Bath sonicators

The actual characteristics of REV produced depend on a number of factors such as choice of lipids (% cholesterol and charged lipids), lipid concentration used in the organic solvent, rate of evaporation, and ionic strength of the aqueous phase (Szoka and Papahadjopoulos, 1980). Modifications of this REV technique were proposed by several groups. The SPLV (stable plurilamellar vesicles) method consists of bath-sonicating an emulsion of the aqueous phase in an ether solution of lipid while evaporating the ether (Griiner et al., 1985). 

Sonication of MLV dispersions above the Tc of the lipids results in the formation of SUV (Saunders, et al., 1962). Sonication can be performed with a bath sonicator (Papahadjopoulos and Watkins, 1967) or a probe sonicator (Huang, 1969). During sonication the MLV structure is broken down and small unilamellar vesicles with a high radius of curvature are formed. In case of SUV with diameters of about 20 nm (maximum radius of curvature), the outer monolayer can contain over 50% of the phospholipids and in the case of lipid... 

The extraliposomal ammonium ion concentration [(NH4)jJ yj ] was measured as ammonia with the ammonia electrode at pH 13.5. Under these conditions, all ammonium ions are converted to ammonia and no leakage of intraliposomal ammonium ion occurred during the measurement. For measurements of total ammonium ion plus ammonia present in both intraliposome aqueous phase and external medium ammonia [(NH4)jJ g4i y +(NH4)Jpg j ] the liposomes were sonicated under acidic conditions (pH 1.5-2.0) using the Transonic 460/H bath sonicator in sealed vials for 45 minutes. Then, in order to convert ammonium ion to ammonia, NaOH was added to bring the pH to... 

Figure 3 (A) Robot system for lipofection screening (A) Worktable with racks for microplates, buffer reservoirs, plastic, and glass vials. (B) Four tip liquid handling arm. (C) Gripper for transport of microplates and glass test tubes. (D) High power water bath sonicator. ( ) Nitrogen evaporator. (F) Microplate washer. (G) Absorbance reader. (H) Luminescence reader. (/) Transparent hood. (/) CO2 incubator with pneumatic door (from the rear, front view in B). (B) Self-constructed robotic conveyor for the transport of cell culture plates from the incubator to the worktable.

To prepare DQAsomes or vesicles composed of dequalinium derivatives, the appropriate amount of bola-lipid (10 mM final) was dissolved in methanol, dried using a rotary evaporator, suspended in 2.5 mL 5mM N-2-hydroxyethylpiperazine-N -2-ethane sulfonic acid (HEPES), pH 7.4, bath sonicated for about one hour followed by probe sonication for 45 minutes (10 W). The sample was then centrifuged for 30 minutes at 3000 rpm, the clear, or in some cases, opaque supernatant collected and the remaining non-solubilized residue lyophilized. The concentration of solubilized bola-lipid can be determined spectrophotometrically or can be inferred from the amount of recovered compound after lyophilization. 

Vacuum source or a bath sonicator to degas buffers. 

Filter BBS through a 0.45-)im filtration membrane. Degas the buffer by applying vacuum for 30 min or by sonicating in a bath sonicator for 5 min. 

Transfer the suspension to a 10-mL stainless steel or glass beaker Chill in an ice-salt bath. With continued cooling in the salt bath, sonicate the suspension at maximum energy for six 5-second bursts. The suspension will warm during somcation. Therefore, after each 5-second somcation, allow the suspension to cool for 30 seconds The tempti.i ture of the suspension should not be allowed to rise above 10°C during somcation. The mitochondrial suspension will become less opaque during the somcation. 

Bath sonication Traditional laboratory bath sonicators normally do not impart enough energy to liposomes to reduce vesicle sizes only cup-horn type sonicators (e.g., of Branson) are powerful enough for liposome preparation. This setup has the advantage of avoiding direct contact of the formulation with the probe, but is limited to small quantities (<100 ml ) of material. 

Support the modified electrodes upright in a beaker containing distilled, deionised water which must then be subsequently positioned into the ultrasonic bath. Sonicate the electrodes for 10s at a frequency of 25 kHz. 

For preparation of aptamer biosensor use gold electrode of 2-mm diameter (CH Instruments Inc., USA). The electrode should be carefully cleaned as follows first immerse it in chloroform (Merck) and extensively clean in an ultrasound bath sonicator for 3 min. Use ultrasound... 

