The August cover of Advanced Healthcare Materials shows a dense diamond nanoneedle array capable of rapidly and conveniently delivering fluorescent probes and drugs to a large number of cells. The work was carried out by Xianfeng Chen, Guangyu Zhu and Wenjun Zhang and their co-workers at the City University of Hong Kong.
Gene and cell therapy is an attractive treatment for certain diseases that are otherwise difficult to cure. To be therapeutically active, it is necessary for genes and molecules, such as plasmid DNA and siRNA, to enter cells. However, factors such as instability, hydrophilicity and negative surface charge inhibit the passage of such molecules through the cell membrane to the desired site of action. To overcome this problem, the Hong Kong team developed a dense nanoneedle array that can facilitate intracellular delivery. The array is formed by nanostructuring the surface of diamond, the hardest material in nature. The work demonstrates that highly efficient intracellular delivery can be achieved by adding drugs or fluorescent probes in cell suspension and simply applying the mixture solution to the nanoneedle array. This facile approach paves the way for potential high-throughput delivery of genes, drugs and fluorescent probes into cells.