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Nanocapsules
Nanocapsules are nanoscale shells made out of a nontoxic polymer. They are vesicular systems that are made up of a polymeric membrane which encapsulates an inner liquid core at the nanoscale level. Nanocapsules have a myriad of uses, which include promising medical applications for drug delivery, food enhancement, nutraceuticals, and for the self-healing of materials. The benefits of encapsulation methods are for protection of these substances to protect in the adverse environment, for controlled release, and for precision targeting. Nanocapsules can potentially be used as MRI-guided nanorobots or "nanobots," although challenges remain.
== Structure ==
The typical size of the nanocapsule used for various applications ranges from 10nm-1000nm. However, depending on the preparation and use of the nanocapsule, the size will be more specific.
Nanocapsule structure consists of nano-vesicular system that is formed in a core-shell arrangement. The shell of a typical nanocapsule is made of a polymeric membrane or coating. The type of polymers used is of biodegradable polyester, as nanocapsules are often used in biological systems. Poly-e-caprolactone (PCL), poly(lactide) (PLA), and poly(lactide-co-glicolide) (PLGA) are typical polymers used in nanocapsule formation. Other polymers include thiolated poly(methacrylic acid) and poly(N-vinyl Pyrrolidone). As synthetic polymers have proven to be more pure and reproducible when compared naturally occurring polymers, they are often preferred for the construction nanocapsules. However, some natural occurring polymers such as chitosan, gelatin, sodium alginate, and albumin are used in some drug delivering nanocapsules.〔 Other nanocapsule shells include liposomes, along with polysaccharides and saccharides. Polysaccharides and saccharides are used due to their non-toxicity and biodegradability. They are attractive to use as they resemble biological membranes.
The core of a nanocapsule is composed of an oil surfactant that is specifically selected to coordinate with the selected drug within the polymeric membrane. The specific oil used must be highly soluble with the drug as well as non-toxic when used in a biological environment. The oil /drug emulsion must have low solubility with the polymer membrane to insure that the drug will be carried throughout the system properly and be released at the proper time and location. When the proper emulsion is obtained the drug should be uniformly dispersed throughout the entire internal cavity of the polymeric membrane.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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