The polystyrene latex (PSL) spheres were obtained from Seragen Diagnostics. The nominal sizes of these standards were from electron microscopy measurements. The samples were prepared by diluting the 10% solids in filtered, doubly distilled water, adding a small amount of SDS to help disperse the samples and sonicating with Branson 60 watt bath sonicator for 30 seconds to disperse any aggregates. The relative volumes (weights) of the two sizes of PSL in the mixed sample were estimated to be accurate to about 5-10%. 

Sonication This approach uses energy (ultrasound) and can be applied to a dispersion of MLVs [127] or to solid lipids mixed with aqueous solution. The flask with the liposome dispersion is placed in a bath sonicator or a probe sonicator (tip) is immersed in the tube containing the liposome dispersion. With the first setup it is difficult to reduce the size to the nanometer level since the energy produced by the bath sonica-tors is rather low. However, it has the advantage that there is no contact with the liposome dispersion. The position of the flask in the sonicator is equally important. It is easy to understand if it is in the right place from the noise produced by ultrasound waves. For instance, if foams are produced or there is no noise at all, that implies the sample is misplaced and finally the size of vesicles will not be reduced. 

Reverse-Phase Evaporation The REV method was developed by Szoka and Papa-hadjopoulos [132], Lipids are dissolved in organic solvent and the solvent is removed with evaporation. The thin film is resuspended in diethyl ether (1 mL solvent/mL liposomes) followed by the addition of one-third of water and sonication in a bath sonicator for 1 min. This water-in-oil (w/o)-emulsion is evaporated until a dry gel is formed, and finaly the gel is broken by agitation and water addition. Sometimes this step is quite difficult. The remnants of the organic solvent are removed by evacuation and the resulting dispersion is REV liposomes. 

After exposure, the samples are immersed in a suitable solvent, their container immersed in an ultrasonic bath, sonicated and the resultant solution analyzed. It is strongly recommended that each sample be run in triplicate and the results compared to those of three similar unexposed controls kept in the dark for the same exposure duration. This protocol is outlined in Figure 10. 

After sonicating for 5 min in a water bath sonicator, the peptide extract was removed, steps 8-9 were repeated and the two peptide containing extracts pooled. 

Filter BBS through a 0.45-pm filtration membrane. Degas the buffer by applying vacuum for 30 min or by sonicating in a bath sonicator for 5 min. Connect the Superose 6 column to the FPLC system see Note 18), and equilibrate the column with 50 mL of BBS at a flow rate of 0,5 mL/min. Check the manufacturer s recommendations for optimal operating back pressures. 

A novel template effect of SiNWs tvas discovered accidentally trying to disperse SiNWs in common solvents such as CHCI3, CH2CI2 and CH3I. A 15 min bath sonication resulted in a colloidal solution, the products of which were characterized by HRTEM, EELS and Raman. The analysis revealed that under sonication the SiNWs acted as templates on which carbon nanotubes and carbon nano-onions formed (figure 10.32). Moreover, in addition to these known carbon structures. 

Transfer the flask containing MLV either to a bath-type sonicator or a probe (tip) sonicator (Fig. 3). For probe soni-cation, place the tip of the sonicator in the MLV flask and sonicate the sample with 20 s ON, 20 s OFF intervals (to avoid over-heating), for a total period of 10-15 min. At this stage, nanoliposomes are formed, which are predominantly in the form of small unilamellar vesicles (SUV) (see Note 3). Alternatively, nanoliposomes can be produced using a bath sonicator as explained in the following section. 

Fill tJie bath sonicator with room temperature water mixed with a couple of drops of liquid detergent. Using a ring stand and test tube clamp, suspend the MLV flask in the bath sonicator. The liquid level inside the flask should be equal to that of outside the flask. Sonicate for a time period of 20-40 min (see Note 4). 

As substrate for the sample preparation, silicon wafers from Wacker Chemie AG (Munich, Germany) with a natural silicon oxide layer (thickness 3.8 nm) and a surface roughness of 0.3 nm is used. The wafers are split into small pieces of about 1x1 cm. The pieces are cleaned in a bath sonicator for 20 min in CHCl they are dried in a atmosphere. 

