Optimization of quantum dots within thermoresponsive nanogel particles for dual channel confocal fluorescence imaging

Green and red luminescent quantum dot- thermoresponsive nanogel composite dispersions has been prepared by hydrogen bonding the thiol capping on the quantum dots to the amide groups of thermoresponsive nanogel particles. The photoluminescence intensities of the green and red luminescent composites have been matched by optimizing the concentrations of the quantum dots within the nanogel particles. The green and red luminescent composites were crystallized individually and mixed them in 1:1 ratio. For the first time the crystalline order in the composite mixture has been imaged in real space in two channel fluorescence mode of a confocal laser scanning microscope using single wavelength excitation. Implications of the present results in regard to investigating the binary colloidal crystal structure in real space and as markers for biological detection are discussed.