Biological pores have been used to study the transport of DNA and other molecules but most pores have channels that allow only the movement of small molecules and single-stranded DNA and RNA. The bacteriophage phi29 DNA-packaging motor, which allows double-stranded DNA to enter and exit during a viral infection, contains a connector protein that has a 3.6 – 6.0 nm wide channel. Here we show that a modified version of the connector protein, when reconstituted into liposomes and inserted into planar lipid bilayers, can act as conductive channels to allow the translocation of double-stranded DNA. Single-channel conductance assays and quantitative PCR confirmed the translocation through the pore. The measured conductance of a single connector channel was 4.8 nS in 1 M KCl. This engineered and membrane-adapted phage connector is expected to have interesting applications in nanotechnology and nanomedicine, such as MEMS sensing, microreactors, gene delivery, drug loading, and DNA sequencing.

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By transactivating expression of miRNAs that repress expression of the ZEB1 and ZEB2 transcription factors, p53 inhibits the epithelial–mesenchymal transition.

Nanotechnology holds many advantages. Here we report another advantage of applying RNA nanotechnology for directional control. The orientation of arrow-shaped RNA was altered to control ligand-display on extracellular vesicle (EV) membranes for specific cell targeting, or to regulate intracellular trafficking of siRNA/miRNA. Placing membrane-anchoring cholesterol at the arrow-tail results in display of RNA aptamer or folate on EV outer surface. In contrast, placing the cholesterol at the arrow-head results in partial loading of RNA nanoparticles into the EVs. Taking advantage of the RNA ligand for specific targeting and EVs for efficient membrane fusion, the resulting ligand-displaying EVs were competent for specific delivery of siRNA to cells, and efficiently block tumor growth in three cancer models. PSMA aptamer-displaying EVs loaded with survivin siRNA inhibited prostate cancer xenograft. The same EV but displaying EGFR aptamer inhibited orthotopic breast cancer models. Likewise, survivin-loaded and folate-displaying EVs inhibited patient derived colorectal cancer xenograft.