Making drug delivery containers with bubbles

Successful use of pharmaceutical drugs depends on their delivery and controlled release so that their bioactivity can be harnessed.  This can mediate poor solubility, degradation and other properties of the drug which might otherwise be problematic.  One way to control delivery is to load the drug into a container which allows the compound to be transported to the desired location, to then be released over a suitable time period.  The behaviour of the container is dependent on both the size and the shape, so simple and reliable fabrication techniques are required.

In a recent CrystEngComm article, scientists from China show how such containers can be made which are shaped like lotus leaves and are nano/microsized.  The Co3O4 nano/microcontainers can be easily prepared from Co(NO3)2.6H2O by evaporation of the acetone solvent followed by calcining (i.e. heating at below the melting point).   In this process, shown in the diagram below, the large amount of gas bubbles produced are key to determining the shape of the containers, with no other shape-directing agents required.  The size and density of the nano/microlotus-leaf arrays can be controlled by variation of the evaporation time and temperature.

Fabrication of Co3O4 lotus-leaf shaped containers

The research team used fluorescein isothiocyanate (FITC) as a model drug to study the controlled drug delivery from the nano/microlotus-leaf arrays.  They found that it could be loaded and released more effectively than for comparable Co3O4 microspheres and showed that cells which were treated with the arrays retained over 80% viability even at high concentration — indicating that these microcontainers are a safe delivery vehicle of active compounds to cells.

For more details, see the paper:

Facile bubble-assisted evaporation-induced assembly of high-density arrays of Co3O4nano/microlotus leaves: fluorescent properties, drug delivery, and biocompatibility

Guo-Xiu Tong, Fang-Ting Liu, Wen-Hua Wu, Chao-Li Tong, Ru Qiao and Hui-Chen Guo
CrystEngComm, 2014, DOI .1039/C3CE42149J
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Gwenda Kyd
 Gwenda Kyd has a PhD in metallocarborane chemistry from the University of Edinburgh. Other research work includes the spectroscopic study of the structure of glasses and organometallic electron-transfer reactions and the preparation of new inorganic phosphors. Currently, she is writing a book on chemicals from plants. 
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