Inkjet-printed optical interference filters.

Optical interference filters (OIFs) are vital components for a wide range of optical and photonic systems. They are pivotal in controlling spectral transmission and reflection upon demand. OIFs rely on optical interference of the incident wave at multilayers, which are fabricated with nanometer precision.

Bone Laser Patterning to Decipher Cell Organization.

The laser patterning of implant materials for bone tissue engineering purposes has proven to be a promising technique for controlling cell properties such as adhesion or differentiation, resulting in enhanced osteointegration. However, the possibility of patterning the bone tissue side interface to generate microstructure effects has never been investigated. In the present study, three different laser-generated patterns were machined on the bone surface with the aim of identifying the best surface morphology compatible with osteogenic-related cell recolonization.

Vascularization of Cell-Laden Microfibres by Femtosecond Laser Processing.

To face the increasing demand for organ transplantation, currently the development of tissue engineering appears as the best opportunity to effectively regenerate functional tissues and organs. However, these approaches still face the lack of an efficient method to produce an efficient vascularization system. To answer these issues, the formation of an intra-volume channel within a three-dimensional, scaffold free, mature, and cell-covered collagen microfibre is here investigated through laser-induced cavitation.

Gold nanoplasmonic particles in tunable porous silicon 3D scaffolds for ultra-low concentration detection by SERS.

A composite material of plasmonic nanoparticles embedded in a scaffold of nano-porous silicon offers unmatched capabilities for use as a SERS substrate. The marriage of these components presents an exclusive combination of tightly focused amplification of Localised Surface Plasmon (LSP) fields inside the material with an extremely high surface-to-volume ratio. This provides favourable conditions for a single molecule or extremely low concentration detection by SERS.

Ablation of Bone Tissue by Femtosecond Laser: A Path to High-Resolution Bone Surgery.

Femtosecond lasers allow for high-precision, high-quality ablation of biological tissues thanks to their capability of minimizing the thermal loads into the irradiated material. Nevertheless, reported ablation rates remain still too limited to enable their exploitation on a clinical level. This study demonstrates the possibility to upscale the process of fs laser ablation of bone tissue by employing industrially available fs laser sources.

Intra-volume processing of gelatine hydrogel by femtosecond laser-induced cavitation.

Cell oxygenation and nutrition are crucial for the viability of tissue-engineered constructs, and different alternatives are currently being developed to achieve an adequate vascularisation of the engineered tissue. One of the alternatives is the generation of channel-like patterns in a bioconstruct. Here, the formation of full-formed channels inside hydrogels by laser-induced cavitation was investigated.

Fused silica ablation by double femtosecond laser pulses: influence of polarization state.

Glass processing is a subject of high interest for many industrial fields such as optics manufacturing, smart electronics or medical devices. With respect to nanosecond technology, the use of femtosecond lasers allows to achieve high processing quality thanks to nonlinear absorption properties. Nevertheless, the throughput of femtosecond processing is still very low when compared to other laser technologies.

Double- and Multi-Femtosecond Pulses Produced by Birefringent Crystals for the Generation of 2D Laser-Induced Structures on a Stainless Steel Surface.

Laser-induced textures have been proven to be excellent solutions for modifying wetting, friction, biocompatibility, and optical properties of solids. The possibility to generate 2D-submicron morphologies by laser processing has been demonstrated recently. Employing double-pulse irradiation, it is possible to control the induced structures and to fabricate novel and more complex 2D-textures.

On the Interplay of DLIP and LIPSS Upon Ultra-Short Laser Pulse Irradiation.

Controlling laser induced surface morphology is essential for developing specialized functional surfaces. This work presents novel, multi-scale periodic patterns with two-dimensional symmetry generated on stainless steel, polyimide and sapphire. The microstructures were realized by combining Direct Laser Interference Patterning with the generation of Laser Induced Periodic Surface Structures in a one-step process.

Towards Laser-Textured Antibacterial Surfaces.

Escherichia coli and Staphylococcus aureus bacterial retention on mirror-polished and ultrashort pulse laser-textured surfaces is quantified with a new approach based on ISO standards for measurement of antibacterial performance. It is shown that both wettability and surface morphology influence antibacterial behavior, with neither superhydrophobicity nor low surface roughness alone sufficient for reducing initial retention of either tested cell type. Surface structures comprising spikes, laser-induced periodic surface structures (LIPSS) and nano-pillars are produced with 1030 nm wavelength 350 fs laser pulses of energy 19.

Generation of micro- and nano-morphologies on a stainless steel surface irradiated with 257 nm femtosecond laser pulses.

Surface structuring by femtosecond lasers has emerged as an efficient tool to functionalize the surfaces of various solid materials. Laser induced periodic surface structures (LIPSS) can drastically impact the wetting, friction and optical properties of the surface depending on the size, aspect ratio and period of the structures. Morphological characteristics in the nanoscale, such as nano roughness, contributing to a hierarchical surface formation are considered to have a significant impact on those properties.

Texturing metal surface with MHz ultra-short laser pulses.

We show, for the first time to our knowledge, the role the heat accumulation plays on the evolution of ultra-short pulse laser-induced surface structures morphology when varying fluence, the number of scans and the repetition rate from 100 kHz up to 2 MHz. We demonstrate how to tailor the size of micro-spikes from nearly ten microns to several tens of microns by a systematic variation of both fluence and overlap. We believe our results will contribute to an in deep understanding of the mechanisms underlying laser surface structuration at high repetition rates.

Upconversion Nanoparticles Synthesized by Ultrashort Pulsed Laser Ablation in Liquid: Effect of the Stabilizing Environment.

The distinctive feature of upconverting compounds to absorb and emit light in the near-infrared region has made upconverting nanoparticles of great interest in various application fields. Nevertheless, these colloids show a highly hydrophobic behavior, and therefore, the use of a proper stabilizing agent is necessary in most cases. Although few chemical techniques for colloid stabilization are available, it is still difficult to achieve a fully reproducible synthesis method for stable upconverting nanoparticle colloids.

Oculo-auriculo-vertebral spectrum (OAVS): clinical evaluation and severity scoring of 53 patients and proposal for a new classification.

Oculo-auriculo-vertebral spectrum (OMIM164210) is a phenotypically and probably also a genetically heterogeneous disorder, characterized by anomalies of the ear (mostly microtia), hemifacial microsomia, and defects of the vertebral column. Associated clinical findings include anomalies of the eye and brain, and developmental delay. We have evaluated the clinical data and photographs of 53 unrelated patients with OAVS, all presenting with either isolated microtia or preauricular tags in association with hemifacial microsomia as minimal diagnostic criteria; five had a positive family history for OAVS.