Clay nanotube encapsulation for functional biocomposites.

Natural halloysite clay nanotubes with 50 nm outer- and 15 nm inner- diameters are described as miniature vehicles for sustained release of drugs and proteins. The release time may be adjusted from 10 to 200 h with the tube surface polymeric coating. An explanation of sustained release through locking electrical potential at the nanotube ends is suggested. These biocompatible ceramic tubes may be also used for architectural construction of nanoshells on microbes through alternation with polycations to enhance the intrinsic properties of biological cells. Halloysite nanotubes (pristine or drug-loaded) are well mixable with polar and low-polar polymers allowing for functional biocomposites with enhanced mechanical strength, adhesivity and slow release of drugs or other chemical agents. Halloysite is nontoxic abundantly available from natural deposit material which does not require exfoliation or other complicated energy consuming processing.