Micropatterning of Porous Silicon Films by Direct Laser Writing

Abstract

In this study, we demonstrate that porous silicon films can be ablated by the pulsed nitrogen laser of a commercial MALDI mass spectrometer. The extent of laser-induced ablation was found to depend on the doping level and surface chemistry of the porous silicon film. Using direct laser writing with or without a mask, micropatterns were generated on the porous silicon surface. These micropatterns were subsequently used to guide the growth of mammalian cells including neuroblastoma. Excellent selectivity of cell growth toward the laser-ablated regions was established.

Control over wettability via surface modification of porous gradients

“…Thermally oxidised pSi was silanised with the silanes N-(triethoxysilylpropyl)-O-polyethylene oxide urethane (PEGS) [24] and with 3-aminopropyl trimethoxysilane (APTES) [21] to produce two hydrophilic organic coatings. On the other hand, ozone oxidised pSi was silanised with fluorinated silanes heptadecafluoro-1,1,2,2-tetrahydrodecyl dimethylchlorosilane (HDFS) and pentafluorophenyl dimethylchlorosilane (PFPS) to produce two hydrophobic coatings [30].…”

“…Porous silicon (pSi) is one of the most promising candidates for the fabrication of nanostructured surfaces for a wide range of applications [20,21]. It has been found to be highly biocompatible and biodegradable [22], displays highly tunable optical properties [23] and a surface chemistry that can easily be modified with very stable Si-C (hydrosilylation) or Si-O bonds (silanisation) [20,24]. pSi is commonly fabricated by electrochemical anodic etching of silicon wafers in the presence of hydrofluoric acid.…”

Ultraviolet laser patterning of porous silicon

“…[8][9][10][11] The standard method for the fabrication of nanoPS allows tailoring its pore size from the micro-to the nanoscale, as well as its optical properties. Moreover, the optical behavior of nanoPS-based structures (1D, 2D, or 3D) is very sensitive to infiltration 12,13 or adsorption 6 of bio-species into the porous material.…”

Nanoporous silicon-based surface patterns fabricated by UV laser interference techniques for biological applications

“…Following this process, amino groups are bonded on the surface of nanoPS by a previous oxidation of the surface, remaining intact most of the O-Si-CH2-CH2-CH2-NH2 groups present in APTS molecules [27,28]. To create selective biofunctionalized platforms, direct laser writing has been previously used [29]. Since laser irradiation alters the properties of the biofunctionalized layers, selective biofunctionalized platforms can only be obtained from homogeneous surfaces by means of an 'on and off' irradiation process, i.e.…”