Direct Creation of Biopatterns via a Combination of Laser-Based Techniques and Click Chemistry.

In this paper, we present the immobilization of thiol-modified aptamers on alkyne- or alkene-terminated silicon nitride surfaces by laser-induced click chemistry reactions. The aptamers are printed onto the surface by laser-induced forward transfer (LIFT), which also induces the covalent bonding of the aptamers by thiol-ene or thiol-yne reactions that occur upon UV irradiation of the thiol-modified aptamers with ns laser pulses. This combination of LIFT and laser-induced click chemistry allows the creation of high-resolution patterns without the need for masks.

Laser Induced Forward Transfer: a study on the enhancement of sensitivity for multianalyte sensing.

In this article novel approaches for the improvement of the recorded signal coupled with the feasibility of multiple analyte detection, irrespective of the biosensor platform are being presented. The techniques that have been developed address commonly encountered issues that have traditionally hindered the commercialization of biosensors, such as cost, reproducibility and sensitivity and most importantly multianalyte detection. The fluorescence-based detection of copper is being described as an example of the use of Laser Induced Forward Transfer technique (LIFT) for the immobilization of biomolecules with high spatial resolution, in addition to a technique that involves the displacement of a short complementary strand to the immobilized probe molecule for the quantification of analyte binding and the enhancement of the recorded signal.

Detection of harmful residues in honey using terahertz time-domain spectroscopy.

Terahertz time-domain spectroscopy (THz-TDS) has been applied for the detection and discrimination of harmful chemical residues in honey. Three antibiotics (sulfapyridine, sulfathiazole, and tetracycline) and two acaricides (coumaphos and amitraz) were characterized in the THz frequency regime between 0.5 THz and 6.

Optically implemented broadband blueshift switch in the terahertz regime.

We experimentally demonstrate, for the first time, an optically implemented blueshift tunable metamaterial in the terahertz (THz) regime. The design implies two potential resonance states, and the photoconductive semiconductor (silicon) settled in the critical region plays the role of intermediary for switching the resonator from mode 1 to mode 2. The observed tuning range of the fabricated device is as high as 26% (from 0.

Coherent control of THz pulses polarization from femtosecond laser filaments in gases.

We demonstrate the possibility to rotate the polarization of linearly polarized THz pulses via the accurate control of the 2-color filament surrounding gas pressure. We also show ways to produce elliptically and circularly polarized THz pulses.

Probing the electronic stability of multiply charged anions: sulfonated pyrene tri- and tetraanions.

The strong intramolecular Coulomb repulsion in multiply charged anions (MCAs) creates a potential barrier that provides dynamic stability to MCAs and allows electronically metastable species to be observed. The 1-hydroxy-3,6,8-pyrene-trisulfonate {[Py(OH)(SO(3))(3)](3-) or HPTS(3-)} was recently observed as a long-lived metastable MCA with a large negative electron binding energy of -0.66 eV.

Vibrational constants and binding energies for the low-lying electronic states of Sr+ CO2 from photodissociation spectroscopy.

By use of photodissociation spectroscopy of mass-selected ions, vibrationally resolved electronic spectra of the Sr+ CO2 complex are recorded in two energy regions, 20,780-22,990 and 16,210-17,550 cm(-1), correlating to the Sr+ 5(2)P <-- 5(2)S and 4(2)D <-- 5(2)S transitions, respectively. The spectra are analyzed to obtain the vibrational constants and dissociation energies of the molecular states. The observed spin-orbit splitting indicates a linear complex in agreement with theoretical calculations.