Programmable Arrays of Micro-Bubble Constructs via Self-Encapsulation

The fabrication of ordered arrays of self-encapsulated micro-bubble material constructs based on the capillary-driven collapse of flexible silk fibroin sheets during propagation of the diffusion front of the encapsulated material is demonstrated. The individual micro-bubbles of different shapes are composed of a sacrificial material encapsulated within the ultrathin silk coating, which covers and seals the inner material during dissolution of supporting layer. The array of microscopic rectangular multi-layer silk sheets on supporting polymer layers can be selectively dissolved along the edges to initiate their self-encapsulation. The resulting micro-bubble morphology, shape, and arrangements can be readily pre-programmed by controlling the geometry of the silk sheets, such as thickness, dimension, and aspect ratio. These microbubble constructs can be utilized for encapsulation of various materials as well as nanoparticles in a single or multi compartmental manner. These biocompatible and biodegradable micro-bubble constructs present a promising platform for one-shot spatial and controllable loading and locking material arrays with addressable abilities.