMS and CI/SiO2@HDMS, respectively, suggesting a new effective material for separating tiny oil droplets. Also, the reusability and chemical durability of the superhydrophobic samples made them a prime candidate for use in different harsh conditions.

An experimental study on the effects of temperature and magnetic field strength on the magnetorheological fluid stability and MR effect.

In this study, the stability and rheological properties of a suspension of carbonyl iron microparticles (CIMs) in silicone oil were investigated within a temperature range of 10 to 85 °C. The effect of adding two hydrophobic (stearic and palmitic) acids on the stability and magnetorheological effect of a suspension of CIMs in silicone oil was studied. According to the results, for preparing a stable and efficient magnetorheological (MR) fluid, additives should be utilized. Therefore, 3 wt% of stearic acid was added to the MR fluid which led to an enhancement of the fluid stability over 92% at 25 °C. By investigating shear stress variation due to the changes in the shear rate for acid-based MR fluids, the maximum yield stress was obtained by fitting the Bingham plastic rheological model at high shear rates. Based on the existing correlations of yield stress and either temperature or magnetic field strength, a new model was fitted to the experimental data to monitor the simultaneous effect of magnetic field strength and temperature on the maximum yield stress. The results demonstrated that as the magnetic field intensified or the temperature decreased, the maximum yield stress increased dramatically. In addition, when the MR fluid reached its magnetic saturation, the viscosity of fluid depended only on the shear rate.