The present study examined the potential of quantum dot bioconjugates to sensitize cells to UV irradiation and to promote the photodynamic activity of the classical photosensitizers such as trifluoperazine (TFPZ) and sulfonated aluminum phthalocyanine (SALPC). Water-soluble CdSe nanocrystals were conjugated with anti-CD antibody with known specificity to leukemia cells. Quantum dot anti-CD conjugates were incubated with the leukemia cell line Jurkat to ensure specific interaction with the cell surface. This interaction was confirmed by fluorescent confocal microscopy. Furthermore, quantum dot anti-CD90-labeled leukemia cells were mixed with normal lymphocytes and subjected to UV irradiation in the presence or absence of a classical photosensitizer (TFPZ or SALPC). The cell fractions were separated by lectin-affinity column chromatography. The cell type was confirmed with fluorescent confocal microscopy and flow cytometry using appropriate antibodies; quantum dot anti-CD90 for leukemia cells, and PE-CD44 for normal lymphocytes. The viability of the separated cell fractions was determined using flow cytometry and the methyl tetrazolium test. The results demonstrated that quantum dot anti-CD conjugates sensitized leukemia cells to UV irradiation and promoted the effect of the classical photosensitizer SALPC. The results are discussed in the context of free radical generation during combined application of quantum dot bioconjugates and UV irradiation, as well as in the context of UV-mediated liberation of free Cd ions and their harmful effect on cell viability.

The authors have investigated the influence of scandium concentration on the power generation figure of merit (FOM) of scandium aluminum nitride (ScxAl1−xN) films prepared by cosputtering. The power generation FOM strongly depends on the scandium concentration. The FOM of Sc0.41Al0.59N film was 67 GPa, indicating that the FOM is five times larger than that of AlN. The FOM of Sc0.41Al0.59N film is higher than those of lead zirconate titanate and Pb(Mg1/3Nb2/3)O3-PbTiO3 films, which is the highest reported for any piezoelectric thin films. The high FOM of Sc0.41Al0.59N film is due to the high d31 and the low relative permittivity.

Aluminum nitride (AlN) is one of piezoelectric materials, which are eagerly anticipated for use in microelectromechanical systems (MEMS) applications such as communication resonators, sensors, and energy harvesters. AlN is particularly excellent in generated voltage characteristics for the MEMS rather than oxide piezoelectric materials such as lead zirconium titanate Pb(Zr, Ti)O3. However, it is necessary to improve the piezoelectric properties of AlN in order to advance the performance of the MEMS. We dramatically increased the piezoelectric coefficient d33 of AlN films by simultaneously adding magnesium (Mg) and niobium (Nb). The d33 of Mg39.3Nb25.0Al35.7N is 22 pC/N, which is about four times that of AlN. The d33 is increased by Mg and Nb simultaneous addition, and is not increased by Mg or Nb single addition. Interestingly, the Nb has multiple chemical states, and which are influenced by the Mg concentration.

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