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Responsive material could be the 'golden ticket' of sensing

Date:
January 7, 2015
Source:
University of Cambridge
Summary:
A new responsive material 'glued' together with short strands of DNA, and capable of translating thermal and chemical signals into visible physical changes, could underpin a new class of biosensors or drug delivery systems.
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This image shows a lipid membrane functionalized with DNA-linkers.
Credit: Lorenzo Di Michele

Researchers from the University of Cambridge have developed a new self-assembled material, which, by changing its shape, can amplify small variations in temperature and concentration of biomolecules, making them easier to detect. The material, which consists of synthetic spheres 'glued' together with short strands of DNA, could be used to underpin a new class of biosensors, or form the basis for new drug delivery systems.

The interplay between the lipid spheres, called giant vesicles, and the strands of DNA produces a unique response when the material is exposed to changes in temperature. Instead of expanding when heated -- as is normally the case -- the material contracts, a phenomenon known as negative thermal expansion. Details are published today (7 January) in the journal Nature Communications.

In addition to its role as a carrier of genetic information, DNA is also useful for building advanced materials. Short strands of DNA, dubbed 'sticky ends', can be customized so that they will only bind to specific complementary sequences. This flexibility allows researchers to use DNA to drive the self-assembly of materials into specific shapes.

Basing self-assembled materials around vesicles -- synthetic versions of the soft sacs which envelop living cells -- allows for even more flexibility, since the vesicles are so easily deformable. Using short DNA tethers with a cholesterol 'anchor' at one end and an exposed sticky DNA sequence at the other, the vesicles can be stuck together. When assembled into a hybrid DNA-lipid network, the DNA tethers can diffuse and rearrange, resulting in massive vesicle shape changes.

Besides negative thermal expansion, the researchers also found that changes in temperature lead to a significant variation in the porosity of the material, which is therefore highly controllable. A similar response is expected by changing the concentration of the DNA tethers, which could also be replaced by other types of ligand-receptor pairs, such as antibodies.

"The characteristics of this material make it suitable for several different applications, ranging from filtration, to the encapsulation and triggered release of drugs, to biosensors," said Dr Lorenzo Di Michele of the University's Cavendish Laboratory, who led the research. "Having this kind of control over a material is like a 'golden ticket' of sensing."


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Materials provided by University of Cambridge. The original story is licensed under a Creative Commons Licence. Note: Content may be edited for style and length.


Cite This Page:

University of Cambridge. "Responsive material could be the 'golden ticket' of sensing." ScienceDaily. ScienceDaily, 7 January 2015. <www.sciencedaily.com/releases/2015/01/150107082221.htm>.
University of Cambridge. (2015, January 7). Responsive material could be the 'golden ticket' of sensing. ScienceDaily. Retrieved May 23, 2017 from www.sciencedaily.com/releases/2015/01/150107082221.htm
University of Cambridge. "Responsive material could be the 'golden ticket' of sensing." ScienceDaily. www.sciencedaily.com/releases/2015/01/150107082221.htm (accessed May 23, 2017).

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