A novel process to gain clear and high edge acuity micropatterns of TiO2 thin films by direct microcontact printing was presented in this paper. Using TiO2 sol as the “ink”, poly（dimethylsiloxane） elastomeric stamp was taken to transfer the TiO2 colloids to the substrate. The process is different from the traditional process using the SAMS to induce the deposition of TiO2. The new way increases the transferred efficiency of the micropatterned TiO2 thin films. The optical micrographs and SEM show that the micropatterned structures of TiO2 were microscale and uniform over a large area as well.
Peptide nucleic acid containing azobenzene (N-PNA) was covalently bound on chip surfaces. Complementary DNA probes labeled by gold nanoparticles hybridizated with PNA on chip surfaces. The hybridization was successfully detected with AFM by the microscopy mothed. The influences of the position and the cis-trans isomerization of azobenzene unit on hybridization were investigated with AFM.
We prepared the azobenzene PNA unit and synthesized various PNAs containing an azobenzene unit by a typical tBoc method. Both the azobenzene PNA unit and PNA containing an azobenzene unit (N-PNA) showed reversible photoisomerization with UV and visible light irradiation. The hybridization of N-PNA with complementary DNA resulted in a considerable decrease of the photoisomerization rate constant of the azobenzene.
