Loading nanotubule

An alternate method to produce templated electrodes is the use of chemical reduction of the monomer in the presence of a track-etched or alumina membrane. Parthasarathy et al. [46] have produced enzyme-loaded nanotubules by a combination of both electrochemical and chemical deposition. Initially, the alumina membrane was sealed at one end with a thick Au film (Figure 1.9a), after which the membrane was placed into a mixture of pyrrole and Et4NBF4. The pyrrole was then electropolymerized to form a small plug of polypyrrole at the closed end of the alumina membrane (Figure 1.9b). Subsequently, the membrane was placed into a... 

We describe below the use of halloysite nanotubules for entrapment and the subsequent release of three drugs Nifedipine (anti-anginal), Furosemide (anti-hypertension and diuretic), and Dexamethasone (synthetic corticosteroid). To increase the loading of these poorly soluble drugs in the tubules, we loaded them into a water-alcohol co-solvent solution (0, 10, and 50% ethanol). 

In conclusion, one can load drug molecules into halloysite nanotubules and get their slow release, typically during 5-30 hours. To achieve slower release kinetics, one needs a range of materials to act as stoppers on the ends of the tubules. 

Theoretical and model analysis based on a nanofluidic approach is needed for this situation. One may ask, is it possible to release proteins loaded in nanotubules We have found that the addition of the polycation PEI in the release solvent resulted in much quicker protein release, as demonstrated in Figure 14.9. In this case, most of the insulin was released in 1 hour instead of 100 hours. 10-40% of glucose oxidase, catalyse, and hemoglobin were released within 4 hours through complexation with PEI. It is unclear, whether the proteins were replaced by the polycation or released in a complex with PEI. 

Figure 1.10 Production scheme for polyaniline nanotubules, loading of enzymes into the tubes and finally exposure to an analyte. (Reprinted with permission from Ref [47]. 1999 American Chemical Society.)...

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