Self-assembly of thermoresponsive nanocomposites and their applications for sensing daunorubicin with DNA

Poly(N-isopropylacrylamide)-co-poly(methylmethacrylate) (PNIPAM-co-PMMA) nanofibers were fabricated by electrospinning. The titanium dioxide (TiO ₂ ) nanoparticles that grafted with thermoresponsive poly(N-isopropylacrylamide) (PNIPAM-gTiO2) were synthesized in our previous report (Gong et al., J. Mater. Chem. 22 (2012) 16872-16879). The blends of PNIPAM-co-PMMA nanofibers with PNIPAM-g-TiO2 nanoparticles (PNIPAM-g-TiO ₂ /PNIPAM-co-PMMA) have been characterized and utilized as detection for daunorubicin. The biorecognition of daunorubicin was measured by electrochemical analysis. Because of the surface grafting polymer, both the nanocomposites of PNIPAM-g-TiO ₂ /PNIPAM-co-PMMA and the PNIPAM-g-TiO ₂ nanoparticles have remarkable enhancement effect on the biorecognition of daunorubicin. Moreover, with the adding DNA, the biorecognition of the daunorubicin can be enhanced from 4% to 31.1%. It was found the self-assembly process occurred amongst the nanocomposites, daunorubicin and the DNA as the temperatures above the critical solution temperature (LCST) of the composites. These are suggested to be the potential valuable applications of sensor in the drug bioanalysis fields.