The bottom-up synthesis of organic nanocomposites typically requires two steps and often leads to materials with a wide size distribution. Organic nanocomposites can be used for drug delivery applications and there is a high demand for better production methods.

Hélder Santos, Harvard University, Cambridge, MA, USA, and colleagues have developed a procedure for the fast production of core/shell nanocomposites in large quantities of up to 700 g per day on a single microfluidic device. The device consists of three sequential nested glass capillary tubes. The innermost tube contains a solvent in which the core precursor precipitates, the second tube contains a solution of the precursors for the core and for the shell, and the outermost and last tube contains a solvent in which both the core and shell precursors precipitate. The device sequentially mixes the three solutions. The core material, e.g., a drug, precipitates first and is then immediately encapsulated in the shell, e.g., a polymer. The process operates in a continuous way.

The researchers demonstrated their method by successfully encapsulating either of the anticancer drugs paclitaxel or sorafenib in a shell of the polymer hypromellose acetate succinate. The obtained materials showed a narrow size distribution and a high drug loading. The team emphasizes that the method does not require any additional stabilizers for the core and is easily scalable to produce industrially relevant quantities.

• Core/Shell Nanocomposites Produced by Superfast Sequential Microfluidic Nanoprecipitation,
  Dongfei Liu, Hongbo Zhang, Salvatore Cito, Jin Fan, Ermei Mäkilä, Jarno Salonen, Jouni Hirvonen, Tiina M. Sikanen, David A. Weitz, Hélder A. Santos,
  Nano Lett. 2017.
  DOI: 10.1021/acs.nanolett.6b03251