Cell Sheet-Like Soft Nanoreactor Arrays

Tissues, which consist of groups of closely packed cell arrays, are essentially sheet-like biosynthesis plants. In tissues, individual cells are discrete microreactors working under highly viscous and confined environments. Herein, soft polystyrene-encased nanoframe (PEN) reactor arrays, as analogous nanoscale "sheet-like chemosynthesis plants", for the controlled synthesis of novel nanocrystals, are reported. Although the soft polystyrene (PS) is only 3 nm thick, it is elastic, robust, and permeable to aqueous solutes, while significantly slowing down their diffusion. PEN-associated palladium (Pd) crystallization follows a diffusion-controlled zero-order kinetics rather than a reaction-controlled first-order kinetics in bulk solution. Each individual PEN reactor has a volume in the zeptoliter range, which offers a unique confined environment, enabling a directional inward crystallization, in contrast to the conventional outward nucleation/growth that occurs in an unconfined bulk solution. This strategy makes it possible to generate a set of mono-, bi-, and trimetallic, and even semiconductor nanocrystals with tunable interior structures, which are difficult to achieve with normal systems based on bulk solutions.