July 01, 2012

Remotely Activated Protein-Producing Nanoparticles

Fightaging - There was recent progress towards placing drug producing microfactories in the body. These are programmable, artificial bacteria-like entities that can be set up to manufacture specific drug compounds in response to their local environment, or to signals from outside the body such as light or ingested chemicals

Nanoletters - The development of responsive nanomaterials, nanoscale systems that actively respond to stimuli, is one general goal of nanotechnology. Here we develop nanoparticles that can be controllably triggered to synthesize proteins. The nanoparticles consist of lipid vesicles filled with the cellular machinery responsible for transcription and translation, including amino acids, ribosomes, and DNA caged with a photolabile protecting group. These particles served as nanofactories capable of producing proteins including green fluorescent protein (GFP) and enzymatically active luciferase. In vitro and in vivo, protein synthesis was spatially and temporally controllable, and could be initiated by irradiating micrometer-scale regions on the time scale of milliseconds. The ability to control protein synthesis inside nanomaterials may enable new strategies to facilitate the study of orthogonal proteins in a confined environment and for remotely activated drug delivery.

Invivo Protein Production

Female, hairless SKH-1 mice (12-wks-old), n=3, were injected with 100 μL (lipid concentration 20 μg/μL) of the particle dispersion to the hind leg. The site of
injection was then irradiated for 120 s at 400 mW/cm2 using a 365 nm light source (BlueWave 75, Dymax). Protein production was detected 1 and 24 hr post administration following intraperitoneal injection of 150 μL ViviRen

7 pages of supplemental material

Scientists are reporting an advance toward treating disease with minute capsules containing not drugs - but the DNA and other biological machinery for making the drug. ... development of nanoscale production units for protein-based drugs in the human body may provide a new approach for treating disease. These production units could be turned on when needed, producing medicines that cannot be taken orally or are toxic and would harm other parts of the body. Until now, researchers have only done this with live bacteria that were designed to make proteins at disease sites. But unlike bacterial systems, artificial ones are modular, and it is easier to modify them. That's why [this research group] developed an artificial, remotely activated nanoparticle system containing DNA and the other "parts" necessary to make proteins, which are the workhorses of the human cell and are often used as drugs.

They describe the nanoscale production units, which are tiny spheres encapsulating protein-making machinery like that found in living cells. The resulting nanoparticles produced active proteins on demand when the researchers shined a laser light on them. The nanoparticles even worked when they were injected into mice, which are stand-ins for humans in the laboratory, producing proteins when a laser was shone onto the animals.

2. Other research from Daniel Anderson.

Nanoletters - FRET-Labeled siRNA Probes for Tracking Assembly and Disassembly of siRNA Nanocomplexes

The assembly, stability, and timely disassembly of short interfering RNA (siRNA) nanocomplexes have the potential to affect the efficiency of siRNA delivery and gene silencing. As such, the design of new probes that can measure these properties without significantly perturbing the nanocomplexes or their environment may facilitate the study and further development of new siRNA nanocomplexes. Herein, we study Förster resonance energy transfer (FRET)-labeled siRNA probes that can track the assembly, stability, and disassembly of siRNA nanocomplexes in different environments. The probe is composed of two identical siRNAs, each labeled with a fluorophore. Upon nanocomplex formation, the siRNA-bound fluorophores become locally aggregated within the nanocomplex and undergo FRET. A key advantage of this technique is that the delivery vehicle (DV) need not be labeled, thus enabling the characterization of a large variety of nanocarriers, some of which may be difficult or even impossible to label. We demonstrate proof-of-concept by measuring the assembly of various DVs with siRNAs and show good agreement with gel electrophoresis experiments. As a consequence of not having to label the DV, we are able to determine nanocomplex biophysical parameters such as the extracellular apparent dissociation constants (KD) and intracellular disassembly half-life for several in-house and proprietary commercial DVs. Furthermore, the lack of DV modification allows for a true direct comparison between DVs as well as correlation between their biophysical properties and gene silencing.

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