Magnetic gel beads

Fast Drug Release Using Rotational Motion of Magnetic Gel Beads... 

Figure It Schematic illustration of the ometry of magnetic 1 bead and permanent magnet. Photographs representing the collapse of magnetic gel beads by rotational motion with 5000 rpm (a) 0 minute, (b) 0.5 minute, (c) 1.0 minute, (d) 1.5 minutes.

Figure 1 shows the time course of the shape of magnetic gel beads showing rotational motion. As seen in Figure 1(a), the bead was turbid and it had a shape of sphere with rough surface. Sodium alginate was soluble in water however keto-profen was insoluble in water, but soluble in methanol. Immediately after mixing... 

Figure 2 Time profile of the ketoprofen release for a magnetic gel bead (sodium alginate 0.3wt%, ketoprofen 5wt%, barium ferrite 3wt%). The bead rotated (5000 rpm) at the time indicated by the arrow.

It should be added here that there was a report of preparing magnetic alginate beads by another in situ technique [171] prior to the above studies. A hydrolysis of urea by urease, producing ammonia, was utilized to make an alkaline atmosphere inside the alginate gel matrix, instead of the treatment with caustic alkali in Scheme 6. 

Preparation of Millimeter-Sized PNIPA and Magnetic mPNIPA Thermosensitive Gel Beads... 

One can see in the figure that for both gel systems the temperature dependence of volume change is not continuous an abrupt change occurs when the temperature exceeds 30 °C. It is also seen that within the experimental accuracy no difference was observed between PNIPA and mPNIPA gel beads. The presence of magnetic nanoparticles influences neither the measure of volume change nor the collapse transition temperature (abbreviated as 7c). A careful analysis based on derivatives of the qr-T curves has shown that for both kinds of PNIPA beads, Tq was found to be 32 °C. We have also studied the effect of cross-linking density on the volume phase transition. Figure 39 shows these results. 

Reagents and Equipment. In a 5.0-mL conical vial containing a magnetic spin vane and equipped with a reflux condenser protected by a calcium chloride drying tube, place 800 gL (7.4 mmol) of isopentyl alcohol, 1.5 mL (26.2 mmol) of glacial acetic acid, 4 drops (Pasteur pipet) of concentrated sulfuric add, and approximately 100 mg of silica gel beads... 

GeUan Gel beads containing magnetic nanoparticles Containing magnetic nanoparticles [40]... 

Wang X, Zhao C, Zhao P, Dou P, Ding Y, Xu P. Gellan gel beads containing magnetic nanoparticles an effective biosorbent for the removal of heavy metals from aqueous system. Bioresour Technol. 2009 100(7) 2301. ... 

Sepharose CL-6B. Product available from Amersham Biosciences (Piscataway, NJ), can be obtained as a suspension of beads in a 20% v/v aqueous ethanol solution. Must be stored at 4°C. Take special care during the handling of this gel to avoid extended periods of dryness and strong shear forces. Agitation of gel suspensions, when required, should be done with an orbital movement and not using a magnetic stirrer. 

In a 2.0- or 1.5-ml microcentrifuge tube, combine the amplified DNA, or prespun product from the optional step, with 100 pi of well-suspended magnetic bead slurry. Place on a rotator or agitate gently by hand for 15-30 min. Remove the liquid. Save at least a 10-pl sample for later analysis of capture efficiency on an agarose gel. (Typically, some dsDNA is visible in this supernatant fraction. Only a very bright band, combined with low yield of ssDNA, should be of concern.)... 

Test the ssDNA yield (as well as the effectiveness of intermediate steps in the procedure, if desired) by agarose gel electrophoresis of the following samples (1) retained PCR product, (2) concentrated filtrate from the prespin, (3) supernatant containing the primers and dsDNA that were not captured on the magnetic beads, and (4) 3-5 fi of ssDNA. (The ssDNA band will not run at the same speed as dsDNA.) A larger volume of ssDNA may be necessary to visualize very short products on an agarose gel. 

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