Long-acting release of small molecules achieved by barrier effect of nano-brick

The long-acting sustained-release of active molecules is of great importance in chemical production, food preservative, drug delivery in vivo, and so on. However, the problems of initial-burst release and short release time (dominated by Fick's lows) commonly exist in sustained-release materials. Herein, we designed and fabricated two types of film materials to achieve slow, continuous, and long-term release of small molecules using methyl orange (MO) as a target release substance. B-MO@polymer films were obtained by embedding MO into polylactic acid/polyethylene glycol (PLA/PEG) substrate and then assembling a layered double hydroxide (LDH)/carboxymethyl chitosan (CMC) barrier layer on the substrate surface. Another type of film (LDH&MO@polymer) was prepared by blending LDH and MO into the PLA/PEG polymer matrix. These films show high loading capacities of similar to 500 mu g/cm(2) for MO and display long-acting sustained-release property arising from the barrier effect of LDH nano-brick. Specifically, for the B-MO@polymer film, the release time of 50% MO is 10 days and the release time of 80% MO can be extended to 30 days. Ultimately, the time for complete release (>96%) reaches over 60 days. By using LDH-embedded polymer as carriers for active molecules, the zero-order release of MO was realized for LDH&MO@polymer films, achieving sustained release within as long as 145 days. This work provides a new paradigm to achieve the long-acting sustained-release of active molecules through the barrier effect of 2D nano-bricks. Highlight Two types of films were obtained to achieve long-term release of small molecules. The films show high loading capacities for active molecules. The long-acting property is derived from the barrier effect of 2D nano-brick. The films can be produced in a large scale and have good application prospects.