Multi-layered stimuli responsive DNA micelles for the stepwise controlled release of small molecules.

Controllable release of multiple distinct cargoes from a nanomaterial is crucial to a variety of therapeutic and catalytic applications. In this study, we describe a DNA functionalized multi-layered surface crosslinked micelle (mlSCM) consisting of individually degradable layers. The DNA modified mlSCM has the ability to encapsulate separate small molecule cargo in distinct compartments within the nanocapsule, separated by chemical crosslinkers. Through a multistep self-assembly process, we show physical separation of internalized cargo as evidenced by electron microscopy, along with observation of chemical control over release, and chemical reaction conditions, as seen by fluorescence spectroscopy and a high-performance liquid chromatography mass spectrometry assay. Additionally, we evaluated the ability of these DNA crosslinked micelles to co-release two separate cargoes into the same cellular environment through an in vitro confocal microscopy assay. We show individualized targeting of two distinct but related dyes for the detection of ATP and mitochondria. The colocalization of these dyes indicates that unique locations and signals related to cellular respiration can be identified using a single mlSCM. Through these studies we ultimately show that the mlSCM has a tailorable design with the potential to be applied to numerous applications, ranging from sensing to drug delivery.