Cell patterning via laser micro/nano structured silicon surfaces.

The surface topography of biomaterials can have an important impact on cellular adhesion, growth and proliferation. Apart from the overall roughness, the detailed morphological features, at all length scales, significantly affect the cell-biomaterial interactions in a plethora of applications including structural implants, tissue engineering scaffolds and biosensors. In this study, we present a simple, one-step direct laser patterning technique to fabricate nanoripples and dual-rough hierarchical micro/nano structures to control SW10 cell attachment and migration. It is shown that, depending on the laser processing conditions, distinct cell-philic or cell-repellant patterned areas can be attained with a desired motif. We envisage that our technique could enable spatial patterning of cells in a controllable manner, giving rise to advanced capabilities in cell biology research.

Laser induced forward transfer of metals by temporally shaped femtosecond laser pulses.

Temporally shaped, femtosecond laser pulses have been used for controlling the size and the morphology of micron-sized metallic structures obtained by using the Laser Induced Forward Transfer (LIFT) technique. We report the effect of pulse shaping on the size and morphology of the deposited structures of Au, Zn, Cr on a function of the pulse separation time ??t (from 0 to 10 ps) of double pulses of variable intensities generated by using a liquid crystal spatial light modulator (SLM). The observed differences in size and morphology are correlated with the outcome of pump-probe experiments for the study of electron-phonon scattering dynamics and subsequent energy transfer processes to the bulk in the different metals employed. We propose that in metals with weak electron-lattice coupling, the electron ballistic motion and the resulting fast electron scattering at the film surface, as well as the internal electron thermalization process are crucial to the morphology and size of the transferred material. Therefore, temporal shaping within the corresponding time scales of these processes may be used for tailoring the features of the metallic structures obtained by LIFT.

Safety of the ArF193 excimer laser for the removal of dental plaque and calculi: an in vitro histological study.

OBJECTIVE: To assay the safety of the ArF excimer laser in the integrity of human pulp elements. BACKGROUND DATA: The use of lasers in dentistry remains controversial, in spite of their increasing application in medical practice. The main reason for this discrepancy is the frequent report of damage to surrounding tissues and the dental pulp, due to the energy transfer, from the site of laser impact. The progress made on laser technology during the last 10 years, could overcome this obstacle and allow the use of lasers in dentistry. METHODS AND RESULTS: The present study reports the use of the ArF 193 excimer laser, under conditions of strict control of frequency and fluency, for the ablation of dental carries, plaque, and calculi, by the use of a new, articulated arm. We have tested 10 teeth, extracted for prosthetic reasons, immediately after extraction. Our in vitro results show that the ArF193 excimer laser does not produce any harm to the dental pulp (at least at the photo- or electronic microscopy level), whereas in a matter of seconds, it can be effective in removing all dental deposits. In addition, the use of the flexible articulated arm, makes this treatment comfortable and easier for both the dentist and patient. CONCLUSION: Under a strict control of laser technology, and the use of the new articulated arm presented, the use of the ArF excimer laser in dentistry is safe and comfortable.