A novel nested liposome drug delivery vehicle capable of ultrasound triggered release of its payload.

The use of focused ultrasound can be an effective method to locally highlight tumor tissue and specifically trigger the activation of echogenic drug delivery vehicles in an effort to reduce systemic chemotherapy side effects. Here we demonstrate a unique ultrasound triggered vehicle design and fabrication method where the payload and a perfluorocarbon gas microbubble are both encapsulated within the internal aqueous space of a liposome. This nested lipid shell geometry both stabilized the microbubble and ensured it was spatially close enough to interact with the liposome membrane at all times. The internal microbubble was shown to fragment the outer liposome membrane upon exposure to ultrasound at intensities of 1-1.5MPa. The focused ultrasound allowed the release of the internal payload to localized regions within tissue phantoms. The vehicles showed high payload loading efficiency of 16%, stability in blood of several hours, and low level macrophage recognition in vitro. High speed fluorescent videos present the first optical images of such vehicles interacting with ultrasound. This ability to open the outer membrane in small regions of deep tissue could provide a second level of spatial and temporal control beyond biochemical targeting, making these particles promising for in vivo animal studies.

DeNAno: Selectable deoxyribonucleic acid nanoparticle libraries.

DNA nanoparticles of approximately 250 nm were produced by rolling circle replication of circular oligonucleotide templates which results in highly condensed DNA particulates presenting concatemeric sequence repeats. Using templates containing randomized sequences, high diversity libraries of particles were produced. A biopanning method that iteratively screens for binding and uses PCR to recover selected particles was developed. The initial application of this technique was the selection of particles that bound to human dendritic cells (DCs). Following nine rounds of selection the population of particles was enriched for particles that bound DCs, and individual binding clones were isolated and confirmed by flow cytometry and microscopy. This process, which we have termed DeNAno, represents a novel library technology akin to aptamer and phage display, but unique in that the selected moiety is a multivalent nanoparticle whose activity is intrinsic to its sequence. Cell targeted DNA nanoparticles may have applications in cell imaging, cell sorting, and cancer therapy.

The subsystems approach to genome annotation and its use in the project to annotate 1000 genomes.

The release of the 1000th complete microbial genome will occur in the next two to three years. In anticipation of this milestone, the Fellowship for Interpretation of Genomes (FIG) launched the Project to Annotate 1000 Genomes. The project is built around the principle that the key to improved accuracy in high-throughput annotation technology is to have experts annotate single subsystems over the complete collection of genomes, rather than having an annotation expert attempt to annotate all of the genes in a single genome. Using the subsystems approach, all of the genes implementing the subsystem are analyzed by an expert in that subsystem. An annotation environment was created where populated subsystems are curated and projected to new genomes. A portable notion of a populated subsystem was defined, and tools developed for exchanging and curating these objects. Tools were also developed to resolve conflicts between populated subsystems. The SEED is the first annotation environment that supports this model of annotation. Here, we describe the subsystem approach, and offer the first release of our growing library of populated subsystems. The initial release of data includes 180 177 distinct proteins with 2133 distinct functional roles. This data comes from 173 subsystems and 383 different organisms.