Nanostructures on Fluoropolymer Nanotextile Prepared Using a High-Energy Excimer Laser

This study is focused on polytetrafluoroethylene (PTFE) porous nanotextile and its modification with thin, silver sputtered nanolayers, combined with a subsequent modification with an excimer laser. The KrF excimer laser was set to single-shot pulse mode. Subsequently, the physico chemical properties, morphology, surface chemistry, and wettability were determined. Minor effects of the excimer laser on the pristine PTFE substrate were described, but significant changes were observed after the application of the excimer laser to the polytetrafluoroethylene with sputtered silver, where the formation of a silver nanoparticles/PTFE/Ag composite was described, with a wettability similar to that of a superhydrophobic surface. Both scanning electron microscopy and atomic force microscopy revealed the formation of superposed globular structures on the polytetrafluoroethylene lamellar primary structure, which was also confirmed using energy dispersive spectroscopy. The combined changes in the surface morphology, chemistry, and thus wettability induced a significant change in the PTFE's antibacterial properties. Samples coated with silver and further treated with the excimer laser 150 mJ/cm² inhibited 100% of the bacterial strain E. coli. The motivation of this study was to find a material with flexible and elastic properties and a hydrophobic character, with antibacterial properties that could be enhanced with silver nanoparticles, but hydrophobic properties that would be maintained. These properties can be used in different types of applications, mainly in tissue engineering and the medicinal industry, where water-repellent materials may play important roles. This synergy was achieved via the technique we proposed, and even when the Ag nanostructures were prepared, the high hydrophobicity of the system Ag-polytetrafluorethylene was maintained.

LIPSS Structures Induced on Graphene-Polystyrene Composite

A laser induced periodic surface structure (LIPSS) on graphene doped polystyrene was prepared by the means of a krypton fluoride (KrF) laser with the wavelength of 248 nm and precisely desired physico-chemical properties were obtained for the structure. Surface morphology after laser modification of polystyrene (PS) doped with graphene nanoplatelets (GNP) was studied. Laser fluence values of modifying laser light varied between 0–40 mJ·cm⁻² and were used on polymeric PS substrates doped with 10, 20, 30, and 40 wt. % of GNP. GNP were incorporated into PS substrate with the solvent casting method and further laser modification was achieved with the same amount of laser pulses of 6000. Formed nanostructures with a periodic pattern were examined by atomic force microscopy (AFM). The morphology was also studied with scanning electron microscopy SEM. Laser irradiation resulted in changes of chemical composition on the PS surface, such as growth of oxygen concentration. This was confirmed with energy-dispersive X-ray spectroscopy (EDS).

Anterior uveitis following eyebrow epilation with alexandrite laser

Ocular tissues are known to be sensitive to damage from exposure to laser emissions. This study reports the case of a female patient with acute unilateral anterior uveitis caused by alexandrite laser-assisted hair removal of the eyebrows. We report a 38-year-old female who presented with unilateral eye pain, redness, and photophobia after receiving alexandrite (755 nm) laser epilation of both eyebrows. Best corrected visual acuity was 20/20 in both eyes. Right eye examination was normal. Left eye examination showed conjunctival injection and 2+/3+ cells in the anterior chamber. Intraocular pressure and fundus examination were normal. Topical steroids and cycloplegic drops were prescribed for 3 weeks. At the end of the 3-week follow-up, best corrected visual acuity was 20/20, and intraocular pressure and fundus examination were normal in both eyes. The left eye was white, and the anterior chamber was clear. The patient continues to be monitored. In conclusion, without adequate protective eyewear, laser hair removal of the eyebrows with alexandrite laser can lead to ocular damage.