Crosslinking the Core of Nanoparticles with Light
In the Link and Prud’homme labs, we are interested in using block copolymer nanoparticles in a DNA sequencing application. In this application, the particles undergo rapid thermal cycling in a polymerase chain reaction (PCR), including temperatures that reach as high as 95 °C. The high temperature treatment causes the nanoparticles to disassemble since the core of the particles is held together only by non-covalent forces. We have recently synthesized a photoactive small molecule, diazidobiphenyl (see the molecule highlighted in blue in the figure), that can easily be encapsulated in the core of the nanoparticle. Upon activation with ultraviolet light, this molecule covalently crosslinks the polymer chains in the core of the particle into a stable network. The crosslinked nanoparticles are stable, even at the high temperatures required for PCR.
This work was published in the journal Polymer Chemistry, where it was highlighted as a “hot article”: http://blogs.rsc.org/py/2011/02/14/hot-article-photocrosslinking-the-polystyrene-core-of-block-copolymer-nanoparticles/