There exists a need for an innovative reconstructive approach for breast reconstruction, tackling current drawbacks and limitations present in the clinic. In this respect, adipose tissue engineering could offer a promising alternative. We have previously shown that methacrylamide-functionalized gelatin scaffolds are suitable to support the adhesion of adipose tissue-derived stem cells as well as their subsequent differentiation into the adipogenic lineage. The current paper aims to compare different techniques to produce such scaffolds including direct versus indirect 3D printing. Extrusion-based (direct) 3D printing was compared to indirect 3D printing exploiting a polylactic acid (PLA) sacrificial mould, thereby focussing on the physico-chemical characteristics of the obtained scaffolds. The results indicate that similar properties can be achieved irrespective of the technique applied. It can therefore be concluded that indirect 3D printing could offer some benefits over direct additive manufacturing (AM) as a more complex design can be created while materials that were previously unsuited for direct printing because of limitations associated with their characteristics (e.g. low viscosity), could potentially be applied as starting materials for indirect 3D printing to generate porous constructs with full control over their design.

Ballistic electron emission microscopy (BEEM) and deep level transient spectroscopy (DLTS) have been used to study the effects of substrate damage introduced by an ion-milling process in PtSi/n-Si Schottky contacts. Argon ions with well-defined energies of 300, 500, 700, 1000, 1500 eV were used to sputter n-type Si substrates in an ion beam sputtering system before metal deposition and silicide formation. Histograms of the PtSi/n-Si Schottky barrier height (SBH) measured by BEEM show that the mean SBH decreases with increasing ion energy, which can be explained as a result of donor-like defects that are introduced by the ion milling treatment. From DLTS measurements, we found direct evidence for the presence of such defects.

GaAs is grown by molecular beam epitaxy (MBE) on composite GaAs-SiO2 nucleation layers fabricated on Si substrates. The composite surface (CS) is formed by an initial deposition of GaAs islands by MBE, followed by oxidation of the bare Si regions surrounding the islands. The oxidation is performed at 265°C in the afterglow of a microwave induced plasma. The fabrication of the composite GaAs-SiO2 nucleation layer is compatible with the epitaxy process. GaAs growth on CS's is performed to study the seeded lateral overgrowth of GaAs on the SiO2. We find single crystal GaAs on SiO2 regions up to 50 nm wide. On the SiO2 a large density of twins is present. The GaAs seeds are not pseudomorphic and misfit dislocation segments constitute a source of threading defects. The potential of the technique for GaAs-on-Si improvement is discussed.