No abstract

A novel three-dimensional (3D) metallic metamaterial structure with asymmetric transmission for linear polarization is demonstrated in the infrared spectral region. The structure was fabricated by direct laser writing and selective electroless silver coating, a straightforward, novel technique producing mechanically and chemically stable 3D photonic structures. The structure unit cell is composed of a pair of conductively coupled magnetic resonators, and the asymmetric transmission response results from interplay of electric and magnetic responses; this equips the structure with almost total opaqueness along one propagation direction versus satisfying transparency along the opposite one. It also offers easily adjustable impedance, 90° one-way pure optical activity and backward propagation possibility, resulting thus in unique capabilities in polarization control and isolation applications. We show also that scaling down the structure can make it capable of exhibiting its asymmetric transmission and its polarization capabilities in the optical region.

A glimpse of light is all it takes: Polymers that undergo main‐chain scission at remarkably low photolysis energies were developed as efficient photodegradable substrates for safe laser‐mediated cell detachment and patterning. The polymers, which contain acetal or ketal units in their backbone along with suitable absorbing groups, underwent fast degradation to release live cells upon irradiation with an excimer laser (see picture).

This paper demonstrates the application of ultrashort-pulsed lasers as a unique tool for controllable modification of the surface wettability of polymers from high hydrophilicity to superhydrophobicity. This is achieved by exploiting the effect of laser pulse duration and photon energy on the surface chemistry and morphology and subsequent wetting properties of polymeric surfaces treated with UV laser pulses. In three different pulse duration regimes, ranging from femtosecond to nanosecond and two different photon wavelengths, we have systematically altered the wettability of polyethersulfone surfaces from highly hydrophilic to superhydrophobic. Our results indicate that, despite the remarkable changes in the surface morphology attained, the surface wettability variations are dominantly caused by laser-induced chemical modifications, which are highly dependent on the pulse energy and duration. The ability of tuning the wetting properties and thus the surface energy of laser-treated polymer surfaces within a broad range makes them excellent candidates for liquid flow control in microfluidics and biological adhesion applications.

The modeling, fabrication, cell loading, and mechanical and in vitro biological testing of biomimetic, interlockable, laser-made, concentric 3D scaffolds are presented. The scaffolds are made by multiphoton polymerization of an organic-inorganic zirconium silicate. Their mechanical properties are theoretically modeled using finite elements analysis and experimentally measured using a Microsquisher(®). They are subsequently loaded with preosteoblastic cells, which remain live after 24 and 72 h. The interlockable scaffolds have maintained their ability to fuse with tissue spheroids. This work represents a novel technological platform, enabling the rapid, laser-based, in situ 3D tissue biofabrication.