Medical applications of RNA and other nanoparticles

Ízaro López García — Tue, 26 Oct 2010 17:50:25 +0000

When we talk about the uses of nanotechnology in medical applications, we can be confident in stating that nanoparticles offer more physical scope for functional engineering than, say, other molecules (I am thinking of either naturally occurring ones and artificially manufactured ones). If reports are to be believed we currently have well over 50 companies pressing forward to exploit this for cancer diagnosis and treatment. Nearly a dozen nanoparticle-based medicines are reportedly in clinical trials, and lab research suggests that a roadmap to programmable control of cellular functions is within reach.

Nanoparticles make good delivery vehicles for molecular cargo in vivo. They have distinct surfaces and interiors, making it possible to individually engineer the solubility, immunological compatibility, targeting and penetration of cells, and controlled release of compounds that, when simply injected into the organism are inert when in contact to healthy cells and react in contact with the targeted cells (either delivering the pharmacological load or entering fully into the cell body). Not just size and surface properties matter: Shape makes a difference (cylinders penetrate cells better than spheres), and even mechanical stiffness is important — soft particles can remain in circulation for almost 100 hours, where rigid particles are cleared in 1/50 that time.

But this is not all nanoparticles can deliver, they can play the role of small interfering RNA, siRNA, delivery vehicles into targeted cells. Once the siRNA load has been delivered into the cell, it accomplishes the objective by modulating protein expression. siRNA therapy promise to provide unprecedented and specific control of cellular processes making current pharmacological arsenal look like medieval leech therapy in comparison. RNA molecules have short half-lives in circulation and don’t readily enter cells, but engineering nanoparticles to overcome this barrier will enable siRNA therapy to revolutionize the way we fight against diseases like cancer.

References

DOI: 10.1038/nature08956
DOI: 10.1126/science.330.6002.314

DNA as ‘new’ information storage devices

Ízaro López García — Sat, 25 Sep 2010 20:25:43 +0000

So a few developments recently are showing that in the not too distant future, we will be able to take advantage of DNA’s vast ability to encode information within its structure, and I know nature has been doing this for a while now, but this will be the first time we are able to harness this ability for our daily electronic devices. Now this is not so much a matter of encoding information into the molecules, but like any storage device, the key is the reading mechanism. And here is where the breakthrough is currently happening, research groups in the US are using nanopores to control the manner in which single DNA strands translocate or flow through, allowing them to be ‘read’.
Nanopores can be used to analyse DNA by monitoring ion currents as individual strands are captured and driven through the pore in single file by an applied voltage. A group at Harvard University, headed by Dr. Garaj recently published in Nature describing this and pointing to graphene as the material that would enable decoding with the best resolution while another group in California has also publish in Nature Nanotechnology a paper on one of the promising new technologies that they are currently working on: nanopore sequencing. These groups are reporting some preliminary success in developing a computerized nanopore system that controls when DNA bases are added, and reads them one-by-one in the process.

While another group at University of Pennsylvania has developed a new, carbon-based nanoscale platform to electrically detect single DNA molecules. Using electric fields, the tiny DNA strands are pushed through nanoscale-sized, atomically thin pores in a graphene nanopore platform that ultimately may be important for fast electronic sequencing of the four chemical bases of DNA based on their unique electrical signature. The pores, burned into graphene membranes using electron beam technology, provide Penn physicists with electronic measurements of the translocation of DNA.

So there you have it, the possibilities are endless and, even if it doesn’t beat some of the alternatives in the market, it’s a very interesting mix of biochemistry and electronics.

References

Nature, 2010. DOI: 10.1038/nature09379
Nature Nanotechnology, 2010. DOI: 10.1038/NNANO.2010.177
Nano Letters, 2010. DOI: 10.1021/NL101046T

On Nanotech » DNA

Medical applications of RNA and other nanoparticles

References

DNA as ‘new’ information storage devices

References