3354
Chem. Mater. 2008, 20, 3354–3359
Temperature-Controlled Uptake and Release in PNIPAM-Modified Porous Silica Nanoparticles Ye-Zi You,† Kennedy K. Kalebaila,‡ Stephanie L. Brock,*,‡ and David Oupicky´*,† Departments of Pharmaceutical Sciences and Chemistry, Wayne State UniVersity, Detroit, Michigan 48202 ReceiVed NoVember 27, 2007. ReVised Manuscript ReceiVed March 10, 2008
Temperature-dependent uptake and release of small molecules within porous silica nanoparticles has been achieved by treatment of preformed, thiol-functionalized micro-to-mesoporous silica nanoparticles (MSN) with pyridyl disulfide-terminated poly(N-isopropylacrylamide) (PNIPAM-S-S-Py). The resulting nanoparticle-polymer composites show uptake and release of fluorescein at room temperature (below the lower critical solution temperature, LCST, of the polymer) and a low level of leakage at 38 °C (above LCST,
