Luminescence excitation spectra are employed to study the electronic states of CdSe nanocrystals ranging in size from 9 to 26 Å radius at 77 K. These studies show that all samples have, in addition to the discrete manifold of quantum confined electronic excitations, a threshold for continuum absorption. Absorption into this continuum results in substantially reduced luminescence efficiency.

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We propose an approach for silica encapsulation of YV((0.7))P((0.3))O(4):Eu(3+), Bi(3+) nanophosphors through a microemulsion process. The resulting YV((0.7))P((0.3))O(4):Eu(3+), Bi(3+)@SiO(2) core-shell nanophosphors were characterized by transmission electron microscopy, UV/vis absorption and photoluminescence spectroscopy, energy-dispersive x-ray analysis (EDAX), selected area electron diffraction and zeta-potential measurements. The obtained nanocomposites have quite a uniform spherical shape and diameters of about 15 nm. Zeta-potential measurements show that coated particles are stable at high volume fractions and can endure large variations in pH and electrolyte concentration without coalescence. These core-shell nanophosphors could also be used as ultrasensitive biological labels, because they are obtained in nanoscale and well dispersible in water.

A nanocompartment system composed of an ABA triblock copolymer, where A is poly(dimethylsiloxane) and B is poly(2-methyloxazoline), has been developed for selective recovery and detection of DNA. Translocation of TAMRA-labeled complementary primers into the nanocompartment system has been achieved through two deletion mutants (FhuA Delta1-129; FhuA Delta1-160) of the channel protein FhuA. Translocation was monitored by fluorescence resonance energy transfer through hybridization of the TAMRA-labeled primer to the complementary sequence of a nanophosphor-DNA-conjugate, which reduces its half-life (FhuA Delta1-129, 16.0% reduced; FhuA Delta1-160, 39.0% reduced).