For hydration, bidistilled water is used to prepare the liposomes in the concentration of 10 mg/ml. To form the lipid vesicles, a bath sonicator at 45°C is used. After obtaining a dispersion of the lipid in water, sonication is continued with a probe type sonicator to increase the energy input. For the following processes, the sample is transferred into a 50 ml plastic mbe. 

This method involves the use of a bath sonicator and a rotary evaporator equipped with the proper adaptor to hold a 3-5-ml round-bottom flask and connected to a vacuum pump. In the absence of a rotary evaporator, a desicator equipped with vacuum can be used to evaporate the chloroform used to dissolve the lipids. 

Probe sonicator (Mandel Scientiflc Co., Inc.) or bath sonicator (Laboratory Supplies Co., Inc.)... 

An alternative to titanium probe sonication is a bath sonicator (see Note 6). SUVs can be formed by sonication for 10 min to an hour. Instead of inserting a probe directly into the sample, a water bath is used to transfer the energy to a tube placed in the center. Glass or plastic tubes can be used and the sample can also be covered with an inert gas such as argon or nitrogen (48). This closed system cannot be accomplished with a probe sonicator. The liquid should go from cloudy to clear after being sonicated. It is an affordable way (under 1,000) to introduce the energy needed to reduce the size of liposomal formulations. These sonicators are available from Laboratory Supplies Company, New York (516-681-7711). 

There are some important points to prepare BLs. The air in the vial containing the liposome suspension is completely replaced with perfluoropropane. After that, it needs to be supercharged in the vial with perfluoropropane. And the vial is sonicated with a bath-type sonicator (42 KHz, 100 W) (BRANSONIC 2510 J-DTH, Branson Ultrasonics). In this step, sonication power and the vial position in the bath are very important. Because we have experimented that BLs were not prepared using other type of bath sonicator (UC-1 (38 KHz, 80 W), IKEDA RIKA, Japan) with low intensity of ultrasound exposure. In addition, BLs were not prepared using other gas such as air, nitrogen gas or carbonic dioxide gas. Therefore, it thought that it is important for the preparation of BL to use hydrophobic gas such as perfluoropropane. 

Bath sonicator (Aquasonic Model 150D, VWR, Bridgeport, NJ). 

A solvent mixture containing 3mL chloroform, 0.5 mL methanol, and 3 mL isopropyl ether is added and the mixture sonicated for 1 min in a bath sonicator. We use sonication level 6 with the Aquasonic Model 150D bath sonicator. 

Be sure that the solution in the flask is being sonicated moderately vigorously and that the flask is not located in a dead spot of the bath. We use sonication level 6 with the Aqua-sonic Model 150D bath sonicator. 

Small sonicated unilamellar vesicles were prepared from egg phosphatidyl choline (Lipid Products, Surrey, England) in a solution containing 2 X 10 5-M NaCl and 0.1-M glucose by sonication in a bath sonicator (Laboratory Supply Company, Hicksville, NY) until a clear dispersion was obtained. After vesicle preparation, small aliqouts of alamethicin in methanol (10 mL) were added to 1.8 mL of vesicle-containing solution. The final lipid concentration was 1 mg/mL and the final polypeptide concentration was 150 (xg/mL. The polypeptide to lipid ratio was about 1 20. The Donnan potentials across the membrane were established as follows (8). 

Preparation of the Cab-O-Sil fumed silica, a multi-stepped procedure, was as follows. The fumed silica powder (25-125 mg) was weighed into a 10-mL vial and then suspended in 5 ml. of a 0.0016 M NaOH solution. After an initial 10-s vortex stage, the sample vial and a sonic probe were both immersed in a small water bath. Sonication was carried out for 5 min at 200 W. (The recommended procedure called for 2-min sonication at 480 W with a microtip inserted directly into the sample solution. This procedure was modified because we did not have a microtip.) Immediately before each injection the sample was vortexed for 10 s. 

CSA was dissolved through ultrasonication in deionized water, networks of PANI-NFs with spherical nodes, nanoparticles, leaf-vein-shaped nanofibers, etc. were obtained, depending on the strength of the ultrasonic treatment. PANI-CSA nanofibers having diameters 1-2 nm were produced by bath sonication of aqueous dispersions of larger nanofibers (30-50 nm diameter) [41]. 

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Add 132 pL of reconstitution buffer to the lipids and use vortexing and sonicating (in a bath sonicator) to resuspend the Upid. At this point, the sample should become cloudy and there should be no Upid stuck to the bottom of the tube. 

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