Silicon, porous

Oxidation is a widely used procedure in carbohydrate chemistry, mainly to access sugars that contain a carbonyl function to serve as valuable intermediates for a variety of derivatizations. Many procedures have been developed, employing either chemical or biochemical methodologies.14 148 While most of these methodologies rely on homogeneous catalysis, the use of heterogeneous catalysts has proved to be a feasible alternative.123c However, the utilization of catalysts based on silicon porous materials for the oxidation of carbohydrates is still a field to be further explored. 

A series of percutaneous implant devices with three stem/flange ratios (1 1, 1 2 and 1 4) was fabricated from three materials (Dacron velour - silicone, porous PU and porous metal). The implants were totally porous (coarse, 150-250 ym) with 1.5 mm diameter holes drilled throughout the device. Figure 6 shows the mold and the polyurethane percutaneous devices with three stem/ flange ratios and 1.5 mm diameter drilled holes. 

XANES and USXES data were used to determine phase composition of surface layers and energy level diagram in porous silicon. Porous silicon consists of Si microcrystals covered with amorphous silicon and silicon oxides. 

Connolly, E. J., O Halloran, G. M.,Pham, H.T. M.,Sarro, P. M. and French,P. J. (2002) Comparison of porous silicon, porous polysUicon and porous silicon carbide as materials for humidity sensing apphcations Sensors and Actuators a-Physical, 99(1-2), 25-30. 

A variety of mammalian cells have been successfully cultured onto porous silicon surfaces. The first publications on this topic by Bayliss et al. demonstrated that attachment of Chinese hamster ovary (CHO) cells proceeded on porous silicon surfaces to a similar extent as on bulk silicon (Bayliss et al. 1997a, b). This was also confirmed with the neuronal cell line B50 (Bayliss et al. 2000). Cell viability in these studies was determined using two colorimetric assays, the MTT based on enzymatic reduction of a tetrazolium salt to a purple formazan and the neutral red uptake assay. B50 and CHO cells were cultured on bulk silicon, porous silicon, glass, and polycrystalline silicon. Both viability assays suggested that the neuronal cells showed preference for porous silicon above the other surfaces, while CHO cells showed the lowest viability on the porous silicon surface (Bayliss et al. 1999, 2000). The surfaces of the porous silicon used in these early studies were not modified post-etching, and it was not until a study utilized porous silicon surfaces with an oxide layer for cell culture that surface chemistry was found to play a crucial factor (Chin et al. 2001). Rat... 

Chuah LS, Hassan Z, Ng SS, Abu Hassan H (2009) Porous Si (111) and Si (100) as an intermediate buffer layer for nanocrystalline InN films. J Alloys Compd 479(1-2) L54-L58 Chuah LS, Hassan Z, Tneh SS, Abu Hassan H (2010) Porous silicon as an intermediate buffer layer for zinc oxide nanorods. Compos Interf 17(8) 733-742 D Arrigo G, Severino A, Leone S, Mauceri M, Abbondanza G, Buongiomo C, Terrasi A, La Via F (2006) Heteroepitaxial growth of 3C-SiC on silicon-porous silicon-silicon (SPS) substrates. ECS Trans 3(5) 287-298... 

Kochergin V, Foil H (2009) Biochemical sensors based on porous silicon. Porous Semicond 197-206... 

Buriak JM, Stewart MP, Geders TW, Allen MJ, Choi HC, Smith J, Raftery D, Canham LT (1999) Lewis acid mediated hydrosilylation on porous silicon surfaces. J Am Chem Soc 121 11491-11502 Connolly EJ, O Halloran GM, Pham HTM, Sarro PM, French PJ (2002) Comparison of porous silicon, porous polysilicon and porous silicon carbide as materials for humidity sensing applications. Sens Actuators B 99 25-30 Ftirjes P, Kovdcs A, Cs D, Addm M, Muller B, Mescheder U (2003) Porous silicon-based humidity sensor with interdigital electrodes and internal heaters. Sens Actuators B 95 140-144 Hedrich F, BiUat S, Lang W (2000) Structuring of membrane sensors using sacrificial porous silicon. Sens Actuators A 84 315-323... 

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