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Lab-on-a-chip strategies using miniaturized devices enable cells to be cultured in a tridimensional (3D) space that offers a real model mimicking in vivo environment. One may provide architectural configurations relevant for specific tissues to maintain them at adequate temperature, oxygen levels, and pH during the necessary time intervals for observation. Herein, we propose a miniaturized lab-on-chip glass device suitable for simultaneous dosimetry measurements and evaluation of the biological effects of ionizing radiation on cancer cells. For the 3D fabrication of biologically relevant microenvironment, high repetition rate picosecond laser-assisted etching is applied to create microfluidic networks between sealed cell culture chambers in photo-sensitive glasses (PG). To evaluate the radiation dose, we employed collimated X-ray beams to generate free electrons in the PG samples by photoreduction of Ag ions to Ag atoms. A subsequent thermal treatment applied to the PG induced clustering of precipitated Ag atoms to color the exposed area to brown, which allows us to directly evaluate a threshold of the applied X-ray radiation dose applied directly on chip. Based on our glass biochip, we tested the response of human melanoma cancer cells exposed to various X-ray doses. This lab-on-chip platform is a valuable tool to analyze and validate the cellular response to new irradiation strategies as alternatives to conventional radiotherapy methods. [ABSTRACT FROM AUTHOR]

The feasibility of the compositional analysis of drugs by calibration-free laser-induced breakdown spectroscopy (LIBS) was investigated using multivitamin tablets as a sample material. The plasma was produced by a frequencyquadrupled Nd:YAG laser delivering UV pulses with a duration of 5 ns and an energy of 12 mJ, operated at a repetition rate of 10 Hz. The relative fractions of the elements composing the multivitamin drug were determined by comparing the emission spectrum of the laser-produced plume with the spectral radiance computed for a plasma in a local thermodynamic equilibrium. Fair agreement of the measured fractions with those given by the manufacturer was observed for all elements mentioned in the leafl et of the drug. Additional elements such as Ca, Na, Sr, Al, Li, K, and Si were detected and quantifi ed. The present investigations demonstrate that laser-induced breakdown spectroscopy is a viable technique for the quality control of drugs. [ABSTRACT FROM AUTHOR]

The use of amorphous and transparent oxides is a key for the development of new thin film transistors and displays. Recently, indium zinc oxide (IZO) was shown to exhibit high transparency in the visible range, low resistivity, and high mobility. Since the properties and the cost of these films depend on the In/(In + Zn) values, the measurement of this ratio is paramount for future developments and applications. We report on accurate analysis of the elemental composition of IZO thin films synthesized using a Combinatorial Pulsed Laser Deposition technique. The monitoring of the thin films elemental composition by Laser-Induced Breakdown Spectroscopy was chosen in view of further in situ and real-time technological developments and process control during IZO fabrication. Our analytical approach is based on plasma modeling, the recorded spectra being then compared to the spectral radiance computed for plasmas in local thermal equilibrium. The cation fractions measured were compared to values obtained by complementary measurements using energy dispersive X-ray spectroscopy and Rutherford backscattering spectrometry. Spectroscopic ellipsometry assisted the scientific discussion. A good agreement between methods was found, independently of the relative fraction of indium and zinc that varied from about 65 to 90 and 35 to 10 at%, respectively, and the measurement uncertainties associated to each analytical method. [ABSTRACT FROM AUTHOR]

Laser direct write techniques represent a prospective alternative for engineering a new generation of hybrid biomaterials via the creation of patterns consisting of biological proteins onto practically any type of substrate. In this paper we report on the characterization of fibronectin features obtained onto titanium substrates by UV nanosecond laser transfer. Fourier-transform infrared spectroscopy measurements evidenced no modification in the secondary structure of the post-transferred protein. The molecular weight of the transferred protein was identical to the initial fibronectin, no fragment bands being found in the transferred protein's Western blot migration profile. The presence of the cell-binding domain sequence and the mannose groups within the transferred molecules was revealed by anti-fibronectin monoclonal antibody immunolabelling and FITC-Concanavalin-A staining, respectively. The in vitro tests performed with MC3T3-E1 osteoblast-like cells and Swiss-3T3 fibroblasts showed that the cells' morphology and spreading were strongly influenced by the presence of the fibronectin spots. [ABSTRACT FROM AUTHOR]

Creatinine thin films were synthesised by matrix assisted pulsed laser deposition (PLD) techniques for enzyme-based biosensor applications. An UV KrF* (λ = 248 nm, τ∼10 ns) excimer laser source was used for the irradiation of the targets at incident fluence values in the 0.3–0.5 J/cm2 range. For the matrix assisted PLD the targets consisted on a frozen composite obtained by dissolving the biomaterials in distilled water. The surface morphology, chemical composition and structure of the obtained biomaterial thin films were investigated by scanning electron microscopy, Fourier transform infrared spectroscopy, and electron dispersive X-ray spectroscopy as a function of the target preparation procedure and incident laser fluence. [ABSTRACT FROM AUTHOR]

Pulsed Laser Photodeposition (PLP) of a-Se from aqueous colloid solutions with KrF laser at a wavelength of λ = 248 nm has been performed. Nanometer thick layers were obtained on quartz substrates in contact with the solution for various Pulse Numbers (PN). Amorphous Se layers, 5–20 nm thick, were obtained typically by 50–500 laser beam pulses of 7 (nsec) duration delivered at RR = 1 Hz with a total fluence of 370 mJ/cm2. The deposited nanometer morphology was analyzed by a Differential-Evanescent Optical Microscopy method and Scanning Electron Microscopy (SEM). The observed leaking electromagnetic field from the waveguide substrates was used to evaluate the thickness profile and growth rate of photodeposited a-Se. Capturing the differential evanescent light leaking image, yielded the PLP nanostructures profiles in the deposited zone. Using this technique in combination with SEM microscopy allowed us to estimate the structural properties of the ultra-thin a-Se nano-structures. [ABSTRACT FROM AUTHOR]

Aluminium nitride (AlN) films obtained by pulsed laser deposition (PLD) at different low ambient nitrogen pressure have been optically investigated by spectral ellipsometry within the 300–800 nm wavelength range, Sellmeier and Wemple–DiDomenico approximation approaches have been applied for the ellipsometric data analysis. Optical parameters such as refractive index and single oscillator energies of deposited films were estimated and their dependence on the N2 pressure was studied. The obtained refractive index values of AlN films are around 2 in a wide wavelength region above 400 nm and suggest the growth of a polycrystalline structure. The relatively low (<3.4 eV) threshold energies indicate the formation of a defective and disordered structure, formed during the deposition process. [ABSTRACT FROM AUTHOR]